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MEMOIRS OF THR aEOLOGICAL SURVEY. 

ENGLAND AND WALES. 
EXPLANATION OF SHEET 352. 



GEOLOGY F 

FALMOUTH AND TRURO 

AND OP THE 

MINING DISTRICT OF CAMBORNE 
AND RRDRUTH. 

II Y 

J. It. IHU„ H.N., 

ANt> 

1>. A. MacATJSTKR, A.H.S.M., F.Ci.S. 
WITH PKTItOI.00I0AL NOTES 

HV 

.r. M. FLETT, M.B., D.Sc. 




LONDON: 

PniNTEO E-Olt HIS MAJKSTV'H STATIONERY OFFICE, 

Itv ^VY^rAN X- sons, Livitkp, Fktikr Laxe, E.r. 

AnrI to be liiirrhasnl fn>iii 

K. -ITASFOKD, 12. 13, aitd 14, I.ONi; .Vjik, I.oNDns ; 

\V. &A. K. JOilNSTOX, Lti».,2", South St, ,\Sphkw Strket, KiiimbI'Roh ; 

HODGES, FJ(:(i[M & Co., Ok.aftos Street, Drm.is ; 

From Any Agent for llie sale of Onlnaiicc Sarvey May* ; <ir tbrougL any 

lioiikseller from the UiJnanFe Surroy Olllce, Sfiiitbaiupton. 

laou. 
J^ioe 7s. (id. 



Ill 



PREFACE. 



The region described in this memoir includes that portion of 
West Cornwall which is represented by Sheet 352 of the new 
series one-inch map of England and Wales. 

■ 

The original geological survey was carried out by De la Beche 
in connection with the Trigonometrical Survey of Great Britain, 
then under the superintendence of Colonel CJolby, R.E., F.R.S., 
and in the course of his work De la Beche received valuable 
assistance from two Ordnance Surveyors, Mr. Henry McLauchlan, 
F.G.S., and Mr. Henry Still, F.G.S. The results of the original 
survey were published in 1839 on the old series maps 31 
and 33, and in the well-known Report on the Geology of 
Cornwall, Devon and West Somerset. Additional lodes were 
inserted on the maps at a later date by Sir W. W. Smyth, and 
new editions of the maps were published in 1866. 

On comparing the new map with the corresponding portions 
of the older iiiaps it will be noted that important additions have 
been made. The area formerly represented as Devonian has 
been separated into Lower Devonian, and into three sub- 
divisions, based on lithological characters, to which the terms 
Portscatho, Falmouth ana Mylor have been applied.^ These 
three sub-divisions, together with the Veryan beds, which were 
classed as Lower Silurian on the earlier maps in consequence of 
the discovery of fossils near Gorran Haven by Mr. C. W. Peach, 
are now regarded as Lower PalaBOzoic, mainly on account of 
the evidence supplied by a coarse conglomerate which is well 
exposed at Flushing on the south side of the Helford 
River (one-inch map 359). This conglomerate contains 
rounded fragments and large masses of Portscatho rocks which 
were veined prior to their inclusion in the conglomerate ; and 
the detailed mapping proves that it comes in contact with various 
members of the earlier series in such a way as to indicate an 
important unconformability. No recognisable Devonian fossils 
have been found in the conglomerate or associated deposits, but 
the stratigraphical evidence is regarded as sufficient to justify 
the conclusion that it is of Lower Devonian age. 

Li the sheet to which this memoir refers the grits of 
Grampound and Probus are taken as the equivalents of the 
conglomerate on the Helford River ; and the line at their base 
which runs near to and parallel with the northern margin of the 
map therefore represents the boundary between the Devonian 
and pre-Devonian rocks. Amongst the igneous rocks the 
dominant representative is granite, with which the mineral 
products of the area are so intimately associated. As this district 
contains the principal seat of the Cornish tin industry it has 



IV PREFACE. 

been described in more detail than is usual in a sheet 
explanation. 

The geological survey of the area on the six-inch scale was 
carried out during the years 1897-1903 by Mr. Hill, with the 
exception of a narrow tract near the north coast that was 
mapped by Mr. E. E. L. Dixon. The mineral survey has been 
done by Air. MacAlister under the supervision of Mr. Hill ; and 
the survey of the entire area since 1901 has been under the 
charge of Mr. Clement Keid as District Geologist 

The memoir has been written by Mr. Hill and Mr. MacAlister, 
while Mr. Dixon has contributed notes of the area which he 
surveyed. The microscopic examination of the rocks previous 
to 1901 was done by Mr. Hill, and subsequently by Dr. Flett. 
The petrographical descriptions of the rocks referred to in 
Part I. are based on detailed notes supplied to Mr. Hill by Dr. 
Flett. Mr. MacAlister is responsible for the petrographical and 
mineralogical information contained in Part II. 

The photographs which have been reproduced as plates, with 
the exception of those representing microscopic features, have 
been taken by Mr. T. C. Hall, of the Geological Survey. 

The MS. six-inch maps of the district, included within the 
area of the one-inch map, have been deposited in the Library for 
reference, and copies of them may be obtained. 

J. J. H. Teall, 

Director, 
Geological Survey Office, 

28, Jermyn Street, London, 

Novembei^ 20th, 1906. 






♦ " 



CONTENTS. 



PAUT I.-GEOLOGY. 



PAQB 



Preface by the Director ... ... ... ... iii 

CHAPTER I. 
Introduction ... ... ... ... ... 1 



CHAPTER II. 
FormaUona awl their General Distribution ... ... 13 

CHAPTER III. 
The KilUu— 

General Description and Tectonics ... ... 16 

CHAPTER IV. 
Lower Palceozoic — 

L — Mylor Series ... ... ... 25 

II. — Falmouth Series ... ... ... ... 29 

III. — Portscatho Series ... ... ... 33 

IV. — Veryan Series ... ... ... ... 37 

CHAPTER V. 
Devonian Rocks — 

Grampound and Probus Series ... ... ... 39 

CHAPTER VI. 
Igneous Hocks — 

I. — Greenstone ... ... ... ... 41 

II. — Granite... ... ... ... ... 52 

III. — El van ... ... ... ... ... 64 

IV. — Mica Traps ... ... ... ... 74 

CHAPTER VII. 
Contact Metamorphiam effected by the Granite ... ... 81 

CHAPTER VIII. 
JTaults ... ... ... ••• ... ••■ Of 

CHAPTER IX. 
Pliocene Deposits — 

Polcrebo Gravels ... ... ... ... 88 



VI CONTENTS. 

CHAPTER X. 
PleiatoceTie Deposits — 

I. — Raised Beaches ... ... ... ... 90 

II. — Head ... ... ... ... ... 93 

1 1 1. — Stream Tin and Submerged Valley Deposits ... 95 



CHAPTER XI. 
Recent Deposits — 

I. — Subuierged Forests ... ... ... 99 

II.— Marine Alluvia ... ... ... ... 100 

III. — Freshwater Alluvia (Valley Systems, &c.) ... 10 1 

IV. — Blown Sand ... ... ... ... 103 



CHAPTER XII. 
Economic Resources (eoccluding the Ores) ... ... 1 04 



PAET II.-MINING, 



CHAPTER XIII. 

Geology of tJie Mineral Area ... ... ... 113 

CHAPTER XIV. 

Natural HisUyry of the Lodes — 

I. — Distribution of the Lodes ... ... ... 125 

II. — Geological Age of the Lodes ... ... 130 

III. — Relative Age of the Tin-Copper and Silver- 
Lead Lodes ... ... ... ... 130 

IV. — Structure of the Lodes ... ... ... 131 

V. — Caunter Lodes ... ... . . ... 140 

VI. — Intersection of Lodes ... ... ... 143 

VIL— Faulting by Lodes ... ... . . 1 46 

VIII.— Trend of the Lodes ... ... ... 148 

IX. — Underlie of the Lodes ... ... ... 1 49 

X. — Length of the Lodes ... ... ... 152 

XL — Breadth of the Lodes ... ... 153 

XII. — Veinstone of the Lodes ... ... ... 1 54 

CHAPTER XV. 

Cross- Courses, Cross- Flucans, and Slides ... ... 157 



CONTENTS. vn 



CHAPTER XVI. 



PAGE 



Natural History of the Ores — 

I. — The Ore Bodies ... ... ... ... 161 

II. — Genesis of the Ores ... ... ... 167 

III. — Distribution of the Ores ... ... ... 171 

I v.— Order of Arrival of the Ores ... ... 182 

V. — Local Conditions Influencing Ore Deposit ... 184 

VI. — Decomposition and Redistribution of the Ores 187 

VII. — Minerals of the Ores ... ... ... 1 94 

CHAPTER XVII. 
The Mines — 

I. — Linear Distribution of the Principal Mines ... 205 

II. — Particulars relating to the Mines ... ... 207 

CHAPTER XVIII. 

Alining Economics ... ... ... ... 258 



APPENDIX. 



Bibliography ... ... ... ... ... 315 



JL^MJiUA ... ... ... ... ... ... tJ^O 



Vlll 



LIST OF ILLUSTRATIONS. 



Plate I.- -Swanpool, Falmouth. Lake formed by a 

natural dam of a Beach piled up across 
the front of the valley. Cliff* Section of 
Falmouth Slate Series in the foreground 

(Frontispiece.) 

AT KND 
OF YOIXHE. 

Plate II. — Trefusis, Falmouth Harbour. The Pliocene 

Platform is seen along the sky-line. The 
leistocene platform, capped by Raised 
Beach and Head, makes the feature skirting 
the shore of the estuary ... ... „ 

Plate III. — The Camborne mining district with Carn 

Brea in the distance ... ... ... ,, 

Plate IV. — Sunny Cove, FalmoutL Portscatho Slate 

Series, showing contortion and quartz 

VvAUlUfif^ ... •*. ... ... «• 

Plate V. — Sunny Cove, Falmouth. Portscatho Series, 

showing bedding, cleavage, and jointing. 
In the sandy bands the cleavage is seen 
oblique to the bedding ... ... ... ,, 

Plate VI. — Restronguet Point, Carrick Roads. Mylor 

Series, showing brecciation resulting in the 

[)roduction of pseudo-conglomerate. The 
arge quartz vem exhibits initial stages of 
the process ... ... ... ... ,, 

Plate VII. — Carn Brea. Granite tor with stratiform 

weathering ... ... ... ... ,, 

Plate VIII. — Sunny Cove, Falmouth. Pleistocene plat- 
forms slightly above the modern coastal 
shelf. They are carved out of the Ports- 
catho Series, and capped on the landward 
side by Head. A relic of the Raised Beach 
is seen in the foreground at the base of the 

XXvivU ..* ... ... ... 9) 

Plate IX. — Longdowns. Mabe. Granite quarrv (worked 

by Messrs. Freeman & Co.), displaying the 
characteristic jointing ... ... 

Plate X. — Lode structures, (a) Middle lode, South 

Crofty Mine, (b) Gaunter lode. East Pool 

XUlUv .«■ ... ... ... .. 

Ptjite XI. — Specimens of veinstone, (a) Wheal Gren- 

ville, 300-fathom level. It is a tough 
brecciated tourmaline peach cemented by 
quartz. (6) East Pool. Quartz, wolfram, 
and mispickel. (c) Dolcoath, 475-fathom 
level. Tough tourmaline peach, finely 
brecciated, and cemented by cassiterite ... „ 



LIST OF ILLUSTRATIONS. 



IX 






AT BND 
OF VOLVTMK. 

Plate XI T. — Microphotographs of veinstones... 

Plate XIII. — Cornish stamps. South Crofty Dressing 

Floors 
Plate XIV. — Friie Vanners. Dolcoath Dressing Floors 
Plate XV.— Wilfley Tables. Dolcoath Dressing Floors 
Plate XVI. — Acme Table. Dolcoath Dressing Floors ... 
Plate XVII. — Convex Buddie. Dolcoath Dressing 

L Iv/L/I O ... ... ... ... 

Plate XVIII. — Concave Buddie. South Crofty Dressing 

Floors 
Plate XIX. — Dumb pit. South Crofty Dressing Floors 
Plate XX. — Kieves. Dolcoath Dressing Floors 
Plate XXI. — Slime pits. Kieve Mill, Reskudinnick ... 
Plate XXII. — Products from ore dressing 
Plate XXIII. — Products from ore dressing ... 
Plate XXIV. — Ragging Frames. Kieve Mill, Reskudin- 

1 11 v/ tV ••• ••• ••• ••• ••• 



9* 






Fio. 
1.- 

2. 
3. 



4.— 

5. 

6. 



a— 

9.— 
10.- 
11.— 
12.- 

13.- 
14.— 
15.— 

16.— 

17 — 

18.— 
19 — 

20.— 
21.— 

23.— 



FIGURES IN TEXT. 

Sketch map to illustrate the geology of the 

Falmouth sheet (3.12) 
Subterranean contour of the granite 
Great Wheal Baddern ... 
Great Wheal Busy 
Sithney and Carnmeal Mine 
West Stray Park Mine 
Section from South Tolcarne Mine to New Wheal 

iOCl;vlI.l ... ... ... ... . 

Section from West Wheal Buller to West Wheal 

loeLoii ... «i. ••■ ... . 

Section from Grillis to Wheal Emily Henrietta 
Section from Filtrick to New North Pool 
Section from Wheal Basset to North Pool 
Section from Buller and Basset United to Wheal 

Tolgus 
Section from West of Penstruthal to Tolgus United 
Section from Trelusback Mine to Wheal Montagu .. 
Section from Tresavean Mine to Treleigh Consols 

XiX 1 LX\7 ... ... ... .a. . 

Section from Ting Tang Mine to North Downs 

^ V JL i Am W ••• ••• ••• ••> • 

Wheal Jane ... 
Killifreth Mine 
Lonc/itudinal Section of the Main Lode of Dolcoath 

and Cam Brea Mines 
Wheal Music... 
Diagram to show Linear Distribution of the Principal 

X*l i H%>o ••■ ••• ••• ••• ■ 

West Basset North Lode (longitudinal section) 
Clifford Amalgamated Mines 



PAOK. 

8 
IIG 
120 
121 
122 
123 

125 

125 
126 
126 
127 

127 
128 
128 

129 

129 
151 
151 

162 
165 

206 
220 
224 



LIST OF ILLt'STrtATIONS. 



& 



& 



FIG. 

24. 

25. 

2().- 

27. 

28.- 

29. 

30 

32. 

3?. 

34. 

35. 

36. 

37.- 

38 

40. 

41.- 

42.- 

43.- 

44.- 

45. 

46.- 

47 

49. 
50.- 

51.- 

52.. 

53. 

54. 

55.- 

56. 

57. 

58. 

59. 

60. 

61. 

62. 

63. 

64.— 

65.— 



Wheal Lushingt 



& 



Poidice 

United Mines 

Consolidated Mines 

East Wheal Lovell 

Great Wheal Fortune . . 

Wheal Gorland 

31.— The Lovell Mine.. 

Wheal Liishington 

Wheal Vincent (part of 

Nangiles 

North Downs 

Pedn an Drea Mine 

Porkellis United Mines 

39._Wheal Seton 

South Wheal Seton 

South Wheal To wan .. 

Tresavean Mine 

Treskerby Mine 

United Hills ... 

Killifroth. Unity Wood 

West Poldice. Unity Wood 

48. — Great Wheal Vor (sections showing 

of shafts to lodes) 
Sithney Wheal Metal ... 
Great Wheal Vor (longitudinal sketch 

lodes) 
Penhale Wheal Vor 
West Condurrow 
Wheal Christopher 
Cliff Down Mine 

Clift' Down Mine (section in valley) 
Clyjfth and Wentworth 
Wheal Wentworth 
Medlyn Moor Mine 
Nancekuke Mines (Wheal Clarence) 
North Pool Mine 
North Wheal Vor 
Polroso Mine... 
South Lovell Mine 
Plan of Restronguet Creek Mine 
Diagram showing the yield of metallic tin and 

copper in Cornwall, estimated from public sales 

v*l \* L X3 ••• ••■ ••• ••• ••• 



• • • • • 


PAGK. 

224 


• » • • • 


224 


• • • • • 


225 


* * • • • 


227 


• • > « • 


228 


• • • • • 


229 


• • • « • 


231 


• • • 


231 


►n) 


232 


• • • • 


232 


• • • • • 


233 


• • • 


234 


■ • • • • 


237 


• • « • • 


238 


• • • • • 


241 


• • • • • 


241 


• • • • • 


214 


• • at* 


245 


# • • • « 


246 


• • • • • 


248 


• • m • 9 


248 


proximity 




• • • • • 


249 


• • • • • 


250 


of main 




• • • ■ • 


251 


• • • • • 


251 


• • • • 


253 


■ • • • • 


254 


• • • • • 


255 


• • • • 


255 


• • • • • 


255 


• • • « • 


256 


• • • • 


25(} 


• • • • • 


256 


• • » • • 


256 




256 


• • • • • 


257 


• • • • • 


257 


• • • • • 


257 



307 



THE 

GEOLOGY OF 

FALMOUTH AND TRURO 

AND OF THE 

MINING DISTRICT OF CAMBORNE 

AND REDRUTH. 

chaptp:r I. 



INTRODUCTION. 
By J. B. Hill, R.N. 

This memoir describes an area of 216 square miles, of which 
186 represent the land surface, while the remainder is occupied 
by the sea.* Whereas the north coast forms a line of cliffs 
extending for about 6 miles from Forth Towan to Reskajeage 
Downs, and broken only by minor indentations, the southern 
seaboard presents a more sinuous course dominated by the bays of 
P^almonth and Grerrans. Moreover, the arms of the sea, repre- 
sented by Falmouth harbour and its confluent creeks, penetrate 
far into the interior of the county. While the coast line facing 
the English Channel is less than 12 miles, the inner waters border 
80 miles of shore, extending to Tret hem, Ruan Lanihorne, Tre- 
silian, Truro, Perranarworthal, Mylor Bridge, and Penryn. 

Those estuaries that make so prominent a feature in the 
eastern belt are the seaward extension of the valleys into which 
they merge^ and it requires little geological discernment to 
recognise their origin in the submergence of that valley system. 
The extensive sheet of water forming the Carrick Roads covers an 
ancient alluvial plain in which the lower reaches of the Fal 
channelled their course to the sea. 

The broader physical features of the area are intimately related 
to its geology : the districts occupied by the dominant rock types^ 
killas and granite, being strongly contrasted. The granite region, 
between Budock and Camborne, forms high land culminating in 
the hill of Carnmenellis^ with an altitude of 819 feet, while the 
summits of Cam Marth and Carn Brea attain heights of 771 feet 
and 740 feet respectively. The district occupied by the killas is 
by comparison low lying ; it rarely attains an elevation of 500 feet, 
and by far the greater portion lies below the level of 300 feet. 

Notwithstanaing the greater elevation and more rugged 

* See Sketch Map of the Area, Fig. 1, page S. 
9256. 750— Wt. 5440. 12/06. Wy. & S, B 



2 IKTHODUCTTON. 

oharaoter of the granite, its surface is, on the whole, less deeply 
trenohed than the killas. The latter, in spite of its smooth 
upland features, has been more extensively channelled by the 
drainage system^ which over large parts of the area has produced 
a set of deep valleys in such close contiguity that stretches of 
flat land are comparatively rare. This is particularly the case in 
the Fal basin^ which drains nearly two-thirds of the entire 
district 

The rivers that water the region are small and of low gradient, 
affording a strong contrast to the deep and extensive valleys which 
they traverse. Those which empty on the north coast are short, 
with a general north-westerly course. The larger of these are 
the Red River, so called from the mine washings which discolour 
it, and the stream that joins the sea at Portreath. The straight 
valley between Parsley and Porth Towan is watered by a very 
small rivulet, and forms a striking feature from the steepness of 
its slopes. Its coincidence with a line of fracture has doubtless 
facilitated its excavation. Dissecting a moorland district covered 
with heath, its beauty is unfortunately marred by the mining 
operations that follow its course. The south-western district is 
mainly drained by the River Cober, which after traversing a large 
granite tract south of Calvadnack, flows past Helston to the Loe 
Pool. 

The northern district, lying on the outer fringe of the Fal 
basin, and extending approximately from Tregavethan to Skin- 
ner^s Bottom, in the parish of St. Agnes, is comparatively flat. 
The adjacent tract, situated between the granite region and the 
north coast, although trenched by numerous valleys, has a far 
more even surface than the corresponding slopes of the eastern 
area. 

Notwithstanding the sharp physical characteristics that distin- 
guish the tracts occupied respectively by granite and killas, that 
differentiation is mainly confined to those major formations. 
Neither the multitude of elvan dykes, the greenstones, nor the 
mica traps are expressed on the topography, and the same may be 
said as regards the smaller granite intrusions that flank the larger 
bosses. Moreover, the killas itself, notwithstanding its lithological 
variations from arenaceous to argillaceous, exhibits a general 
absence both of rock protrusion and features. The inequalities 
of its surface appear to have resulted almost entirely from river 
erosion, so that if the valleys were refilled the outline so restored 
would constitute an undulating platform. The latter would slope 
seaward to either coast from more elevated land situated on the 
northern margin of the map between Trevissome and Mount 
Hawke, where about three square miles range from 400 to 500 
feet above sea level. Thus almost the whole of this plain, built 
up chiefly of killas, and extending across the county from the 
English to the Bristol Channel, lies below a level of 400 feet, 
while the greater part does not attain a height of 300 feet. 
Moreover, the line of cliffs, sometimes reaching 250 feet on the 
north coast and 100 feet on the southern seafront, tends still 
further to bring out the even surface of the platform, which, 



AREA AND PHYSICAL FEATURES. 3 

devoid of craggy features, is saggestive of a plain of marine 
denudation that was upheaved in comparatively late geological 
times. Although the gravels of Folcrebo represent the sole evi- 
dence of deposit between the Palaeozoic period and the era of the 
Pleistocene raised beaches, the adjoining districts on the north, 
west and south contain the relics of Tertiary sediments that in all 
probability were formerly spread over the lesa elevated portion of 
this sheet. The Tertiary beds of St. Agnes are indeed only a mile 
distant, where they reach a height of 375 feet. The gravel deposit 
of Grousa Downs, in the map to the south, occurs at 360 feet above 
sea level, while the Pliocene beds of St'. Erth^ on the map to the 
west, attain an elevation of 150 feet. From these considerations 
it appears probable that the killas platform was entirely buried 
beneath the Pliocene seas, from which the granite domes of 
Carnmenellis, Carn Marth, and Cam Brea rose out as islands. 

The scenery of the area, therefore, has been mainly sculptured 
since the early part of the Pliocene period, although the solid 
structure from which it has been evolved is of Palaeozoic age : the 
post-Tertiary accumulations being comparatively meagre, while 
Tertiary deposits are marked by the solitary instance at Polcrebo. 

Although the greater part of the rock platform consists of 
killas, the less elevated granite tracts likewise cover a considerable 
area. The killas is of '' Silurian "* age, with the exception of a 
narrow tract across the northern edge of the map, forming the 
most elevated killas area, that represents the basal Devonian, and 
marks an important unconformity between the older and newer 
Palaeozoic formations of Cornwall. 

In the original Geological Survey map of Cornwall, De la Beche 
separated the killas into two divisions, viz.^ a grauwacke group 
and a carbonaceous series. Thus the former^ lyi^g below the 
Culm-measures, was undififerentiated for the reason^ as explained 
in his Report,t that the progress of geology at that time only 
warranted the broadest generalisations. He then expressed the 
opinion that the terms Cambrian and Silurian should be restricted 
to the areas that gave rise to the prolonged researches of Sedg- 
wick and Murchison, and deprecated the extension of that no- 
menclature to districts that had not received the same detailed 
investigations. In a later and undated issue of the map the 
grauwacke group is divided into Devonian and Silurian, presum- 
ably by the authority of Murchison. The Devonian colour was 
not only applied to the fossiliferous strata of East and Mid-Corn- 
wall but likewise to the unfossiliferous strata in the west. The 
Silurian colour, on the other hand, was restricted to a belt that 
had yielded organic remains. Murchison, however, was of opinion 
that the older division extended far beyond those limits into the 
barren stiata coloured as Devonian, and it is evident that the 
latter tint was adopted as a matter of convenience, in the absence 
of sufficient data to go upon, as no re-examination of the area 

* The term Silurian is here used in the sense adopted by Murchison for the 
Upper Silurian and Lower Silurian (Ordovician). 

t ** Report on the Geology of Cornwall, Devon and West Somerset," pp. 38 
to 41. 

b2 



4 INTRODUCTION. 

seems to have been undertaken.* The known Silurian region was 
confined to the coastal belt between Chapel Point and G-errans 
Bay, a boundary connecting those localities admitting of the ready 
isolation of that region from the rest of the country. That such 
a broad generalisation, however, was only regarded as provisional, 
may be inferred from the absence of a line on the map between 
the two divisions. 

It will be seen, therefore, that the sub-division of the killas as 
the result of the recent survey in no sense invalidates the map 

Eublished by De la Beche, who made no attempt to distinguish 
etween Silurian and Devonian, while as regards the amended 
issue of the map, the boundary between those systems, evidently 
intended as provisional, and for which no line was attempted, has 
been replaced by a line that more accurately demarcates their 
limits. 

In the present state of our knowledge with regard to South- 
West Cornwall it is clear that the main portion of the rocks 
originally grouped as " Silurian " is of Lower Silurian or Ordo- 
vician age; that some bands of Silurian proper, or Upper 
Silurian^ also occur in places ; and that some of the killas may 
possibly be of older date. Therefore, in referring generally to 
these rocks, the term Lower Piilaeozoic will be most appropriate. 

Prior to the accumulation of the Devonian sediments, these 
older strata were consolidated, cleaved, and brecciated, and to some 
extent upheaved. 

At the close of the Carboniferous period these Lower PalsBOZoic 
rocks were again brought within the influence of crustal disturb- 
ance, by which they were folded, fractured, and cleaved in common 
with the overlying Devonian. As a result of this deformation, 
almost all trace of organic life appears to have been obliterated 
from the killas represented in this sheet. With the exception of 
an occasional crinoid fragment, the sole relics of life that have 
survived are radiolaria, the preservation of their casts being in no 
small measure due to the minuteness of these tiny creatures, as 
well as to the siliceous nature of their skeletons. Although it is 
to be hoped that definite species of fossils may yet be obtained 
in our district from these strata, they have yielded nothing 
to warrant their precise correlation with the well-known Lower 
Palaeozoic sub-divisions. The small Devonian tract along the 
northern edge of the sheet has hitherto proved unfossiliferous, 
but its northerly extension in the adjoining map has yielded Lower 
Devonian fossils. , 

The post-Carboniferous crustal movements ultimately found 
relief in the intrusions of granite that enter so largely into the 
geology of this area. These igneous irruptions have metamor- 
phosed the adjacent killas, so that in addition to mechanical 
alteration induced by the earth movements, the killas lying within 
that metamorphic aureole has been subjected to chemical change, 
resulting in the production of new minerals. These granites are 
also flanked by intrusive greenstones that share both in the pre- 

* See references, p. 19. 



AREA AM) PHYSICAL FEATURES. 5 

granitic earth-movements and in the subsequent contact meta- 
naorphism. After the solidification of the granite the igneous 
disturbances were still fuither expressed by an extensive Assuring 
of the area. While some of these fractures were occupied by 
elvan intrusions, others became the repositories of the mineral 
ores. 

At the close of the Carboniferous period the rockbuilding of 
the area had apparently been completed, with the doubtful excep- 
tion of the small assemblage of mica traps that are possibly of 
Permian age. The geological history is not again taken up until 
the emergence of the plain of marine denudation from beneath the 
Pliocene sea. The uprise of that sea floor, with its islands of 
granite^ produced a land surface that has since been deeply fur- 
rowed by erosion. The sculpture of the district has not, however, 
been confined to denudation, but oscillatory movements, involving 
fluctuations in the mutual boundary of land and sea, have been 
potent factors in determining the character of the scenery. Thus 
while erosion has been in constant operation on the body of the 
land^ its coastal fringe has been subjected to oscillations that have 
checked the ravages of the waves. The preservation of shreds of 
the Pleistocene beach at only a few feet above high-water mark 
shows that the modern cliff line has undergone but slight modifi- 
cation since pre-glacial times. Similar evidence demonstrates that 
the existence of the Carrick Boads as an arm of the sea is of like 
antiquity, and that its divergent estuaries penetrated the adjacent 
valley system, at least as far as the tidal waters do to-day. After 
the close of the glacial period the land stood fully 50 feet higher, 
so that the sea must have retreated from the river valleys of the 
Fal. Finally, the land surface so upheaved once more began to 
sink, and the valley floors from which the sea had been excluded 
were again buried beneath the waves. Moreover, the ancient 
woodlands that flourished in those vales are still partially preserved 
beneath the shingle^ as the existence of the submarine forests 
fronting the valleys so clearly testifies. That submergence has 
resulted in the general coincidence of the modern shore line with 
that of the Pleistocene sea, (Plate II.) 

The geological history, therefore, since the evolution of the 
Pliocene valley system, records two submergences of approximately 
equal magnitude, divided by a period of elevation. The latter 
was characterised by the rigorous climatic conditions of the 
glacial age, during which glaciers issuing from the ice-field of 
South Wales reached the Bristol Channel. Although this district 
lay beyond the southerly limits of the mir de glace beneath 
which the greater part of Britain was buried, and therefore 
escaped the devastating effects of glacial action, to which 
immunity we owe the preservation of the china clay deposits, 
that epoch nevertheless set its mark on the topography. In 
winter, while the higher ground was covered by snow, the soil 
cap on the barren slopes was deeply frozen, so that the summer 
thaws, acting on a surface unchecked by vegetation, induced an 
extensive sweeping of the subsoil to the lower lands, which 
creeping seaward, ultimately found repose on the elevated platform 



6 UTTRODtTCTlOir. 

of the Pleistooene beach. The post-g^lacial subsidence brought 
this "head" within the destructive action of the breakers, but 
sufficient jet remains on the more sheltered portions of the sea- 
front to modify the coastal scenery. Concomitant with this great 
surface creep over the body of the land, the valleys were swept out 
and deepened by the torrential conditions that then prevailed, 
under which only the heaviest materials could find a resting-place 
along their beds. It is to the violence of those denuding agencies 
that we owe the formation of the stream tin deposits, that not 
only were the means of bringing Cornwall into contact with the 
ancient civilisations of the East, but afforded its inhabitants a 
thriving industry for many centuries. 

The history of the topography would be incomplete without a 
brief reference to tne later physical changes that not only bring 
the cycle of evolution down to historic times, but carry it for- 
ward to the present day, so that by studying the geographical 
modifications that are yet taking place within our own observation 
we may anticipate the changes that the future has in store. 

That the present denudation of the land is undoubtedly slower 
than of old may be gathered from the small volume and sluggish 
currents of the streams that now water valleys of considerable 
magnitude. This inference is confirmed by the scanty alluvial 
deposits that have accumulated on the valley floors since the 
glacial period. That denudation is nevertheless effecting its 
influence on the configuration of the area is vividly brought home 
by the rapid silting up of some of the estuaries. This is well 
exemplified by the mud flats of the River Fal, which below 
Ardevora are creeping rapidly seaward. Above Lamorran and 
Ruan Lanihorne the alluvial terrace has been formed since the 
sixteenth century, while the upper extension of that flat as far as 
Tregoney has been recovered from the sea since the time of the 
Boman occupation, when that place served as a port accessible to 
shipping. The seaward growth of the valleys and the shallowing 
of the tidal estuaries are further discussed in the subsequent 
chapters. While denudation, therefore, in spite of lowering the 
surface of the land^ is gradually extending its frontiers within the 
sheltered estuaries, the sea front is brought under the ceaseless 
action of the breakers, and the cliffs are undergoing a slow but 
constant degradation. During the last quarter of a century the 
footpaths skirting Gerrans Bay have been gradually shifted back, 
consequent on the landslips that accompany the undermining of 
the cliff foot, while the picturesque caverns along the seaboard 
have undergone extensive alteration. It is evident, therefore, that 
the effects of coastal erosion alone, if unchecked by elevatory 
movements of the land, will gradually evolve a submarine plain 
from which the granite domes will emerge as islets, and that the 
general conditions of the ancient Pliocene sea will be reproduced.* 

The mineral area is practically restricted to the western 

* For a fuller account of the evolution of the valley system, its relation 
to the estuaries, and the history of the deposits that line their respective 
floors, the reader is referred to the sequel. (Chapters X« and XL) 



AREA AND PHYSICAL FEATURES. 7 

half of the sheet. A line drawn from Metheruny on the 
extreme south, to Baldhu, and from thence in a north-west 
direction to the coast, defines the eastern limits of the principal 
metalliferous zones. Between that line and the meridian of Truro 
the mineral ores are sparsely distributed, while the area farther to 
the east has proved unproductive. The belt of country enclosing 
Camborne and Bedruth has ever been and still remains the 
principal seat of the Cornish mining industry. Mining operations 
within this sheet are practically confined to that limited tract, 
beyond which, where not entirely discontinued they are conducted 
on a restricted scale. 

A glance at the map reveals the close connection between the 
metalliferous deposits and the granite. The eastern half of the 
Carnmenellis mass is comparatively free from mineral veining, 
and this has materially contributed to the commercial value of the 
granite which has been so largely wrought in that area. Proceed- 
ing westward, however, from the parish of Wendron, mineral veins 
make their appearance. They reach their greatest extent on the 
north-westerly margin of the granite, while the tract enclosing the 
two adjacent masses of Cam Biea and Cam Marth constitutes the 
heart of the mineral area. (Fig. 1.) 

The granites are dome-shaped masses and slope beneath the 
kiilas for considerable distances from their surface outcrops. The 
sediments which flank them have been considerably altered by 
contact action, producing an encircling metamorpbic belt the 
variable width of which is controlled by the angle at which 
the granite slopes below the surface. This dip is by no means 
constant, as mining operations show. The unevenness of the 
granite surface is exemplified by the Cam Brea mass, which has 
been shown to be connected with the granite of Carnmenellis 
beneath the basin of kiilas that divides them. 

The aureole of metamorphism flanking the eastern portion of 
the Carnmenellis granite seldom exceeds a width of a thousand 
yards, and is in some places considerably less ; that area, both as 
regards the granite and the metamorpbic belt, being comparatively 
non-metalliferous. On the western side, however; the granite 
plunges less steeply beneath the surface, and the metamorpbic 
aureole is therefore considerably larger. Between the Cober Valley 
and Crowan its average breadth is about a mile. From the 
granites of Cam Brea and Cam Marth, in the direction of the 
north coast, the kiilas is metamorphosed for distances of two and 
even three miles^ and it may be confidently inferred that this 
tract is underlain by granite, in some places within a thousand 
feet of the surface. 

The mineral district of Gwennap, St. Day, and Baldhu occupies 
the Cam Marth aureole on its western side, while its eastern 
extension is characterised by a plexus of el van dykes amongst 
kiilas which exhibits a feeble degree of metamorphism, as indicated 
by the development of an incipient type of spotting. The south- 
western region of Crowan and Wendron contains mineral lodes 
not only within the Carnmenellis granite, but in the intervening 
kiilas area, separating that mass from the granite of G-odolphin. 



AREA AND PHYSICAL FEATURES. 9 

Id the remaiDing district west of Truro and the Carriok Roads 
the lodes are scattered and of comparative unimportance, and 
mainly confined to ores of lead and zinc. These minerals, how- 
ever, have no necessary connection with the granite intrusions, as 
is the case with tin and copper. 

It will be seen, therefore, that not only are the tin and copper 
lodes restricted to the granite regions and the adjacent killas, but 
that they principally occur in areas where the granite plunges 
beneath the sediments at a low angle. The ores of tin and copper 
have furnished the staple mining industry of the district, the 
metals with which they are associated being seldom sufficiently 
abundant to be profitably wrought on their own account. Beyond 
the tin and copper districts, however, lead ores have proved 
remunerative, but mainly from their argentiferous products, which 
in some cases have yielded a high percentage of silver. 

The concentration of the mineral ores is intimately related to 
the rock structure of the district. Besides the restriction of the 
tin and copper ores to the granite, and the killas that is 
immediately contiguous, their concentration in the form of lodes 
has been controlled by the system of rock fracture per- 
taining to the area, the fissures having afforded the necessary 
channels by which the metallic vapours and solutions have 
travelled, while their walls have received the metallic and other 
contents with which those currents have parted. The tin and 
copper lodes are probably of late Carboniferous age, and followed 
closely on that phase of volcanic activity which is represented by 
the cooling of the granite and the disruptions that accom- 
panied it. The absence of those metals in the cross-courses, 
that represent lines of fissure transverse to the Carboniferous 
fractures, shows that their deposit had ceased prior to that 
later phase of disruption which there is reason to suppose 
was brought about by the volcanic disturbances of early Tertiary 
times.* The deposition of other ores, however, and notably those 
of lead, silver, and zinc, have continued into Tertiary times, and 
are of common occurrence in the cross courses. 

The decadence of the mining industry has proved a serious 
obstacle to the survey of the mineral area, and the limited 
number of workings available for inspection has precluded such 
systematic investigation as would warrant the formulating of 
general laws governing the vein deposits of the region. The 
active mines have been explored by Mr. MacAlister, but much of 
the mining material in the subsequent chapters has necessarily 
been derived from previous publications, the authority for which 
has been acknowledged. The most laborious work in connection 
with the mineral survey has consisted in the reduction of the lodes 
to a uniforni scale from the mine plans. Most of the latter are 
laid down to their individual magnetic meridians, so that a plan 
in use for many years contains errors due to compass variation. 
Each mine has its own datum line, the depths being taken 
either from the brace of its shaft, or its adit, which may occur 
at any depth down to the 40-fathom level. The depths, more* 

♦ .1. B Hill. Trans. m*y. Geol. Sac. Ctyni., 1901, vol. xii., p. 599. 



10 INTBX)DUCTION. 

over, instead of being vertical, are calculated along the under- 
lie of the lode. The scales adopted in the different mines likewise 
vary from 4 to 20 fathoms to the inch. While the accuracy of 
the plans of the mines now working leaves nothing to be desired, 
those relating to many of the abandoned undertakings abound 
with errors, and in some cases Mr. MacAlister has been unable to 
obtain any plans. 

On the map the tops of the lodes only have been delineated. 
On the 6-inch mining maps, however, the most important of 
which will be published, they are also represented by underground 
parallels, the highest of which is at sea level, while the remainder 
are drawn at uniform vertical distances from Ordnance datum, so 
that their subterranean behaviour may be grasped. The lodes of 
the principal mineral areas have also been drawn in MS. on 25- 
nch maps, which may be consulted in the Geological Survey 
Office in London. 

With the revival of the Cornish mining industry that is now 
taking place, the mapping of these underground fissures on a 
uniform scale, with the depths to which they have been proved 
and by which they can be systematically traced, should materially 
facilitate future exploration for their mineral wealth. Even if the 
present attempts to resuscitate the industry should prove abortive, 
this mineral region is in no sense an abandoned mining field in 
which the products have been exhausted. The history of Cornish 
mining presents times of prosperity succeeded by periods of 
depression, and whatever may be the outcome in the immediate 
future the time will inevitably recur when economic conditions 
will again justify a vigorous prosecution of the industry. 

The scenery of the area is strongly contrasted. While the 
eastern region constitutes one of the most picturesque districts of 
Southern England, the central and western areas are com- 
paratively tame. Moreover, the despoiling of large tracts in the 
west by the many centuries of mining still further accentuates 
these scenic contrasts. Although the former region, extending to 
the west as far as Penryn, Perranwell, Killiow, and the valley of 
the Kenwyn, is highly fertile and entirely under cultivation, and 
broken by deep valleys along the slopes of which woodland 
tracts are profusely scattered, the dominant feature in the 
topography is the submerged valley system, which has given access 
to the sea along the numerous creeks that penetrate the very 
heart of the district. The navigable waters of the Kal, winding 
amid verdant slopes that are sometimes clothed with woodland to 
the water's brink, constitute a waterway the beauty of which is 
probably unrivalled in England, while its seaward extension has 
furnished one of the finest harbours of the world. 

Whereas beyond Truro and Falmouth the passage westward 
into tamer scenery is somewhat gradual, the central belt between 
Truro and Perranwell is suddenly replaced by a dreary tract, 
the bleakness of which is accentuated by the most abrupt 
transition. The oncoming of these conditions is due to the 
presence of the mineral belt extending from Carnon and Baldha 



AREA AND PHYSICAL FEATURES. 11 

to St. Day. Althoagh mining operations in the district have 
ceased, a considerable part of the ground is out of cultivation, and 
large tracts mark the site of the old spoil heaps which in the 
district east of St. Day cover a considerable area. This wide 
expanse, that may be described as a vast wreckage, is dotted by 
engine houses and mine stacks in various stages of decay that 
still further add to the unsightliness of the landscape. The 
borders of this tract have in some cases been reclaimed from the 
dreary features of an abandoned mining district by the planting 
of timber, as at Gwennap and Scorrier. The Pimts insignia and 
other conifers easily thrive on such burrows as do not carry a 
high percentage of arsenic, and it cannot be doubted that much 
of the landscape could be restored by judicious planting from 
the waste to which mining operations have reduced it. The 
extensive nature of the subterranean excavations is vividly brought 
home in this district by the steam which issues from some of 
the shafts that reach the heated waters below. 

The extension of this mineral belt from Hedruth to Camborne 
is accompanied by a softening of the scenery. That tract forms 
a slope extending to the north coast. Not only does the land- 
scape improve from its blending with the sea, but it is backed by 
the rugged and picturesque peak of Cam Brea, which commands 
a magnificent prospect extending right across the county from sea 
to sea. Viewed from that summit the vast array of stacks forms 
an imposing scene, and in spite of the large number that repre- 
sent abandoned operations, the principal seat of Cornish mining 
still lies beneath the shadow of Cam Brea, and contains the 
deepest tin mine in the world. (Plate III.) The decadence of 
mining after the abandonment of operations in the outlying 
mineral districts, has driven the industry back to its last hold, and 
on the ability of this mining centre to emerge successfully from 
the recent period of depression lies the hope of the regeneration 
of Comish mining in the immediate future. 

The south-western district is dominated by the Cammenellis 
granite that forms an elevated dome without conspicuous features. 
Except on its flanks the population is sparse, and the area is 
largely made up of moorland out of cultivation and given over 
to gorse and heath. The western portion, especially in the 
parish of Wendron, marks the site of an abandoned tin industry. 
Many valleys and basins, in which the stream-tin has been 
worked, are choked from side to side with disordered ground. 
Large tracts of such waste land occur in the upper parts of the 
Cober Valley, and notably at Porkellis Moor, while another 
basin similarly desolated lies between Calvadnack and Menerdue. 
The eastem portion of the granite region is more thickly 
populated, and forms the seat of the important granite industry, 
the headquarters of which is at Penryn. The rudely stratiform 
weathering of the granite frequently results in the production of 
picturesque tors, of which Cam Brea forms a conspicuous example, 
while Crowan Beacon and other summits display the same type of 
scenery on a less imposing scale. 

The scenic contrasts of the tracts bordering the northern 



12 INTRODFCTTOK. 

coast and those fronting the English Channel are most marked. 
Although somewhat similar in their geological characters, the 
greater elevation and bleaker aspect of the former has produced 
large expanses of moorland represented by Reskajeage Downs, 
Carvannel Downs, and Nancekuke Common. The southern slopes, 
on the other hand, are in a high state of cultivation, diversified by 
luxuriant hedgerows and frequent clumps of woodland, while the 
more sheltered hollows are capable of sustaining a sub-tropical 
vegetation that has induced the garden culture of palms and 
other exotics. 

The inland area is entirely devoid of lakes, with the exception 
of those artificially formed near Antron and Crowan by damming 
the streams, for the water supply of Falmouth, Penryn, and 
Camborne. At Swanpool, however, a storm beach that has been 
piled up across the mouth of the valley has succeeded in ponding 
back a freshwater lake. (Plate I.) 

A conspicuous feature in the upland areas is the presence of 
shallow basins, which are especially common at the heads of the 
valleys. They are largely composed of clay, and the want of fall 
rendering drainage difficult, their bottoms are frequently lined 
with marshes. Being on this account unsuitable for cultivation, 
these moors are given over to scrub and gorse and afford coverts 
for game, just as many of the rocky slopes in the granite district 
consist of moorland stretches, clothed with gorse and bracken, the 
recesses of which form the congenial haunts of the fox. 

The larger towns in the area comprise Falmouth, Truro, 
Bedruth, and Camborne. While the latter is the principal 
mining centre, Redruth serves, in addition, as a market town for 
the western region, while Truro and Falmouth fulfil a similar 
object for the eastern districts. Although the shipping trade of 
Falmouth has suffered a serious decline since the advent of steam, 
it still yields employment to a considerable section of the popu- 
lation, both ashore and afloat. Of late years the town has advanced 
rapidly in favour as a health resort, the mildness of the climate 
and the beauty of its surroundings being responsible for a large 
influx of winter visitors. 



13 



PART I. 

GEOLOGY. 

BY 
J. B. HILL, R.N. 

CHAPTER IL 
FORMATIONS AND THEIR GENERAL DISTRIBUTION, 

As a glance at the map will show, the south-western portion of 
the area is occupied mainly by CiRAMTE. The principal mass, the 
most elevated portion of which forms the hill of Carnmenellis, is 
rudely circular in shape, and, with the exception of a small portion 
of its southern edge, falls entirely within the district. It extends 
from Budock on the east to the neighbourhood of Crowan on 
the west, while its northern limits occur at Buller Downs, about 
a mile to the south of Redruth. The lenticular mass of Cam Brea, 
with a linear extent exceeding four miles, is an inlier of the Carn- 
menellis granite, and separated from it by a narrow basin of slate. 
The granite sitnated between Redruth and St. Day, the highest 
point of which forms the bill of Cam Marth, is boss-like in form, 
and its southern edge is separated from the Cammenellis granite 
in the neighbourhood of Lanner by less than half a mile. 

Besides the masses of Carn Brea and Carn Marth, the Cam- 
menellis granite is fringed by smaller granite intrusions between 
Crowan and the valley of the Cober, numerous sections of which 
are exposed in the cuttings of the railway between Praze and 
Helston. On the east two small bosses of granite are seen at 
Budock, and fine-grained granite is also exposed close to the main 
mass in the railway cutting near Treluswell. 

The GREENSTONES are mainly confined to the neighbourhood of 
the granite aureole. They are most extensively developed between 
Camborne and Coswinsawsin, and continue from the former locality 
as far as Redruth, in which direction, however, they are seldom 
visible at the surface. They occur also in the park of Pendarves 
House, but do not protrude there from beneath the soil. A 
fairly extensive mass of greenstone lies to the south of Gwennap, 
between Treviskey and Pengreep, and it follows the same line 
in close contiguity to the granite between Ponsanooth and 
Lower Treluswell. Rocks of this group occur on both sides of 
Penryn Creek, between Flushing and Falmouth, and a few ex- 
posures of small size are seen at Carclew and Restrongnet Creek. 
On the southern fringe of the granite, extending from Budock and 
Praze to the southern limit of the sheet, the sole greenstone that 
has been recognised is situated in the valley of the Cober, near 
Tregannock Mill, and is a member of an important group lying 
farther south in the vicinity of Helston. 



14 FORMATIONS AND THEIR DISTRIBUTION. 

Elvan dykes are abundantly distributed along a belt of country 
about three miles in breadth, extending from Truro to the neigh- 
bourhood of Camborne, and including the districts of Chacewater, 
Gwennap, and Redruth. Beyond that belt tbey are sparsely met 
with west of the Carrick Roads, and the continuation of that 
waterway to Truro and the valley of the Kenwyn. In the 
remaining area to the east of that line they have not been 
detected. 

The Mica traps are confined to a narrow belt of country 
between Pendennis Point and Malpas, and to a small isolated 
tract at Shortiand End, lying to the north-west of Truro. 

Of the '* Killas " or Slate divisions the Mylor series is largely 
developed in the south-west. It completely encloses the granite 
masses and the greenstones^ and contains also the bulk of the 
elvan dykes. It is bounded approximately by a line drawn from 
Falmouth along the Carrick Roads to Restronguet Creek, whence 
it extends north-west to Carrine Common, Baldhu, and the vicinity 
of Mawla. Thence the line sweeps to the south-west by Illogan, 
Tehidy House, and Kehellan, at the western margin of the map. 

The Falmouth series is not so extensive as the Mylor and 
Portscatho series which it divides. It likewise occurs as lenticles 
within those groups. To the north-west it occupies a narrow 
strip which reaches the sea at Reskajeage Downs. A broad 
tract extends from Chacewater to Truro, from which it 
branches irregularly to the north-east, south-east, and south. 
Numerous lenticles occur amongst the Portscatho slates in the 
basin of the Fal, where they are well developed between Ruan 
Lanihorne and Philleigh, and from Coombe to Feock. Similar 
strips appear on the eastern side of the Carrick Roads between 
Turnaware Point and St. Just, while further to the south these 
slates are developed at St. Mawes. A wide belt of this series 
extends from Falmouth to Pennance, and a smaller band occurs at 
Maen Perth. This group, situated in the neighbourhood of 
Falmouth, presents favourable faciUties for its study from the 
excellent coast sections in that vicinity. 

The Portscatho series occupies almost the entire area east of 
the Carrick Roads and Truro. It extends west of the Fal from 
Feock to Killiow and Truro. From Truro to Perth Towan it is 
developed in a continuous belt. In the neighbourhood of Port- 
reath a large mass borders the north coast with a sea frontage 
of nearly three miles. The extensive coast sections, both along 
the seaboard and those afforded by the estuaries that have pene- 
trated far into the interior of the area, present unrivalled oppor- 
tunities for the investigation of this series. 

The Veryan series occupies a small tract on the north of 
Grerrans Bay to the east of Pendower. 

The GrRAMPOUND AND Probus SERIES forms a narrow strip across 
the northern edge of the map between Probus and Perth Towan, 

The SUPERFICIAL DEPOSITS are of relative unimportance. The 
gravels referred to the Pliocene occupy an insignificant tract in 
the vicinity of Polcrebo. Although the extensive valley system 
is a marked feature in the district, its floors are seldom 



TABULAR STATEMENT OF FORMATIONa 15 

lined with alluvial deposits at all commensurate with the mag- 
nitude of the valleys. Moreover, the margins of the alluvia are 
generally far less defined than is usual with this class of deposit, 
and it has been found desirable in some instances to include within 
the alluvial boundary tracts which in other districts would have 
been excluded. Marine alluvia are mainl v confined to the estuaries 
diverging from the Carrick Roads, which, on the recession of 
the tide, reveal extensive tracts of mud and clay. The raised 
beaches are merely expressed by discontinuous shreds still 
adhering to the present cliff faces. The stream-tin deposits 
have been worked over so extensively that they are now represented 
largely by tumbled and disordered ground along the valleys and 
hollows, many of which are included amongst the alluvial deposits. 
Blown sand is rare; a patch occurs on the north coast at Forth 
Towan, and smaller tracts are seen at Pendower in Crerrans Bay. 
Deposits of **head " are practically restricted to the coastal areas, 
where they form strips mainly in sheltered bays, with a very small 
landward extension. Submerged forests are known at Falmouth, 
Maen Forth, Fendower, and Forthcurnick. 

The following table shows the various formations occurring in 
the area. In the chapters which follow they are successively 
described in chronological order, commencing with the most 
ancient : — 

Blown sand ' ' ' \ 
Freshwater alluvia - - ( „ . 
Marine alluvia - - j- Recent. 

Submerged forests - - / 
Stream - tin and submerged \ 
^raUey deposits - - I pieigfcocene. 

Raised beaches - - / 

Folcrebo gravels - - Fliocene. 

Killas, viz., slate deposits : — 

Grrampound and Frobus series Lower Devonian. 
Veryan series - - - Ordovician (Lower 

Silurian). 
Fortscatho series - - i 
Falmouth series - - . Lower FalsQOZoic. 
Mylor series - - - . 

Igneous. 
G-ranite. 

El van (Quart z-Forphyry, &c.). 
Mica Trap. 
G-reenstone. 



i6 



CHAPTER III. 

T H K K I L 1. A S . 

General Description and Tectonics. 

The rock formations that enter mainly into the geology of the 
sheet are killas. Notwithstanding a general uniformity in the 
killas or slate formation of this part of Cornwall, it has been found 
possible to differentiate it into certain divisions. Owing, however, 
to the practical absence of organic remains, the ssones so differen- 
tiated are purely lithological. The impersistence of lithological 
types^ added to the advanced stage of decomposition of many inland 
areas, and the paucity of sections, has in many cases rendered the 
mapping of definite boundaries impossible. Nevertheless, the 
demarcation of these rock bands over the area generally has been 
accomplished with sufficient accuracy for the interpretation of the 
general tectonic arrangement of the district. 

As the extreme plication which has prevailed over the area 
renders the dip valueless as a stratigraphical criterion, there is 
still, in the absence of palaaontological evidence, some uncertainty 
as to what is the upward succession. 

For ^he same reason the thickness of the bands de6es any 
attempts at calculation. All that can be said with certainty is 
that they are immeasurably thinner than their surface indications 
would appear to indicate, and that the immense thickness ascribed 
to the killas by the early observers is based on data that are 
erroneous. The four lithological divisions enumerated below 
represent the older Palaeozoic strata, and succeed one another from 
east to west in the order named : — 

Veryan series. 
Portscatho series. 
Falmouth series. 
Mylor series. 

A fifth, the Grampound and Probus series, which represents the 
newer Palaeozoic, departs from that succession and extends right 
across the area from east to west. The distinctive characteristics 
of the various groups are as follows : — 

Mylor Series. — This series consists of blue argillaceous and 
fine sandy beds. The latter are often more quartzose than in the 
Portscatho series, and occasionally a thin quartzite seam is met 
with. In addition to the more siliceous character of the sandy 
alternations, tho latter are usually of finer texture than in the 
Portscatho group. The distinguishing feature of this series, 
however, is its usual striped and ribbon-like appearance, due 
to very fine interlaminations of siliceous and argillaceous material. 
In some cases, liowevcr, the laininas are argillaceous only, but of 
varying composition and colour. This interlaminated character 
which diHtinguinhes the group is rarely absent, but it is not to be 
underNtood that it {h confmed to this series. It is sometimes seen 



DESCRIPTION OF THE KILLAS. 17 

in the Falmoath division^ and is frequently strongly developed in 
the Portscatho beds^ especially in the district extending from 
Chacewater to the north coast ' 

Falmouth SERiEa — This series comprises alternations of 
argillaceous and fine sandy material, varying in colour from green 
to grey and buff, though occasionally blue argillaceous bands are 
seen amongst them. The colour, which varies with the character 
of the sediment, produces the general variegated appearance 
common to this series. Their mode of decomposition is equally 
characteristic. The beds become extremely friable, especially those 
of a sandy natqre, are unctuous to the touchy and weather into a 
deep buff colour. On the whole the material is finer than in the 
Portscatho series, and the strong grit bands which occur in the 
latter are absent. Occasionally a narrow zone is seen of purple 
and green slate, often strongly contrasted, which forms a valuable 
guide in correlating these beds throughout the district, especially 
in the absence of the characteristics already described. 

PoBTSCATHO SERiEa — ^This consists of blue and grey clay slates^ 
alternating with harder beds, which show every gradation from a 
sandy slate to a fairly strong grit. The sandy beds are of the 
same bluish hues as the argillaceous, and are characterised by the 
large amount of clastic mica which is scattered through them. 
The great feature, however, which distinguishes them from the 
Veryan series is the absence of limestone, except at their 
junction with the latter. This absence of calcareous material 
distinguishes also the Falmouth and Mylor series. 

Veryan Series. — This group, so far as it enters the area of 
this sheet, consists of blue and grey slate with alternations of 
sandy beds, thin dark limestones, and dark-coloured cherts, some 
of which are graphitic. Notwithstanding the occurrence of chert 
and limestone, the sandy interlaminations are frequently coarse, 
but are largely made up of soft grains, so that these coarser seams 
are well cleaved. The series is characterised in this area by the 
presence of manganese, which stains the slate. 

GRABiPOUND AND Probus SERiEa — This Series consists of fine- 
grained conglomerates, sandstones, and clay slates. They repre- 
sent the base of the Devonian, and are distinguished from the 
underlying Portscatho division by a general calcareous character 
which never, however, gives rise to limestone, and by a more 
feeble degree of metamorphism. 

Natural Sequence of the LiOWEr Paljsozoic DrvisiONa — 
The Veryan series lies in the western portion of the area coloured 
as Silurian in the later issues of the old map. The Portscatho 
series lies immediately next to it, and falls within the area 
formerly coloured as Devonian. The two groups, however, pass 
uninterruptedly into one another without any stratigraphical 
break. Although the appearance within the Veryan series of 
limestone serves to indicate the apparent incoming of another 
division of the stratigraphical series, there is no evidence here for 
drawing a sharp divisional line to mark off two distinct geological 
formations. 
Not only does the Veryan series pass uninterruptedly into the 



18 THE KILLA8. 

Portscatfao groap, boi these latter also graduate imperceptibly 
into the Falmouth series, which in their turn merge insensibly 
into the Mylos beds. While advantage has been taken of litho- 
logical distinctions to separate them into divisions, that repre- 
sented on the map would explain the stratigraphy, it must be 
distinctly borne in mind that we are apparently dealing with 
a continuous series of deposits. 

Evidence of GEOLCXfiCAL Age. — Notwithstanding the com- 
parative absence of palseontological data, the researches of Mr. 
Howard Fox and other observers on the radiolarian cherts of 
South Cornwall tend to confirm the conclusions aiready set forth 
of the unbroken sequence of these deposits. The radiolarian beds 
are not always confined to chert, but these organisms sometimes 
occur in cherty shales. They have been found by Mr. Fox in the 
cherts of the Veryan series east of Pendower, and near Middle 
Point, Falmouth^ close to the junction of the Falmouth and 
Portscatho series. Mr. F. J. Stephens* has also described radio- 
larian cherts from Little Falmouth and other localities in the 
Penryn Creek, within the Mylor series, which Mr. Fox's researches 
in that area have confirmed. They have not been observed in the 
Portscatho series, but the locality near Middle Point, although 
within the Falmouth series^ is only about 35 yards distant from 
the line adopted as the boundary of the Falmouth and Portscatho 
groups, which merge almost insensibly into one another, but 
in the adjoining sheet to the south their presence within 
the Portscatho series has been detected. Messrs. Fox and 
Hinde have also found radiolarian beds in North-Eastern Corn- 
wall at the base of the Culm>measures, but the intermediate 
region, which is mainly made up of Devonian rocks, has hitherto 
^iled to yield radiolaria. That is to say, these organisms have 
not been detected on any horizons that are known to be of 
Devonian age. Mr. Fox in his paperf assigns the age of the 
Veryan cherts to the Lower Silurian (Ordovician) period ; the other 
radiolarian localities at Falmouth and Penryn Creek have been 
subsequently discovered. The occurrence of chert pebbles in the 
conglomerate at Nare Point tends to confirm Mr. Fox's hypothesis. 
The presence of radiolaria in this otherwise barren sequence, and 
their absence in the Devonian formation, undoubtedly accentuates 
the divergence between these deposits. 

It will be seen in the description of the Probus grits that there 
is reason to correlate those beds with the well-known conglomerate 
south of the Helford River, and that both rest unconformably on 
the Portscatho beds. 

The survey of the ** killas'* area in the adjoining map to the 
south has thrown much light on the elucidation of the geology of 
this district. For a detailed account of the evidence the reader is 
referred to a recent publication by the author.J The main con- 
clusions therein arrived at are as follows : — 

* Roy. Com. Polytechnic Soc., 1897. 
t Trant, Roy. Geol. :<oc. Cornwall, 1896. 
t Qeol. Mag. 1906, p. 206. 



8TBUCJTURES OF THE KILL AS. 19 

1. The Verjan series ioclades Qaartzite of Lower Silnrian age. 

2. The Veryan, Portsoatbo, Falmouth and Mylor groups form a 
natural sequence. 

3. That the evidence favours a descending sequence from the 
Veryan to the Mylor groups. 

4. That these Lower Pakeozoic rocks were extensively deformed 
by earth movements in pre-Devonian times. 

5. That the Lower PalsBozoics are unconformably overlain by 
the basement beds of the Devonian. 

The evidence therefore at our disposal may be summarised as 
follows : — ^The killas divisions occupying this sheet are below the 
Probus grits and the Meneage conglomerate. The nearest 
fossiliferous horizon is the Lower Silurian Quartzite^ which 
also underlies the conglomerate. There is no evidence at 
present for separating any of these killas divisions from the 
liower Silurian. The age of the conglomerate has not been 
definitely proved, but there is a general consensus of opinion that 
it defines at least the local base of the Devonian. Moreover, its 
apparent continuity with that formation in the adjoining areas to 

the north lends support to that conclusion.* 

« 

Structures of the Killas. 

Before tracing farther the local stratigraphy it will be con- 
venient to refer to the typical structures of the killas. 

Isoclinal Folding. — A detailed study of the coast sections 
reveals a complex set of structures that have been brought 
about as the result of compression. Folds and faults may be 

* Sir R. I. Mnrohison expressed the opinion in 1846 that the killas oetween 
Grerrans Bay and Falmouth was of Silnrian age {Royal Geal. Soc, ComwM, 
vol. vi, p. 322). Mr. J. H. Collins published a sketch map with a paper on the 
" Geology of Central and West Cornwall " in 1881 [Journ. Boy. Intt, Corn., 
vol. vii., p. 17), in which he marks the killas (included in Sheet 352) as mainly 
pre-Devonian. Mr. A. Soraervail (in the same volume, pp. 262-273) contro- 
verts some of Mr. Collins' conclusions, but assigns a Lower Silurian a^ to the 
slates from near Penryn to (jrerrans Bay, most of which had been similarly 
classified by Mr. Collins. Mr. Soinervail suggested that they were of Llandeilo 
ajB;e. The author, who has been engaged on the survey of West dlomwall 
since 1897, has always considered these barren strata (Mylor, Falmouth, and 
Portscatho series) to be linked with the Silurian system, for reasons set forth 
in the "Summaries of Procrressof the Geological Survey from 1897 onwards." 
(See also papers by J. 6. Hill, Trans. Roy. Oeol. Soc, Cornwall, 1899 and 1901). 
Mr. Upfield Green has claimed these beds as Lower Devonian, of which the 
Dartmouth slates represent the upper member, while the base is marked by 
the conglomerate of Meneage, &c. (Geol. Mag.^ 1904, p. 403). Mr. Green's con- 
clusions were criticised by Mr. Ussher, who contended that the superposition 
of the Dartmouth slates to the Mylor, Falmouth, and Portscatho series was 
not supported by proof {Oeol. Mag,, 1904, p. 590). Mr. Ussher recalled that 
althougn he formerly correlated the Gramp<mnd grits with the Gedinnien, 
he would now hesitate to do so, the inference apparently being that they 
might occupy a higher horizon. In the map accompanying his previous paper 
(Boy. Greol. Soc Ck>rn., 1891) Mr. Ussher has coloured the killas (now repre- 
senting the Mylor, Fidmoutn,and Portscatho series) as " (?) pre-Devonian " and 
has placed the Grampound grits at the base of the series classed as undoubted 
Devonian. From a persual of his paper it would appear that these particular 
beds had not been studied by him on the ground, out that his remarks were 
based on his interpretation of the observations recorded in De la Beche's 
report. (See piges 32 and 64.) The Lower Silurian Quartzite occurs within 
the Gonran Sheet, and its included fossils have been determined by 
palfBontologists as (3aradoc. 

c2 



20 THE KILLAS. 

detected immediately in any of the divisions, bat as the folds are 
generally isoclinal, the plication is not so conspicnoas as in a 
region of normal folding. But the evidence of plication is every- 
where so marked that the apparent dip can only be interpreted as 
the inclination of limbs of folds. (Plate IV.) The plication has 
been accompanied by rock fracture, the faults being almost as 
numerous as the folds to which they bear a direct relation. 

Cleavage. — Under the influence of earth movements not only 
have the strata been closely folded until relief has been finally 
obtained from the strains by actual disruption, but the material 
of which the strata is composed has been also affected. Of the 
mechanical changes which the rocks have undergone, the most 
conspicuous are undoubtedly the cleavage planes that have 
produced the slates. These cleavage planes have been among 
the last mechanical changes effected by the lateral strains. They 
traverse the strata independent of the original stratification, and 
to some extent of the folding in which the stratification has been 
involved. Although bearing no relation to the original bedding, 
their disposition in regard to the flexures is more defined, as the 
cleavage planes sho\|[ a marked tendency to lie parallel with the 
axial planes of the folds. When the material so cleaved was 
originally pure and of uniform consistency, the result has been a 
perfect slate in which the earlier structures of stratification and 
folding have been either completely obliterated or faintly pre- 
served by colour banding. Instead, however^ of possessing these 
necessary characters for the production of roofing slate, the killas 
consists of such an intimate banding of diverse material that the 
cleavage is subject to marked variations; so that slate of commercial 
value is rare, and it is doubtful if any such has been successfully 
wrought in the area under description. 

The ^' killas " being largely made up of alternating bands of 
diverse texture^ its compression has introduced a complex set of 
structures. Where cleavage has been set up in alternating layers 
strongly contrasted^ such as shale and sandstone, the cleavage 
planes change their character according to the nature of the 
layer which they traverse. Those which cross the argillaceous 
baud are not only more numerous than those which traverse the 
arenaceous layer, but incline at different angles ; so that two shale 
bands which are divided by a sandstone display parallel cleavage, 
but this parallelism is broken in the interposing sandstone. 
Moreover, if the latter is &u6Sciently massive, it has resisted 
cleavage altogether, so that we see the phenomena of fissility in 
perfect parallelism as regards the upper and lower members, while 
it is absolutely severed by an intermediate band in which this 
structure is wanting. As the arenaceous beds present every 
gradation in their texture, there are corresponding gradations in 
the degree of fissility which they exhibit. Another factor which 
constitutes a disturbing element is the disruption of the rocks ; 
the fractures produced having acted as planes of relief bringing 
about a cessation of stresses in their neighbourhood, so that beds 
of similar crushing strength present different degrees of fissility. 
In studying the effects of cleavage on the strata of the area the 



CLEAVAGE — FOLDING — PSEUDO-CONGLOMERATES. 2 1 

fact is apparent that flexure, fracture, and cleavage are intimately 
related, and express different phases of rock deformation. The 
coast sections display marked variation in the degree of deforma- 
tion, both as regards the intensity of folding and the nature of 
the fissility in strata of similar lithological type. 

Secondary Cleavage, Overfolds, and Shear Structures. — 
While the cleavage has resulted merely in the flattening of the 
component particles of the strata, the rearrangement of material 
does not always stop at this process, but the crushing to which 
the rocks have been subjected has set up further interstitial 
movements. These latter resolve themselves into a succession 
of small slips along the cleavage planes, and have often been 
sufficiently pronounced to produce a transverse cleavage which 
may locally develop to such an extent as to constitute the dominant 
cleavage of the rock. 

In response to lateral pressure the strata have been folded, the 
flexures have been closely packed together, bringing their limbs 
into a general parallelism, so that no further relief from pressure 
is to be obtained by plication. But the strength of the rock 
sometimes fails before the stresses which still continue to bear, 
and rupture occurs. The fractures still follow the disposition of 
the folds and snap their arches, the planes so formed allowing one 
part of the mass to override its neighbour, and the rock is 
divided into segments bounded by miniature faults and thrusts. 

While the strata on the large scale have been thus modified, 
their component particles have been undergoing on the small 
scale precisely the same process which has set up interstitial 
movements. The individual layers which form the beds have 
been thrown into a set of minute folds, the arches of which have 
been broken by tiny cleavage planes which resolve themselves 
into miniature faults, and there is the same tendency to override 
as is seen in the larger divisions of the beds. On examination, 
the rock is frequently seen to be full of such small folds and 
thrust planes, with a disposition to a secondary cleavage, while 
minor movement planes appear in the more resisting core itself, 
with accompanying strain-slip cleavage ; and the cleavage planes 
which pass through the axes of the minute folds often culminate 
in small thrusts. 

Pseudo-Conglomerates. — Besides the structures already enu- 
merated, these crushing processes, acting on heterogeneous strata, 
have in this region produced a set of widely distributed breccias 
which closely simulate the coarser products of erosion. These 
breccias or pseudo-conglomerates are well developed on the western 
side of the Garrick Roads, in a belt that extends from Feock to 
Falmouth; that tract of country is broken by the estuaries which 
form the creeks of Penryn, Mylor, and Restronguet, along the 
banks of which they may be conveniently studied. 

They consist of slate fragments enclosed within the strata, 
ranging from the size of peas up to five or six inches in length, 
with their flat sides lying in more or less parallel planes. As a 
rule the larger fragments are angular, while the smaller are sub- 
angular and sometimes perfectly rounded. They may consist 



22 THE KiLLAS. 

of either siliceous or argillaceous material, and are identical 
in composition with the matrix of the slate in which they 
are enveloped, and from which they have obviously been 
derived. Instead, however, of being waterwom, as their appear- 
ance suggests, they are the products of brecciation. The Mylor 
beds, in which these phenomena are best displayed, are, as already 
pointed out, an interlaminated series, in which the thin bands vary 
in composition. The changing nature of these interlaminations, 
and the corresponding variation in their limits of compression, 
have resulted in different degrees of resistance to the crustal 
movements, the softer beds having easily yielded^ while the more 
resistant strata, separated from each other by bands which are 
beginning to yield, and being thus deprived of support, are 
smashed, and the fragments become involved in the more plastic 
mass. Under the influence of these movements the particles not 
only become detached from the parent rock, but are frequently so 
rolled in the process as to simulate pebbles. In tracing the 
normal laminated beds into the fragmental or brecciated type it is 
seen that the former gradually lose their regular appearance, and 
become disturbed by small folds and thrusts, finally culminating 
in a mass of segments more or less detached, and it becomes 
apparent that the breccia has originated in little overfolds which 
have been isolated by small thrust faults. Although direct 
evidence of this origin is not always forthcoming, we occasionally 
see, step by step, every stage in the process, beginning with a 
regular banded rock^ followed by minute folding and small thrust 
planes, partially severing the bands, until at last these processes 
have not only succeeded in brecciating the rock, but have 
culminated in the rolling and rounding of the fragments to such 
an eitent that a pseudo-conglomerate has been produced. 

This type of rock brecciation has sometimes been brought 
about without folding ; instead of fractures succeeding plication^ 
the stresses have resulted in the direct production of movement 
planes, which have isolated the fragments from the main mass. 

Fractukes. — Faults often occur every few yards, both parallel 
to the strike and in oblique directions, with the result that the 
whole rock mass when seen in ground plan presents the appear- 
ance of a huge mosaic. Over the district generally neither large 
faults nor deep folds are common. It would appear that at an 
early stage of the folding process the resistance to the strains 
was so feeble that fractures were readily produced, and in many 
districts reversed faults are as numerous as those of normal 
type. 

Relation of Cleavage to Bedding. — Although the rocks are 
everywhere cleaved, the argillaceous and arenaceous alternations 
are so numerous that the bedding can usually be detected. Be- 
sides the deflection of cleavage in crossing from an argillaceous 
to an arenaceous bed, to which allusion has already been made, 
there is a general tendency for the cleavage to cross the bedding 
somewhat obliquely. The obliquity between cleavage and bed- 
ding is not constant. As the cleavage and folding have both 
been brought about by the same agencies, we see every variation 



STRUCTURES — DIRECTION OF STRESS. 23 

depeDding on the character and carvature of the fold, and the 
obliquity of the cleavage to the bedding will often vary over the 
di£ferent portions of the fold. Although the cleavage is often 
transverse to the bedding, the general tendency has been for the 
beds to be thrown into a set of isoclinal folds with a definite 
general hade, and for the cleavage to cross somewhat obliquely 
at a low angle. The more the folds depart from this general 
hade, the greater are the variations between cleavage and bed- 
ding. (Plate V.) 

Schistose Structures. — Besides cleavage, the slate?, as already 
noticed, are traversed by other structural planes which are 
analogous to those found in schistose rocks. Indeed, in highly 
mineralised areas, such as those on the granite margin, the 
phyllites have often been converted into mica schists, and, given 
the necessary mineralisation, the bulk of the killas of this part of 
Cornwall would readily be transformed into typical crystalline 
schists. 

Direction of Stress.— In spite of various exceptions, the 
constancy of the cleavage dips and the hades of the axial planes 
is so general over the whole region that there can be little doubt 
that the later stresses to which the rocks owe their deformation 
acted from a direction about south-south-east. Over the eastern 
part of the district, where sections are most numerous, a large 
series of observations show that the bedding has an average south- 
easterly dip, and the cleavage, which is somewhat oblique, averages 
about south-south-east. The most marked deviation from this 
general dip is seen on the beds that abut on the granite margin 
between Penryn and Lanner, where the hade is to the north- 
east. The deflection of the strike here is well brought out by 
the greenstone masses ; and it probably indicates the vertical 
uprise of the granite column before it spread laterally as a 
laccolite. Between the granite masses of Cam Marth and 
Carj] Brea and the north coast, the dip is frequently reversed, but 
this may to some extent be due to the presence of granite under- 
lying the killas at no great depth. 

Effect of Superinduced Structures on the General 
Tectonics. — Owing to the folded nature of the killas, the various 
lithological divisions, instead of occupying well-detiQed areas, tend 
to encroach on one another, and lenticles of one division are 
commonly found in the adjacent group. This is more especially 
the case as regards the Portscatho and Falmouth groups. The 
Veryan series occupies but a very small tract on the eastern part 
of the sheet to the north of Gerrans Bay. The granite masses 
of Carnmenellis, Cam Brea, and Cam Marth that are entirely 
enveloped by the Mylor series, are lying in a major fold which 
dies out to the north-east in the vicinity of Truro. The Falmouth 
and Portscatho groups, in spite of irregularities due to lenticular 
inclusions previously referred to, sweep round this irregular curve 
cf the Mylor group, from the north-west coast to the south-east 
coast, and occfupy between them not only most of the northern 
part of the map, but the greater portion of the eastern area lying 
beyond Truro and the Carrick Roads. If, as appears probable, the 



24 TU£ KILLAS. 

Veryan series represents the top of the sequence, the major fold 
woald be an anticline. 

The characteristic structure of the district is well illustrated in 
the area between Falmouth and Truto. Here, although we are 
apparently crossing the strike from the coast to the heart of the 
county with a steady south-easterly dip, yet instead of getting 
deeper in the stratigraphical sequence, we are on precisely the same 
geological horizon at Truro as at Falmouth, the intervening 
ground being made up of a succession of isoclinal folds. 

The general features of the killas having now been described, 
the two succeeding chapters will be devoted to a brief sketch of 
the distribution and field relations of the various divisions, to- 
gether with any local points of interest that they present. 



25 



CHAPTER IV. 

LOWER PALiEOZOlC. 

I. Mylor Series. 

This division of the killas occapies a large area on the south- 
western portion of the map. It encloses the granite masses of 
Garnmenellis, Cam Brea, and Carn Marth, the various green- 
stoneS) together with the greater portion of the elvan dykes. It 
contains^ moreover, in conjunction with the granites, almost the 
whole of the mineral lodes. The group, therefore, has not only 
been metamorphosed by the granites for large distances from their 
margins, but has been fissured to a much greater extent than the 
other divisions, and has over large tracts been impregnated by 
mineral solutions that have affected the nature of its decomposi- 
tion. This is especially shown by the iron ozide with which it 
has often been richly charged, and by the amount of vein quartz 
that is frequently so abundant as to impoverish the soil. This 
group^ which is succeeded by the Falmouth series, contains few 
infolds of that division, in striking contrast to the Portscatho beds. 
In the area between Perranwell and Falmouth, beyond the limit 
of the granite aureole which is here of slight extent, the group is 
seen in its normal condition, lying outside the tracts of important 
mineral alteration. This district, therefore, will be described first. 

As pointed out in a previous section, this division is essentially 
an interlaminated series, in which the ribbon-like structure is 
often modified by brecciation^ that has been set up by the 
stresses which have folded, cleaved, and fractured the killas. 
This minute type of brecciation presents every variation : from 
beds in which the fragments are rare, to others in which this 
structure so far predominates as to pervade the whole rock mass. 
This superinduced structure, however, instead of producing a rock 
of incohesive type, has generally had just the opposite eff'ect, so 
that the series, notwithstanding its broken condition, has a more 
homogeneous and massive appearance than the less heterogeneous 
Portscatho group. 

These beds are exposed along the shore of Falmouth Harbour 
from Arwenack to the Penryn Creek. In the section between 
the piers at Market Strand and Greenbank they are of the 
brecciated type, in parts so coarse that some of the fragments 
exceed 2 inches in length. As the stone has been largely 
utilised for building purposes^ the structure of the Mylor crush 
breccias can be admirably studied in the blocks contained in 
the walls and buildings. The railway cuttings between Falmouth 
and Penryn also afford sections of the different phases of the 
Mylor series. The cutting, for instance, between Kimberley 
Park and Penmere, shows these slates dipping south-east, with 
fine pale coloured siliceous partings, and brecciation in its initial 
stage. The cleavage is regular, and traverses the bedding. 
Similar beds, but without brecciation, are seen in the cutting at 



26 liOWKR PAUBOEOIC. 

Tregenver. The partings, when of a siliceoos character, give a 
massive character to the section. The rocks are frequently very 
dark in colour, and must contain much carbonaceous material, as 
in the railway cutting north of the bridge near Tresoobeas. 
Frequently the beds are purely argillaceous. 

Grood sections are exposed along the Penryn Creek, at the 
upper portion of which the dips frequently change their direction. 
Between Boyers Cellars and Tehidy Terrace, and also on the 
north side of the creek, the brecciated type is seen, and when 
fine sandy beds alternate with argillaceous, the folding is at once 
appaient. On the north side of Grreenbank Quay typical brecci- 
ated beds, with fragments from 2 to 3 inches in size, are 
succeeded by banded slates in which the dark and pale layers are 
from 2 to 3 inches thick. In the same vicinity two outcrops of 
fine-grained greyish-blue qoartzite occur, about a foot in breadth. 

The old quarry adjoining the High Street at Flushing has 
been worked in brecciated Mylor slate. It is a coarse, massive 
detrital rock, in which the fragments are angular, sub-angular, 
and rounded, and range to an inch in size and even larger. The 
individuals are of argillaceous or of fine-grained quartzose 
material, and the matrix is massive. The rock has been sub- 
jected to movements and is highly disturbed, and even on the 
small scale minute puckering is general. The cleavage planes 
usually curve round the fragments but traverse some of the 
argillaceous individuals. 

The coast between Flushing and Trefusis Point aflfords an 
excellent dip section that is more or less continuous and easily 
accessible. Commencing at Wheal Clinton, brecciated slates 
appear in which fragments of slate, some dark in colour, are 
embedded in a pale greyish-green matrix. These are succeeded by 
very dark argillaceous slates, in which the striping, although 
visible, is of a very fine character. This dark, carbonaceous- 
looking rock is replaced about 150 yards west of the quay by 
striped grey and blue slate much fractured and disturbed, with 
some quartz veining. East of the quay these fissile beds are 
succeeded by greenish bands, rather massive, and containing the 
pebble-like fragments due to brecciation. These again are re- 
placed by hard slates, much faulted, and veined with quartz, in 
which small pebbly beds occasionally appear. At Trefusis Point 
fine sandy bands alternate with blue argillaceous slates, and 
striping is conspicuous, especially in the latter. The sandy beds 
frequently reveal the isoclinal folding. The cleavage-dip along 
the whole section is to the south-east, varying from 30 deg. to 
45 deg., but minor faults and folds are so numerous that the dip 
is most incouEtant. On the shores of Mylor Creek the brecciated 
beds or pseudo-conglomerates are well seen, alternating with more 
argillaceous zones in which this structure has not been developed. 
On the north side of that creek, and about one-third of a mile 
south-east of Mylor Bridge, the beds have an unaltered appear- 
ance, and contain a seam of massive mudstone 2 or 3 feet in 
thickness. This, submitted to microscopic examination (3,573) 
proves to be a tine micaceous shale, with very small angular 



BfTLOB SERIES. 27 

fragments of quartz, scales of mica^ and dark carbonaceous streaks, 
which give the rock a well-defined bedding. 

The quarrj at Enys presents a good illustration of the inter- 
laminated character of the Mylor series, where it has not been sub- 
jected to the brecciat ion that has evolved the crush conglomerates. 
The slate is very massive, and coarsely stripeil ; the cleavage 
and bedding planes both hade to the south-east, the former at 
45 deg.y and the latter at 25 deg. It consists of alternations of 
pale and dark material, the latter being always argillaceous, while 
the former varies from argillaceous to siliceous. The pale bands 
predominate, and are often half an inch in thickness. This com- 
posite structure enables the fractures and folds to be readily 
detected. The brecciated structure is absent, but where the pale 
laminations are severed by small shear planes the first stage in 
the process has been set up. 

The pseudo-conglomerates are conspicuously developed along 
the southern shore of Restronguet Creek. Commencing at Weir 
Point, the slates are brecciated. Below Weir Villa thin bluish 
argillaceous rocks enclose flattened lenses of rather harder 
materials, but the slate here is fairly homogeneous, without 
bedding planes. A little further west, just before reaching Post, 
a brecciated structure appears, which is more pronounced, bow- 
ever, in the vicinity of faulting. To the west of Post, and 
immediately opposite Restronguet Point, the slate is massive and 
homogeneous, with u cleavage dip of 35 deg. to east-north-east. 
A little further up the creek the beds are well striped, both in 
thin laminations and in coarser seams an inch in thickness, of 
pale argillaceous, alternating with dark seams. Brecciation here 
is slight, and the mass is fairly homogeneous. The cleavage, 
which is still in the same direction, crosses the bands at all 
angles. The massive blue slates with occasional striping, and 
often studded with cubes of pyrites, continue to the Ship Inn. 
At the quay similar beds occur with a low cleavage dip to 
east-north-east, and are striped. The dominant cleavage here 
is often at right angles to the bedding, which is puckered, while 
the cleavage planes are regular. The quartz veins, moreover, 
have shared in the folding. In the neighbourhood of a fault, 
carrying a quartz vein, 1 foot in thickness, brecciation again 
appears. 

The striped slates, much disturbed with faulting and folding, 
can be followed along the shore to the bay below Tregunwitb, to 
the south of which some greenstone bands and an elvan occur, all 
in a highly decomposed condition. On the north side of this bay 
the interlaminated character of the beds is pronounced. The dip is 
itregular, as the bands are much folded. These contorted zones 
alternate with others of regular hade, but the former predominate. 
Occasionally bands with brecciated slate appear about a foot or so 
in thickness, the isolated fragments being clearlj^ due to rocK 
fracture. These pseudo-conglomerates soon get more conspicuous, 
but are still subordinate to the normal rock type. 

At Restronguet Point the coarse brecciated structure is ex- 
ceedingly well developed* (Plate VI.) Fragments up to an inch 



28 LOWER PAL^^OZOTC. 

or more in length are profusely scattered in a darker matrix. 
Amongst the argillaceous beds thin gritty seams are observed, in 
which deformation has commenced. The killas here has been 
so involved in these movements that in many places the entire 
rock mass has undergone mechaDioal reconstruction. The 
structures are analogous to those of schistose rocks, but have 
stopped short at these mechanical processes. Chemical changes 
have, however, been initiated, as in many parts of this section the 
slates have been converted into phyllite, with micaceous lustre 
clearly defined. The brecciated structure is most pronounced 
where the fragments are of a quartzose nature, as being less 
flattened they protrude from the rock surface. Some quartz 
veining occurs in the section which has been involved in the 
folding. Occasionally a coarser bed occurs revealing the dip; 
these limbs, however, are generally parallel to the dominant 
cleavage. On the side of Restronguet Point fronting the Carrick 
Beads numerous small faults, slightly oblique to the strike, are 
seen to repeat the beds. Indeed, the whole section proceeding 
north along this coast is of a most disturbed and plicated 
character, consisting of a series of segments and lenticles that 
have been torn from the original homogeneous mass. In this 
brecciated series there are, nevertheless, some zones in which such 
deformation is absent. This is seen about 200 yards north-east 
of Bestronguet Point, where the undisturbed seam is a hard, dark 
arenaceous bed. The disrupted condition of the section, as well as 
its re-duplication, is clearly illustrated by a quartzite seam which 
occurs along the coast for a distance of about a third of a mile 
from Restronguet Point. This quartzite is about a foot in thick- 
ness and is probably related to the quartzite already referred to, 
at the entrance to Penryn Oeek, near Greenbank Quay. It is 
rather dark in colour and is often associated with much vein 
quartz. The quartzite, instead of forming a continuous seam, is 
represented by a series of detached lenticles, some of which are 
several feet in length. At its most northern exposure the 
quartzite has been folded on itself, causing thickening, but in 
places the limb thins out entirely. The " head " which fringes 
the shore here contains at its base some lenticular blocks of 
quartzite about three feet across. 

A quartzose band from Carclew, a specimen of which was sliced, 
shows under the microscope (3,389) fragments of organisms which 
Mr. E. T. Newton believes to be pieces of much altered echino- 
derms, perhaps crinoids. Dr. Flett considers that the rock has 
the appearance of a modified chert. 

From Restronguet Creek the Mylor beds swing round to the 
north-west of the map, as already indicated, in conformity with the 
Falmouth and Portscatho groups, the Mylor beds forming the 
inner zone. From Restronguet Creek they extend to Carrine 
Common, near Truro, whence they curve round to the west 
through the districts of Baldhu, St. Day, and Scorrier, to Stencoose 
and Mawla. Thence they follow a south-westerly course through 
the parishes of Redruth, Illogan, and Camborne. From Camborne 
they extend southwards through the districts of Crowan and 



FALMOUTH SERIEa 29 

Breage, occupying the area between the margin of the Carn- 
menellis granite and the western edge of the sheet. Over the 
greater part of the area between Baldha and Camborne they are 
highly decomposed^ their surface debris being stained deep red 
and varioas shades of buff by the iron oxides with which they are 
frequently charged in the mineral area. In the south-western 
portions of the sheet, however, in the parishes of Breage and 
Sithney, this discoloration is comparatively rare, and the rock is 
often extremely fresh at the surface. That part of the Mylor 
series which more immediately fringes the granite masses will be 
treated separately in the section dealing with the contact 
metamorphism produced by those granites. 

Mr. F. J. Stephens* has recorded various localities between 
Trefusis Point and Penryn where radiolarian cherts occur. These 
have since been supplemented by Mr. Howard Fox.f The micro- 
sections were submitted to Dr. G-. J. Hinde» who determined some 
of them to be full of radioiaria^ although the rock shows evidence 
of great distortion. 

II. Falmouth Series. 

On the southern side of Falmouth a strong band of this series 
extends from the Pendennis peninsula to Swanpool and Penrose. 
From the latter locality to Carlidnack it contracts, but widens 
again in the neighbourhood of Mawnan Smith, where it is con- 
tinuous with a band that reaches the coast between Maen Porth 
and High Cliff. It can thus be demonstrated that the Falmouth 
and Maen Porth bands, separated by the Portscatho slates between 
Pennance Point and Maen Porth, are in reality a single unit 
repeated by folding. The coast between Swanpool and the 
vicinity of the Falmouth Hotel presents an excellent section 
of this group, and was described by De la Beche as a variegated 
8eries4 The prevailing blue colour of the adjoining Portscatho 
group has been replaced by tints that vary from green to grey and 
buff, although blue argillaceous bands are still to be seen amongst 
them. The deep cliff sections^ moreover, frequently display a 
reddish hue from the presence of iron oxide. The strata consist 
of alternations of argillaceous and fine sandy material, the colour 
varying with the character of the sediment; hence the general 
variegated appearance of the series. The weathering is equally 
characteristic ; the beds become extremely friable, especially those 
of a sandy nature, and assume a deep buff colour. Lamination 
is sometimes conspicuous, thus Unking them with the Mylor 
beds on the north-west. Although there is a general dip to the 
south-east, the section shows a high degree of disturbance. The 
amount of minor contortion and fracture is such that a most con- 
fused section is the result, and this is accentuated by the presence 
of much quartz veining. Within this series a small zone of 
sharply contrasted purple and green slate is seen in the large dry 

• Eoyal Cornwall Polytechnic Society ^ 1897, p. 104. 

t From unpublished information furnished by Mr. Fox. 

X ** Report on the Geology of Cornwall," &c., p. 93. 



30 LOWER PAUBOaSOIO. 

dock at Falmotitb. Three purple bands, one of which ii 10 feet 
in thickness, are separated by green slate. 

On the eastern side of the Carrick Roads an infold of the 
Falmouth series occurs within the Portscatho beds. It forms a 
strip skirting St. Mawes Harbour between Castle Cove and 
Polvarth Point. Here the buff beds seen at Falmouth are 
practically absent, and the rocks are distinguished from the 
adjacent Portscatho group^ into which thev insensibly merge, by 
pale greenish hues, which not only pervade the killas but also occur 
occasionally amongst the quartz veining. Like the band, how- 
ever^ at Falmouth, the slaty beds here contain the characteristic 
purple and green zone, which is exposed at Castle Point, and 
again on the shore to the north-east of the quay at St. Mawes. 
The section between St. Mawes and Polvarth Point illustrates the 
constant rej)etition by folding. Being transverse to the strike, 
the various fluctuations in the plication are brought out, and 
notwithstanding that the beds are often nearly horizontal, with 
slight undulations as exhibited by the harder sandy bands, the 
prevailing dip of the various limbs, whether regular or contorted, 
is to the south-east. 

Further to the north a band of variegated buff and green beds 
occurs at St Just Creek. They are much crumpled, and in places 
show small thrusts from the south-east. About half a mile north 
of Messack Point the typical purple and green slates form a small 
belt, into which a mica trap has been intruded. Another band of 
the Falmouth series occupies a strip running nearly south to the 
coast from Camerance Wood, where purple and green slates are 
exposed. Near Tumaware Point a band occurs containing purple 
and green beds, pale greyish green slate, and some of the 
buff beds. From the amount of plication exhibited there can 
be little doubt that they represent isolated lenticles due to 
folding. To the west of Philleigh, a band which passes through 
Polmesk can be traced by the purple and green slate, both in the 
solid condition and as surface debris. Between Buan Laaihorne 
and Philleigh an extensive strip of Falmouth beds occurs in which 
the sandy buff beds predominate, but the purple and green bands 
have not been noted. Along this comparatively low-lying land 
they disintegrate more rapidly than the Portscatho group which 
they adjoin, and thus form a deeper soil, as can be well seen at the 
promontory at Ardevora Veor, which stands higher than the land 
further east ; the former being occupied by the Portscatho series 
and the latter by the Falmouth beds. The lenticles that occur 
still further east, at Trenestrall and Treworga, are characterised by 
the typical buff beds, but as they appear to be intermixed with 
some Portscatho slate the boundaries drawn are necessarily 
general. Between Merther and Trevervoe buft beds of this type 
occur infolded with the Portscatho group, but whether they form 
a continuous band or consist of a line of lenticles the evidence 
is insufficient to show. The infolds of this group amongst the 
Portscatho series between the Truro River and Feock call for no 
special comment ; they consist of the usual variegated and buff 
beds of this series. At Malpas, however, the Falmouth beds are 



FALMOUTH SERIES. 31 

associated with some of the greenish and purple bands that still 
farther define the horizon. 

We will now more particularly refer to the occurrence of the 
Falmouth beds on their true geological position, separating the 
Portscatbo from the Mjlor group. Their position at Falmouth 
between those groups has already been referred to. These 
marginal relations are then broken by the estuary of the Carrick 
Roads, at the head of which, in the district of Feock, the geo- 
logical sequence, represented by the My lor, Falmouth, and Ports- 
catbo groups, sweeps round in a big curve to the north-west, the 
apex of which lies in the neighbourhood of Truro. This great 
fold, is, of course, complicated by the general isoclinal plication 
and accompanying fracture that has involved the whole area. In 
spite of this disturbing element, however, the larger fold is 
sufficiently brought out by the mapping, showing an inner ring 
of Mylor beds partially encircled by the Falmouth and Portscatbo 
groups respectively. Notwithstanding this generalisation, how- 
ever, the marginal lines are necessarily irregular, on account of 
the disturbing elements already referred to. Thus the subdivision 
of the killas is often a matter of great difficulty, owing to the 
impersistence of lithological types, and in some cases to their 
close resemblance to one another. Not only do the Portscatbo 
and Mjlor groups sometimes shade into types that are practically 
indistinguishable, but the Falmouth group which divides them, 
and on the whole exhibits a stronger lithological contrast to 
either, is not always persistent in character. Nevertheless, the 
correct identification of the Falmouth group furnishes the key to 
the interpretation of the major geological structure of the area. 
Notwithstanding the many fluctuations in lithological condition 
exhibited by this series, the Falmouth beds are evidently much 
thinner than the Mylor and Portscatbo groups which they 
separate, so that in some areas, where the surface geology is 
obscure, they either cannot be identified at all or their recognition 
is attended with much uncertainty. In mapping this group, 
however, the presence of the purple and green zone in any 
recognisable form is of the utmost value, and fixes the horizon 
with precif^ion. So far is this the case that a band of this nature, 
however narrow, and unaccompanied by the more general buff 
and decomposing strata of Falmouth type, would be confidently 
interpreted as unmistakable evidence of the geological horizon. 

The Falmouth beds will now be briefly described in their passage 
round the great fold in their relation to the Portscatbo and Mylor 
groups which they divide. In the neighbourhood of Feock and 
Restronguet Creek,although all three groups are in close proximity, 
their, boundaries seem to be marked by north-westerly faults, the 
evidence of which is clearly seen along the banks of that creek. 
Between Porthgwidden and Restronguet Point a fault if; seen with 
three or four feet of vein breccia, which apparently brings the 
Mylor and Portscatbo beds in juxtaposition. On the north side 
of Restronguet Creek a strip of the Falmouth beds fringes the 
coast for about half a mile, extending as far north as Pen Poll 
Creek; it succeeds the Mylor beds, but its relations to the 



S2 LOWER PALEOZOIC. 

Portscatho group are not seen. The Falmoath beds are not again 
recognised between this and the north of Carnon Downs, near 
Killiganoon, and if they occur can only be feebly represented. 
They are probably cut out by a fault extending from the north 
side of Carnon Downs to the south side of Feock Downs. In this 
band they are far from typical^ and good sections are rare. 
Between Killiow and Truro the band cannot be satisfactorily 
followed owing to the absence of sections, and to some extent also 
to the nondescript character of the rocks. In the neighbourhood 
of Truro this group is strongly represented by deep sections of 
the characteristic bright buff beds, highly decomposed^ that 
alternate with the fresher and more solid blue slates of the 
Portscatho group. The irregularity of the outcrops at Truro is 
due to the nose of the major fold acting on the close isoclinal 
plication, and to the broken nature of the topography represented 
by the extensive valleys that radiate from that centre. From 
thence to Chacewater the band extends in a westerly direction ; 
it is necessarily very generalised, and contains portions of the 
adjacent groups which cannot be separated. Over a great part 
of this belt the country is flat and practically devoid of sections, 
more especially in the district lying to the north of Chacewater. 
Moreover, the mineralisation in these metalliferous areas has 
contributed to obscure the nature of the killas. Here and there, 
however, traces of the purple and green zone have been noted. 
Purple and green detritus is also seen at Creegbrose, and between 
that locality and Grreystown. On a mine burrow at Cox Hill, just 
within the Mylor group, some large blocks of purple and green 
slate were observed that had apparently been raised from the 
mine. Moreover, De la Beche records the occurrence of this kind 
of slate in the mines at Grwennap.* So far as it goes, therefore, this 
might be taken as evidence of the superposition of the Mylor 
beds to the Falmouth group, and that the sequence from the 
Mylor series to the Veryan beds may be a descending succession, 
but the area is too folded to warrant such a deduction. Perhaps 
the best section of the Falmouth beds in this locality is 
that formed by the road cutting at Green Bottom, on the north 
side of Saveock Water. Between Blackwater and Parsley they 
have not been detected, a fact due perhaps to the paucity of 
sections, but they may possibly have been cut out by the fault 
that meets the coast at Porth Towan. From Parsley, however, to 
Beskajeage Downs on the north coast, and to Treswithian Downs, 
the purple and green beds are abundantly developed, and the zone 
has been traced by Mr. Dixon between the Mylor and Portscatho 
groups. 

The purple and green huf»s so characteristic of this formation 
are well exhibited in the north-western region in the cove south 
of Gully n Rock, in quarries between the latter and North View, 
and in the cliffs facing Beskajeage Downs. Inland the colours are 
seldom clearly seen, so that the boundary between these slates and 
those of the Mylor beds is not well defined. 

The sole organic remains at present known from the Falmouth 
beds are the radiolaria, discovered by Mr. Howard Fox, near 

* Report previously cited, p. 93. 



PORTSCATHO SERIES. 33 

Middle Point, Falmouth, to which attention has already been 
drawn. 

III. PORTSCATHO SERIES. 

This series immediately succeeds the Veryan group in a 
westerly direction. Its principal distinguishing feature from 
the latter is the total absence of limestone^ except at their 
mutual junction. Although the coast line south of Pendower 
forms the boundary of this series, yet small calcareous layers, 
linking it with the Veryan group, are seen along the shore as 
far south as Creek Stephen. The true boundary between the 
two divisions possibly includes a little of this southern coast 
line. The natural transition between the Veryan and Poitscatho 
types along the shore between Pendower and Creek Stephen 
Point is suflBciently attested by the gradual dying out of the 
limestone. Excellent cliflF sections of the Portscatho series are 
exhibited between Grerrans Bay and the Zoze Point. Estuary 
sections of shallower depth are continuous for several miles along 
the various creeks converging to the Eiver Fal and the eastern 
side of the Carrick Roads. On the north coast this series can be 
studied along the shore for at least four miles between Porth 
Towan and Reskajeage Downs, 

The section between Pendower and the Zoze Point admirably 
illustrates the disturbed nature of the killas. The beds are 
frequently wavy, while the sandy seams reveal the curving and 
nosing out of folds. Faults often occur every few yards, and 
even feet : either of normal type coincident with strike or dip, or 
small reversed faults or slides hading at a low angle. They 
appear to have but small throw, often being limited to a foot or 
so. The picturesque caverns which make a feature of this coast 
have been formed along the strike faults. Vein quartz is often 
very abundant, and has frequently shared in the folding. Here 
and there the argillaceous beds show striping like that seen in 
the My lor series. In the neighbourhood of faults the clay slates 
sometimes take on a phyllitic aspect. Notwithstanding the 
general south-easterly dip, the coast is so broken by faults that 
there are numerous deflections, both as regards direction and 
hade, beds comparatively flat being closely adjacent to those 
highly inclined ; others, again, with even bedding, are sharply 
succeeded by strata highly contorted. The Shag Rock at St. 
Anthony Head afl'ords an excellent section of the constant 
repetition by small folds and faults hading to the south-east. 
At the Lighthouse, although the individual beds are folded, 
there is a steady cleavage dip. 

The Portscatho beds from the St. Anthony peninsula re- 
appear at Pendennis Point on the western entraiice of the 
Carrick Roads, and are seen also on the Black Rocks which 
project at low water at the mouth of the harbour. At Pendennis 
Point they occupy a strip about a third of a mile wide when 
they merge into the Falmouth beds. The Pendennis section 
is a repetition of that of St. Anthony, being made up of 
fairly haid, wavy, argillaceous slates, with sandy alternations. 

D 



34 LOWElEl PALEOZOIC. 

There is a moderate amount of vein quartz, and small faults are 
numerous, especially those following the trend of the strike, 
along which gullies, locally known as ^^drangs," have been 
excavated on the coast. This band, after crossing Falmouth 
Bay, re-emerges close to Pennance Point, and is admirably dis- 
played on the coast section from thence to Maen Porth. At Pen- 
nance Point the beds are fairly free from contortion. They are 
hard, and of the nature of fine arenaceous slate, being well cleaved, 
with regular linear striping, but without the conspicuous sandy 
alternations. Between Sunny Cove and Newporth Head the 
typical dark blue argillaceous slates reappear, with a dip of 
48 deg. to the south-east, and a cleavage dip of 60 deg. in the 
same direction. (Plate VI.) At Newporth Head the finely 
quartzose beds recur with a brown weathering, and producing an 
uneven rockshelf. 

On the eastern side of the Carrick Soads the continuity of the 
Portscatho series is broken by no less than five infolded len- 
ticles of the Falmouth beds, and others occur south of the 
River Fal between Buan Lanihorne and Philleigh. The tract 
between the Eiver Fal and the Tresilian River is almost entirely 
confined to the Portscatho group, except for a strip of Falmouth 
slate between Merther and Trevervoe. West of the Fal several 
infolds of the Falmouth beds occur between Truro and Feock. 

In this broad tract between Truro and Grerrans Bay the con- 
stancy of the dips of both cleavage and bedding in a south- 
easterly direction is well marked. Notwithstanding contortion 
and small faults, which are as frequent as on the coast section at 
Gerrans Bay, it is unusual to find the dip reversed. In spite also 
of the fractured nature of the district, as indicated by the in- 
numerable small faults, there is no evidence in this wide tract of 
the existence of faults of sufficient magnitude to be shown on 
the map. It is true that the uniform nature of the strata is un- 
favourable for their detection, but the many miles of section 
afforded by the estuaries would be expected to reveal fault 
breccia if fractures of any magnitude were present. Moreover, 
the absence of elvan dykes and mineral lodes, tends to confirm 
the conclusion that fissuring on the large scale is not prevalent 
in this district. 

The killas, which is so frequently decomposed in inland sections 
for some depth from the surface, presents in some localities ex- 
posures that are singularly fresh. This is especially the case in 
the parishes of St. Michael Penkevil, St. Clement, and Merther. 
The Portscatho beds usually weather to different shades of brown, 
but in the mineral areas, like the rest of the killas, they fre- 
quently become deep red from the oxidation of the iron ores, 
and shades of rich buff and even very pale whitish grey are also 
common. 

At Governs, about 2^ miles west-north-west of Truro, some 
very massive greenish slate is seen in a quarry. The massiveness 
of the rock is due to its silicification, which takes the form of fine 
interlaminations of quartz between the argillaceous folia that at 
first sight suggest original bedding, as they share in the undula- 



PORTSCATHO SERIES. 35 

tions of the rock. Bat the silicification has followed the folding, 
although it has taken advantage of the lamination with singular 
regularity. At times^ however, patches of phjllite are seen 
entirely enclosed by quartz, while isolated quartz fragments point 
to a certain amount of brecciation. As this quarry occurs in the 
vicinity of abandoned mine workings, it is possible that the 
unusual green hues are due to secondary mineralisation. Still 
further to the westward, between Croft West and Treveskas, some 
of the Portscatho sandy beds are similarly tinted with a greenish 
hue, but this is also in the vicinity of a mineral lode, and a little 
of the argillaceous rock exhibits tiny knotting. Thence to the 
westward the mineral area has been reached, and the reddening of 
the surface rocks is a common feature. Moreover, this coloration 
is sometimes accompanied by greenish hues, which, beyond 
the area of mineralisation, would have led to the supposition that 
the debris was derived from Falmouth beds. 

Within the mineral region the evidence of colour is no 
longer a safe criterion in mapping the lithological divisions, and 
has to be used with caution. Thus, large tracts of the mineral 
area lie in comparatively^ flat country, buried under a covering of 
decomposed rock or debris, which is variously coloured by iron 
oxides, as in the area surrounding Chacewater, Blackwater, and 
Skinner's Bottom. In these districts, however, the contents of 
the mine-burrows often aflford good evidence of the nature of the 
underlying killas. For instance, to the north-west of Carnhot, 
where the surface debris is often of a red and greenish tint, 
the mine tips show the solid rock to belong to the Portscatho 
group, though often very pale in colour, due to bleaching. 
Occasionally, however, the argillaceous members are more 
interlaminated than in the typical areas. Further to the 
west, in the district of Blackwater, the evidence of the burrows 
shows this interlamination to be a common feature, and it 
retains this characteristic in its westerly extension to the north 
coast. The depth of the decomposition and mineral staining is 
well seen in the cuttings of the new railway connecting Chace- 
water with St. Agnes. The cutting at Blackwater affords a 
vertical section from 12 to 20 feet deep, in which the sandy and 
argillaceous beds are stained deep red for the entire depth of the 
exposure. In spite of the obscurity caused by this soaking in 
iron oxide, the resemblance to the Portscatho type is sufficiently 
retained, while folds and small faults are often seen. The red 
staining is sometimes replaced by buff hues. The fault planes 
contain little quartz, but are often richly charged with hematite. 
The reddened slate, moreover, sometimes suddenly ceases, and 
is succeeded laterally by bluish slate, in which the upper surface 
is often of a buff colour for a depth of 2 or 3 feet. Some of the 
fine bleached arenaceous beds readily crumble into a clay-like 
substance. 

Mr. Dixon has observed that the Portscatho series of Perth 
Towan pitch to the south-west, and disappear in that direction 
beneath the Falmouth beds. Along the northern margin of the 
Portreath mass the cleavage generally inclines north-north-west, 

d2 



36 LOW£B PALJBOZOIC. 

while north-east of Portreath the folds are generally inclined to 
the sonth-south-east. In the cliff south of Gallyn Bock^ and 
beneath Tregea Hill^ slides of different inclinations intersect, and 
the steeper faults hading south disturb the others, which incline 
to the north. At the latter locality the later faulting is clearly 
of normal type. 

The most conspicuous cross courses seen along the northern 
coast are as follows: Cliff, south-west of Tobban Horse (2); 
Cove, south of Gullyn Bock (1); Cove, south of Gooden Heane 
Point (2); Porthcadjack Cove (l). With the exception of one 
of those occurring at Tobban Horse, they all hade to the west. 
Their throw is not known ; they are accompanied by thick vein 
quartz, and most of them discharge water. A little iron, lead, 
and copper staining is the sole indication of their metalliferous 
contents. In several cases valleys have been eroded along lines 
of fault. 

Along the northern edge of the map this division of the Lower 
Palaeozoic group is unconformably overlain by the Probus series 
of the Lower Devonian formation, and their marginal relations 
are described in the chapters devoted to the latter. 

Under the microscope the Portscatho slates show no character- 
istics of special interest. The argillaceous seams can be seen to 
contain minute grains of quartz, together with films of biotite 
and muscovite (3,392)4 Sometimes, besides cleavage, a well- 
defined parallel structure representing bedding is seen, and there 
is occasionally minute brown staining, due to iron oxide (3,574). 

The grit bands are principally composed of quartz, mica, and 
slate fragments. Felspar also occurs, but in small quantity as 
compared with quartz. 

The small dark concretions of nodular form that are often 
scattered in the slate are quartzose lenticles, consisting chiefly of 
very finely granular quartz with a few larger grains, and only 
imperfectly cleaved. 

Mr. J. H. Collins has recorded the presence of corals at Lower 
Newham, in the neighbourhood of Truro. The late Dr. P. M. 
Duncan, to whom he submitted specimens, suggested that the 
markings on the surface of some of the schistose planes resembled 
infiltrated corallites of a genus like Favosites, and concluded that 
it was probably a metamorphosed coral.''^ 

The siliceous schist containing these suggested coralline mark- 
ings was analysed by Mr. Collins, with the following result : — 

a. 6. 

Silica ------ 

Ferric oxide and alumina 
Magnesia - - - - - 

Lime ------ 

Phosphoric acid - - - - 

Moisture ----- 



66^81 


69-88 


27-21 


23-28 


•75 


M7 


•08 


•15 


trace 




5-62 


6-11 


100-47 


100 59 



* Journ, Roy, Trut Cornwall^ vol. viL, p. 31. Messrs. Upfield Green and 
Sherborn, however, regard the structure as inorganic. 



VERYAN SEBIES. 37 

Mr. Colling suggests that the low percentage of lime is due to 
ohange in chemical composition since the formation of the rock.* 

Mr. C. W. Peach found part of the stem of an encrinite at 
Truro, in a quarry near the Patent Wood Works, where he also 
observed other indistinct fossiliferous marks.f 

IV. Very AN Series. 

This group is restricted on the map to a triangular tract of 
about half a square mile lying to the east of the valley connecting 
Pendower and Crugaillick. An excellent section is afforded by the 
coast of Grerrans Bay, extending from Pendower to the eastern 
margin of the sheet. It is composed mainly of dark slate, with 
subordinate sandy seams, but it is especially characterised by the 
presence of limestone and chert. These members, so hetero- 
geneous in type, are closely associated ; slates, sandstones, lime- 
stones, and chert occurring together in a limited section. The 
sandy beds, moreover, are frequently coarse, but shale fragments 
enter largely into their composition, so that they readily cleave. 
The limestone^ occurs in thin bands, ranging from a few feet to a 
few inches in thickness. This section has been described by Mr. 
Howard Fox,§ who states that the limestones increase in thickness 
and frequency towards the eastern part of the section, which our 
examination confirms. A little to the east of Pendower the lime- 
stone is represented by a few thin seams, which westward become 
still more attenuated as they are traced within ^he Portscatho 
series, where they soon die out altogether, the calcareous zones 
forming the connecting link between the two groups. The lime- 
stones, although containing organic fragments, have failed to 
yield recognisable fossils. The chert beds on the western part of 
Pendower Beach have been figured in the work already cited by 
Mr. Fox, who states that black chert is there seen interbedded with 
shales on the foreshore and also at the base of the cliff, which is 
*' occasionally composed of black chert several feet thick, at other 
times of chert sheared into thin bands, which are more or less 
disturbed." In one place Mr. Fox observed the apparent passage 
of chert into quartz, and he states that '* black chert occurs at 
intervals in the foreshore and cliff for more than 1,000 yards 
eastward," and gradually becomes thinner and less frequent, as 
well as more impure and decomposed. This decomposition was 
attributed by Dr. Teall to the decay of pyrites crystals, which the 
microscope shows to be present in the chert. Micro-sections of the 
chert examined by Dr. Gr. J. Hinde reveal indications of radiolaria 
with marked signs of shearing. In the shales associated with the 
chert crinoidal remains have been found. The Veryan beds yield 
appreciable quantities of manganese in association with oxide of 

• Jounu Roy, Inst, Cornwall^ vol. vL, p. 418. 

t Tra/ns, Roy, Qeol. 8oc. Cornwall, vol. vi., p. 181. 

X Tneae limestones were described in 1818 by Mr. S. J. Trist and the Rev. 
J. Rogers. Tram, Royal Qeol, Soc. Cornwall, 1818, vol. i., pp. 107 and 
114. 

§ Trans, Roy, Qeol. Soc, Cornwall^ 1896. 



38 LOWEK FALJEOZOIC. 

iron, which occar along the divisional planes. Near the western 
end of the section the slates are studded by circular bodies^ some 
of which attain half an inch in size; a specimen, tested by Dr. 
Flett, consisted mainly of impure limonite^ with little or no 
manganese. They are surrounded by a thin periphery of quartz, 
and, owing to the weathering of the decomposed core, they are 
frequently represented by cup-shaped hollows lined with quartz. 
Considering the disturbed state of the slates and the absence of 
distortion in these spherical bodies the latter are not likely to be 
organic. Below high-water mark the slates are very dark in 
colour, at times almost black, while the bulk of the sandy alterna- 
tions are of a pale colour and therefore strongly contrasted. In 
the cliff sections, however, where the beds are more decomposed, 
the weathering of the slates exhibits strong colour contrasts, 
some parts being pale yellow and brown, while seams a foot or 
more in thickness of rusty brown material probably indicate beds 
charged with manganese and iron oxide, the varied colour 
of the phyllite being doubtless due to the presence of these 
oxides in a less concentrated form. A quantitative analysis of the 
manganiferous band undertaken by Dr. Pollard revealed the 
presence of a small quantity of carbonate, in addition to man- 
ganese and iron, and manganese is in excess of iron. 

While the general dip of the beds is to the east, they are 
frequently lying at a very low angle not far from the horizontal, 
with gentle undulations, so that their thickness may be slight not- 
withstanding a considerable breadth of outcrop. 

Mr. J. H. Collins has published an analysis of the limestone.* 
He describes it as " a very dark-coloured rock, occurring in narrow 
bands in the dark slate of Grerrans Bay. It contains microscopic 
organisms in abundance," some of which are fragments of 
encrinite.f The analysis is as follows : — 

SiUca 6-67 

Alumina and ferric oxide .... 2*55 

Magnesia --..... l«7l 

Lime --.-.--- 43*45 

Phosphoric acid .---.- traces 

Carbonic acid --.-_- 39*42 

Moisture 5*69 



99-49 



♦ Joum. Roy. Inst, Cornwall^ vol. vi., p. 419. 

+ Jra^ns, Geol Soc. Comrvall, vol. x., p. 6. Mr. J. H. Collint ** On the 
Stratigraphy of West Cornwall." 



S9 



CHAPTER V. 



DEVONIAN ROOKS. 

GkAMPOUND and PROBtTS SERIES. 

This series, consisting of fine-grained conglomerates, sandstones, 
and clay slates, is slightly calcareous, and is equivalent to the 
Manaccan series that occurs in the adjoining map to the south of 
the Helford River, except that in the latter locality, besides the 
fine-grained conglomerates like those of Probus and Grampound, 
these beds frequently attain an extreme coarseness, many of the 
included boulders exceeding a foot in size. The conglomerate in 
that area is by no means continuous, but the base of the formation 
is frequently of fine texture. There is, moreover, a tendency for 
the coarser conglomerate to die out in a westerly direction, so that 
the demarcation of the Manaccan series from the older Palaeozoics 
id attended with difficulties in the cultivated areas. These con- 
ditions are exactly reproduced in the Probus beds, the coarse 
conglomerates, analogous to those of Manaccan, occurring only in 
the Grorran district to the east of this map, while in a western 
direction towards the coast of the Bristol Ohannel the fine-grained 
conglomerates of Probus disappear. The Probus series likewise 
corresponds in strike with the beds of Manaccan, these lower 
Devonian strata having a general east and west trend, oblique 
to that of the underlying Lower Palaeozoic strata. The fine- 
grained conglomerates of the Probus area were recognised from 
their lithological characters in 1902* as the equivalent of the 
Manaccan conglomerate. This likeness is borne out by micro- 
scopic examination, from which they are seen to contain a similar 
assemblage of rock fragments, resembling one another so closely 
as practically to preclude the possibility of their derivation 
from different sources, or from the same source at widely 
different periods. From these considerations it was at the same 
time recognised that it might represent an unconformity between 
the Silurian or older rocks and the Devonian rocks of Cornwall. 
The detailed investigation of the Manaccan district has proved the 
correctness of that interpretation.! The coarseness of the con- 
glomerate in that area em^bles its constituents to be easily 
identified, and where it is closely associated with the Portscatho 
beds it is seen to be almost entirely composed of fragments derived 
from that series. The fact, moreover, that the boulders were 
veined with quartz prior to their incorporation in the con- 
glomerate sufficiently indicates the magnitude of the break. 

The Probus series follows a westerly course across the northern 



* J. B. Hill. "Summary of Progress of the Geological Survey for 1902," 
p. 25. 

t J. B. Hill. " Summary of Progress of the Geological Survey for 1905/' 
and Geol. Mag,, 190t$, pp. 206-216. 



40 DEVONIAN ROCKS. 

edge of the area to the coast at Forth Towan with an average 
width of a mile. Althoagh no fossils have been found within this 
narrow strip, its northward extension in the adjoining map contains 
Lower Devonian fossils. 

The sandy beds are frequently very tough and highly siliceous, 
and constitute good road metal. They are, moreover, often veined 
with calcite. Their common characteristic, however, is the thick- 
ness of the bands, which may sometimes attain to 20 feet, 
whereas the sandy beds of the Portscatho group seldom exceed a 
few feet in breadth, so that this feature, as well as the coarser 
texture and presence, of lime, help to distinguish them. These 
grits contain pebbles of fioe slate, sandy slate, fine impure grit or 
grauwacke, granular quartzite, sheared quartz, felsitic igneous 
rocks rich in felspar, and fine quart z-felsite, together with pyrites, 
tourmaline, muscovite^ chlorite and limonite. The igneous 
pebbles sometimes include fluidal felspathic rocks, which Dr. Flett 
considers to be probably trachytes or orthophyres. Pebbles of 
felspar often occur in large numbers (3,870).* A specimen from a 
more quartzose type (3,871)* contains pebbles of quartz, orthoclase, 
oligoclase, felsite, and fine grit, lying in a fine quartzose matrix. 
There is less slate and fewer igneous fragments than in the 
preceding, but one or two small pieces of the characteristic 
igneous rocks are to be found, together with the sheared meta- 
morphic quartzite. 

The discontinuous nature of the coarser beds and the frequent 
paucity of rock sections has precluded its boundary being traced 
with accuracy ; nevertheless, its east and west trend is suffi- 
ciently apparent, as a glance at the map will show ; and in 
spite of the general absence of its coarser representatives, the 
group forms more elevated features than the Lower Palaeozoic 
tract. At Perth Towan, where it reaches the coast, it is separated 
from the Portscatho group to the south by a fault. The latter 
group consists of sandy and argillaceous beds ; while on the north 
side of the fault sandstones are rare, although some of Hhe fine- 
grained sandy silts weather out into conspicuous bands from the 
argillaceous alternations. These beds are, moreover, slightly 
calcareous, and effervesce with cold hydrochloric acid, both as 
regards the normal rock and the small brown veins that ramify 
through it. 

♦ These apecimeni were obtained from the area closely adjacent in Shoet346. 



41 



CHAPTER VI. 



IGNEOUS ROCKS. 
I. Greenstone. 

The greenstones that occur within this area are largely refer- 
able to the group of epidiorites. Taking Cornwall, however, as a 
whole, these rocks could not be conveniently classed with the 
latter, as many of them still retain original augite. It has been 
found convenient, therefore, to retain the older synonym, which is 
suflBciently wide to embrace the various petrological types that are 
nevertheless linked together by close ties of affinity. 

The dominant minerals in these rocks are hornblende and 
felspar, while chlorite, biotite, epidote, iron ores, and quartz form 
the most important accessories ; augite, garnet and axinite are in 
this area exceptionally present. They occur in elongated sill- 
like masses, some of which attain considerable size. As they 
have been involved in the earth movements that have affected 
this region, they have to a very large extent shared in the process 
of deformation to which the slates have been subjected. More- 
over, their great development within the granite aureole of con- 
tact alteration has involved thermal metamorphism in addition. 
As the result of these changes they have often been profoundly 
modified, both as regards structure and mineral composition. 

So far as this area is concerned, there is no good evidence that 
the grou^ contains either lavas or tuffs. The coarser varieties are 
almost certainly intrusive, and the absence of well-defined ash 
beds points to the conclusion that the Palaeozoic sediments of this 
part of Cornwall were unaccompanied by volcanic products. On the 
other hand, the decomposition of these greenstones and the adja- 
cent killas obscures the junctions. Moreover, the mechanical 
deformation to which the rocks have been subjected still farther 
masks their mutual relations ; whilst, finally, the paucity of marginal 
sections is such that deductions based on such data are far from 
conclusive. 

Although these rocks have a considerable petrological range, it 
is clear that most of them were originally dolerites or basalts, in 
which the primary augite has been replaced by hornblende. The 
researches of Messrs. AUport and Phillips* on the Cornish green- 
stones conclusively demonstrate this fact. While the more 
massive varieties of the rock have so far resisted dynamic meta- 
morphism as to still preserve much of the original felspar, in 
others that mineral is recrystallised or profoundly altered. More- 
over, considerable variation attends the relative proportions of the 
hornblende and felspar that form the principal constituents^ while 
in the crushed varieties the secondary products may be so widely 
diffused as to efface the original character of the rook. The green- 

* Q.J.G.S,, vol xxzii., pp. 156 and 407, and vol. xxxiv., p. 471. 



42 IGNEOUS BOCKS. 

stones, however, are not confined to the basic types, but rocks of 
intermediate and possibly even of acid composition find their 
place within that group. That members of the andesitic family 
are present is certain, and it appears highly probable that trachytes 
are represented also. 

For convenience, the greenstones will be described under four 
heads, according to districts, as follows : — Firstly, those in the 
granite aureole between Gwennap and Penryn. Secondly, those 
occurring to the east of Penryn, which are scattered over a broad 
tract west of the Carrick Roads, between Devoran and Falmouth, 
and lying mainly beyond the granite aureole. Thirdly, those 
between Camborne and Redruth that flank the smaller granite 
masses of Cam Brea and Carn Marth ; and, lastly, the greenstone 
flanking the south-western margin of the Carnmeuellis granite. 

Area between Gwennap and Penryn. — From Bellevue to 
Ponsanooth there appears to be a continuous line of -greenstone. 
After a break of about a mile and a quarter, it is again seen 
between Pengreep and Treviskey. That between Bellevue and 
Ponsanooth will be first described. 

Bellevue and Ponsanooth, — Owing to the area being under 
cultivation and the infrequency with which the rock protrudes 
from the soil, the continuity of the sills cannot be demonstrated. 
At Bellevue a coarse-grained greenstone is seen, having apparently a 
width of about 80 yards. This rock is again visible at Lower 
Treluswell. Between that place and Burnthouse, where it has 
been quarried, it cannot be traced, but large blocks occur in a 
field between Treluswell and Burnthouse. Beyond the latter 
locality it has been quarried at Cosawes Pascoe. Another pit 
has been opened on this band about half a mile to the north-west, 
and this is the only quarry at present being worked. The 
seam appears to die out before reaching Ponsanooth. The coarse 
greenstone is accompanied by a smaller band of finer texture, 
which appears on its western side, in close proximity to it, at 
Lower Treluswell, Burnthouse, and on the main road near Ponsa- 
nooth, where a corresponding band also occurs on its eastern side. 

The larger and coarser band is a massive amphibolite, resulting 
from the alteration of a coarse dolerite or gabbro, A specimen 
from near Bellevue (3,367) shows under the microscope large 
masses of fibrous hornblende, in a matrix of coarse felspar, in 
which a large number of the crystals are still idiomorphic, while 
many are broken and crushed. The rock is half a mile distant 
from the Carnmenellis granite, and it would appear that prior to 
contact metamorphism by the latter that it was decomposed, and 
while the original felspar remains, the decomposed pyroxene is re- 
placed by actinolite. There is a sporadic appearance of actinolite 
amongst the felspars, probably due to a migration of the decom- 
position products. Iron ore is present in process of alteration to 
granular sphene, as well as fine needles of apatite, some of which 
are broken and may possibly be original. A specimen obtained 
from the new quarry near Cosawes Pascoe, and within 300 yards 
of the granite margin, is essentially the same rock, but under the 
microscope (3,371) is seen to be slightly sheared, and shows a 



GREENSl'ONE. 43 

higher degree of gran ulitisat ion. It is a massive amphibolite, and 
the hornblende is more abundant than in the last rock, forming 
compact masses, very pale green towards their centres, mixed with 
a little pale brown biotite, the latter probably being a direct 
result of contact alteration. The felspar is partly in large plates. 
but occurs mainly in a fine granulitic condition, especially in the 
shear planes. Some magnetite and apatite are also present. 

De la Beche* records that this greenstone is traversed at Burnt- 
house by an elvan. At present the quarries at that locality are 
no longer working, and, being densely overgrown, cannot be satis- 
factorily inspected. In one of the old greenstone pits on the 
north side of the inn a few elvan fragments are seen that corre- 
spond to the description given by De la Beche, but no trace of the 
rock in situ is now visible. 

The nner-grained greenstone sill already referred to has been 
quarried at Lower Treluswell and at Burnthouse. A specimen 
selected from the latter locality, about 150 yards south of the inn 
(3,562), shows the rock to be decomposed and sheared. It is full 
of pale green fibrous hornblende, mostly divergent, and of felspar 
which is decomposed and sheared. The rock is almost in contact 
with the granite, and contains a few scales of biotite, probably due 
to contact metamorphism. The original structure of the rock, 
however, has been obliterated. 

The fine-grained greenstone seen in a corresponding position to 
the amphibolite on the main road leading to Ponsanooth (one- 
eighth of a mile east of Cosawes) is little more than 100 yards 
from the granite margin. Fresher specimens are to be obtained 
than at Burnthouse, one of which (3,569) is seen under the micro- 
scope to consist of fibrous pale green matted hornblende ; iron ores, 
surrounded by rims of sphene; felspars, partly simply twinned, 
partly untwinned, and partly polysynthetic. The latter are 
fractured, but in many cases their original outline can be detected. 
In other cases, however, (3,568) the felspar has been entirely 
decomposed to micaceous aggregates. Another specimen (3,567), 
which appears to belong to the same mass, shows the igneous rock 
to be brecciated and to contain veins of pyroxene and quartz, 
which may be ascribed to secondary alteration and the meta- 
morphic action of the adjacent granite. 

Pengreep and Treviakey. — This greenstone, like that of Ponsa- 
nooth and Bellevue, flanks the Carnmenellis granite, and its junction 
with the slate can only be approximately defined. It is about 1^ 
miles in length, and its extreme breadth exceeds a third of a mile. 
It forms an irregular lenticle, the western portion of which con- 
tracts more rapidly than the eastern part. In the neighbourhood 
of Trebowland Vean it is only separated by about 70 yards from 
the granite. Notwithstanding its extent, the rock is of much 
finer texture than the mass extending from Bellevue to Ponsa- 
nooth. While portions are as coarse as in the latter, the greater 
part of the rock is of fine grain. Moreover, its texture is exceed- 
ingly variable, as may be seen within the compass of a limited 

• ** Keport on the Geology of Cornwall," &c., p. 484. 



44 IGNEOUS ROCKS. 

section. This is well exhibited in the quarry at Devis (half mile 
S.S.W. of Gwennap) where patches, the crystalline nature of 
which is easily visible, succeed bands so fine in texture that the 
crystals can only be detected with a lens. Both types, more- 
over, alternate sharply with zones that are very finely sheared. 
The mass has evidently undergone considerable compression, the 
finer, more compact zones and those of coarser texture having 
been packed and squeezed together, and shearing set up along the 
latter type. The rock is partially mineralised with secondary 
pyritous products, while quartz veins apparently mixed with 
epidote cross the prevailing banding. Some of the finer cross 
veins are hornblendic. 

Under the microscope all these bands are seen to be slightly 
schistose. Those most foliated consist of fibrous green actinolitic 
hornblende, arranged to form irregular wavy folia; the crystals 
are small and in some bands are densely matted, while in others 
they are scattered through a ground mass of felspar which is finely 
granular and shows no crystalline form. Epidote is common in 
very minute grains, and there are comparatively large masses of 
iron oxides and pyrites (3,443). 

The two less schistose bands are rocks of essentially the same 
type, but contain in addition some fine scaly deep brown biotite, 
which in all probability indicates contact alteration. 

The eastern portion of the mass near Pengreep is partly of 
coarser texture, a specimen of which (3,368) bears a strong resem- 
blance to the rock described from Bellevue (3,367). It consists of 
large crystals of fibrous hornblende, while the felspar is partly 
idiomoiphic and partly granulitic, and the section shows foliation 
planes. The iron ores in this rock are well preserved. A finer- 
grained rock from the same locality resembles the greenstone of 
Devis Quarry. It shows no sign of crushing beyond traces of 
shear planes like those in the last specimen. The felspar is much 
weathered, and there is a little brown biotite. This greenstone 
is pierced at Burncoose by an elvan dyke. It is seen in a 
quarry amid the adjacent killas, but it is not now visible 
within the greenstone zone itself, where the land is under culti- 
vation. De la Beche, however, states that it traverses that 
rock.* 

A small mass of greenstone occurs beyond the main band about 
a mile to the north-east of Burncoose. Its limits, however, cannot 
be precisely defined, as its presence is only detected by the debris 
turned up in the soil. In the larger mass quarries have been 
opened, the principal of which are at Devis and near Gear. 

Area East of Penryn. — The greenstones of this district occur 
in a zone from Bestronguet Creek on the north to the neighbour- 
hood of Falmouth on the south, and are most strongly developed 
in Penryn Creek, where they are seen both on the Flushing and 
the Falmouth shores. They occupy smaller bands than most of 
those already described, are usually highly decomposed^ but appear 
to be less sheared and are marked by a more acid composition. 

* Report previously cited, p. ISd. 



GREENSTONE. 45 

The most extensive of these mavises is seen at Flashing, at the 
entrance of Penryn Greek, where it has a breadth of about 200 
yards ; it ascends the hill for about 350 yards and then disappears. 
The rock has been extensively quarried, and formerly a silver lead 
lode was worked along its eastern margin at Wheal Clinton. It 
occurs at the extreme limits of the metamorphic aureole, and its 
easterly margins have a knotted appearance. Apart from this, 
the rock does not appear to have suffered from contact alteration. 
It is usually much decomposed, with an occasional tendency to a 
foliated arrangement. The colour is pale green and the texture 
is fine, but can be resolved by the naked eye into an admixture of 
felspar and a green chloritic mineral. Under the microscope 
(3,373) it is seen to be largely made up of felspar, very little 
granalitised, but consisting mainly of large and often idiomorphic 
individuals, though frequently broken. The hornblende has all 
decomposed to chlorite, and the iron ores are weathering to 
lencoxene. The rock is a somewhat basic andesite that has 
suffered but little from cataclastic movements. 

The rock is not visible on the Falmouth shore,* but two out- 
crops that occur along the same line on the east and south of 
Penwerris appear to be identical with it in composition. The 
former has been quarried along a band of white quartz about 8 yards 
wide, while the latter can only be detected by the detritus among 
the soil. Where the texture is finest it appears to have been 
cleaved. 

The following analyses of these rocks were made by Mr. J. H. 
Collins.t The first refers to the rock at Flushing, and the second 
to that east of Penwerris from Beacon Hill : — 



SiO, 

A1,0, 

FeaOj 

FeO 

CaO 

MgO 

K,0 

Na.0 

HaO 



} 



I. 


II. 


55-45 


53-30 


25-95 


24-48 


6-07 


1202 


1-26 


0-73 


2-39 


3-75 


1-48 


trace 


4-30 


1-27 


2-85 


4-70 


99-76 


100-25 



Sp. Gr. - - . 2-66 2-72 



* It was apparently noticed, however, both by Mr. Collins, and later by Mr. 
F. J. Stephens on the Falmouth shore south of Green Bank Pier. Trs. R. 0.8. 
Cor%.y lSi96, vol. xil., part ii., p. 51. 

t Jown^Roy, Inst* (3?r»., vol. viii., p. 202. In that publication Mr. Collins 
has included these greenstones with the mica traps. See paper on the plutonic 
and other intrusive rocks of West Cornwall by J. B. Hill. Trs. RM.h, Com., 
vol. xii., p. 7., 1901. Mr. F. J. Stephens noted iis difference from the normal 
mica traps of the district in a paper on the greenstones of Penryn Creek in 
1896, one of which he considered to be an altered asli bed. Trs. R. G. S. Corn. , 
▼ol. xii., part ii., p. 49 



46 IGNEOUS ROCKS. 

On the soath side of Penryn Creek, below Penwerris Church, two 
greenstones are seen about 55 yards apart. The easterly mass has 
a width of about 80 yards^ but the whole breadth of outcrop is 
not visible. At its eastern margin the rock is most massive, 
enclosing harder and fresher cores. It is grey in colour, and 
vesicular, and even in the finer and less massive portions tiny 
felspars project on the weathered surface. The rock is much 
decomposed, even where most solid, and the boundary with the 
slate is not seen. The westerly mass is exposed for about 12 to 14 
yards, but it may be larger. It is more decomposed and never 
solid, but tiny felspars can be detected on the weathered surface. 
Above high-water mark it is brown and friable. The bed contains 
similar vesicles^ notwithstanding that it is more cleaved than the 
band to the east. Under the microscope a specimen from the 
latter and more solid mass (3,565) is seen to be a much decomposed, 
and practically unsheared^ porphyritic and vesicular igneous rock 
which apparently belongs to the trachyte group. It contains 
abundant phenocrysts of idiomorphic felspar, some of which are 
untwinned, but most are simply twinned on the Carlsbad plan ; a 
few are plagioclase. These lie in a gtound mass composed of 
small felspar crystals, and filled with small scales of secondary 
mica and chlorite, so that the original structures can no longer be 
deciphered. The abundant steam cavities are filled with granular 
quartz, mica, and chlorite. So far as the micro-section shows, this 
rock is practically unsheared, the porpbyrilic felspars are unbroken, 
and the vesicles retain their original irregular shape, but the hand 
specimen indicates that it has been subjected to a certain amount 
of deformation. 

These bands appear also on the northern shore of the creek 
west of Flushing, where they are only about 15 yards apart. 
Here they are much disturbed by interfolding with the slates, and 
by small faults and thrusts that are often so closely arranged that 
the truncated cores are reduced to the thickness of a foot. 

At Mongleath, about a mile to the west of Falmouth Parish 
Church, a highly decomposed greenstone has been quarried that is 
probably allied to the rocks last described. It is a lilac grey fine- 
grained rock in which small felspars are seen in the more solid 
portions. The boundary with the slate is not seen. Under the 
microscope (3,564) it is so much altered and decomposed as to 
entirely lose its original character. It consists principally of a 
turbid felspar in very irregular grains, decomposed and obscured 
by abundant enclosures of biotite, chlorite, and iron ores. These 
felspars are mostly untwinned, sometimes simply twinned, rarely 
polysynthetic. They are never idiomorphic, but form masses of 
extremely irregular shape. The other minerals form small specks 
or tiny flakes. Biotite is the most: common ; it is usually irregu- 
larly scattered, but is in some parts arranged along definite 
curving lines. Irregular black patches of iron ore are frequent, 
and there is a good deal of disseminated chlorite. There is here 
and there a very small quantity of quartz, and diflFused ferruginous 
stains are conspicuous in places. Dr. Flett is of opinion that the 
rock is undoubtedly igneous, that it is both decomposed and 



GREENSTONE. 47 

sheared, and belongs, in consequence, to the greenstone group. It 
is exceptional in the absence of hornblende, the abundance of 
felspar, and the general resemblance it presents to the paler fels- 
pathic andesites. It may even approach the trachytes, but without 
detailed chemical analysis its affinities cannot be determined. 

To revert to the sections along Penryn Creek, a small green- 
stone mass occurs on the southern shore near Boyers Cellars. It 
is a grey massive band, fine grained, cleaved, and much decom- 
posed. It varies in width from 6 feet upwards. The ground is so 
disturbed by small fractures as to obscure its relations to the 
slate. It weathers with a yellowish brown crust, and fresh portions 
are difficult to obtain. It appears to be very felspathic, and is 
probably related to the greenstones ofPenwerris and Flushing 
already described. This rock has been considered as a volcanic 
ash* but there does not appear to be good grounds for separating 
it from the bands just referred to farther east, the igneous origin 
of which is clear. 

Between Penryn Creek and Restronguet Creek a few greenstones 
are met with. They can seldom, however, be traced for any 
distance, and are usually highly decomposed, and in most cases 
seem to be allied to the andesitic greenstone of Flushing. At 
Carclew one of these bands is sufficiently fresh for microscopic 
examination (3,563). It contains large patches of chlorite, mixed 
with granular felspar, a little quartz, and iron ores in large grains. 
Hornblende is less common, having usually weathered to chlorite. 
The rock is both decomposed and sheared. 

A band appears to extend from Sailor's Creek to Woodlands 
where it has been quarried, both at the latter locality and near 
Trevissome Farm. On the south side of Restronguet Creek, 
about one-third of a mile north-west of the quay, there are three 
exposures of decomposing greenstone, one of which is 30 yards 
broad. These, like the band last described, have suffered but 
slight deformation from mechanical stress, and resemble the 
andesitic greenstone of Flushing. A similar rock is met with on 
the shore of Carrick Roads, below Great Wood, only 4 or 5 feet in 
width, in which shearing has proceeded further. The greenstone 
coloured on the old map to the east of Trevissome Farm was not 
seen in our survey, but Mr. Collins confirms its existence at that 
localitv.t 

if 

Camborne and Redruth District. — The greenstones of this 
area are distinguished by a basic composition, a fine-grained tex- 
ture, a more or less uniform shearing, and the presence of veins 
that are frequently strongly garnet iferous. A broad band extends 
south-westerly from Camborne to the margin of the map. In 
a north-easterly direction, from Camborne to Treleigh,the band 
is apparently discontinuous. It is, moreover, found in isolated 
bodies in the mine workings of this area, as at South Ros- 
kear. East Pool, and many other localities. The boundaries 

* F. J. StephenB. Trans. Roy. Geol. Son. Corn,^ 1897. 

t Joum. Hoy. Jnst. Corn.^ vol. viii., p. 194, Mr. CoIUns, however, \m% 
included this band amongst his mica traps. 



48 IGNEOUS BOCKS. 

of this greenstone can onlj be approximate! j drawn as sections 
and surface exposures are few. An excellent section, however, 
is aflforded by the railway cutting west of Camborne Station, 
where an elvan is seen to traverse it. Two smaller patches 
of greenstone are dissected by the railway cutting between Cam- 
borne and Pengegon Coombe. It has also been quarried in the 
neighbourhood of Tuckingmil). In other localities reliance has 
to be placed on the rock fragments of the soil and on local 
information. As this stone has been extensively utilised for the 
building of hedges and other purposes, and as the blocks employed 
are often of enormous size, great difficulty is experienced in dis- 
criminating the nature of the country rock where sections are 
scarce, greenstone debris often predominating where slate con- 
stitutes the bedrock. 

The railway cutting between the goods shed at Camborne 
Station and the bridge near Osborne House affords a continuous 
section of the garnetiferous greenstone for a length of one-third 
of a mile, and exposes its junction with the slates. The green- 
stone is of exceedingly fine texture, and is usually very closely 
banded. It is seldom massive, but is generally rudely fissile and 
decomposing, with a tendency to cleavage somewhat like the 
slates. It frequently weathers to an ochreous crust, and is often 
friable and soft. The rock is not only characterised by an absence 
of vein quartz, but by the presence of abundant veins of brown 
garnet. The veins are often two or three inches in thickness, 
and are at times so closely packed as to occupy half the mass 
of the rock. They are usually, however, much thinner, and are 
often represented by mere cores, some of which are of small size. 
They are parallel to the banding of the rock, in the crumpling of 
which they share. They are not confined, however, to these planes, 
which they frequently transgress, and often coalesce. The 
garnetiferous veining is bounded by a very pale greenish 
margin, contrasting strongly with the darker green matrix of 
the rock. Moreover, veins of this nature are common in which 
the garnet is absent. This mineral occurs both in a massive 
condition and in well-defined crystals, while the veins fre- 
quently decompose into ochreous material. The junction 
with the slate is seen ai both ends of the section, but the 
disturbances which have affected both rocks do not admit of 
its precise nature being determined. Under the microscope 
(3,919) the greenstone is seen to consist of small green horn- 
blendes, arranged in strings and bundles in a matrix of clear 
granular felspar, so fine grained as to form in some places almost 
a crypt o-crystalline mosaic. Besides grains of iron oxide occa- 
sionally converted into sphene, clear brown biotite and chlorite are 
present, but no garnet. 

At Weeth Farm, at the spoil heap of Gustavus Mine, a 
specimen of greenstone of the same general type was veined 
with green hornblende, quartz, and greenish pyroxene (3,920). 
Another fragment in a field from the same locality (3,921) 
is a fine-grained greenstone traversed by one of the pale 
green veins formerly alluded to, the latter consisting of 



GREENSTONE. 49 

granular pale green or colourless pyroxene, mixed with 
micaceous products after felspar. Epidote is rare or absent in the 
vein, and there is no garnet, but it is cut by another which is filled 
with colourless fibrous highly-polarising mineral^!, probably of the 
zeolite group. In a quarry near Tuckingmill Gasworks a gar- 
uetiferous patch in the greenstone (3,922) consists of pink isotropic 
garnet, sometimes zonal, frequently intergrown with epidote, and 
never distinctly idiomorphic, but often in skeleton crystals. It is 
mixed with pale green pyroxene, colourless epidote, chlorite, 
granular and crystalline sphene, and colourless micaceous patches 
which are secondary after plagioclase felspar. Hornblende 
occurs in the greenstone, but very seldom in the vein. Calcite, 
although not visible in the slide, occurs in the band specimen in 
large patches. There are some fairly large crystals of pyrites and 
a few scales of chlorite. 

The greenstone met with in North Pool Mine, presumably from 
the Daubuz lode, has been brought to the surface at Broad Lane. 
A specimen shows the rock to be full of parallel bands or veins of 
the pale green material in which garnets are interspersed. Under 
the microscope (3,923) it is seen to consist of fibrous horn- 
blende, epidote, weathered felspar, and chlorite, with pyrites, a 
few grains of garnet, sphene, a small quantity of carbonates, and 
occasional traces of pyroxene, but epidote and felspar are the 
principal constituents. The epidote is pale greenish yellow, 
and very similar to the pyroxene, though not so green in 
colour. The hornblende may be partly secondary after pyroxene. 
The weathered felspar is nearly always untwinned, and may be 
an orthoclase. The garnet is more conspicuous in the hand 
specimen than in the slide. The veins in this rock, therefore, are 
largely made up of epidote with garnet subordinate, which an 
inspection of the burrow debris suggests. 

The greenstone exposed in the railway cutting about half a 
mile north-east of Camborne Station is of the same type, although 
generally much weathered, but the veins are characterised by an 
absence of augite. One specimen (3,924) is a sheared greenstone, 
with finely fibrous or prismatic hornblende disseminated in a 
matrix of granulitic felspar with iron ores and minute grains of 
sphene. Small scales of brown biotite are mixed with the horn- 
blende. A vein of hornblende traverses the section, but this 
contains no garnet, pyroxene, or epidote. Another specimen 
(3,925) is a similar rock, but coarser in grain, in which the horn- 
blende is compact instead of fibrous, and the slide contains a 
little pale epidote, aogite, and sphene. Another part of this 
mass is a compact fine-grained sheared greenstone, but 
without veining. This rock (3,926) is conspicuous for the 
abundance of the secondary augite in its matrix. It occurs as 
a clear pale green pyroxene in crystals up to a millimetre in 
diameter, occasionally showing crystalline outline, though as a 
rule not displaying distinctive form. They contain a few 
enclosures of granular sphene or felspar, and sometimes of 
clear green hornblende in small compact crystals, but 
occasionally fibrous and radiate. These all lie iu a matrix of 



uO IGNEOUS BOCKS. 

minute felspars, forming a mosaic of small grains mixed with 
granular spbene. Epidote is scarce, although a thin vein of this 
mineral traverses the section, but no garnet is observed. The 
matrix of the rock is very like that of some of the sheared green- 
stones, but the large pyroxenes have evidently developed 
after the shearing was complete, and may be ascribed to the 
contact action oi the adjacent granite, two fine-grained sills of 
which are seen in the railway cutting to pierce the greenstone. 

The south-westward extension of the Camborne mass was traced 
by Mr. Dixon to the edge of the map and into the adjoining 
sheet (351). In the latter area the rock is sometimes both un- 
crushed and unweathered, and constitutes an ophitic diabase, the 
structure of which often approaches that of a gabbro, so that 
its intrusive nature may be confidently accepted. To the south 
of Polstrong, although not deformed, it has experienced mineral 
reconstruction, hornblende having replaced augite, and the 
twinning planes of the felspar are obliterated (3,787). On the 
other hand, according to Mr. Dixon, ** spotting" has been confined 
to sheared zones. A specimen of this nature from the railway 
cutting west of Penponds Viaduct consists mainly of pulverised 
felspar, containing parallel streaks of magnetite and leucoxene, 
together with spots of sub-radial hornblende, epidote, and chlorite, 
of square or rhomboidal shape, whose absence of distortion points 
to their production subsequent to the deformation of the rock 
(3,785). Another example of " spotting" in which the felspathic 
constituents have been modified is afforded by the sheared green- 
stone exposed in a quarry to the north-east of the latter locality 
(3,784). The crag lying to the south of the same viaduct, on the 
eastern side of the valley, is formed of sheared greenstone in 
which the felspar has retained its original structure. Other 
greenstone outcrops occur at Penhale and south of Trevoole, while 
a rock resembling this type was noted by Mr. Dixon near Water- 
gate (Illogan), at a considerable distance from the nearest green- 
stone horizon (3,646). 

These peculiar intrusions, therefore, of the Camborne district 
are characterised by secondary veins infilled with garnet, epidote, 
augite, hornblende, felspar, and quartz, either singly or in com- 
bination. Not only are these secondary minerals disposed in veins, 
but, with the exception of garnet, occur diffused in the matrix of the 
rock in the same manner as the secondary biotite. These rocks 
lie within the aureole of contact metamorphism of the granite, 
and the presence of those secondary minerals may be confidently 
attributed to such contact action. It may be noted, however, 
that where they are in closest proximity to the granite the 
garnet appears to be absent. Mr. J. A. Phillips* thought it 
probable that they also contained axinite, and considered them 
to represent volcanic ash beds. While their fineness of texture 
might well lead to the supposition that they were the meta- 
morphosed products of volcanic muds, their matrix frequently 

2 On the ao-called greenstones of Western Cornwall. Q.J.G.S., vol. xxxii, 
1876 



OSEENSTONE. 



51 



closely resembles that of the normal sheared greenstones^ the 
igneoas origin of which is undoubted, and their passage into coarse 
types that represent gabbros points unmistakably to their in- 
trusive origin. There is an entire absence, moreover, of clastic 
structure, and in this connection it may also be remarked that 
the presence of undoubted ash beds, or even lavas, has not been 
demonstrated in this part of Cornwall. 

The following analysis in duplicate of a gametiferous green- 
stone from Cam Camborne is taken from the paper of J. A. 
Phillips, already cited : — 

Water /hyg«>.'°«tri<' - 
\ combmed 

Silica ... - 

Phosphoric anhydride 

Alumina ... 

Ferric oxide - - - 

„ persulphide - 

Ferrous oxide 

Manganous oxide - 

Lime - - - - 

Magnesia ... 

Potassa - - - - 

Soda ... - 



•14 


•12 


•60 


•65 


48 30 


48-41 


trace 


trace 


1704 


17-02 


2-73 


2-68 


traces 


traces 


9-50 


941 


trace 


trace 


13-30 


13-15 


6-18 


6-20 


•30 


•30 


201 


213 


10010 


100-07 



Specific gravity = 303. 

As pointed out by Mr. Phillips, the composition of this rock 
closely resembles that of the metamorphosed dolerites in the 
Penzance district. Moreover, the only rocks in the latter area 
that were regarded by De la Beche as highly altered ash beds 
difier widely in chemical composition from the rocks at present 
under consideration. 

To the east of Pendarves House, and also at Treslothan, two 
bands of greenstone occur that beloug to the class just described. 
Their exposures, however, are scanty, and their boundaries have 
been taken from the old map. In Rosewarne Park and in the 
north-east of Camborne there are two greenstone exposures, 
each of which is traversed by an elvan dyke. In other localities, 
as at Higher Rosewarne, North Pool, and Broad Lane, where these 
greenstone bands have been drawn on the map, there are no 
surface indications, but the position of their outcrops has been 
approximately drawn by Mr. MacAlister from information afforded 
by mine plans. 

The band that is quarried at Tuckingmill* is of coarse texture 
and is a fine-grained dark green sheared greenstone in which 
the characteristic veining of the gametiferous type is absent. 
The quarry is extensive, so that the rock can be satisfactorily 
examined. Under the microscope (3,914) it is seen to consist of 



* 780 yards north by west of All Saints' Church. 



E 2 



52 lONEOUS KOCKS. 

fibrous subradiate green hornblende, forming irregular bundles and 
tufted growths, mfzed with granulitic felspar^ iron oxides, apatite, 
and a little brown biotite. The felspar forms a mosaic of very 
small grains, which resembles the ground mass of a felsite. 

South- Western District. — An exposure of greenstone situated 
in the south-western corner of the sheet, at Wheal Trannack, 
in the Cober Valley, and in close proximity to the margin of 
the Carnmenellis granite, may be referred to here. This mass 
is exposed on the hillside forming the eastern banks of the 
stream, where it has been quarried ; the eastern tongue of the 
lenticle is seen in the railway cutting above, where it has been 
pierced by a fine-grained granite. To the west of the Cober 
River the greenstone is at present being quarried. It is a 
compact rock of normal type, like that already described from 
near Tuckingmill, but contains much more biotite, due to the 
close proximity of the granite, this mineral being the only 
ingredient due to contact action. A specimen from the railway 
cutting (3,953) at the thin end of the lenticle shows acicular 
green hornblende, forming divergent aggregates in a matrix of 
finely granulitic felspar, scattered masses of iron ores surrounded 
by borders of sphene, and a few small crystals of apatite and 
pyrites. A specimen from the quarry on the left bank of the 
stream from the interior of the rock is coarser in grain, dark 
green in colour, and with bronzy areas, owing to the develop- 
ment of numerous fine scales of brown biotite. Under the micro- 
scope (3,916) it is massive, not schistose, with much pale, 
clear green amphibole that forms large compact masses with 
very irregular borders, and, consequently, differs from the 
aggregates of fine hornblende needles which are usual in the 
greenstones. This hornblende has only a very slight pleochroism 
and is generally perfectly fresh. A clear matrix of fine granular 
felspar surrounds the hornblende, forming a mosaic of irregular, 
usually untwinned grains, with occasionally larger individuals, 
which, however, are never idiomorphic. The biotite is of a dark 
chestnut brown colour, and occurs in small scales, usually grouped 
together to form patches of irregular shape, either in the felspar 
or scattered through the hornblende. Small prisms of hornblende 
and scales of biotite lie in the felspatbic matrix. There is also a 
little apatite and iron ores, the latter sometimes surrounded by 
borders of sphene. The abundance of biotite, the compact nature 
of the hornblende, and the coarseness of the felspar mosaic, 
all indicate that this rock has been subjected to contact 
metamorphism. 

II. Granite. 

The principal granite mass within this sheet is that of 
Carnmenellis, which forms a rudely circular boss extending from 
Buller Downs, about one mile south of Redruth, on the north, 
to slightly beyond the southern edge of the map. On the 
east it extends to Budock and Penryn, while its western margin 
reaches from the vicinity of Nancegollan Station to the west- 
ward of Crowan and Garnick, To the north of the Carnmenellis 



GRANITE. 63 

boss lie the two adjacent masses of Gam Brea and Cam 
Marth. Subordinate intrusions flank the Carnmenellis granite 
near Treluswell and Badock on the east, and on the south-western 
margin from the vicinity of Crowan to the valley of the Cober. 
On the north side of the Carn Brea granite a small sill of aplite 
or fine-grained granite traverses a greenstone in the railway 
cutting near Pengegon. 

Carnmenellis Granite. — The Carnmenellis mass is essentially 
a muscovite-biotite granite, of acid composition, in which tourma- 
line is a common constituent, while andalusite is frequently 
present. Apatite and zircon iiometimes occur, while topaz and 
pinite are rare. The granite has often undergone great modi- 
fication, especially in the vicinity of the mineral lodes, and in 
these cases new minerals have been introduced. The rock is 
frequently porphyritic by the dispersion of large idiomorphic 
felspars of orthoclase and plagioclase in a finer-grained base. 
Such felspars often exceed an inch and, exceptionally, two or 
three inches in length, but seldom attain the abnormal dimensions 
that characterise the granites of the Land's End and St. Austell. 
The texture is, nevertheless, coarse as compared with British 
granites generally. 

This rock, while fairly uniform throughout, nevertheless 
exhibits local deviation, both as regards composition and coarse- 
ness. Speaking generally, the eastern margin is not only of finer 
texture, but is perceptibly richer in biotite. These characteristics 
mark also a greater part of the southern margin. On the south- 
west and west, however, there is no perceptible difference as 
regards texture, but it continues to be rich in biotite, almost to 
the entire exclusion of white mica. It is sometimes veined 
with pegmatite, especially in the vicinity of Ponsanooth. Con- 
temporaneous veins of fine-grained granite or aplite are common 
over the mass. They are less abundant, however, in the eastern 
portion, but are extremely numerous in the central district, while 
in the west two areas of fine-grained granite occupy tracts 
sufficiently extensive to be separated on the map. One of these, 
exceeding a square mile, occurs between Bolitho and Boswyn, the 
other forms a protruding lobe, comprising a quarter of a square 
mile, on the margin of the granite at Praze. The latter is a 
a fine-grained biotite-tourmaline-granite occurring amongst coarse 
granite of similar composition, to which its marginal relations are 
obscure. The mass between Bolitho and Boswyn yields more 
exposures. Over a large part of its area the fine texture is 
fairly uniform, often approaching that of an elvan, but veins of 
coarser granite are of frequent occurrence, while at times the finer 
type itself may contain idiomorphic felspars an inch in size. 
The marginal relations are usually obscure, but occasionally the fine 
granite sends veins into the coarser normal rock. At Crowan 
Beacon, however, the passage of the normal granite into the fine- 
grained type is seen. Here the former gives rise to tors with rudely 
stratiform structure which are absent in the area occupied by the 
latter. It passes first into a coarsely porphyritic granite, the 
porphyritic constituents being identical with the individual 



54 IGNEOUS ROCKS. 

crystals of the normal rock, but lying in a ground mass of 
finer material. The porphyritic individuals, however, both 
felspar and quartz, are idiomorphic, so that with a sufficiently 
fine matrix we reach a rock indistinguishable from some of the 
elvans. 

Stracturea. — ^The system of jointing pertaining to the Carn- 
menellis granite bears a definite relation to the crystalline 
arrangement There are three well-defined joint planes: one 
set of vertical joints, having a prevalent direction of north- 
north-west, is crossed by another vertical set at right angles. 
These two systems, in conjunction with a third set more or less 
horizontal, divide the whole rock into a set of rough prismatic 
segments. The regularity of these joint planes has been an 
important factor in the development of the granite industry of 
Cornwall. The planes which trend north-north-west are termed 
^^ cleaving-way " joints, those at right angles are the ^' tough- 
way " joints, while the horizontal planes are known as ^' floors '* 
or "quartering-way" joints. The grain of the rock has been 
found to correspond with the position of the joints, hence their 
names. 

The "tough-way" joints, or those which approximate to an 
east-north-east direction, may sometimes be faults ; instances 
being common where the horizontal *^ floors " have been thrown 
by them as much as 2 feet, or where the joints display slicken- 
slided surfaces, indicative of relative displacement of the walls. 
Further, the fine-grained granite and aplite veins tend to take a 
course parallel to these same joints, while the elvari dykes 
undoubtedly follow the same parallelism. 

The horizontal joints or " floors " producing stratiform weather- 
ing are characteristic features in the field. De la Beche* 
considered them as original structures, and the fact of their 
being faulted by the "tough-way" joints proves them to be 
older than the movements along those divisional planes. 
Later joints, however, occur which cannot always be dis- 
tinguished from the true '^ floors," into which they appear to 
merge. The intervals between these horizontal joints or " floors " 
increase with depth from the surface. In Pelastine quarry the 
joints are 60 feet apart, while in Polkanuggof quarry the disposi- 
tion of the joint planes would admit of blocks being raised 
120 feet long, 28 feet wide, and 30 feet deep. 

The rock cleaves most readily along planes parallel to the 
" floors " or horizontal joints. The next easiest cleaving plane is 
that parallel to the " cleaving-way " joints, while the rock 
cleaves most irregularly parallel to the " tough-way " joints. An 
examination of numerous sections in which this triple jointing is 
visible appears to show a distinct tendency to orientation along 
planes parallel to the horizontal " floors," and to the " cleaving- 
way " joints, although no absolute regularity in this respect has 

* Report (previously cited), p. 163. This structure was also noted by Dr. 
Boase. — *t Treatise on Primary Geology," 1834, p. 96. 

t The quarries are thus designated by Messrs. John Freeman & Ck)., by 
whom they are worked. 



GRANITE. 55 

been observed. While in many instances these planes depart from 
the normal direction, it is anusoal to find more than one joint 
system deflected in the same exposure. The greatest irregularities 
in the jointing and corresponding cleavage occur in the vicinity 
of the granite veins. The horizontal joints, although often un- 
dulating, are the most regular of all. The cleaving planes of the 
rock are not always strictly parallel to the joints^ yet, on the 
whole, the parallelism between the joints and the directions 
along which the rock most readily splits is unmistakable. 
From the evidence of a large number of sections there is reason 
to conclude that not only is there a close connection between the 
major joints and the grain of the rock, but that this grain is 
dependent on the mineral arrangement of the granite, and that 
all three phenomena are closely related. The crystalline structure 
appears to consist, first, in a tendency for the mica to lie with its 
basal planes horizontal ; secondly, in a disposition of the felspars, 
both as constituents of the matrix and as porphyritic individuals, 
to rest with their flat sides in a similar position ; and, thirdly^ in 
the orientation of the felspars with their long axes parallel to the 
'* cleaving-way " joints. The first and second of these structures 
probably explain the proneness to cleave parallel to the horizontal 
joints, while the third seems to show why the rock tends to cleave 
in planes parallel to the " cleaving-way " joints. The rock does 
not differ outwardly in any marked degree from ordinary granite ; 
yet it has evidently undergone a rude and initial stage of foliation, 
whereby its component minerals have been forced to rearrange 
themselves in a definite direction so as to acquire a cleavage. 

The set of major joints, which trends approximately east-north- 
east, corresponds to an extensive system of fissures that has been 
formed in the granites and Palseozoic rocks of Cornwall by the 
subterranean disturbances, to which the former owe their origin 
and the latter their deformation. This system of fracture is 
parallel with the axis of granitic intrusion, and also with the 
general trend of the elvan dykes and mineral lodes, both of which 
have occupied its fissures. 

These phenomena are well illustrated in the Carnmenellis mass. 
Within that granite, in the Mabe and Constaatine districts, 
mineral lodes and elvan dykes are practically absent, while the 
east-north-east system of fissuring is almost entirely confined to 
the visible joints. In the parish of Wendron, which forms the 
central belt of that granite, this system of fissuring has been so 
sensibly increased that the stone, which is raised on a large scale 
in the two former parishes^ can seldom be profitably wrought. 
With this change elvan dykes make their appearance, likewise an 
extremely attenuated set of mineral veins that have been worked 
for tin ; moreover, the granite, which is of coarse texture, is 
extensively veined by finer-grained material. The east-north-east 
fissuring is no longer confined to the major joints, but the inter- 
spaces between them are very closely fractured along parallel 
planes. Frequently they consist of tiny cracks that sever the 
various crystals along their course. In the next stage, the cracks 
have been infilled with quartz, which has been followed by the in- 



56 IGNEOUS BOCKS. 

troduction of schorl as an accompaniment of that mineral, and 
finally to almost its total exclusion. With the oncoming of wider 
veins the rock takes on a banded appearance, the black schorlaceous 
seams standing out in striking contrast to the granite. The 
schorlaceous veins carry tin, and in some instances it is quite 
clear that the lode coincides with the east-north-east joint Over 
the whole district the schorlaceous bands rarelv exceed a few inches 
in width. 

When this granite is followed, however, further north, towards 
the marginal zone, the extent of the elvans and the magnitude 
of both fissure and lode have reached their maximum. 

Microscopical Character, — Having given a general description 
of this granite, it will be convenient, before touching on local 
characteristics^ to present a brief relation of its microscopic 
characters. 

A fairly typical specimen of the coarser granite representing 
the interior of the mass was taken from Eathorne, in the parish of 
Mabe. As a whole the rock is very fresh, and is a muscovite- 
biotite-granite with accessory tourmaline and andalusite. The 
felspar is mainly perthitic orthoclase, but there is also some 
microcline and plagioclase. The biotite is rich brown, with strong 
pleochroic halos. Muscovite is common, and often occurs in 
parallel growth with biotite. Numerous small grains and prisms 
of andalusite lie scattered through the section. They are some- 
times nearly colourless, but others exhibit marked pleochroism, 
which ranges from rose pink to colourless. There are one or two 
irregular grains of deep brown tourmaline, and apatite is common 
in unusually large crystals. Zircon is present in considerable 
quantity, especially in the biotite. The quartz contains numerous 
large fluid cavities with mobile bubbles. In parts of the section 
the felspar is decomposed, and the biotite has passed into chlorite 
(3,556). 

To the north of the latter locality, in the vicinity of Long- 
downs, a specimen was obtained at the junction of the normal 
granite with one of the finer-grained veins. Here the coarse rock 
is a biotite granite containing andalusite, while the finer-grained 
vein is a tourmaline granite (3,356). 

At Chywoon the fine-grained granite that occurs amongst the 
coarser and more normal type is a tourmaline-muscovite-granite 
(3,357). On the other hand, a fine-grained granite from Trevales 
is a muscovite-biotite-granite containing both andalusite and 
tourmaline. The felspar is largely perthitic orthoclase, but there 
is also an early generation of well-crystallised plagioclase. The 
biotite is deep brown, with strong halos. Muscovite is abundant, 
and andalusite occurs in small grains with characteristic pleo- 
chroism. There are a few small grains of brown tourmaline, and 
apatite is common (3.557). 

The preceding specimens, taken from the eastern region of the 
granite, represent its normal condition in an area free from 
brecciation and mineral veins. 

It has been mentioned that two fairly large tracts of fine- 
grained granite have been mapped in the west, in the parish of 



GRANITE. 57 

Crowan. A specimen from the more westerly mass, and near the 
granite margin from Trethannas, shows a fine-grained tourmaline 
granite with a little chlorite after biotite, and much muscovite. 
Perthitic orthoclase occurs in small porphyritic crystals (3,933). 

The corresponding granite extending from Bolitho to Boswyn 
shows a passage to quartz porphyry, and the quartz is often 
idiomorphic. A specimen ftom Crowan Beacon may be described 
as a fine-grained porphyritic muscovite-biotite-granite with topaz. 
Both quartz and felspar occur as porphyritic constituents. The 
biotite is clear brown and weathering to chlorite. Topaz is fairly 
common^ but never idiomorphic. Muscovite is less frequent than 
usual. The ground mass is micro-granitic, and in places some- 
what poikilitic. Tourmaline is rare and occurs only in one or two 
small crystals (3,853). A specimen from the northern part of the 
mass, obtained from a locality a quarter of a mile south-east of 
Croft Michell, is really a quartz porphyry with porphyritic quartz 
and turbid felspars. These are often surrounded by coarsely 
graphic halos^ but the main part of the ground-mass is micro- 
granitic. Chlorite is common, probably after biotite. Muscovite 
is mainly secondary in the felspars. There are many large rough 
apatites, but only a few grains of tourmaline are visible. Dr. 
Fleit observes that the amount of micro-pegmatite in this rock is 
exceptionally large for a Cornish granite (3,851). 

A sample from the same locality, but in which mineral alteration 
and silicification is developing, is a porphyritic granite, with mus- 
covite, tourmaline, and biotite. The biotite is weathering into 
chlorite with strong black pleochroic halos. The tourmaline is in 
small ill-shaped prisms and always of a brown colour. Apatite is 
common. Muscovite is both primary and secondary. There is 
not much evidence of secondary quartz-tourmaline infiltration, 
although some of the felspars of the ground mass have been partly 
replaced by quartz and muscovite ; the porphyritic crystals, how- 
ever, are unaffected (3,852). 

Besides the normal condition of the granite^ in which the 
original mineral constitution is still intact save for a few un- 
important decomposition products, there are large areas in the 
parish of Wendron and on the western border where planes of 
fracture closely traverse the granite, and in which infiltration of 
quartz and tourmaline has modified the character of the rock. 
The bands and veins of quartz and tourmaline have already been 
alluded to, but in addition to these secondary veins the granite 
Itself has been converted into greisen, and the various stages of 
alteration can be followed from the unaltered granite into a normal 
greisen. Sometimes this complete change has been effected 
within the limits of a few inches. The veins have frequently 
been subjected to movement and breccias produced ; moreover, by 
the introduction of stanniferous material into the latter, we reach 
the stage of a mineral vein. The lateral transition from such 
mineral veins into normal granite can be favourably studied in the 
district of Wendron. Besides the decomposition of the felspar 
and its replacement by quartz and schorl, the biotite has been 
converted into chlorite ; the tourmaline, which in the normal 



58 IGNEOUS BOCKS. 

granite is usually brown, is often either entirely blue or edged by 
blue borders. The succeeding examples will illustrate the pro- 
cesses of alteration. 

The following specimen (3,850), taken from East Wheal Lovell, 
about half a mile east by north of Hendra, represents a fine- 
grained granite which passes gradually into the coarse normal 
type. The fine granite becomes progressively studded with 
porphyritic felspar crystals until finally the matrix is insignificant 
and the felspars exceed a square inch in size. The fine-grained 
specimen is a muscovite-tourmaline-graoite without biotite. 
The felspar is orthoclase with a small amount of plagioclase. The 
tourmaline occurs in irregular zonal brown prisms, sometimes 
edged with blue, and often with blue pleochroic halos, but never 
fibrous and rarely idiomorphic. Muscovite is common in large 
idiomorphic tablets, and also as small secondary scales in the 
felspars. Large irregular apatites are numerous, and the quartz is 
full of fluid cavities. 

The next specimen (3,854), from a locality three-quarters of a 
mile north-east of Hendra, is a granite which, although showing 
mineralisation in the field, yet in the slide only exhibits the earliest 
changes in the form of conversion of the felspars into micaceous 
aggregates. It is a muscovite-biotite-granite with tourmaline. 
The rock is fairly coarse in grain, and shows pink felspars, which, 
at a distance of rather more than an inch from the joint face are 
fairly fresh and have their characteristic twinning and micro- 
structure, but nearer the joint become dark grey and are changed 
into aggregates of pale shimmering mica. Silicification is not 
conspicuous. Muscovite and biotite are both present in well- 
formed crystals. The latter is decomposing into dark green 
chlorite. Brown tourmaline occurs in scattered grains and in 
spongy masses which prove to be in graphic intergrowth with 
quartz. It is only rarely blue upon its edges. 

In the next rock (3,864), from Medlyn Moor Mine, the granite 
is passing laterally into a quartzose modification or schorlaceous 
greisen. In the granite there is a little brown schorl and much 
muscovite, chlorite probably after biotite, and large crystals of 
perthitic orthoclase. In the greisen quartz preponderates, the 
brown tourmaline has well-marked blue borders, the felspar has 
disappeared, and its place is taken by aggregates of quartz, fine 
muscovite, green chlorite in small subradiate scales, and occasional 
needles of pale blue tourmaline. The original muscovite, in large 
stout crystals, remains unchanged. The slide shows the various 
stages of alteration of the felspar, which can be clearly followed 
in a distance of less than a quarter of an inch measured at right 
angles to the surface of the fissure. 

In another specimen from the same locality (3,855) the felspar 
has practically entirely disappeared, having been replaced by 
quartz and muscovite. There are a few prisms of tourmaline, 
brown in their centres and blue on their surfaces. Apatite and 
chlorite are also present. This is a granite that has been con- 
verted into greisen. 

The granite is often traversed, a"^ already described, by quartz- 



GRANITE. 59 

toarmaline veins. A specimen was sliced from Rame Common 
(3,856). In the vein the quartz is granular, and the tourmaline 
is blue and prismatic. The granite is rich in muscovite and in 
chlorite after biotite, some of this chlorite being vermicular. 
Tourmaline is found in the granite in large brown crystals ed^ed 
with blue, and apatite is rather common. The felspar is much 
altered and rarely shows its characteristic micro-structure, being 
largely converted into muscovite, quartz, and kaolin. 

A quartz-tourmaline vein in the granite half a mile north-west 
of White Alice (3,862) is filled with alternating layers of dark blue 
tourmaline peach, and quartz with a smaller amount of tourmaline. 
Some of the quartz veins are comby, but there is little or no 
brecciation. 

The next stage is represented by the brecciation of the vein- 
stone. A specimen from East Wheal Lovell illustrates this type 
(3,863). It consists of fragments of white milky quartz, with 
many fluid cavities, and filled with small tx)urmaline crystals. 
These are surrounded by fine dark bluish green peach, and some 
large crystals of brown tourmaline are also present in the slide, 
with their cracks and borders often fringed with blue needles. 
This tourmaline is frequently broken, and is probably of the same 
age as the early milky quartz. A few thin later quartz veins cut 
the whole mass. The blue tourmaline, therefore, is clearly later 
than the brown crystals, having filled its cracks. 

The following specimen from Porkellis Moor (3,857) illustrates 
still more clearly the progressive products of infiltration. This is a 
brecciated quartz-tourmaline vein, in which white fragments of 
quartz are lying in a dark blue matrix of tourmaline peach. This 
quartz is white, milky, and contains vast numbers of nuid cavities, 
but little tourmaline. It is surrounded by a cementing material 
of finely granular quartz filled witti blue or bruish green needles 
of tourmaline, and the whole mass is cut by later veins of clear 
quartz with small indigo-blue tints. The earlier quartz fragments 
are often crushed and give undulatory extinction ; the quartz 
of the later veins is granular and uncrushed. There are thus 
three periods of infiltration, viz. : — 

1. Quartz. 

2. Peach. 

3. Quartz with tourmaline. 

Local folicUian, — Besides the rude orientation of the granite 
to which attention has already been drawn, a more pronounced 
foliation has been occasionally set up both in the main mass 
and in some of the smaller sills that fringe its border. 

In the neighbourhood of Kennal Vale, near Ponsanooth, the 
granite is very distinctly foliated for a distance of about half a 
mile from its margin. The orientation set up is very obvious, 
having a strike of about north-north-west, which corresponds to 
the trend of the *^ cleaving-way " joints. Here the orientation is no 
longer restricted to the parallelism of a number of the elongated 
minerals (porphyritio felspars) producing the '^ grain/' but there 



60 IGNEOUS BOCKS. 

are definite planes in the rock which dip steeply towards the 
margin of the granite, and the mass is sometimes so foliated that 
its schistose character can be detected in a hand specimen. The 
foliation agrees in its trend and general hade with the correspond- 
ing planes in the slates which flank its margin. A specimen 
obtained one-sixth of a mile north-east of the Powder Mills, near 
Ponsanooth, is seen under the microscope (3,558) to be a sheared 
muscovite granite. The rock is pale coloured and contains very 
little biotite. The felspar is mainly perthitic orthoclase, much 
weathered with the production of secondary muscovite. Primary 
muscovite is common, and there are one or two grains of tourma- 
line, but no andalusite. In many places the rock shows cataclastic 
structures. The quartz is often broken up into a mosaic of 
interlocking grains. The amount of crushing varies in different 
parts of the section and is most pronounced in certain narrow 
undulating bands, along which there is often a layer of parallel 
scales of muscovite.' 

About 200 yards north-north-west of Lower Tretharrup, in the 
district of Lanner, a fine-grained granite has been quarried. It 
occurs within the normal granite, and is in the nature of a con- 
temporaneous vein. It is about 15 yards in width, but thins 
in a south-westerly direction. It behaves somewhat like an 
elvan, and hades steeply to the south-east. The normal, coarse- 
textured granite is rich in biotite. This mineral, however, is 
absent in the vein, a specimen of which, seen under the micro- 
scope (3,872), is a fine-grained muscovite granite, with a few 
crystals of brown and green tourmaline. The rock is very rich in 
muscovite, but contains neither biotite nor chlorite. 

For the following analyses of the Carnmenellis granite we are 
indebted to Messrs. John Freeman & Co. : — 





Ptnryn. 


Camaew. 


Silica . - - 


72-84 


7205 


Alumina - - - 


16-25 


15-83 


Ferric oxide - 


•14 


•39 


Ferrous oxide - 


1-49 


1-50 


Lime - - . 


110 


114 


Magnesia 


•55 


•51 


Sodium oxide - 


2-25 


2-65 


Potassium oxide 


519 


^•79 


Moisture and loss 


•63 


•64 




100-44 


99-50 



Smaller Intrusions Flanking the Carnmenellis Granite. — 
The smaller granite intrusions which fringe the Carnmenellis 
mass are mainly confined to that portion of its western border 
situated between Crowan and the valley of the Cober. On the 
east two pmall examples occur near Budock, and another in the 
neighbourhood oi IVeluswell. 

With the exception of the bosses near Budock, these marginal 
intrusions usually take the form of small sill-like masses parallel 



ORANIIE. 61 

to the granite border. They are marked by a teztare finer than 
that of the main mass, and differ in minend composition, owing 
to the presence or absence of tourmaline or of biotite. Some 
are trae aplites, while in other cases the rock more properly falls 
under the category of greisen. Moreover, their structure shows 
an equal variation, some exhibiting cataclastic characters, and 
even foliation. An example of the latter is afforded by two sills 
that flank the granite margin at Treluswell, near Penryn. In 
the railway cutting these foliated sills are interposed between the 
slates, and appear to have participated in some of the stresses to 
which the latter have been subjected. They are about 30 yards 
distant from the granite junction, and share in the hade of the 
slates, which dip away from the main granite. Their foliation 
planes correspond with the cleavage planes of the slate between 
which they are intercalated. Microscopic examination (3,364), 
shows them to be fine-grained granite, cataclastic, and distinctly 
foliated. The quartz is all crushed, and in addition to felspar 
the rock contains both muscovite and biotite. The evidence 
favours their modification by pressure before final consolidation, 
the repeated intercalation with the slate that marks their upper 
junctions suggesting folding. It is possible, however, that the 
irregularities of the junctions may represent the original in- 
trusion, and that the foliation may have been induced after 
solidification. 

Between Trannack and Praze, sills of granite, often closely 
contiguous, are exposed in the cuttings of the railway. The 
absence of good sections in this district precludes a satisfactory 
examination of the granite margin, and it is probable that the sills 
drawn on the map, and which are almost entirely confined to the 
railway cuttings, quite inadequately represent the minor granite 
intrusions of this tract of country. 

The largest mass noted is seen in the railway cutting above 
Wheal Trannack, at a distance of about 200 yards from the 
edge of the main granite. Although of variable texture, this 
marginal intrusion is chiefly of fine grain, often recalling the 
finer veins of the Carnmenellis granite. It is frequently studded, 
however, with porphyritic felspars, some of which attain an inch in 
length, but their occurrence is attended with great variation. 
Biotite is often very plentiful, and tourmaline is sometimes 
present. It differs from the main granite mass in its immediate 
vicinity, which is of coarse and uniform texture as far as its 
margin. On the valley slope, where a quarry has been opened, it 
is interbanded with the slate. 

A small sill, a quarter of a mile west of Truthall, is seen under 
the microscope (3,934) to be a rather fine-grained schorlaceous 
greisen, which has been sheared, so that the quartz and felspar are 
often granulitic, the quartz showing undulatory extinction, and 
forming an interlocking granulitic mosaic. The muscovite is 
bent and dragged out. The shearing, however, is not visible in 
the hand specimen. 

Another sill, occurring about half a mile west of Tregathennan, 
is a highly quanzose rock, containing very little felspar, and is 



62 IGNEOUS SOCKS. 

almost a schorlaceous greisen. It is fine-grained, with primary 
and secondary muscovite, orthoclase^ plagioclase^ and apatite 
(3,935). 

A sill situated one-third of a mile east of Chynbale is a fine 
aplite (3,936), with decomposed felspar and quartz in a mosaic of 
very irregular interlocking grains. In the hand specimen a 
few blebs of quartz are visible. There is no tourmaline or 
biotite. 

Carn Brea Granite. — This granite forms a lenticular mass, 
trending north-east and south-west for a length of about four 
miles between Hedruth and Pendarves. It is clearly an extension 
of the Carnmenellis granite, being separated from the latter by a 
strip of killas with an average width of little more than half a 
mile, while in the neighbourhood of the Condurrow and Grenville 
mines the two granites more closely approach one another, 
the intervening killas occupying about one-eighth of a mile. 
The subterranean connection between the two masses is demon- 
strated by mining operations. 

This granite forms the rugged and picturesque hill of Carn 
Brea, where its rude prismatic jointing and coarsely stratiform 
structure are admirably displayed. (Plate VII.) To the north- 
east, after crossing Church Coombe, it contracts to a thin tongue, 
which extends as far as Hedruth, about half a mile distant from 
the western margin of the Carn Marth granite. On the south- 
west, from Camborne Beacon to the neighbourhood of Bottetoe 
Bridge, it occurs as a narrow strip, converging to a point For 
the Tatter part of its course, however, within the grounds of 
Pendarves, it does not protrude at the surface, and its boundaries 
can only be appioximately drawn. 

It is a tourmaline-muscovite-biotite-granite like that of Carn- 
menellis, and conforming to the same system of jointing, and in- 
cludes a similar assemblage of contemporaneous veins of fine- 
grained granite or aplite. On the slopes of Carn Brea it is of 
coarse texture, but at The Hocks, between Camborne Beacon and 
Pendarves, where it contracts to less than 300 yards in width, the 
texture is finer, but it still contains porphyritic felspars up to an 
inch in length. 

In a quarry about a quarter of a mile north-east of Bosleake 
the granite exhibits a singular regularity in the arrangement of 
the finer-grained aplite veins. The normal rock is of coarse 
texture, the felspars exceeding an inch in size. Tourmaline is 
scarce. Biotite is abundant, and also white mica, the latter often 
a lithia mica and occurring in large plates with pinkish hues. 
The aplite veins are marked by a strict parallelism with a 
dip of 30 deg. to the south-east, and are sometimes studded 
with large felspars identical with those in the adjoining granite. 
These finer veins vary in width from six inches to one inch. 
Moreover, there is a subordinate system of jointing parallel to 
them. The " cleaving-way " joints of the granite are N, 85 deg. 
W., with the larger felspars orientated in a like direction. The 
'^ tough-way " joints are about N. 45 deg. E. There is also a vertical 
system of Assuring parallel to the " tough-way " joints, which cut 



OBANITE. 63 

throagh the aplites and contain tourmaline. The aplites are 
moreover disturbed by the subordinate system of parallel jointing 
already alluded to. The coarse granite in this quarry contains 
some fluorspar. 

A quarry on the western border of the granite, about a quarter 
of a mile west south-west of Camborne Beacon, shows a mixture 
of tine-grained biotite-granite and pegmatite. Amongpt the 
granite large individuals of white felspar, of irregular shapes, and 
reaching a size of five or six inches, are abundantly interspersed. 

The margin of the granite is exposed along the railway cutting 
between Brea and Penhellick, and a specimen obtained at the 
railway cutting near Cook's Kitchen Mine shows an unusual 
amount of mechanical deformation. Under the microscope (3,931) 
it is seen to be a granulitic fine-grained muscovite granite. The 
quartz is much crushed, and everywhere shows cataclastic 
structures, and the felspar is mainly replaced by aggregates of 
quartz and muscovite. There are a few grains of sphene and of 
brown tourmaline. The muscovite is often much puckered and 
bent. 

About half a mile north-east of Camborne Station, and rather 
over 200 yards from the granite margin, a sm^l dyke of fine- 
grained granite traverses a greenstone. It is a tourmaline granite, 
containing also a little biotite but no primary muscovite. Plagio- 
clase is common in well- formed crystals, but the orthoclase and 
quartz are quite irregular. 

The following analysis of the Cam Brea granite was made by 
Mr. J. A. Phillips* :— 

Water i ^^Jgr^metric - - -34 

^^^^ \ combined ... -89 

Silica 74-69 

Alumina 16-21 

Ferrous oxide - - - - 1*16 

Ferric oxide ----- trace 

Manganous oxide - - - - -58 

Lime -28 

Magnesia '48 

Potassa - ... - 3-64 

Soda 118 

Lithia - . - . . -10 



99-55 



Specific gravity - - 2'64 

Garn Marth Ghanite. — The Carn Marth granite forms an 
irregular boss between two and three square miles in size. It ex- 
tends from the eastern side of Redruth to St. Day, and from the 
vicinity of Mount Ambrose on the north to the southern slopes of 
Carn Marth on the south. Its southern margin approaches within 

♦ Q.J,0,:$. y'yol xxxi., 1875, p. 330, 



64 IGNEOUS BOCKS. 

about 130 yards of the Garnmenellis granite, in the neighboarhood 
of Pennance, while mining operations show that below the surface 
these granites still further approach one another, even if they are 
not actually contiguous Its boss-like shape, however, rather 
suggests an independent intrusion than an outlier of the Cam- 
menellis granite. Moreover^ in spite of its general petrological 
relationship to the latter, its teztural arrangement appears to be 
somewhat different, while tourmaline is also probably of more con- 
stant occurrence. The textural character of this granite is marked 
by the slenderness of the porphyritic felspars, a feature which 
appears to give it a distinct individuality as compared with the 
granites of Garnmenellis and Carn Brea, and it possibly represents 
an independent intrusion from the same magma basin. 

This rock is likewise characterised by an excess of biotite, 
the muscovite being usually subordinate. In some cases, how- 
ever, the two micas are more equally apportioned. It is rare, 
however, to find a section in which either tourmaline or biotite 
are not prominent constituents, and in this respect the granite 
markedly differs from that of Garnmenellis. In the quarries at 
Garn Marth the texture is often somewhat coarse, some of the 
felspars measuring 1^ inches by 1 inch. 

In a quarry about 70 yards north-west of Garn Marth it is sub- 
ject to considerable differentiation and banding is common, the 
rock being as a whole of somewhat coarse texture^ but inter- 
mixed with a fine-grained biotite granite, which sometimes con- 
tains porphyritic felspars. This fine-grained porphyritic type 
may occur along the horizontal floors, or as irregular veins, and 
sometimes in large nodular forms. In some of this granite there 
are concentric selvages. In one instance a coie of coarse dark 
granite three feet in diameter is bounded by a thin ring of 
schorl ; this is succeeded by a zone one to two inches wide of 
felspar, that passes outwards into granite very rich in tourmaline, 
parts of which are highly felspathic. 

In another instance the successive rings of schorlaceous and 
felspathic material contain felspars with a uniform orientation in- 
dependent of the concentric structure. 

In some cases the core is of fine-grained schorlaceous granite, 
surrounded by rings of coarser normal granite. The interbanding 
and concentric structures are not constant, but the various segre- 
gatory types are sometimes imperfectly mixed. A few of the 
vertical bands that coincide in direction with the '' tough-way " 
joints contain porphyritic felspars two to three inches in size. 

III. Elvan. 

Elvan dykes are abundantly distributed in the districts of 
Camborne, Redruth, Gwennap, and Chacewater.- To the east of 
Truro and tne Carrick Roads they have not been detected, and 
they are likewise absent in the belt of country that fringes the 
north coast. In the remaining area, lying approximately south of 
Garnmenellis, their occurrence is sporadic. The tract in which the 
elvans are conspicuous, extending approximately from Camborne 



ELVAN. 65 

to Baldhn, also represents the principal metalliferous region. 
Moreover, the trend of the elvans (about east-north-east) corre- 
sponds with the general direction of the mineral lodes. Elvan 
dykes occasionally trend in other directions, but this is far from 
common. While some can undoubtedly be traced for two or three 
miles, the bulk of these dykes are continuous for only very short 
distances, and it is probable that the map somewhat exaggerates 
their general continuity. They vary from a few feet to many 
yards in thickness, while in some instances they attain great 
dimensions. They are usually very steep, and the hade in the 
majority of cases is to the north-west. A considerable number 
traverse the granite and a few cut the greenstones. No instances, 
however, have been observed during the progress of the survey 
where the elvans and mica traps are in juxtaposition, and their 
relative ages, therefore, cannot be definitely fixed.* 

Their petrological relationship to the granite is so obvious that 
there can be little doubt that they represent its dyke phase. 
They exhibit, however, considerable variation both as regards 
texture and mineral composition. In their resistance to weather- 
ing they differ considerably, some affording excellent building 
stone, while others have so decomposed as to be worked for clay. 
Their colour ranges from pale grey to pink, while some are dark 
and of a greenish hue. They are frequently bounded by a finer- 
grained selvage, and in exceptional cases the rock is somewhat 
banded. So far as this districtt is concerned, they are character- 
ised by a micro-granitic ground mass, which varies in texture 
from fine to fairly coarse. In this matrix phenocrysts are usually 
scattered, and they are often idiomorphic, and consist of quartz, 
felspar, generally perthitic orthoclase, sometimes plagioclase, 
biotite, and occasionally muscovite. The porphyritic constituents 
may all be present, or be represented by one or two of these 
minerals only, but quartz is seldom absent, while occasionally no 
porphyritic minerals are enclosed. The porphyritic quartz is often 
corroded at its edges, while the felspars are frequently wholly 
or partially decomposed, with production of secondary white 
mica, and the biotite frequently passes into chlorite. Original 
white mica is not common as a porphyritic constituent. The 
minerals of the ground mass are quartz, felspar, usually ortho- 
clase, white mica, biotite, and apatite. Finite is rare, but 
tourmaline is often present, sometimes as an original con- 
stituent, but generally as a secondary infiltration product. 
The groundmass often contains micropegmatite and is occa- 
sionally micropoikilitic. Very frequently its felspar has been 
more or less completely replaced by a fine-grained mixture of 
muscovite and quartz. Most of the elvans are granite-porphyries 
or micro-granites, and some are aplites, while others belong to the 
granophyres. The schorlaceous varieties are mainly confined to 



♦ Mr. Collins, however, has described a junction that yv\\\ be referred to 
in the description of the mica traps. 

t Mr. J. A. Phillips has described the general petrographical characters of 
the CJomish elvans. Q.J,O.S., vol. xxxi., 1875, p. 334. 



66 IGNEOUS ROCKS. 

the great belt in which the mineral veins are sitoated. Toar- 
maline, when original^ is usually of the ordinary brown colour, 
while the blae varieties are more commonly found as secondary 
infiltration products^ the latter tint either pervading the entire 
mineral or forming a border around the brown individuals. In 
the process of mineral alteration by impregnation with silica and 
schorl, the felspar of the rock has often entirely disappeared, and 
biotite has been wholly or partially replaced by chlorite. In some 
mineralised elvans^ however, the biotite has not been attacked, 
and apatite has also offered considerable resistance to decom- 
position. 

As these dykes are so numerous, only a few of the more 
important will be described. A typical elvan is quarried at 
^Nansavallan Wood, about a mile to the south-west of Truro. 
This dyke, which hades steeply to the west, is probably at least 
from 26 to 30 feet thick. It is a granite porphyry, with por- 
phyritic felspar, quartz, and biotite. These felspars attain an 
inch in lengthy while occasionally the biotites are equally large. 
The quartz occurs in bleb-like forms, which sometimes exceed a 
quarter of an inch. The groundmass of the rock is rather coarse. 
For several feet from the edge of the dyke the porphyritic crystals 
are absent, and this portion of the rock is sometimes banded 
(3,358). 

The elvan that is quarried at Enys is of similar type, but finer in 
texture, and hades about 70 deg. to the east-south-east. 

A dyke traverses the gpranite for over a mile between Town- 
tanna and Trevales — on the old map it has been drawn for a mile 
farther in a south-west direction, but no evidence is at present 
available for such extension. At the quarry at Towntanna it 
occurs as a medium-grained grey elvan, 25 to 30 feet in thickness, 
with porphyritic felspars up to half an inch in size. It is 
irregularly jointed, with the prominent joint planes oblique to the 
horizontal. Under the microscope (3,360) it is seen to be much 
decomposed, with many small phenocrysts, and only a little ground- 
mass. This dyke, where it is quarried near Trevales, is more 
regularly jointed, some of the "quartering-way" joints ("floors*^ 
of the granite being continuous into the elvan. Moreover, one of 
the main joints of the latter corresponds with the *' cleaving- 
way *' joint of the granite. The more horizontal joints, however, 
of the elvan are uneven, and cut one another obliquely. The 
dyke is more or less vertical, with a junction not quite regular. 
Its margin is veined with haematite, which partially stains the 
dyke, imparting a red colour. It is here about 18 yards in 
width, and its face is slicken-sided. There are some large 
individuals of porphyritic felspar and some quartz blebs, but 
the biotites are small. Under the microscope (3,361) the ground- 
mass is seen to be micro-granitic. 

An elvan which attains abnormal dimensions extends from 
Greensplat to Lanner Moor. From Greensplat it follows a 
westerly direction by Frogpool, Pulla Cross, and Gwennap. It 
passes to the south of Trevince, and soon after curves round 
in a west-south-west direction to Lanner Moor. It varies in 



ELVAN. 67 

width from 150 to at least 300 yards. This dyke conforms 
to the normal type, and contains porphyritic crystals of quartz 
and turbid orthodase in a microgranitio groundmass of quartz, 
felspar, and secondary muscovite. Many of the felspars are 
entirely replaced by white mica (3,834). At Frogpool the 
phenocrysts are quartz« felspar, and biotite, and the matrix is 
micropoikilitic (3,442). To what extent the width of outcrop 
represents its thickness cannot be ascertained^ as its hade is 
uncertain. The porphyritic felspars are sometimes of one-half to 
one inch in size, and the quartz is frequently idiomorphic. A 
good section is afforded by the road cutting in the hill above 
Comford. On its eastern boundary, two smaller dykes in the 
neighbourhood of Cold wind may possibly represent branches, but 
the evidence is insufficient to connect them with the large mass, 
and a like obscurity attends its western limits at Lanner Moor. 

The elvan dykes between St. Day and Perranwell are extremely 
difficult to trace. Information from mine plans has been utilised 
where available, but as many bands encountered underground do 
not appear at the surface, this source of information is far from 
reliable. A few of the dykes from this area will now be 
described. 

A band that can be followed from the vicinity of the large 
Owennap elvan, from Greensplat to Greenwitb, and which 
is possibly identical with the elvan extending from Higher 
Camon to Killiow, is seen at the quarry near Pencoose to bade 
30 deg. to the north-west. It is about 20 to 30 yards in width, 
and contains porphyritic felspars an inch in length, with smaller 
quartz blebs and mica in a fine-grained grey matrix. It is 
traversed by strong splitting planes hading 60 deg. to the south- 
east. In the quarry near Grreen with the rock is somewhat fresher, 
while under the microscope (3,441) it is seen to contain phenocrysts 
of corroded quartz, weathered felspar, and decomposed biotite, in a 
groundmass which is granular crystalline, composed of quartz 
and felspar, with secondary muscovite, chlorite, and calcite. 
Many of the elvans of this district occurring in the metalliferous 
area have been modified by mineral infiltration. A dyke at Wheal 
Itfaid is a schorlaceous quartz-porphyry, containing small, slightly 
corroded blebs of quartz, with plates of perfectly colourless musco- 
vite, in a matrix which is a micro-granitic aggregate of quartz 
and untwinned felspar filled with scaly secondary muscovik?. 
Tourmaline occurs throughout the rock in fairly large prisms, 
which in their centres are brown, but at their edges are blue 
with strongly-marked pleochroic halos, giving colours ranging from 
pale yellow to dark blue. Smaller prisms also occur, mostly blue, 
and in some instances a brown tourmaline is enclosed in a quartz 
phenocryst, but blue borders are then absent. Grrains of zinc- 
blende are also scattered through the rock (3,836). 

A dyke near Sparry Bottom has undergone considerable silicifi- 
cation. It is a dark coloured schorlaceous quartz-porphyry (3,842) 
containing porphyritic crystals of quartz which are not highly 
idiomorphic. The groundmass is chiefly quartz and muscovite, 
felspar being almost entirely removed, a change comparable to that 

F 2 



68 IGNEOUS SOCKS. 

taking place in the formation of greisen. Tourmaline is not 
abandant ; it occars mostly in small irregular prisms of yellow- 
brown colour, rarely bluish, and never fibrous. A specimen taken 
from another part of the dyke shows yet further alteration (3,841), 
but contains abundant blebs of the original quartz pheno- 
crysts. The whole rock has been filled with bluish tourmaline, 
which forms veins and irregular patches, and it is, moreover, 
fractured and distinctly brecciated. Areas of granular quartz are 
frequently developed in the groundmass, the remainder consisting 
of an aggregate of fine mica and minute quartz grains, while 
no felspar appears to be left. The tourmaline, in very fine needles 
mixed with quartz, resembles the *' peach '^ of the veinstones, but 
the section shows no tinstone. Another el van from near the same 
locality (3,845) is more thoroughly silicified, but contains a few 
conspicuous quartz crystals, one of which is an idiomorphio double 
pyramid. It consists of a fine mosaic of quartz, chlorite, and 
muscovite, with iron ores, pyrites, and limonite, and was probably 
originally a fine-grained non-porphyritic elvan. These rocks bear 
the same relation to the normal elvans as do the greisens and 
schorlaceous greisens to the granite. 

In the Ghacewater district, lying immediately to the north, a 
well-known elvan has long been quarried at Saveock Water. This 
rock is characterised by schorlaceous nests and patches which 
sometimes attain an inch in size. The dyke hades north-west, and 
the quarry is traversed by a cross course. The porphyritic con- 
stituents are felspar, which are about a quarter of an inch in size, 
and quartz blebs. Under the microscope (3,833) the phenocrysts 
of quartz and orthoclase are seen to be idiomorphic, the quartz 
showing few signs of corrosion and filled with large fluid cavities 
with mobile bubbles. Many of these cavities are negative 
crystals, and some contain small transparent cubes. The por- 
phyritic felspars are much decomposed, but are mainly perthitic 
orthoclase, although some are possibly oligoclase. A curious 
feature is the presence of porphyritic groups of coarser micro- 
pegmatite. Some of the porphyritic quartz is surrounded by an 
ill-defined narrow halo of smaller quartz grains in optical con- 
tinuity. The matrix is a microgranitic aggregate of quartz, 
cloudy untwinned felspar, and fine scales of muscovite. Chlorite 
is also present, often in radiate bundles, fairly dichroic. The 
tourmaline is practically confined to the rounded patches seen in 
the hand specimen. It forms small irregular grains, highly 
pleochroic, in shades of blue, bluish green, and pink, and appears 
to fill up the interstices between the grains of quarts, which 
constitute the remainder of the aggregates. It never yields perfect 
crystals and occasionally forms radiate groups. The structure of 
these patches is not poikilitic, but in some parts of the section 
there are small poikilitic areas. Larger crystals of quartz occur in 
them, evidently phenocrysts, and lead to the conclusion that these 
rounded spots are due to local tourmalinisation. Another well- 
marked dyke traverses Kerling Downs, where it has been quarried. 
This is a greenish elvan, rather fine grained, and dipping about 
40 deg. to the north-west, and sometimes decomposes to a rich 



ELVAN. 69 

orange coloar. UDder the microscope (3,848) this rock retains 
no igneous structure, except, perhaps, the chloritic pseudomorphs 
after idiomorphic biotite. It consists entirely of irregular grains 
of quartz with highly sinuous borders, turbid with innuni* 
erable enclosures of muscovite and of chlorite in small scales, 
sometimes radiate, but mainly quite irregularly dispersed. Felspar 
is absent, but some of the apatite remains, and the original quartz 
grains may occasionally be traced, surrounded by an extensive 
growth of newly-deposited silica, with which it is in optical con- 
tinuity. Pyrites and limonite are present in small quantity. 
This rock furnishes a good instance of silicification by post-volcanic 
processes. 

A silicified elvan that is quarried about half a mile south-west 
of Chacewater has been a fine-grained non-porphyritic pinitiferous 
biotite granite. It is about 5 or 6 yards wide and apparently 
hades to the north. It contains black scales of biotite, which 
under the microscope (3,835) are seen to be weathering to chlorite 
and rutile. One large pseudomorpb, consisting of scaly muscovite 
and chlorite, belongs to the pinite group. The mass of the rock 
consists of irregular grains of quartz, the felspar being almost 
completely replaced by silicification. Veins of granular quartz 
traverse the section, and in places this mineral forms nests which 
contain small needles of tourmaline. A peculiar clear green 
chlorite occurs in circular patches consisting of radiate bladed 
crystals, usually closely related to the infiltrated quartz and tour- 
maline, so that it may be regarded as a mineral of subsequent 
aqueous deposition, and is very similar to the chlorite of the 
tin-bearing veins. 

Another good example of a silicified elvan occurs in the same 
locality. Under the microscope (3,844) it shows many corroded 
quartz phenocrysts, and patches of scaly brown biotite absolutely 
fresh, some pyrites, apatite, and iron oxides. The matrix of the 
rock is a mosaic of rather large irregular quartz grains, which are 
filled with fine flakes of secondary muscovite, and no felspar is 
present. The secondary quartz of the groundmass surrounds 
the original quartz pbenocrysts, usually in the form of a broiid 
border in optical continuity with the central crystal, but easily 
distinguished from it by its turbidity and by the large number of 
enclosures which it contains. It is clear that the whole ground- 
mass has been reconstructed under the action of percolating 
siliceous solutions. 

Between Chacewater and the Camborne district there are 
numerous el vans that can be more continuously traced than usual. 
They lie mainly on the north side of the Carn Brea granite, and 
are most conspicuous in the tract between Pool and the western 
edge of the map, in the vicinity of Penhale Moor. To the east of 
Higher Gardew, near Redruth, a band is quarried on the margin 
of the Carn Marth granite, which it pierces. It is a porphyritic 
pinitiferous elvan (3,837), the phenocrysts being orthoclase and 
biotite, the latter decomposed into chlorite, together with pinite 
in well-formed idiomorphic small six-sided prisms. The band 
which cuts the granite further to the east, and which has been 



70 IGNEOUS BOCKS. 

quarried close to the main road, is possibly a continoation of the 
dyke last described. It has, however, suffered a great deal of 
alteration from mineral impregnation. It is a schorlaceous quartz 
porphyry, containing a considerable amount of ortboclase, with 
quartz, muscovite, tourmaline, and chlorite. The rock has been 
porphyritic, with a ratber coarse-grained quartzo-felspathic ground- 
mass, but this has suffered largely from silicification, and has be- 
come impregnated with quartz, tourmaline, and chlorite. The 
tourmaline is mainly brown, but sometimes bluish yellow, grey 
or colourlesF. The cblorite is of the grey-green variety with high 
polarisation colours characteristic of the tin veins (3,846). 

A dyke that pierces the Cam Brea granite, a little to the east of 
the Castle, is unusually coarse in texture, owing to the large number 
of phenocrysts. This is a granite-porphyry in which porphyritic 
crystals of quartz, orthoclase, and chloritised biotite are lying in 
a microgranitic groundmass of quartz, felspar, and scaly musco- 
vite. This elvan is about 12 yards wide, and nearly vertical 
Some of the porphyritic felspars exceed an inch in length, and 
there are schorlaceous patches 2 or 3 inches in size. On either 
side there is a chilled margin against the coarse granite about 2 
or 3 feet wide, but in this fine marginal portion porphyritic fel- 
spars are occasionally scattered. 

At Tuckingmill a pinitiferous elvan contains rounded nodules of 
quartz and blue tourmaline. The phenocrysts are quartz, ortho- 
clase, and pinite, and the groundmass is micro-granitic with scaly 
muscovite (3,941). 

An elvan from Higher Kosewame of the silicified type is 
seen under the microscope (3,942) to contain small phenocrysts of 
orthoclase, quartz, and chloritised biotite, in a turbid and flinty- 
looking groundmass, which, between crossed nicols, breaks up 
into irregular rounded patches of quartz, with intervening areas 
of fine decomposed products. 

The railway cutting west of Camborne Station affords an 
excellent example of an elvan intersecting a greenstone. The dyke 
which hades to the north is the usual type of granite porphyry. 
Phenocrysts of quartz, perthitic orthoclase, and chloritised biotite 
lie in a fine microgranitic groundmass, which in places is micro- 
poikilitic, and apatite is common (3,939). The north-easterly 
continuation of this band in the direction of Camborne is obscure, 
but to the south-west it appears to run for some distance through 
Higher Penponds and Barripper. 

Another elvan traverses the greenstone for a considerable dis- 
tance between Weeth and the railway cutting near the western 
edge of the sheet. Other localities where these dykes cut the green- 
stone are in the grounds of Bosewarne, and on the mineral rail- 
way track a little to the east of the latter locality. The el vans 
occurring to the south of Camborne between Beacon Hill and 
Gear Farm cannot be satisfactorily connected, owing to the 
paucity of the sections and the somewhat conflicting evidence 
obtained from the mining plans. 

On the east side of Beacon Hill a large quarry has been 
formerly worked, in which an elvan, about 30 yards wide. 



ELVAN. 7 1 

appears to uDderlie north. The rock, where seen, is fine grained, 
bat this textore may possibly represent its margin ; otherwise if 
this is the same dyke that occupies the railway cutting at Pengegon 
Coombe, just beyond the granite margin, it would appear to have 
undergone a considerable change in texture. It there underlies 
north, and is so coarse in grain that its decomposed portions 
might readily be mistaken for granite, the felspars often reaching 
three-quarters of an inch in size. 

The dykes that pierce the Garnmenellis granite are most 
abundant along its northern margin, especially at Bailer Downs, 
Four Lanes, and Croft Michell. Between Troon and Bolenowe 
Crofts a grey elvan occurs, with the usual northerly hade, and 
contains porphyritic felspars up to an inch in size, with some 
tourmaline. 

A very coarse-textured band runs from Bolenowe Moor to 
Croft Michell. It is a granite porphyry, 30 to 40 yards in width, 
hades steeply to the south, and presents chilled margins to the 
granite. A little to the east of Trebowland an elvan has been 
traced through Tredeague as far to the south-west as Treweege. 
It varies in texture from coarse to fine grain, and contains 
tourmaline in varying proportions, while in the coarser zones the 
porphyritic felspars reach three-quarters of an inch in size. 
Under the microscope (3,838), this rock is a schorlaceous granite 
porphyry, with porphyritic quartz, orthoclase, and biotite, in a 
rather coarse groundmass of microgranitic quartz and untwinned 
felspar. There is a little brown tourmaline, and blue needles of 
that mineral form occasional radiating bunches. A somewhat 
similar rock occurs a little to the south between Angear and 
Treskewes, a specimen from which (3,849) is a brecciated coarse 
elvan with tourmaline and muscovite, and traversed by veins of 
quartz and tourmaline. Short rough prisms of brown tourmaline 
are common, but the blue variety is rare, except in the quartz 
veins. The groundmass is coarsely microgranitic ; most of the 
muscovite and tourmaline are primary, and large irregular apatites 
are rather frequent. An elvan which occurs about three-quarters 
of a mile south-west of Carnmenellis somewhat resembles the 
dyke just described from Trebowland. Although not traced in 
the intervening area, which exceeds a distance of two miles, it 
seems to be on the same line. It is grey to pink in colour, 
contains porphyritic felspars up to three-quarters of an inch, 
porphyritic quartz, and much tourmaline, forming nests of stellate 
individuals as in the Trewbowland dyke. Under the microscope 
the rock is a schorlaceous granite porphyry (3,840), with numerous 
crystals of idiomorphic quartz and orthoclase, the latter having 
sometimes plagioclase at their centres. Biotite occurs also in large 
crystals, but is not common, and the presence of pinite is doubtful. 
The groundmass is microgranitic, and is filled with small musco- 
vites, while blue tourmaline with quartz forms certain rounded 
patches. Tourmaline is often radiate, but is usually granular, and 
the pleochroism of some crystals ranges from pale pink to dark 
indigo blue. Sometimes this mineral occurs in the interior of 
felspar crystals, but it is mainly confined to the groundmass. 



72 IGNEOUS ROCKS. 

A fiae-teztured grey elvan, belonging to the aplite groap, 
occurs at Tresevern Croft, where it appears to extend for at least 
half a mile. After being lost sight of for a mile, it again appears 
at Polmarth, and can 1^ followed for about three-quarters of a 
mile in the direction of White AKce. Whether the dyke is 
really continuous with that at Tresevern is uncertain. It is of 
precisely similar character, however, and is on the same line. 
Moreover, in neither locality would its presence have been 
detected were it not for the quarries and the assistance of local 
information. As in the quarry at Tresevern it pinches out 
entirely at its southern end, it is probable that the dyke reaches 
the surface in discontinuous strips. In this quarry it is about 
15 yards wide. At the northern end it deflects to the east, and 
becomes intermixed with the granite, but there is always a sharp 
distinction between the two rocks, and pieces of granite are often 
enclosed in the dyke. The horizontal joints of the adjacent 
granite are continued through the elvan. The dyke is fine 
grained and of a pale grey colour, with a few small phenocrysts 
of clear quartz, while porphyritic felspars are rare and 
always small. Under the microscope (3,831) the rock has the 
structure of an aplite, and consists of small irregular crystals of 
untwinned felspar and of quartz, the felspar occasionally showing 
rudimentary crystalline form. Much muscovite is scattered 
through the slide in small scales, apparently secondary ; but there 
are also occasionally idiomorphic plateii, which are, perhaps, 
primary. Plagioclase is practically absent. There are one or 
two small porphyritic crystals of quartz and felspar, the former 
not strongly idiomorphic, the latter well formed, but much de- 
composed. The rock is a very fair example of an aplite. In the 
quarry at Polmarth the elvan is precisely similar in appearance, 
and, like the rock at Tresevern Croft, pinches out to the south- 
west, after which it again widens. It is about 12 to 15 yards in 
breadth^ and hades very steeply to the north-west. The adjacent 
granite is partly mineralised, due to secondary infiltration, the 
vertical joint separating the granite and elvan forming a marked 
line of mineralisation. To the north-west of White Alice this 
dyke is again exposed in a small quairy with a similar hade, 
where it is about 12 feet wide. It may be considered as a type 
of elvan in which the felspar was especially abundant, but has 
been extensively replaced by secondary quartz and white mica 
(3,832). 

About half a mile south of TregoUs a fine-textured grey el van 
occurs, in which porphyritic felspars are rare, and, as seen in the 
field, bears a strong resemblance to the dyke just described. 
Under the microscope (3,847), irregular phenocrysts of orthoclase 
and quartz are seen in a groundmass of quartz, felspar, muscovite, 
and chlorite, some of the latter being after biotite, and much of the 
muscovite is also secondary. Tourmaline is only represented by 
a few small grains, but apatite is fairly abundant. Nearly two 
miles further to the south-west, but along the same line, this dyke 
apparently reappears between Wheal Enys and Bodilly Veor. It 
has been quarried about one-third of a mile north-nori:h-west of 



KLVAN. 73 

Crelly, where the width is about 20 to 25 yards, and the hade is 
steep to the Dorth-west. Under the microscope it is seen to be a 
fine-grained, pale grey aplite, consisting of quartz and felspar in 
sniall irregular granules, niized with minute scales of muscovite. 
There are one or two large idiomorphic felspars, and here and 
there an idiomorphic crystal of muscovite. 

At Polcrebo an el van about 16 yards in width crosses the 
railway. It is porphyritic^ with a microgranitic groundmass of 
quartz, felspar, and scaly muscovite. In this lie phenocrysts of 
quartz, pertbitic orthoclase, graphic intergrowths of quartz and 
felspar, and biotite weathered into chlorite. A few of the pheno- 
crysts are plagioclase, and there is one micaceous aggregate, 
suggesting pinite (3,938). 

An elvan which in the field resembles a very fine-grained granite 
is quarried at Praze Station. It is grey in colour and of very 
even texture, but occasionally a porphyritic felspar of larger size 
is seen. This dyke, which is from 15 to 20 yards in width, 
hades to the north. It has not been observed within the granite 
which is closely adjacent, but it extends in a south-westerly direc- 
tion to the margin of the map at Little Drym. Its passage 
through the park at Clowance can be followed by the line of pits 
from which stone has been formerly raised. It has also been 
quarried between Clowance Wood and Wheal Sarah. Under the 
microscope (3,946) it is seen to contain many small phenocrysts of 
felspar and of quartz, in a groundmass which is partly micro- 
graphic and partly microgranitic. Both biotite and muscovite 
are present. Dr. Flett observes that micropegmatiteis unusually 
common in this rock for a Cornish elvan, and generally forms 
well-developed halos around the smaller irregular phenocrysts. 
This rock belongs to the granophyre group. The elvan that is 
quarried near the roadside between Trevoole and Trenoweth 
closely resembles the dyke at Praze Station in outward appear- 
ance, but contains in addition small nesU of tourmaline. 

In the railway cutting, about one hundred yards south-east of 
Praze Station, an elvan appears to pierce a fine-grained tourmaline 
granite. This dyke (3,944) is the usual type of granite i)orphyry, 
in which the quartz phenocrysts are slightly corroded. One or two 
crystals of tourmaline occur enclosed within porphyritic felspar. 

In the region bordering the north coast two elvar.s have been 
traced for considerable distances, one passing through Menagissey, 
and the other extending from Treswithian Downs to Mawla. 
They both hade to the north-west, and sometimes, in the case of 
the latter, at a very low angle, as may be seen at Illogan. In these 
dykes the original orthoclase phenocrysts have frequently dis- 
appeared. Under the microscope the original quartz phenocrysts 
are bounded by a secondary outgrowth in optical continuity, while 
the felspars occasionally exhibit a similar structure (3,803, 3,804). 
Another group of dykes, extending from near Camborne to the 
western edge of the sheet, resembles the former, but according to 
Mr. Dixon their northerly hade is less, their felspars are less prone 
to alteration, and the outgrowths of the quartz phenocrysts are 
not constant. A further group occurs to the south of the latter, 



74 IGNEOUS ROCKS. 

to which it is oblique, having a trend more approaching east and 
west^ and in some cases hading to the south. Mr. Dixon observes 
that their matrix is generally coarser, that phenocrysts are rare, 
and that greisen and kaolin have been developed associated with 
tinstone. One of the latter type intersects a dyke of the pre- 
ceding group, and this evidence of posterior age, together with 
their pnenmatoly tic alteration, has led Mr. Dixon to the conclusion 
that tbe groups represent two successive periods of intrusion, the 
interval between which was possibly greater than that separating 
the latter injections from the metalliferous impregnations with 
which they were subsequently charged. 

Elvan branches occupying north-north-west fractures occur in 
the cuttings west of Two Barrows, and north-west of Coswinsawsin. 

The following analysis of the elvan from Newham Quarry, near 
Truro, was made by Mr. J. H. Collins, who describes it as a re- 
markably tine-grained elvan, showing almost no porphjfitic 
character* : — 

Water (hygroscopic) - - - -24 

„ combined - - - 2*04 

Silica 72-88 

Alumina ----- 14*47 

Ferric oxide ... - 2*45 

Manganous oxide - - - -82 

Lime '10 

Magnesia ----- trace 

Potash ) ^ ..,^ 

Soda / ^ ^^ 

Lithia 1 
Fluorine J " 



trace 



10015 



IV. Mica Traps. 

General Description and Lithological Characters. — The 
mica traps of this area were formerly included amongst the elvan 
group, but De la Beche refers to them as greenstone ; one of this 
tjpe was described as an elvan from Trelissick by Mr. J. A. 
Phillips.t Later the mica traps of Cornwall were described by Mr. 
J. H. Collins,^ who states that Mr. A. E. Bamett was the first to 
draw attention to this class of dyke in the Truro Kiver. Subse- 
quently the mica traps of this particular area have been described 
by the author.§ The course of some of these bands is shown on 
the old map by faint dotted lines. 

In this sheet they appear to be entirely confined to the minette 



♦ J<yum^ Roy. In$t. Com,, vol. vL, p. 419. 

t Q.J.O.S., vol. xxxi., 1875, p. 337. 

X Joum, Roy, Imt, Com,, part ii., vol. viiL, 1884. 

§ J. B. Hill. Tran9, R^, Geol, 8oe, Com,, vol. zii., part vii.^ 1902. 



MICA TRAPS. 75 

&mil7^ that is to say, the two principal ingredients are orthoclase 
felspar and biotite, while apatite, qoartz, and carbonates form 
the principal accessories. Augite has been rarely detected, and 
in these cases the rock is more correctly designated as augite 
minette. Owing to their advanced state of decomposition the 
felspars are not always sufficiently well preserved for identifi- 
cation, and it is posAible that kersantites may be included 
in the group. In their field behaviour they bear a close 
resemblance to the lamprophyres of the Scottish Highlands, 
especially in their irregular sill-like characters and in their in- 
clusions. In Cornwall, however^ they are far more decomposed, 
bat this character is shared in common with Cornish rocks 
generally. These rocks are similar in composition, state of pre- 
servation, geological age, and mode of occurrence to the lampro- 
phyres of GiimbeU which occur as small dykes (usually running 
N. and S.) in the PalsBozoic strata of the Fichtelgebirge, Tbiiringer 
Wald and Voigtland, that occur in strata as high as the Culm 
measures.* In the South of Scotland and the North of England 
they pierce Lower Palsdozoic rocks, while in the Scottish Highlands 
they are allied to the newer granites, and may possibly be of Lower 
Old Bed Sandstone age. In Cornwall Mr. J. H. Collinsf considers 
them to be anterior to the granites, an opinion that finds some 
support in their having undoubtedly shared to some degree in the 
stresses that have affected the district, as will be shown later. On 
the other hand, rocks of this class in Devonshire have been found 
by Mr. Ussher to pierce the Permian. 

The minettes do not occur within the granite aureole, nor do 
they exhibit metamorphism other than that resulting from 
atmospheric decomposition. They are never granulitised, but 
there are instances in which the micas have been bent and 
contorted. The biotite is sometimes bleached to a pale white 
colour, and in some instances this mineral has been entirely 
replaced by chlorite. They present a rusty brown aspect in the 
field, and are so weathered that fresh specimens are obtained with 
difficulty. They occur as sills and dykes that can be followed for 
very short distances among the slates, on which they have effected 
a limited amount of contact alteration, confined to the induration 
of the marginal slate for a width of six or nine inches. Their 
intrusive character is apparent ; the same mass which lies between 
the strata as a sill may suddenly divert its course and behave as 
a dyke, while small veins penetrate the adjoining strata. They 
vary from a foot in width to fifty yards, but the latter does not 
correspond to the thickness of the sill, which is probably consider- 
ably less. They frequently display spheroidal weathering, the more 
solid cores beitg encircled by concentric outer layers of exfoliating 
material. Flow structure is not uncommon, especially in the finer- 
grained marginal portions. In some rocks exhibiting fluxion 



• Teall, •• British Petrography,"^. 351. 

t Jimm, Boy, Intt. Cam., vol. xiii., p. 203. Mr. Collins considers the mica 
traps to have been injected *' about Uie close of the Devonian period." 



76 IGNEOUS BOCKS. 

the spheroidal cores are elongated Id the direction of flow, 
while rounded quartz inclusions lie with their long axes in a 
corresponding position. Notwithstanding their decomposition, 
the mineral constitution of these rocks can generally be recognised 
as a medium-grained admixture of biotite and felspar, while in- 
clusions of quartz and crystalline felspathic rock are characteristic, 
and slate fragments are frequently seen. The inclusions both of 
quartz and felspar are of rounded, angular, or even of rectangular 
shape. Notwithstanding the abundance of quartz inclusions, this 
mineral does not appear to enter largely into the composition of 
the matrix. They vary considerably in the distribution and 
abundance of felspar, some of the fresher parts appearing to be 
made up almost entirely of this mineral. They dififer likewise in 
texture, some corresponding to coarse-grained dolerites^ while 
others assume the texture of basalt. In the coarser sills the 
biotite plates retain their normal dimensions in the fine-textured 
marginal portions. 

They appear to have been intruded after the slates had been 
cleaved, but before the cessation of the stresses. This may to 
some extent account for their occurrence in discontinuous patches. 
Some of their joint planes are parallel to the movement planes in 
the adjoining slates, and there is a tendency to a parallel structure 
and orientation corresponding to the latter. The minor faults in 
the adjacent killas have often afifected the mica traps and 
heaved them. They do not penetrate the cross courses (N.N.W. 
faults) and are almost certainly older than those fissures. 

Distribution and Field Relations. — The mica traps are of 
sporadic distribution in a narrow belt of country running approxi- 
mately north and south across the map, on the horizon of the 
Carrick Roads and the continuation of the Fal estuary as far as 
Truro. In that tract these rocks occur at the following localities, 
viz., Pendennis Point, Penryn, on the coast of Carrick Roads 
below Messack ; on the River Fal at Channals Creek, and on the 
coast below Pill Farm (south of Trelissick), and at the entrance of 
Cowlands Creek and of Lamouth Creek ; at Higher Trelease and 
Penpoll, at the western mouth of Lambe Creek, and on the t^hore 
below Penpoll Wood. To the north-west of Truro they occur 
near Gloweth, Boscolleth, and at Shortlane End. 

Of these various exposures those occurring on the coast are alone 
susceptible of critical study, the inland localities yielding only the 
decomposing surfaces of their outer crusts. 

One of these mica trap?, originally noticed by Mr. A. K. 
Barnett,* was analysed by Mr. J. A. Phillips,t and subsequently 
by Mr. J. H. Collins. J The following analysis and description of 
this rock is taken from Mr. Phillips' analysis of the rock from 
Trellissick Creek, north of Carrick Roads : — 



* Report Miners' Assoc, of Cornwall and Devon, 1S73 

t Q.J,0,S„ vol. xxxi., 1876, p.- 336. 

t irons. Boy. Geol, Soc, Cornwall, vol.ix.,p. 221 



MICA 


TRAPS. 






''•'" {SEfi" 


- 


- 


•34 
611 


Silica . 


- 


- 


47-35 


Alamina - - - 


- 


. 


20-60 


Ferrous oxide - 


- 


- 


1-60 


Ferric oxide - 


- 


- 


310 


Manganous oxide 


- 


- 


trace 


Lime - - - 


- 


- 


4-72 


Magnesium oxide - 


- 


- 


612 


Potash - 


- 


^ «i 


6-29 


Soda 


- 


- 


3-58 


Fluorine 






trace 
99-81 


Specific gravity 


- 


2-70 





77 



Mr. Phillips remarks that this elvan belongs to the north and 
south class. The width is about 30 feet, '^ and its colour varies from 
yellow or buff to a dark chocolate-brown, in accordance with the 
less or greater degree to which the iron present has become 
peroxidised. Its general appearance is that of a rock composed of 
a large quantity of mica, with a little fels^mr, enclosing occasional 
crystalline fragments of quartz." 

" Under the microscope thin sections are seen to consist of a 
nearly equal mixture of quartz, felspar^ and brown mica, enclosed 
in a felspathic base. The felspar is monoclinic, and the quartz 
contains a few small gas-cavities ; but no well-defined fluid- 
cavities containing bubbles were observed.'* 

Dr. Teall* records that a section in the British Museum, pre- 
pared from a rock in the same locality, contains a nearly colourless 
augite^ abundant apatite, and octahedra of magnetite, in addition 
to the constituents mentioned by Mr. Phillips, and that the rock 
is a typical augite minette. 

The dyke described by Mr. Phillips is in all probability the 
mass that strikes the coast about half a mile S.S.W. of Trelissick. 
It is here about 50 yards in width and cuts the killas at low 
angles. Its southern junction is dipping at an angle of 10 deg., 
while its northern wall hades at an angle of 30 deg. in the 
opposite direction. The latter margin is highly disturbed, and 
some of the mica trap is seen abutting against the slate at a 
distance of 12 yards from the main junction, which is apparently 
marked by a small thrusU The rock is much decomposed and 
displays spheroidal weathering. The matrix is an admixture of 
biotite and felspar, but it contains quartz inclusions two or three 
inches in size and pegmatite veins an inch in width. The quartz 
inelusions are often rounded and sometimes brecciated. Some 
of the spheroids are bound by material showing fluxion structure. 
It has a narrow selvage of finer-grained material confined to a few 
inches in width, in which the biotite flakes, however, are still of 



* (t 



British Petrography," pp. 353 and 355. 



78 IGNEOUS BOCKS. 

large size. It indarates the adjoining slate for a distance of eight 
or nine inches. The parallelism of its joints to those of the 
adjoining slates, the brecciation of some of its qaartz inclusions, and 
the character of its northern junction, points to its having shared 
in some of the disturbances that have affected the killas. A 
specimen examined under the microscope (3,365) shows a large 
quantity of biotite in long broad laths, some of which are bent, 
and variations from striated laths, greenish to brown in colour, 
to dark brownish decomposed masses devoid of structure. Apatite 
in elongated prismatic and in transverse sections is very abundant 
and forms a striking characteristic of this rock. Turbid felspar 
without striation, probably orthoclase, seems to behave as a ground- 
mass, together with calcite and quartz ; sphene is also present. 
It contains likewise a ^reen decomposition mineral, in which faint 
cleavage traces are discernible, as a pseudomorph, that may 
possibly represent augite. 

Two small sills are seen further south along the coast, one 
to two feet in thicknestt, about 150 and 560 yards distant 
respectively, the former of which has been split by earth move- 
ments, while about 70 yards north of the large intrusion a sill 
6 feet in width has been involved in the faulting of the slate. 
It is probable that the resistance offered by the dyke has 
given rise to the fracture along its junction. At its base the 
rupture is slight, but its upper junction is accompanied by 
much dislocation and contortion of the slate, while the sill itself 
has suffered from the disturbance. On the north side of 
Channals Creek, in the immediate vicinity, a 4-foot sill is seen 
50 yards east of the Fish Pond, and about 8 yards farther east 
another about 2 feet in thickness, while yet another about 4 feet 
wide occurs about 200 yards east of the same locality. The last 
three dykes are highly decomposed, and these, together with those 
previouslv described, are intruded in the Falmouth series. On 
the south side of Channals Creek these rocks are not at present 
visible, although, according to Mr. Collins, four distinct bands 
were seen by him in 1878,* which are probably now concealed 
beneath the mud. 

A good example is furnished on the east side of the Carrick 
Soads^ about 1,000 yards north of Messack Point, which also 
occurs within the Falmouth series, and varies in width from 3 to 5 
feet Its intrusive character is obvious, as veins extend into the 
adjoining slate. The sill exhibits fluxion structure, more especially 
on its margin, and both the spheroids and the majority of the 
rounded quartz inclusions that occur up to 2 inches in size lie with 
their long axes parallel to its walls. 

The mica trap at Pendennis Point, near Falmouth, skirts the 
coast for a considerable distance below high-water mark, so that 
its relations to the adjoining Portscatho beds are exceptionally 
clear. This band, with an average width of about 6 feet, after 
behaving for some distance as a sill, suddenly deflects to the north 
and cuts transversely across the strata as a dyke. It has been 

* JoMrn, Roy, Inst, Cornwall, vol, viii., p. 194. 



MICA TRAPS. 79 

heaved alightly by one of the nnmeroas small faults that traverse 
the slates, and its veins penetrate the adjoining strata. The rock 
is highly decomposed, and the biotite has been bleached to a 
pale white colour resembling muscovite. A marked characteristic 
of this rock is its pronounced veining and the abundant inclusions 
of quartz, felspar, and pegmatite. The pegmatites form rounded 
cores, and some of the quartz fragments are likewise rounded, 
while others are angular and even of rectangular shape. The 
very fine-grained veins not only contain quartz fragments similar 
to those in the body of the rock, but in many instances rectangular 
felspar fragments are so abundant as to monopolise the greater 
portion of the veins, which vary from an inch to a foot in width. 
In the narrowest of these the individual felspathic fragments 
occupy the entire breadth of the vein. 

Mica trap occurs on both shores forming the entrance to Cow- 
land and I^mouth Creeks, to the south of Halwyn. It is about 
15 feet thick and is lying at a very low angle, while the exposure 
on the southern shore shows the sill as strictly conforming to the 
bedding of the Portscatho beds. They are characterised by 
numerous quartz inclusions, both angular and sub-angular, one of 
which is 8 or 9 inches in size. The band is visible at Higher 
Trelease following the same direction about a quarter of a mile 
further north. According to Mr. Collins mica trap also occurs 
in Cowland Creek, in a faulted condition, which he has figured.* 

At PenpoU, west of Lambe Creek, a decomposing mica trap has 
a width of 6 or 8 yards. It is also seen on the shore below 
PenpoU Wood, forming a series of disconnected patches and lying 
nearly flat amongst highly disturbed Portscatho beds. It shares 
in the dislocations of the slate,.and is in one instance divided by a 
slide plane containing slate along the line of fissure. Seeing, 
however, that the rock is intrusive, the slate seam may be in its 
natural position, and it thus served as a plane of weakness. On 
the opposite shore, at Victoria Point, Mr. Collins has figuredf two 
mica trap dykes, 2 feet and 8 feet thick respectively, in close 
proximity, that share in an abrupt contortion of the killas. Un- 
fortunately, at the time of the survey, these rocks were not visible 
on account of the muddy condition of the shore, so that we are 
unable to confirm Mr. Collins' description. A 2-foot sill> however, 
is seen in the immediate vicinity (170 yards N.N.W. of Victoria 
Point) in a quarry, conforming strictly to the bedding of the 
Portscatho strata, and showing no disturbance. 

To the north-west of Truro these rocks are seen in the vicinity 
of Shortlane End, Gloweth, and Boscolleth. At the former 
locality they are marked by a line of pits on the farm of Car- 
vinack, the buildings of which have largely been constructed of 
this stone. 

At Grloweth a mica trap has been wrought, and an old quarry 
that formerly existed north of the road in the same locality 
doubtless marks a continuation of the same band. Two exposures 

• Jov/m, Boy, Inst, Corn,^ vol, vjii., p. 195, 
t Op. (fU., p. 196. 



80 IGNEOUS BOCKS. 

are seen nearly a quarter of a mile north of BoscoUetb. Mr. 
Collins states* that this band is intersected at Treliske b; 
an elvan. We were unable to discover its junction in the 
course of the survey, nor has another instance been recorded 
in the West of England of an intersection of a mica trap 
and elvan. Mr. Collins' statement, however, is important, as if he 
has correctly interpreted the nature of the intersection the 
relative ages of the mica traps and elvans are defined. It must 
be confessed that the fractured condition of the mica traps sup- 
ports their greater antiquity, as already pointed out by us.f Their 
probable association, however, with the Permian volcanic rocks^ and 
the Carboniferous age of the elvans have naturally led to the 
opinion that the mica traps are of later age ; and until a section 
can be laid bare showing unequivocally the intersection of the two 
rocks the question is an open one. As Mr. Collins has not de- 
scribed the section showing their junction, we have no means of 
judging whether the evidence was sufficiently clear as to be abso- 
lutely decisive. 

According to Mr. Collins, a mica trap showing spheroidal struc- 
ture occurs in a quarry at Ashfield, between Falmouth and Pen- 
rynj, and another occurs at Penryn.§ 

There are doubtless other bands that have been exposed which 
we have been unable to trace, through the infilling of the pits from 
which the material was formerly raised, either as stone, or for 
manurial purposes. 

* Jaurn. Roy, Inst. Corn,, vol. viii., pp. 197 and 202. 

+ Trans. Roy. Geol. Sac. ComwoUl, vol. xii., part vii., 1901. On the plu- 
tonicand other igneous rocks of West Cornwall, by J. B. Hill. 

X Joum. Roy. Inst, Com., vol. viii., p. 193. This quarry is at present over- 
grown and largely inaccessible. 

§ At the back of Messrs. Fox's timber yard. We were unable to inspect 
the section, as it was blocked by timber. Mr. Howard Fox described the rock 
and noted its spheroidal structure in a paper read before the Miners' Associa- 
tion of Cornwall in 1873. 



81 



CHAPTER VII. 



CONTACT METAMOBPHISM EFFECTED BY THE 

GRANITE. 

The granite masses of Carnmenellis, Carn Brea, and Carn 
Marth are in sach close proximity that their metamorphic aureoles 
overlap. It will be convenient, therefore, to describe their contact 
alteration on the surrounding killas without reference to these 
individual masses, but rather to regard the granite as a unit. 
Moreover, as already remarked, it has been demonstrated that 
the granites of Carnmenellis and Carn Brea are connected beneath 
the surface. The killas into which it has been intruded is con- 
fined to one division, viz., the Mylor series, and where it flanks 
the granite has been considerably altered by contact action, so 
that we have an encircling metamorphic aureole^ the width of 
which exhibits great variation. 

While the extent of the aureole depends on the subterranean 
contour of the granite, the degree of metamorphism, notwith- 
standing a general decrease from the granite margin outwards, is 
by no means uniform. While this is to some extent connected 
with the diverse chemical composition of the killas, it can- 
not be doubted that the structural features must likewise con- 
tribute to this result. The sediments were folded, fractured, 
and cleaved prior to the irruption of the granite. Moreover, the 
compression to which they owe their deformation has taken place 
at depths sufficiently shallow to lie well within the zone of frac- 
ture. Consequently, the folds are rarely of great amplitude, as re- 
lief from strain has been readily afforded by actual disruption. In 
some instances plication is altogether absent, and fault planes 
have. been directly produced unaccompanied by folding. More 
frequently, however, plication and fracture accompany one 
another. As a result the rock mass is divided into a series of 
irregular segments that may be compared to a regional breccia. 
The fracture planes have but slight displacement and the con- 
tinuity of the general dip is not seriously affected. This breccia- 
tion has in some cases been carried so far as to permeate the in- 
terstitial portion of the rock mass, so that crush breccias and 
pseudo-conglomerates have been extensively developed. As the 
ultimate result of these mechanical changes the killas is on the 
large scale singularly incohesive. The intrusion of the granite, in 
spite of the concomitant disturbances necessitated by its injection, 
has to some extent restored the solidity of the killas ; the contact 
alteration to which it has been subjected being comparable to a 
process of rock welding, so that within the metamorphic aureole 
the beds are more massive than beyond it. The heterogeneous 
nature of the killas due to these structural changes alone, doubt- 
less played an important part in controlling the chemical changes 
set up during the cooling of the granite. Not only must the 

Q 



82 CONTACT BiETAMORPHISM EFFECTED BY THE GRANITE, 

rock have exhibited great variation as a conductor of heat, bat 
the unequal cohesion would have affected the outward passage of 
the thermal currents. 

The varying widths of the contact aureole have been already 
described in Chapter I. in connection with the hade at which the 
granite plunges beneath the surface. The differentiation of the 
various degrees of mineral alteration within the aureole is in this 
area unfortunately impossible. A study, moreover, of a series of 
specimens taken at progressive distances from the granite margin, 
leads to the conclusion that such zonal division could not have 
been accomplished if all difficulties in connection with the 
obscurity of the sections were removed. 

Throughout the contact zone the dominant feature is the 
development of spots or knots forming '* spotted slates *' or knot' 
enschiefeTfYrhich are especially marked in the argillaceous members 
of the killas. This peculiar aggregation of material that charac- 
terises the earlier stages of thermal metamorphism is, so far as 
the outer portion of the aureole is concerned, the sole product of 
alteration. It is, however, also strongly developed among the 
more highly modified products of the inner zone. 

As the rocks are mainly argillaceous, the contact minerals 
formed are chiefly aluminous silicates, the most characteristic of 
which are andalusite, muscovite, and biotite. These minerals 
occupy the inner zone. Andalusite is distributed for a distance 
of about 150 yards from the granite. Secondary white mica and 
biotite are especially conspicuous in the inner zone, the biotite 
perhaps occupying a wider range than the muscovite. Both micas, 
however, closely aggregated, occur generally in very tiny scales, 
the biotite being of the characteristic reddish brown colour of the 
contact type. In some areas hornfels has been produced in which 
the spotted structure is absent. Pyroxene and garnet have only 
been exceptionally noted in the contact zone, and usually in 
association with the greenstones. The knots exhibit various 
forms ; they are sometimes aggregations of carbonaceous matter, 
in others they represent andalusite in an imperfect state of 
crystallisation, while again they may be aggregates of mica and 
quartz. Tourmaline is occasionally present, but in this area it is 
not often a common mineral in the contact zone. It has been 
already remarked that the killas is frequently divided by shear 
planes that impart the mechanical structure of a schist. Con- 
sequently, in the inner zone of alteration mica schists have been 
developed, the crystallisation of which has been the result of 
contact metamorphism. 

Microscopic Characters of the Metamorphic Zone. — A 
description, however, of some of the micro-slides will better illus- 
trate the phenomena of the contact zone. At Tregarne Mill, a 
specimen taken from close to the junction of the killas with the 
granite is an andalusite slate, with large crystals of colourless 
andalusite, which is only rarely pleochroic, in a matrix of biotite 
and quartz (3,385). A specimen about 80 yards distant from 
the granite margin, near Penryn, is a knotted andalusite slate, 
showing an advanced stage of contact alteration. The mass of the 



BOCROSCOPIC CHARACTERS OF THE METAMORPHIC ZONE. 83 

slate consists of biotite, muscovite, and qaartz, and these form 
winding, irregular, sinuoas, interrupted folia. There are large paler 
kuots, consisting principally of qaartz and biotite, and others 
which are mainly muscovite and biotite. Many large crystals 
of andalusite.are scattered through the rock; they are occasionally 
pleochroic, but are usually nearly colourless. The enclosures are 
biotite, magnetite, and dark matter, apparently graphitic, and as 
they are sometimes arranged to form a rude cross the mineral 
approaches chiastolite. The folia curve around and never pass 
through them (3,434). About 100 yards from the granite 
junction, at Treviades, a knotted andalusite slate is composed 
principally of quartz, biotite, and muscovite. The quartz forms 
strongly-marked parallel bands running along the foliation. The 
biotite is deep brown, and is partly weathered into chlorite and 
limonite. Andalusite is abundant, although the crystals are not 
large, but tend rather to form aggregates of small grain?. In this 
rock knotting is neither conspicuous in the hand specimen nor 
in the slide (3,435). At Penwarne, at a distance of 120 yards from 
the granite, the rock is essentially similar. It is roughly foliated 
and rather nodular, but the knotted character is not very pro- 
nounced (3,436). 

At Polwheveral, about 135 yards from the granite, a specimen 
shows on its surface pale, divergent, sheaf-like masses, resembling 
those of the garbenschiefer. Under the microscope (3,437) it 
consists of biotite, muscovite, quartz, andalusite with a small 
amount of tourmaline, magnetite, and chlorite. The andalusite is 
often full of biotite, but never resembles chiastolite in the arrange- 
ment of its enclosures. The foliation of the rock is rude and 
imperfect. 

Specimens obtained at greater distances from the granite, where 
the rock is more in the condition of typical spotted slate, were 
also examined under the microscope by Dr. Flett. One obtained 
at Boscarrack, about 500 yards from the granite, is a sheared 
decomposed killas, that is contact altered. It consists principally 
of pale muscovite and quartz, with spots of clustered biotite. 
There is a little tourmaline, but no andalusite. The rock is a 
good deal sheared, and fractures pass through it in curved branch- 
ing lines that are well defined by a deposit of limonite. The 
contact alteration is principally displayed in this rock by the 
spotting (3,438). 

A specimen from the outer margin of the aureole, about 900 
yards from the granite junction, is a grey slate much spotted on 
the surface (3,439). 

In Penryn Creek the aureole of metamorphism suddenly diverts 
to the., eastward, forming a narrow loop extending as far as 
Flushing. Whether this feature, whereby the contact zone is 
locally enlarged to the width of a mile and three-quarters, is 
the result of unevenness in the subterranean contour of the 
granite, or to crustal movements, is not apparent. On the coast 
below Trevissome, in Penryn Creek, a specimen of a silky slate or 
phyllite, that is knotted, is seen under the microscope to be 
crushed, and crossed by quartz veins that are distinctly granu- 

o2 



84 (X)NTACT METAMOKPHISM EFFECTED BY THE GRAI7ITE. 

litic in character, and are broken and interrupted. Lines of 
fractnre cross the cleavage, and along them the laminse of the 
rock are faulted, forming a sort of auaweichuTigsdivdge, The 
knots are obscure, being filled with limonite, and largely com- 
posed of mica (3^576). A little further up the creek, about a 
quarter of a mile south-east of St. Gluvias Church, the rock is a 
fine shale with prominent quartz veins. Under the microscope it 
consists of small plates of mica mixed with fine angular quartz. 
There are a few rounded knots containing small crystals of biotite 
and quartz (3,577). 

At Treluswell, within 300 yards of the granite, a pyroxene 
homfels occurs. The sections here are very obscure, but 
greenstone is probably in close proximity. The shale, 
therefore, had probably been modified by the latter before the 
granite intrusion. The rock is crumpled with dark wavy lines, 
suggesting that it was originally an argillaceous sediment, 
but it is very rich in clear, shapeless crystals of colourless 
pyroxene, which are developed in rounded patches and along 
certain belts. The intervening matrix is a fine mosaic of 
quartz, and perhaps felspar, filled with dark opaque granules. 
Although having the appearance of an altered calcareous shale it is 
probable that the lime has been derived from the adjacent green- 
stone (3,380). 

At Ponsanooth, on the eastern side of the stream, the Mylor 
series is very siliceous, containing very fine-grained quartzose 
bands, some of which are 4 feet in thickness. A specimen 
selected from the latter about 100 yards from the granite 
junction was determined under the microscope to be a contact- 
altered sheared grit. It consists of a mosaic of quartz grains, 
which have largely lost their rounded clastic form as the result 
of hornfelsing. A reddish brown biotite forms wavy streaks and 
irregular clusters, and is apparently a product of contact 
alteration. Zircon, iron ores, and garnet are the principal 
accessories (3,447). 

A contact-altered shale from the same district and equally 
distant from the granite, one-eighth of a mile east of Gosawes, 
shows under the microscope the lamination and slate structure 
well preserved. There is no knotting, but the specimen is 
crossed with veins of granular quartz. The rock consists of 
small angular quartz grains, with biotite and muscovite. The 
biotite is dark brown, quite fresh and very abundant, and its 
parallel scales impart to the rock a distinctly schistose appear- 
ance. In the hand specimen it resembles an indurated homfels 
(3,578). 

In the district of Sedruth a very coarse type of andalusite hom- 
fels was noticed amongst the mine burrows, about 170 yards west 
of Grambler. The andalusite occurs in needles^ nearly half 
an inch in length, and somewhat pink in colour in the hand 
specimen. Under the microscope (3,861) it is often colourless, or 
shows a dichroism from colourless to pale pink. The remainder of 
the slide consists of muscovite, biotite, and quartz, with a few 
grains of brown tourmaline. The rock is an andalusite biotite 



MICRO-STBUCTURES — CHEMICAL ANALYSIS. 85 

hornfels, in a highly crystalline condition, that has been much 
decomposed. 

In the soath-west portion of the map the actual junction 
of the granite and killas is seen in the railway cutting, one- 
sixth of a mile south by west of Trannack. Under the micro- 
scope the Mylor slate is seen to consist of alternating layers of grit 
and shale, much altered by contact metamorphism. The gritty 
bands are changed into a mosaic of quartz grains filled with small 
scales of chlorite and brown biotite, while the argillaceous layers 
are represented by chlorite and muscovite, with iron ores, and 
occasionally a little biotite. The chlorite has probably all resulted 
from the decomposition of the original biotite, so that the rock is 
a decomposed biotite hornfels. The contact structures in the 
grit bands are well developed, but andalusite was not found in the 
slide (3,951), 

A homfelB occurring in the railway cutting 100 yards south-east 
of Praze Station is likewise of the chloritic type. The biotite is 
replaced by chlorite, and it contains also muscovite, quartz, iron 
oxides, together with a little tourmaline in small brown prisms^ 
and the rock is indistinctly spotted (3,952), 

To the west of Crowan the aureole of metamorphism reaches 
beyond Clowance to the western edge of the map, near Penhale 
Moor, According to Mr. Dixon, the altered belt extends thence 
to the north coast and connects this aureole with the metamorphio 
region north of Gwinear. The outer limit of the sporadic spotting 
has been traced by Mr. Dixon to Illogan, from which it extends to 
Forth Towan on one side and to Crane Islands on the other ; and 
be remarks that some of the spots are rhombohedral, and composed 
of carbonates. 

Mr. J. Arthur Phillips, in his description of the rocks oi the 
mining districts of Cornwall,* gives two chemical analyses from 
the metamorphic aureole of this area, as follows : — 

Water Jhygrometric - -48 '94 

^^^^ \ combined - -67 218 

Silica - - - 6732 67-82 

Phosphoric anhydride - — — 

Titanic anhydride - '13 — 

Alumina anhydride - 20-85 9-56 

Ferrous oxide - - 1*66 5*02 

Ferric oxide - - 2*83 trace 

Ferric persulphide. - — '68 

Manganous oxide - — 120 

Lime - - . - 203 258 

Magnesia - - - trace 3*42 

Potash . -60 2-37 

Soda . - - - 3-37 432 



99-94 10009 



Specific gravity - - 2-71 2-73 

• QJ.O,S., vol. xxxi., 1876, p. 322. 



86 CONTACT METAMORPHISM EFFECTED BY THE GRANITE. 

The analysis in the first column was taken from killas in 
the 215-fathom level of the Dolcoath Mine, while the other 
refers to a specimen taken from Hael Seton, Camborne, at the 
160- fathom level. From the author's description the latter has 
apparently been more metamorphosed than the former. It will be 
noted that although the percentage of silica in the two rocks is 
almost identical, there is a marked reduction of alumina in the 
latter, together with an excess of iron and potassium, while man- 
ganese and magnesia are present in appreciable quantities. Mr. 
Phillips remarks that the amount of magnesia in the rock 
bounding the great cross course at Huel Seton, " which is tra- 
versed by the modified sea-water constituting the well-known 
lithia spring, is twice as large as in the normal killas of the 
locality. The magnesium of the sea-water has in this case almost 
entirely disappeared." 

Mr. J. H. Collins has described some contact-altered killas from 
Penryn as gneiss. The Mylor slates there, in the vicinity of 
the granite, have been highly metamorphosed and may be 
accurately designated as mica schists. Mr. Collins made an 
analysis, as follows* : — 

Combined water - . . - -90 

Silica 76-85 

Alumina ------ 15*05 

Ferric oxide ----- 0*50 

Ferrous oxide ----- 1*80 

Lime O'lO 

Magnesia - - - - -0*10 

Potash - - - - - - 1-39 

Soda 2-33 

Loss 0-98 



1 00-00 



Specific gravity - - - . 2-587 

A specimen was examined by Professor Judd, who detected the 
presence of minute garnets. Although portions of the altered 
killas may contain transitional stages between mica schist and 
gneiss, the rock as a whole does not approach the latter categorj.t 

• Joum, Roy, Inst. Corn.^ vol. viii., p. 82. 

t The occurrence of gneiss at Penryn was contested by Mr. A. Somervail. 
Journ. Boy, Inst. Corn,^ vol. vii. p, 264. 



87 



CHAPTER VIII. 



FAULTS. 



In Chapter III., dealing with the structure of the killas, it has 
been pointed out that the Palaeozoic earth movements which pre- 
ceded the granite intrusions resulted in a system of rock flexure 
and fracture that were directly related. Under the influence of 
compression the crust was broken up into rock segments so closely 
aggregated as to present on a large scale the character of a 
regional breccia. These pre-granitic fractures are individually of 
slight displacement, and their profusion is such that they cannot 
be delineated on a small scale map. 

The rock deformation in mass, which not only effected that 
regional breccia but evolved pseudo-conglomerates on a large 
scale, was brought to a close by the granite intrusions towards the 
close of the Carboniferous period. That volcanic phase was ac- 
companied by a system of rock fracture parallel to the belt of 
intrusions represented both by granite and elvan. These fractures 
have a trend of about E.N.E.,and agreeing with the main trend of 
the sediments they form strike faults which are not readily detected. 
Many of them, however, occur in the mineral areas, where they 
form the home of the lodes. Although their average trend is 
E.N.E. many follow directions oblique to that course. 

There is another set of faults with a N.N.W. direction, that 
are of later age, and not only cut the E.N.E. group but also the 
elvans, and their transverse course both to these and to the normal 
strike of the sediments renders them more conspicuous than the 
former group of faults. Many of them are known to the miner 
as cross courses, some of which heave the E.N.E. lodes, a de- 
scription of which is given in Chapter XV. These faults are 
especially prominent along the belt occupied by the Carnon 
Valley, and extending to the north coast on the one band, and to 
Restronguet Creek on the other. This system of fracture has 
originated since the formation of the tin and copper lodes, and 
their close parallelism with the Assuring produced by the volcanic 
eruptions of early Tertiary times render it extremely probable that 
they should be referred to that period. 

Although these two prominent types of dislocation are the 
products of the later Carboniferous and the early Tertiary periods 
respectively, it is not implied that fractures can be rigidly assigned 
from their directions alone to those two phases of dislocation. 
Doubtless, fissures following either trend have been produced over 
the extended period that has elapsed since Carboniferous times. 



88 



CHAPTER IX. 



PLIOCENE DEPOSITS. 

POLCREBO <tRAVELS. 

A deposit of quartz gravel at Blae Pool, in Crowan, has been 
described by Mr. W. Tyack.* As it occurs at an elevation of 
about 500 feet, and as remarked by Mr. Tyack does not appear to 
have any connection with the alluvia of the district, there are 
some grounds for the opinion that it represents a patch of the 
Pliocene deposits that formerly spread over the killas platform of 
this area, and the only other representatives of which are found at 
St. Erth, St. Agnes, and Crousa Downs, in the adjacent maps. 

The deposit occurs on a common near Polcrebo, in the heart of 
the granite district. Mr. Tyack describes the bed as consisting of 
quartz pebbles, evidently akin to the spar of the district, and 
varying both in structure and colour. They are more waterworn 
than the stream deposits of the Cober River, but in his opinion 
have been subjected to less attrition than the pebbles in the 
marine beaches at Loe Bar and Perranuthnoe. " They are of all 
sizes, from boulders as large as a pumpkin to pebbles as small as 
hazel-nuts; the larger ones are few in number and generally 
found most deeply bedded in the soft clay on which the greater 
part of the pebbles lie ; they are also the smoothest. The small 
ones are most numerous, and are generally on, or very near, the 
surface. Most of the pebbles are about the size of a hen's egg ; 
the very small ones are but slightly more waterworn than those 
of any river-bed pebbles in the district." 

The deposit occupies an area less than half a mile in length 
and about a quarter of a mile in breadth, and thins away 
towards the margin. Mr. Tyack also states that it overlies a 
substratum of clay, derived from the decomposition of the 
granite, in which some of the larger pebbles have sunk to 
various depths ; the subsoil being soft and saturated with water 
in the winter months. The gravel has been worked for tin, but 
it was never rich. Similar pebbles are seen about a mile distant 
in the valley below, at an old abandoned stream-work, at 
Velanhausen, but whether -they were carted, or brought down 
by the stream, is uncertain. 

Mr. Tyack was of opinion that the pebbles were derived from 
quartz veins in a killas district, but drew attention to the fact 
that they occurred at a greater elevation than the killas in their 
vicinity ; and that, moreover, they could not have reached their 
position by stream deposit in the present surface configuration of 
the area. He attributed their origin, nevertheless, to an ancient 
river the traces of which have been removed by a vast amount of 

* Trans. Koy, Oeol. Soc. Corn,, vol. ix., pp. 177—181. 



POLCREBO GRAVELS. 89 

denudation that has obliterated all traces of the valley in which 
the river flowed. 

According to that observer, the few granite fragments with 
which the qoartz pebbles are mixed are rough and angular, so that 
we may conclude that they were not embedded in the original 
gravel deposit, but represent detached fragments from the under* 
lying granite. Mr. Tyack was evidently of the same opinion, 
as he lays such great stress on the deposit having originated in a 
killas area. 

As we are unable to conceive of a river whose volume per- 
mitted of the transportation and attrition of the large boulders 
described flowing over a bedrock of granite, without the in- 
corporation of that material in its alluvia, the origin of these 
Polcrebo gravels must be sought elsewhere. 

As the deposit accords approximately in elevation with the old 
Pliocene shore-line, it is probably a relic of the marine accumnla- 
tions that lined the floor of the Pliocene sea ; and Mr. Clement 
Beid, who has recently examined the deposit, agrees with this 
opinion.* The association of gravel and bedrock, sharply con- 
trasted in their lithology, may be readily accounted for by the 
shore deposits being swept forward by the currents to such 
portions of the rocky bottom as were beyond the destructive action 
of the breakers. 

* See also remArks by C. Reid, in '* Samniary of Progress " for 190], p. 31. 



90 



CHAPTER X. 



PLEISTOCENE DEPOSITS. 
I. Raised Beaches. 

With the exception of the Polcrebo gravels, this area affords 
no evidence of stratified deposits from the Palaeozoic period until 
the Pleistocene, the latter being represented by the raised beaches 
underlying the Head, which is probably a product of the glacial age. 

These ancient beaches* that were laid down in the Pleistocene 
seas, form ledges which fringe the coast seldom more than a 
few feet above the present sea level. The raised beaches, 
composed of material identical with that of their modern counter- 
parts, are sometimes cemented by oxide of iron that has con- 
solidated them into a condition of durability. In this state they 
offer great resistance to wave action, as is well seen in Grerrans 
Bay on the beach of Pendower. In some instances the ancient 
caves of the Pleistocene coast have been partially preserved by the 
old beach floor being sufficiently consolidated to form the roof of 
modern caverns that have been excavated in a lower portion of 
the same cleft, examples of which are seen in Falmouth Bay. 

Even on the coast-line, where beaches are absent, a tiny fringe 
of gravel is often visible. It may be observed along some of the 
steeper cliffs, where its preservation is obviously due to the 
durability of the cementing material, which has not only held the 
particles together, but has firmly bound the gravel to the rock 
on which it rests. 

Every gradation is seen between well-defined beaches and mere 
shreds of gravel, either cemented or incoherent, that occur in 
isolated strips above the present high-water mark, the degrada- 
tion of which causes the commingling on the modern beach of 
the Pleistocene pebbles with those of recent origin. The beaches 
of either age contain, in addition to fragmental material repre- 
senting the detritus of the adjacent rock formations, numerous 
foreign pebbles, mainly chalk flints and cherts, which in some 
situations are profusely distributed. They have either been 
swept around the coast by current action, or have been derived 
from a deposit more ancient than the raised beach which may 
fringe the coast beneath the level of the sea.t 

In some instances the recent rock shelf, planed by wave action, 
has been shaped from the more ancient Pleistocene platform. 
This is well seen at Sunny Cove, in Falmouth Bay, where the 
older platform, standing but 5 or 6 feet above the present eroded 

• These raised beaches were described by local geologists prior to the survey 
by De la Beche. See also W. A. E. Ussher on ** The Kecent Geology of 
Cornwall" (articles reprinted from the Oeol, Mag.)^ 1879; and "The Post- 
Tertiary Geology of Cornwall " (printed ^r private circulation), 1879. 

t The latter explanation is supported by the occurrence of a gravel deposit, 
largely composed of flint and chert, in St. Martinis Island, that is probably of 
Eocene age. See page 15, ** Geology of the Isles of Scilly " (Mem, tfeol. 
Survey), by George Barrow. 



RAISED BEACHES. 91 

shelf, is fringed along the coastal notch by the innermost edges 
of the raised beach, averaging but a foot or so in thickness, that 
has escaped destruction. (Plate VIII.) Notwithstanding the 
close juxtaposition of these Pleistocene and Recent formations, the 
interval which separates them has been marked by consider- 
able vertical oscillations of the coast-line, the evidence of which 
will be given later. The final results of such crustal movements 
have been that the relative level of land and sea more closely 
approximates to the old Pleistocene coast-line than in the periods 
that have intervened. The appearance of the ancient ledges 
along the present cliflF faces would at first suggest that the coastal 
erosion due to wave action had been slight since Pleistocene times, 
but the explanation is to be found in the oscillations of level that 
have taRen place in the interval, so that the erosion of the 
modern coastal shelf has been restricted to the period that has 
succeeded the submerij^ence of the forest beds. 

Between Gerrans Bav and the Zoze Point there are three 
examples of the Pleistocene beach, one of which occurs at 
Pendower, along the north front of Gerrans Bay ; another lines 
the inner portion of the small bay at Portscatho ; while the last 
is similarly situated in the bay fronting Towan beach. The 
raised beach of Pendower is a magnificent example, and 
owes its preservation to a very thick deposit of Head, which 
has acted as a protective covering. It is resting on a killas 
floor, a very few feet above the level of high-water mark: the 
base consists of coarse fragments of slate and quartz with which 
pebbly beds of the same nature are mixed, while the upper 
portions consist of red and brown sandstone and sand, bound 
together by a cementing material of oxide of iron. It 
sometimes attains a thickness of 8 to 10 feet, but is often 
much less, and the deposit is not always continuous. This beach 
has been described and figured with its relations to the under- 
lying rocky base and the overlying Head by Mr. Howard Fox.* 
At Portscatho it is represented by an insignificant shelf of 
gravel and rusty sand that follows the coastal shelf below the 
Head, a little above high-water mark. At Towan beach^ how- 
ever, there in a more extensive exposure of Head, and the under- 
lying beach is consequently well preserved. On the southern edge 
of the deposit there is a thickness of about 15 feet of Head that 
overlies about 2 or 3 feet of sand and gravel, some of which is 
compacted by iron oxide, as at Pendower, while in other parts it 
is a friable deposit of gravel and sand. Continued further north, 
the beach deposit, as at Pendower, is seen to be discontinuous, 
and in some places appears to be represented by a gravelly clay. 
The raised beach here, together with the overlying Head, has 
been trenched by a small channel connecting Towan beach with 
Forth Creek, the seaward portion of which has been covered by a 
deposit of blown sand. 

In Falmouth Bayf the raised beach is also seen in a corre- 

♦ Trans* Royal GeoU Soc, Cornwall, 1896, p. 9. 

t In 1832, li. W. Fox drew attention to the raised beaches of Falmouth Baj*. 
Phil. Mag.^ vol. L, December, 1832, p. 471. 



92 PLEISTOCENE DEPOSITS. 

spending position at th6 base of the Head, between Swan Pool 
and the Falmouth Hotel. It consists of gravel, partly cemented, 
in which quartz is usually the chief constituent, and its base 
stands a very few feet above high-water mark. A little to the 
north of Pennance Point there is a small deposit of Head, from 
20 to 25 feet in thickness, beneath which there is a layer of com- 
pact stratified sand from 1| feet to 2 feet in depth, the shelf 
being only three or four feet above high-water mark. 

Between Pennance Point and Maen Porth a deposit of Head 
lines the coast in the neighbourhood of Sunny Cove, and rests 
on a rock shelf a few feet above high-water mark ; moreover, as 
remarked earlier, this platform stands about five or six feet 
above another which marks the modem shore-line. In Sunny 
Cove the ancient beach, about three or four feet in thickness, 
is dissected by the cleft which forms the cove, and consists 
of gravel, often stained yellow, and even black, and frequently 
very compact, while angular blocks of slate are also enclosed, 
especially towards its base. Between Newporth Head and Maen 
Porth a small portion of the old beach is adhering to the cli£f 
face at a height of from twelve to fifteen fe^t above high-water 
mark. 

Traces of this raised beach are also seen along the coast of the 
Camck Koads and the harbours of St. Mawes and Falmouth. In 
St. Mawes Harbour, on the coast north-east of Carricknath Point, 
a deposit of white quartz gravel, well rounded, and about a foot in 
thickness, is overlain by Head. The gravel contains also some 
blocks of slate, while some of the quartz pebbles are six inches in 
length. The deposit is only three or four feet above high-water 
mark, and appears to be slightly distorted from the creep of the 
overlying Head. 

Between Castle Point (St. Mawes) and St Just the coast is 
lined more or less continuously with a narrow ledge of Head, at 
the base of which there is a deposit of quartz gravel about a foot 
in thickness. A little to the south of St. Just the raised beach, 
about a foot thick, consists of sand and gravel ; the band is not 
horizontal, but slightly undulating. In the upper part of the 
Carrick Beads it has not been observed, although the Head 
is sometimes present. North of a line drawn between Mylor and 
St. Just the only example is on the coast to the south of 
Weir Point, where a bed of quartz fragments about a foot thick 
is seen below a thin covering of Head. Between Penarrow Point 
and Trefusis Point the deposit, however, is almost continuous at 
the base of the Head. It averages about a foot in thickness, and 
consists of white quartz gravel, usually incohesive, but sometimes 
cemented firmly together. It is often very 'coarse^ with blocks up 
to six inches in size that are more or less rounded, but at times 
angular. On the north side of Falmouth Harbour^ notwith- 
standing an extensive deposit of Head that fringes the coast, the 
raised beach is almost entirely absent ; a small ledge, however, 
underlies the Head, to the east of Wheal Clinton. 

Traces of the platform are met with in the cliffs and islets 
along the north coast, while at Portreath and Kerriack Cove 



HEAD. 93 

patches of the Pleistocene shingle are found firmly cemented to it 
by manganese dioxide. 

II, Head. 

This deposit forms an irregular accumulation, in which stony 
material preponderates, often reaching great depths on the coast, 
and overlying the raised beaches and the killas. The Head is 
sometimes almost identical with the subsoil, into which it 
frequently merges. In fact, this abnormal deposit may be 
looked upon largely as subsoil that has been transported to lower 
levels. It is sometimes stratified, and may even contain beds 
of sand and fairly rounded gravel ; more often, however, it 
presents an irregular accumulation of stones^ mostly angular^ and 
occasionally subangular. 

This formation is probably of glacial age. While nowhere on the 
mainland of Cornwall* is there evidence of glacial action, its 
proximity to the icefield that lay to the north necessarily entailed 
the rigours of an Arctic climate, under which the land was 
incapable of supporting any but the sparsest vegetation. The 
melting of the winter snows and the ice which bound the frozen 
soil, acting on a surface unchecked by vegetation, probably involved 
the sweeping of material down the slopes that would amply account 
for the abnormal nature of the deposit. In its downward course 
it has filled the hollows on the coast-line, and covered the shelf of 
the ancient beach, to which it has afi'orded a protection, so that 
the thickest deposits of Head are found in the smaller bays, 
by the infilling of which the shore-line has been modified. Some 
writers have considered the Head to have been formed beneath 
the sea, but the phenomena which it presents can be more satis- 
factorily accounted for on the above hypothesis. 

The Head which covers the raised beach at Pendower 
in Gerrans Bay forms a cliff from 20 to 50 feet in height. 
Mr. Howard Fox described it as '* composed of loam and sand, and 
containing occasional angular fragments of quartz, chert, and 
shale.^t This deposit also extends from Pendower to Creek 
Stephen Point ; and about a quarter of a mile before reaching the 
latter locality it is fully a hundred feet deep ; this section contains 
also some sandy material. At Creek Stephen Point, where it is 
only fifteen feet thick, the basal portion consists of stratified 
brown sand. As the upper surface merges into the hill slope, its 
inland limits can rarely be ascertained, but the strip is usually 
very narrow. Another shelf skirts the cliflF between Portscatho 
and Porthcurnick, and overlies the raised beach, but that coast- 

♦ In 1843 Sir R. I. Murchison, in his address to the Geological Society 
of London, expressed the opinion that the search in Cornwall for the 
evidence oi ancient glaciers would be unsuccessful. The principal exponent 
of the theory of glacial action in Cornwall has been Mr. Nicholas \Vnitley. 
We have failed, however, to detect any indications of glacial phenomena, 
althonsh some blocks herein described are of tlie nature of erratics that 
have sfid to lower levels over a frozen surface. In the Scilly Isles Mr. Barrow 
has reoently described a glacial deposit, with ice-scratched stones, that over- 
lies the Head, and which is attributed to the action of ice-floes. See 
pp. 21 -SS, " Geoloffy of the Isles of Scilly " {Mem. QeoL Surrey), 

t Tram. Roy, GeoL 8oc, Com,^ 1896, p. 9. 



94 PLEISTOCENE DEPOSITS. 

line is rapidly receding, from the effect of landslips : south of 
Pencahe the section is aboat twenty feet thick. Another exten* 
sive deposit forms a cliff fronting Towan beach, and is in part 
sandy and rudely stratified : towards the north its upper part 
consists of sandy material and fine gravel mixed with soil for a 
depth of a foot or eighteen inche?. The cliff at Falmouth front- 
ing the bay affords a good section of Head overlying the raised 
beach, where it is frequently sandy and stratified. A thick deposit 
also reposes on the raised beach at Sunny Cove. 

Within the Falmouth estuary ledges of Head frequently 
line the coast. Opposite St. Mawes a deposit of this nature 
overlies the raised beach north-west of Carricknath Point. Be- 
tween St. Mawes Point and St. Just Pool a similar ledge is 
almost continuously exposed^ occasionally from 15 to 20 feet in 
thickness, and frequently underlain by the ancient beach. On 
the coast, rather more than half a mile south of Messack Point, 
the Head is from 8 to 10 feet in depth, rudely stratified, and 
capped by a thin layer of loose gravel. On the north side of the 
Carrick Roads a deposit lines the coast from Pill to within a short 
distance of Kestronguet Point. Between the entrances to 
Restronguet Creek and Mylor Creek are two smaller patches; 
one, south of Weir Point, is about 4 or 5 feet in depth, and rests 
on the raised beach ; the other, south of Great Wood, is 12 feet 
thick, and reposes directly on the rock platform of the modern 
shore. From Penarrow Point to Flushing it forms a well- 
marked ledge, sloping to the coast, and underlain almost con- 
tinuously by the raised beach. Another conspicuous deposit of 
this type fronts the shore of Pendennis Peninsula from Middle 
Point to the Docks, where it has been quarried : the pit section 
exhibits at the base fine sand that is overlain by about 12 feet 
of more typical Head, which, however, is stratified; the slate 
fragments, instead of being irregularly disposed, lie with their fiat 
sides parallel with the dip, which is towards the sea. Although 
this is a well-marked ledge, the landward boundary cannot be 
accurately drawn, as it merges gradually into the hill slope,* 

In the valleys and estuaries which converge to the Carrick Roads, 
deposits of Head are less frequent. There is, moreover, in the 
interior a difficulty in distinguishing it from the subsoil, 
especially where the latter is of great thick)iess. Some of the 
inland accumulations, however, which are in the nature of drift, 
may have been formed contemporaneously and under the same 
general conditions. In the district of Bissoe, for instance, between 
Wheal Baddon and Wheal Clifford, the slopes are covered with 
debris for a depth of several feet. In the vicinity of Pennance, 
below Carn Marth, the slopes are strewn with granite detritus far 
below the granite margin. Moreover, the size of some of the 
blocks and the general nature of the ground preclude the 
possibility of the phenomena being due to the downward creep 
of the surface debris under the conditions that prevail at the 

* A characteristic of the Head that reposes on the Pleistocene platform is 
its smooth surface, ^hich from a distance recalls the features of the Raised 
Beaches of the West of Scotland. This is especially noticeable within the 
Falmouth estuary. (See Plate II.) 



STREAM TIN. 95 

present day. A more striking instance still of the transport of 
material from a distance is seen on the northern flank of the Cam 
Brea granite. A section along the railway cutting, between Cam 
Brea Mine and Bamcoose, exposes a deposit of granite detritus, 
several feet in thickness, resting upon killas. In the finer material 
blocks of granite are incorporated, some of which attain a size of 
5 or 6 feet. The granite margin is probably about 70 yards 
distant at the west end of the section, and about 180 yards at the 
eastern portion. If the ground were steep, this deposit at such a 
short distance from the granite would not be unusual, but as a 
matter of fact the land here is comparatively flat, the angle of 
slope being only from 1? to 2^ while the declivity from the base 
of Cam Brea hill extending to a distance of 500 yards only 
averages 4^, It is clear, therefore, that the larger granite blocks 
could only have reached their present situation under abnormal 
conditions, and in all probability they were detached from the 
summit of Cam Brea while its slopes were covered with frozen 
snow, over which they slid to their present position. 

IIL Stream Tin and Submerged Valley Deposits. 

Stream Tin. — The stream tin industry in Cornwall is now a 
matter of the past^ the valleys and basins in which these deposits 
occurred having been repeatedly worked over, and their sites 
now remain as tumbled and disordered ground, much of which 
from an agricultural standpoint is a waste. While we are unfortu- 
nately precluded from the examination of these deposits in their 
natural condition, they present interesting questions of post- 
Tertiary geology that cannot be overlooked. As will be seen later, 
at Restronguet Creek, where the section is below the level of the 
sea, the stream tin deposit immediately overlies the rock shelf. 
This relative position of the rocky floor and stream tin, according 
to all accounts, holds good wherever these deposits have been 
worked. As observed by De la Beche,* while the submerged 
stream tin deposits were being covered by marine or estuarine 
accumulations, " the stanniferous gravel strewed down the higher 
parts of the valleys became simply covered by ordinary river 
alluvium, mingled with trees and vegetable matter ; in flat places, 
sach as may have constituted marshy ground or shallow lakes, 
peat accumulating intermingled with the waste of gravels, sand?, 
and clays, from the adjoining higher lands, in the same manner as 
now takes place commonly in peat -countries." 

The peculiar association of the stream tin with the subjacent 
rock, instead of being interstratified with the alluvial deposits, 
was ascribed by the earlier geologists to the effects of a sweeping 
denudation having passed over the land, and in the words of Mr. 
Came,t " the effects produced by which have never been repeated 
by any subsequent flood." Moreover, the fact that the more ex- 
tensive deposits of stream tin occurred in the valleys that opened 
to the south, notwithstanding that the richer tin veins were 
situated in the northern region, was considered to indicate that 

• '* Reporb on the Geoloj?y of Cornwall, Devon, and West Somerset," p. 406. 
t Trans, Bay, Geol, Soc, Camuxill, vol. iv., p. 5o. 



96 PLEISTOCENE DEPOSITS. 

the current of the delage* swept from the north.f This theory 
was apparently countenanced by De la Beche, who suggested that 
a great body of water crossing the Bristol Channel from South 
Wales carried forward the disintegrated material of the rocks that 
opposed it on this side of the Channel, ** transporting them into 
the chief inequalities, and carrying them down the principal 
valleys, according to the directions of the minor currents pro- 
duced by the inequalities of the land beneath."^ 

Although we have failed to detect evidence of glaciation in 
this part of Cornwall, it is known that glaciers reached the 
Bristol Channel, and its proximity to the Welsh icefield must 
have entailed an Arctic climate during the period of maximum 
glaciation. Not only does the highly decomposed condition of 
the surface rocks discountenance the idea of glacial action, but 
further confirmation is a£forded by the absence of rock strisB, and 
erratics from the north. 

As already premised, in treating of the origin of the Head, 
in glacial times the ground must have been covered with snow, 
and it is probable that the more elevated tracts lay permanently 
above the snow-line. The melting of the winter snows and the 
ice that bound the frozen soil must have been productive of floods 
that swept the valley floors with a volume and velocity altogether 
incomparable with the insignificant and sluggish streams that 
water the valleys at the present day. Under such conditions, it 
can be readily understood that only the denser detrital matter 
could find a resting place along their channels. No doubt pre- 
vious to this period the bottoms of the valleys were not bare, but 
assuming that they were lined with alluvia no thicker than that 
which obtains at present, its removal by such torrential floods 
would be a simple process. It is unnecessary to assume that 
the occurrence of stream tin adjacent to the bedrock, without 
occupying higher positions between the overlying alluvia, im- 
plies a simple and continuous sequence of deposit with the 
heavier material at the base. In all probability the intervals 
between the periodical floods were marked by the deposition of 
normal alluvia. With the renewal, however, of torrential condi- 
tions, these lighter deposits would be swept away, just as we 
suppose the alluvia that originally lined the valley floor was dis- 
persed. No doubt these periodical scourings of the river basins 
succeeded in carrying to the sea much of the stream tin itself. 
At the close of this period, when the severity of its climatal 
conditions had passed away, the deposit of stream tin lying on the 
bedrock was the sole relic of a long period of deposition, extend- 
ing not only over the era which evolved such deposit, but over the 
period which preceded it. To put the case succinctly, the condi- 
tions which permitted of the formation of the stream tin involved 
the destruction of normal alluvial deposits, both older and con- 
temporaneous. 

The explanation suggested herein to account for the phenomena 

♦ Tram. Oeol. Soc, Cornwall^ vol. iv., p. 55. 
t Ihid. p. 110. 
-^ Report previously cited, p. 401. 



STREAM TIN. 97 

presented by the stream tin supports the theories ndvanced by 
the earlier observers, to the extent that both hypotheses invoke 
torrential conditions. Whilst their view of a general diluvial 
immersion and the advance of a large body of water from north to 
south cannot be sustained, yet the facts on which it is based are 
substantially correct, although admitting of a simpler interpreta- 
tion. That, so far as this area is concerned, the stream tin was 
principally located in the valleys opening on the south coast, and 
that the more important tin lodes lie in the northern tracts, may 
be admitted. These phenomena, however, appear to be in harmony 
with the physical features of the district. The watershed is not 
only nearer to the north coast, but the rivers which drain 
that area are shorter, and therefore of greater declivity ; 
consequently, more of the stream tin proportionately reached the 
sea. Now the rivers emptying on the south are not only of lower 
gradient but traverse a larger area, and also more frequently 
become confluent, so that their lower portions have received the 
deposits brought down by numerous tributaries. This is illus- 
trated by the river which discharges into Restronguet Creek, and 
contains the celebrated tin stream works oi Carnon. This river 
system attains a total length of about 45 miles, 25 miles of which 
are situated in the metalliferous districts of Chacewater, Scorrier, 
St. Day, Gwennap, Baldhu, and Bissoe. Although it is true that 
the individual lodes of this central area are not so rich as those 
situated in the northern tract of Camborne and Kedruth, yet 
the amount of stanniferous detritus spread over the surface 
and susceptible of denudation mav quite well have equalled or 
even exceeded the tin-bearing detritus of the northern area, in 
spite of greater mineral concentration in the latter. Moreover, 
when it is considered that the stream tin of the northern region 
has been distributed by numerous rivers, whereas the drainage 
system of the district which culminates in the Carnon Valley 
converges to a single channel, the more extensive alluvial deposits 
of the latter are readily accounted for. 

Submerged Valley Deposits. — The submergence of the land 
which the forest beds imply is further supported by the evidence 
of the deposits that will now be described. The search for stream 
tin has been the means of dissecting these accumulations at 
Bestrongnet below the level of the sea, where remains of a forest 
growth in its natural position are buried beneath deposits exceed- 
ing 50 feet in thickness that overlie the stream tin. The 
following is a section of the Carnon stream-works by Mr. 
Hen wood* : — 

ft. in. 

1. Sand and mud ; the river wash ..... 30 

2. Silt and shells — three successive beds . - - . 10 

3. Sand and shells 2 

4. SUt— three beds 12 

5. Sand and shells - - - - - - - -3to40 

6. Silt mixed with shells in large quantities ... 12 
7* Silt, in some places containing stones - - - - 18 to 22 

* Trans, Roy, Qeol, a^'oc, Cornnall, vol. iv., p. 58. 



98 IXEISTOCENE DEPOSITS. ' 

8. WoocU moss, leaves, nuts, &o., all of a dark colour, much ft. in. 
resembling what has been charred ; a few oyster shells ; 

animal remains, those of the deer being most abundant ; 

and some human skulls ....... 16 

Towards the sea the bed 8 entirely disappears, giving 
place to 7, which reposes on 

9. The tin-ground, which consists of rounded masses of tin- 
ore, in some cases unmixed with any other substance, in 
others in a matrix of quartz, and quartz and schorl, with 
rounded pieces of slate, granite, and quartz, varying in 

thickness from a few inches to------ 12 

The following section was supplied by Edward Smith in 1807.* 
As pointed out by De la Beche, the name '^ Carnon Streams ^ has 
been given to a long line of works down the valley, so that the 
section is subject to variations: — 

ft 

1. Mud and sand .......... 7 

2. Granite gravel, intermingled with small pieces of a substance 
resembling charcoal, and a few shells .-.-.. 4 

3. Fine gravel, mud, and shells ....... 12 

About this depth are several irregular strata of oysters, about 

4 or 5 feet in thickness, extending irregularly to within 4 or 5 
feet of the tin ground. 

4. Closer mud, intermingled with shells - ... - 19 
In this stratum have been found several branches and trunks of 

trees, some of which had evident marks of being cut with an axe 
or other sharp instrument ; antlers and bones of stags, likewise 
human skulls. 

5. Tin-ground, varying from - - • - - - -lto2 
De la Beche states that the shells from these sections which he had 

examined, corresponded with the species still found in the Falmouth 
estuary.f 

At the time when De la Beche wrote, the higher Carnon Works 
had been '* abandoned, the search for stream tin in the same 
valley being confined to the bottom of Bestronguet Greek, beneath 
the tidal waters of the estuary, on the south of Daniell's Point.**! 
These submarine operations, however, have long since ceased. 
Beyond the area of the present sheet a very similar section has 
been described at Pentuan, where human skulls are stated to have 
been found 40 feet below the surface, mingled with the remains 
of deer, oxen, hogs, and whales. Assuming these facts to be 
correct, then, as De la Beche remarks, " a considerable change took 
place in the relative levels of sea and land since man inhabited 
Cornwall, allowing estuary or marine deposits to be eflFected in 
creeks upon a surface that previously permitted the growth of 
terrestrial vegetation, the remains of the marine creatures entombed 
in the mud, silt, or sand showing that these creatures were of the 
same species as those which now exist in the adjoining sea."§ 

As these submerged valley deposits have only been brought to 
light by the search for tin, their occurrence can only in these 
instances be demonstrated. It cannot be doubted, however, that 
similar evidence exists in other valleys which extend seaward as 
tidal estuaries. 

♦ TraTis, Geol. Soc., vol. iv., 1817, p. 404. 

t Report previously cited, p. 404. 

X Report previously cited, pp. 404 and 405. 

§ ** Report on Cornwall, Devon, and West Somerset," p. 407. 



99 



CHAPTER XI. 



EECENT DEPOSITS. 
I. Submerged Forests. 

While the raised beaches demonstrate the elevation of the coast- 
line, the presence of forest beds beneath the level of the sea point 
just as clearly to its subsidence. The existence of the subnaarine 
forest fronting the valley at Maen Porth has long been known. 
It can, however, rarely be observed, being baried beneath sand 
and shingle. Portions of it are, nevertheless, occasionally laid bare 
after heavy gales, during the lowest tides. It has been described 
by the Rev, Canon Rogers,* who observed the stump of an oak in 
its position of growth, with peaty material enclosing its roots, and 
containing the remains of the common yellow flag (Iris paeudo- 
corua) still flourishing in the adjoining swamp. In 1895, after a 
succession of easterly gales, the overlying shingle was removed, 
and part of this submarine forest was exposed. It was described 
by Mr. S. Roberts,! who found the j;iwbone of a small horse 
that has been doubtfully referred to an extinct species. On 
the same occasion an antler of a deer was obtained by a work- 
man.^ The mould was excavated to a depth of 3 feet by Mr^ 
Roberts without reaching the bottom. It emitted a noxious odour 
of sulphuretted hydrogen, and contained the '* remains of aquatic 
plants, the impress of the leaves, stems, rootlets, and flags being 
very marked. Hazel-nut shells, hazel twig with the bark on, as 
well as fir cones partially deprived of their seeds, were abundant. 
These were so compacted together that, when removed, their 
prints were well-defined in the mould." The mould contained a 
number of trees lying in various positions, some of them from 
12 to 20 feet in length, the largest reaching a diameter of 2 feet, 
and all yielded readily to the touch. Mr. Roberts states that 
some of the timber was nearly black, and some of a reddish 
colour, and considered that it was represented by oak, pine, alder, 
willow and hazel. The jawbone was found close to a large pros- 
trate tree trunk. ''It was about 1 foot in length, and set in it in 
perfect order were five large teeth — the whole set — all molars, well 
preserved with labyrinthine crowns." 

In 1871 a submarine forest was laid bare at Market Strand, 
Falmouth, and described by Mr. H. M. Whitley.§ The forest bed 
was about 7 feet thick, and its surface about the level of low-water 
mark, and buried beneath a bed of sand about 2 feet in thickness, 
while it was separated from the underlying rock by about 4 feet of 
gravel. It consisted of compact peat containing the remains of 
flags, ferns, and trees, few of which exceeded 12 inches in diameter, 

♦ Trs. R.O.S. Corn,, vol. iv., p. 481. 
t T','», li.G.S. Cnm,, vol. xii., part ii., p. 68. 

% Both the antler and the jawbone are in the possession of Mr. Robert Fox, 
of Grove Hill, Falmouth. 

§ Jowm, Roy. Inst. Corn., 1872, No. 13, p. 77. 

h2 



100 DECENT DEPOSITS. 

chiefly of hazel, oak, and fir, but beech and birch were also abun- 
dant. The forest bed is continuoas for some distance inland along 
the valley known as the Moor,* while another portion of the forest 
was exposed daring excavations at the Bar pools. 

In Gerrans Bay a submerged forest was observed some years ago 
at Porthcurnick by Mr. H. G. Handsombody, who saw tree stumps 
projecting from the sand at low tide. In 1898 we observed a large 
root at Pendower beach that had evidently been detached from 
the forest bed at the mouth of the valley at Pendower, which 
was seen quite recently by Mr. Clement Reid. 

At Portreath, on the north coast, peat was encountered beneath 
the sand in a dock excavation. 

While the beginning of the submergence in which these forest 
beds are involved may have followed closely on the termination of 
the glacial period, there are some grounds for the opinion that it 
may have continued to historic times. 

II. Marine Alluvia. 

Numerous beaches of sand and shingle have accumulated 
in the various bays along the seaboard, the most extensive of 
which on the south coast occur at Pendower, Porthcurnick, To wan, 
Falmouth, and Maen Porth. The beach at Swanpool that fronts 
the mouth of a valley, has acted as a natural dam and ponded 
back a considerable freshwater lake, while in other localities the 
free egress of the streams has been so far checked as to produce 
swamps at the valley mouths, as at Gyllyngvase and Maen Porth. 

The deposits, however, that line the estuaries, and which are 
laid bare at low tide, are of far greater extent than the accumula- 
tions which have collected in the more sheltered situations along 
the seafront. The mud discharged by the streams into these 
estuaries is gradually filling them. At Bestronguet, ships 
could ride at anchor considerably farther up the Creek than at 
present, within the memory of the present generation ; while the 
mud-flats of the River Fal, below Ardevora, are creeping rapidly 
seaward at a rate that is readily detected. Tradition avers 
that Tregoney was an important Roman settlement accessible 
to shipping, and there is historic evidence that the tidal waters 
reached that place in the sixteenth century. The Fal estuary is of 
especial interest, as the tidal flats, instead of forming banks of 
dark mud derived from the decomposition of the killas, consist of 
pale tenacious clay, brought down from the surface of the western 
portion of the St. Austell granite mass. That rock, being in a 
highly decomposed condition, is eroded more rapidly than the 
killas, so that the material deposited in the estuary consists largely 
of impure kaolin from that district, considerably augmented by 
the drainage of the waste water from the china clay works. 

An instructive paper on the silting up of the creeks of Fal- 
mouth Haven was communicated by Mr. H. M. Whitley in 1881 
to the Royal Institution of Cornwall.| The comparison between 

* The lower part of this valley was formerly the site of a tidal inlet that 
has since been artificially reclaimed. 
t Jovm.y vol. vii., pp. 12—17 ; also pp. 60—52. 



ALU- VIA. 101 

the aocxent and modern charts affords concla>ive evidence of the 
serions nature of the shoaling, and to some extent of the rate at 
which the mad banks are accumaUting. Between the vear^ 1698 
and 1855 the bottom has risen 12 feet at Tolvem Point, and 
18 feet at Tregothnan boathouse. 

The most extensive silting appears to have taken place in 
Devoran Creek, being considerabiv angmented there by the 
mining operations along the Camon Valley. Mr. Richard Thomas, 
in his history of Falmooth. states that the channel opposite Penpoll 
has silted op 10 feet since the Admiralty survey of 1698, and at 
Restrongaet Pool, at the higher end, where in 1698 there was a 
depth of 42 feet at low water, was in 1855 dry at the same period, 
and at the lower end there was a growth of 12 feet in the same 
interval ; whilst the bank between the main channel of the 
Haven and Restrongaet " has shoaled during the same {.leriod 
from 12 to 3 feet at low water." Although the creeks are shoaling 
more rapidly than the main harbour, Mr. Thomas calculated that 
the silt brought down into the harbour would form a layer 1 foot 
thick in about 43 years, supposing it uniformly distributed through- 
out the haven and its branches. 

III. Freshwater Alluvia. 

Notwithstanding the extensive valley system that prevails over 
the area, the alluvial deposits that line its floors are comparatively 
meagre, while the streams that water them are proportionately 
insignificant. 

Age of the Valleys. — From what has been alrealy said, it 
will be understood that these deposits have been laid down since 
the stream tin^ even in those localities where the latter is absent, 
for it is evident that the cleaning out of the valleys was universal 
over the district. The evidence, moreover, of the submarine 
valley section at Restronguet, shows that these deposits which 
overlie the stream tin belong to the Recent period. While the 
age of the valleys cannot be demonstrated, they may probably be 
referred to the later Pliocene period. Subsequent to the emergence 
of the Pliocene sea floor, more ancient valleys, however, may have 
been sealed beneath Pliocene deposits, the evidence of which has 
been lost by the removal of the material that tilled them. That 
the valleys were enlarged in the Pleistocene epoch is very evident, 
as the raised beach which lines the coast of the lower portion of 
the Carrick Roads is not met with in the estuaries that diverge 
from that inlet. Moreover, the deposits of Head along the valleys 
and estuaries are insignificant. We may conclude, therefore, that 
both deposits were removed by the torrential conditions attending 
the formation of the stream tin. Notwithstanding their great 
depth, some of the valleys have very narrow floors, probably due 
to their being deepened rapidly in the glacial epoch, when they 
must have presented the appearance of narrow gorges. 

Nature of the Alluvia. — The alluvium of the killas districts 
consists of a muddy silt in which sand and gravel deposits are rare, 
except where the higher portions of the streams have traversed 



102 EECENT DEP06ITS. 

granite areas, when detritus from that rock has been brought down in 
the form of gravel, the grains of which are unrounded. In granite 
districts the alluvia is mainly of the latter description. In some 
situations, where the declivity is slight, clay has been formed, 
more especially in the upland basins. River terraces, marking 
different stages of deposit, are rare : moreover, the alluvial flat 
itself, which lines the valley floor, occasionally presents difficulties 
in its demarcation. Not only does it often merge insensibly into the 
d6bris of the valley slopes, but the streams frequently originate in 
broad, open basins, and the tracing of the alluvia along the&e 
hollows is attended with much uncertainty. This is especially 
the case in granite areas, as the debris formed by the decomposi- 
tion of this rock is practically indistinguishable from the granitic 
alluvia. In valleys that have been worked for stream tin, or 
which have been used for treatment of the ores raised from the 
mines, the alluvial margins have often been obliterated, and along 
some of the hollows the ground is so disordered that it is uncer- 
tain to what extent they were lined with alluvia. The stream tin 
valley of Porkellis, in the parish of Wendron, may be instanced 
a^ an example. Moreover, this valley is fringed by gentle slopes, 
in which the underlying granite is completely hidden by a soil 
cap made up of its debris, and corresponding precisely with the 
granite alluvia which floors the valley, and the one shades 
iniperceptibly into the other. The uplands occupied by the 
granite present numerous instances of alluvial basins in which the 
original flat is gradually being modified by the soil creep from 
the slopes. Some of the moors which so frequently occur at the 
heads of the valleys have thus been formed. The want of fall 
renders drainage difficult, and their clay bottoms are frequently 
lined with marshes. 

The Valley Systems. — The valleys are disposed in three 
prevalent directions that are common to the whole district, but 
each type predominates in certain areas. On the eastern portion 
of the sheet the principal valleys trend from north-east to north- 
north-east. On the horizon of Truro and Falmouth there is a 
strong tendency for the larger hollows to run north and south, 
while west of that belt the majority of the streams lie in valleys 
ti'ending from north-west to north-north- west. The north and 
south system is in all probability the oldest, as it appears to have 
no relation to the structural features of the geological formations 
which make up the existing land surface. The north-north-east 
system approximates to the general strike of the killas and to the 
system of fracture produced by the volcanic disturbances of the 
newer Palseozoic period ; while the north-north-west system 
coincides with the direction of fracture that probably 
originated in early Tertiary times. To what extent the valleys 
coincide with faults there is seldom evidence to show, but the 
straightness of some of them, and in other cases their parallelism, 
suggests that their course has frequently been determined 
by lines of dislocation or well-marked joints. Moreover, two 
valleys divided by a ridge are often in perfect alignment as if 
their course had been determined by a single line of fissure. 



BLOWN SAXD, 103 

Bate op Growth of the Alluvial D£ro2«iTS.--The Fal is 
the largest river within the regioD, but only its lower reaches 
eoter this area. As that part of the river was, however, in historic 
times, a tidal estuary, the age of the alluvinm can be approxi- 
mately ascertained. In the description of the marine alluvia the 
seaward growth of the valleys and their encroachment on the tidal 
estuaries is referred to. There is evidence to show that the alluvial 
flat above Lamorran and Ruan Lanihorne has been formed since 
the sixteenth century, and Mr. H. M. Whitley has e^timateii thai 
it has been silted up at the rate of I foot in about thirty year?.* 

The deposits lining the Carnon Valley have been still more 
rapidly accumulated, mainly as the result of the extensive mining 
operations that formerly prevailed. In 1620 the tide tloweti 
beyond Lower Carnon, and, accordinsf to tradition, it even once 
flowed above Bissoe Bridge.t It has been calcuhiteii that at the 
height of mining activity — in the 21 yearsi between 1821 and 
1842 — deposition was at the rate of 1 foot in five years. Accord- 
ing to the late Mr. VV, J. Henwood,} the surface of the vjdlej at 
Higher Carnon was raised between the years 1820 and I8ii7 at tiia 
rate of about 1 foot in ten years. 

IV. Blown Sand. 

Sand dunes and towans are seldom developed in this area. 
These aeolian deposits are mainly composed of finely cominiiiiited 
sea shells, such as form the shelly beaches, and have i^een lar^jely 
utilised in Cornwall for enricliing the soil by the lime contained in 
their composition. On the north coast there is an extensive 
development of blown sand at Porth Towan, from which the naine 
has evidently been derived. On the south coast saixl dunes occur 
at Pendower and at the mouth of the hollow a fjiiarter of a mile 
east-south-east of Gwendra. At Porthcurniek blown sanrl (K-eurs, 
but not to any appreciable extent. Further south, in the ^Nirish of 
St. Anthony, a trnct of blown sand fronts Towan beach below 
Porth Farm, and has succeeded in choking an old channel con- 
necting the estuary with the open sea that formerly constituted 
the present peninsula of St. Anthony an island. 

* Journal liojf' In»t. Cortncall, vol. vii., p. 12. 

t About I'll niileri above the point now reachetl by ordinary tide^. 

t Presidential Address, Hoy. Inst. Cornwall, 1870. 



104 



CHAPTER XII. 



ECONOMIC RESOURCES, EXCLUDING THE ORES.* 

Soils and Vegetation. — The fertility of the district is subject 
to great variation. While the larger part of the area yields a 
generous soil susceptible of a high degree of cultivation, there are 
large tracts occupied by gorse and heath that are cooiparatively 
barren. Not only do these fluctuations depend on the character 
of the underlying rock, but an important influence has been 
exercised by physical situation. Among the latter, such conditions 
as elevation, proximity to the north or south coast, the shelter 
afforded by valleys, and the varying declivities of the slopes have 
materially contributed. The geological conditions are very pro- 
nounced in areas occupied by granite as compared with districts 
characterised by killas. There is a further marked distinction in the 
metalliferous areas and the districts that bound them ; in much 
of the former the mineral alteration and excess of quartz has 
materially impoverished the soil, while in some oases the extensive 
mining operations and stream washings have devastated large 
tracts that would otherwise have been susceptible of cultivation. 

The eastern area is very fertile and is given over entirely to 
agriculture. The district lying within the basin of the Fal and 
its extensive tributary system is in a high state of cultivation, 
and includes the parishes of Probus, St. Erme, St. Clement, 
Kenwyn, Kea, Feock, Merther, Lamorran, Cornelly, St. Michael- 
Penkevil, Ruan Lanihorne, and Philleigh. The peninsula south 
of Philleigh, embracing the parishes of St. Just, Grerrans, and St. 
Anthony, is almost equally fertile. West of the Carrick Roads 
and Falmouth Bay, the tract extending inland as far as the 
granite produces good agricultural land in the parishes of Mylor, 
Penryn, Falmouth, and Budock. 

The killas which enters into the geology of the eastern area is 
mainly confined to the Portscatho division, but the Falmouth and 
Mylor groups are also represented. There is no very marked 
difference in the lithological types of these divisions,so that the soils 
resulting from their disintegration present no striking contrasts. 
On the whole, perhaps, the Falmouth group furnishes the best 
soil, especially when represented by the sandy friable type that so 
readily decomposes. This is well illustrated by the rich lands 
of Ardevora, in the parish of Ruan Lanihorne. In the area 
occupied by the Portscatho group it has been observed that the 
soil is lighter and of a higher agricultural value where the sandy 
types prevail. 

The extensive valley system, into which the eastern area has 
been trenched, has produced marked variations in the agricultural 

* Mining economics are treated in Part II. 



SOILS AND VEGETATION. 105 

value of the Jand. In some parts of the region the valleys are so 
closely adjacent that the intervening ground affords little or no 
flat land. In fiskct^ it may be claimed generally that in this area 
level ground is almost entirely restricted to the valley floors, and that 
the difference between one tract and another is that characterised 
by the relative declivities of their slopes : some valleys being 
broad and open, while others are narrow and steep. In the 
former the soil is deep, while in the latter the covering is so thin 
that the rock often protrudes at the surface. The wash of the 
soil from steep slopes to their base is counteracted by the farmer^ 
who periodically respreads it on the higher land to preserve its 
fertility. 

The great mineral area between Camborne and Baldhu con- 
sists largely of killas. The extensive mining operations have laid 
waste large tracts, especially in the districts between Baldhu and 
Scorrier. Besides this cause, the soil is often materially im- 
poverished by the large amount of quartz detritus, derived from 
the disintegration of the siliceous veins. Apart, however, from 
these considerations, the belt of country fringing the north coast, 
and in which mineralisation is not conspicuous, is markedly less 
fertile than the killas on the south, and there are large tracts 
which are out of cultivation.* These northern slopes not only 
suffer from their bleaker aspect, but the district is not so ex- 
tensively trenched by valleys as the south, and is consequently 
more exposed to the winds. This is particularly brought out by 
the comparative absence of woodland in the northern district, 
whereas the southern tract sustains flourishing plantations, and 
exotics from warmer climes thrive in its gardens. 

The killas area on the extreme western portion of the sheet, 
between Camborne and Carnmeal Downs, is fertile and almost 
entirely under cultivation, while the timber at Clowance flourishes 
in a degree altogether unusual in the district, comparing favour- 
ably with the woods of the Fal basin. 

The granite district exhibits marked variations in its agri- 
cultural value. While over large tracts the rock is buried beneath 
a soil cap through which it rarely protrudes, these areas are often 
suddenly replaced by rocky wastes ihat are sterile, while in other 
situations good arable land is broken by extensive protrusions of 
rock. Whereas the differences in elevation over the granite areas 
partly accounts for these variations, this cause does not altogether 
explain the phenomena. Fertile tracts and barren areas are 
frequently closely adjacent, and although resulting doubtless from 
chemical distinctions in the granite that have affected the nature 
of its decomposition, these mineralogical variations in the field are 
not always to be detected. 

The Cammenellis granite reaches a height of 819 feet. Its 
northern margin has an average elevation of about 500 feet, while 
the eastern portion descends to the 300-ft. level and sometimes 



• Mach of the Downs has been reclaimed comparatively recently, thick 
dressings of •* marl " being applied, the material of which has been mainly 
derived from greenstone. 



106 ECONOMICS. 

lower. The western portion is higher than the eastern , and 
succeeds the killas between .SOO and 400 feet above sea level. 
The most fertile areas are the eastern and southern slopes in the 
parishes of Stithians, St. Gluvias, Budock, Mabe, and Constantine. 
On the other hand the most elevated region at Cammenellis, 
and including Nine Maidens, Calvadnack and from thence to 
Cannebone, is the naost barren part of the tract, little of 
which is under cultivation, the remainder consisting of rocky 
wastes covered with gorse and heath. The land also lying between 
East Wheal Lovell and Wendron is an abandoned mining district, 
the agricultural value of which is poor. The whole of the western 
region of Crowan, and including Polcrebo, contains large tracts 
of uncultivated downs. On the north, about Carwynnen, there is 
also a large area out of cultivation. > 

As already remarked, there is a great discordance in the depth 
of the granitic soils apart from differences in elevation. In some 
districts the granite is decomposed for a considerable depth from 
the surface, as is seen in the neighbourhood of Kame Common, 
and extending to Menerdue on the north and to Butteriss Downs 
on the south. While in this district the granite disintegrates to 
a friable soil which is light to work, it frequently yields a stiff 
clay. Indeed, over the granite area generally, the soil is cold 
as compared to the killas, and crops are later. Although some 
portions of the granite region include lands that are highly pro- 
ductive, the killas areas are the most fertile, irrespective of the 
factor of their being more low lying. This is exemplified on 
the granite margin, where there are sharp differences in fertility 
at its junction with the killas, the area occupied by the latter 
being markedly superior. 

The summit of Cam Brea reaches an elevation of 740 feet 
in the granite region named after that peak. This rugged 
country is replaced near Bosleake by cultivated lands that occupy 
the remainder of the granite area in its course to the south-west, 
the continuity of which is occasionally broken by rock as at Carn 
Art hen, and further west at The Rocks, near Croft Danger. 

The Carn Marth granite area is mainly under cultivation, 
except in the southern and most elevated tract, culminating in its 
summit at an elevation of 771 feet. 

The decomposition of the greenstones yields a rich soil, but 
these rocks occupy an insignificant portion of the area. 

The mica traps, while still more sparsely distributed, disintegrate 
readier and possess a manurial value from the phosphoric acid 
which they contain. 

The Stone Industry. — This area furnishes a large proportion 
of the granite that forms the well-known Cornish granite industry, 
the rock being mainly raised from the Cammenellis mass. 

The headquarters of this industry is situated at Penryn, where 
the stone is dressed, and from which port it is shipped. The 
granite raised, however, in the more southern districts of Mabe 
and Constantino is shipped at Porthnavis. The stone is mainly 
wrought in a belt of country lying to the west of Penryn, extend- 
ing from the south of Scithians to Long Downs and Burnthouse, 



THE STONE INDUSTRY. 107 

Eathorne, and Brill. In this tract qaarries are both numerous 
and extensive. Beyond this region granite is wrought along 
the Cober Valley, south-west of Wendron, and at Carwynnen, 
about two miles south of Camborne. Besides these localities, 
quarries on a smaller scale, many of which are no longer working, 
occur on the eastern margin of the Carnmenellis granite near 
Pencoose, at Kennal Vale, Ponsanooth, Penryn, Budock, and 
Penwarne. In the western area the principal localities where the 
stone has been raised are at Croft Michell, Praze, Crowan, Bognio, 
Nancegollan, and Prospidnick. Quarries have been worked also 
at Lower Trethanup, near Carrannel, Tretheague, Halabezack, 
Tolcarne, and at other localities which need not be enumerated. 

The granite is grey in colour, and its principal mineral con- 
stituents are felspar, quartz, and two micas, viz., muscovite and 
biotite, while tourmaline is commonly present as an accessory 
mineral. In texture there are two varieties, known com- 
mercially as " fine grit " and '* coarse grit." The former, which 
usually occupies the outer belt for an average width of about a 
mile, although the superior stone, is not so extensively worked as 
the ** coarse grit," on account of its being more expensive to dress. 
It is not only finer in texture, but is darker in colour, containing 
more biotite, and has a higher specific gravity (about 1 per cent.). 
A good example of this stone is seen at the quarries at Canisew, 
about one mile west of Penryn. The *' coarse grit '* is a more 
attractive stone, and is studded with porphyritic felspars that reach 
an inch or more in size, some of the most beautiful varieties of 
which occur in the parish of Mabe. 

As remarked in a former chapter, the granite is divided by a 
threefold set of joint planes, one of which is horizontal and the 
others vertical, the latter intersecting one another approximately 
at right angles. Moreover, the joints are sufficiently far apart to 
admit of the extraction of immense blocks. In fact, the favour- 
able disposition of the jointing is one of the most important 
factors in contributing to the success of the Cornish granite in- 
dustry. (Plate IX.) 

The principal quarries are confined to the eastern portion of 
the Carnmenellis mass, where the rock is little disturbed, and 
in which elvans are rare. In the central and north-western area 
the granite has been subject to much Assuring and disturbance, 
in connection with the oncoming of the mineral veins, and in 
these districts the stone has only been raised for local purposes. 
Not only so, but the rock is frequently less uniform from the 
abundance of finer-grained granite and aplite veins with which 
the normal rock is mixed. These differences in texture cause 
irregularities in the joint planes, which renders its working un- 
profitable. 

Even in the granite belt which forms the heart of the industry 
these veins are of too frequent occurrence, and are often the 
cause of the quarry being abandoned. 

These finer-grained granites or aplites are rarely, however, 
sufficiently large to be independently quarried, and in some in- 
stances they are not easily distinguished from the elvans. In 



108 



ECONOMiaS. 



fact, the term elvan as used by the quarrymen includes these finer 
varieties. A quarry of this nature occurs at Lower Tretharrup, 
near Lanner. 

The Cam Brea granite is of similar texture to that of Carn- 
menellis, and has been raised in various places between Cam 
Brea and Cam Art hen. At Bosleake a quarry has been opened 
on one of the finer-grained veins. 

The Cam Marth granite is of somewhat similar texture to the 
**fine grit" stone of the Carnmenellis granite, but the felspars are 
usually porphyritic, and of a slender habit. It is quarried ex- 
tensively on the hill of Cam Marth. It is frequently, however, 
mixed with veins, and is inferior commercially to the granite of 
Mabe and Constantine. It has supplied the principal building 
stone of the town of Redruth. 

The following table, for which we are indebted to Messrs. John 
Freeman & Co., Penryn, illustrates the crushing strength of the 
CarDmenellis granite, as determined by Mr. David Kircaldy in 
May, 1904 :— 





Dimensions. 

Inches. 
3-92 3-96 X 3-95 
400 3-98 X 3-97 
3-98 3-98 X 3-98 

Mean 

3-9(5 3-96 X 3-96 
3-90 3-9GX3-96 
3-97 3-96x3-9ti 

Mean 


Base 
Area. 

sq. ins. 
15-64 
15-80 
15-84 


Crushed. 


Locality. 


Stress. 

lbs. 
314,200 
a*i5,700 
269.500 


per 
sq. in. 


per 
sq.ft. 


Tresahoe (Parish of 
Constantine) 


lbs. 
20,090 
21,247 
17,014 


tons. 
1,2920 
1,366-4 
1,094-1 




15-76 


306,467 


19,450 


1,250-8 


Carnsew (Parish of 
Mabe) 


15-68 
15-68 
15*68 


398,500 
357,400 
294,800 


25,415 
22,793 
18301 


1 

1,634-4 
1.465-8 
19091 




15-68 


350,233 


22,336 1 1,436-4 




I 


1 



At the present time the granite industry is undergoing a period 
of depression consequent on its inability to compete with Norway, 
where the conditions of labour^ the ease with which the rock is 
diessed, and its presence on the seaboard^ facilitate its importa- 
tion at a cost below that at which the stone can be remuneratively 
wrought in this country. The decline of the industry is being 
severely felt in the district of Penryn, whence some of the skilled 
workmen are emigrating to America.* 



* Some idea of the extent of the granite trade in this part of Cornwall 
during recent years may be gathered from a perusal of the following table, 
which represents the supply of dressed stones by Messrs. J. Freeman & Co. 
or dock and harbour works, bridges, and lighthouse alone : — 



THE STONE INDUSTRY. 109 

The elvans afford some of the best building stones of the district, 
and have been extensively utilised. The harder varieties are 
extremely durable, but in many instances those in which a certain 
amount of decomposition has set in have been selected on account 
of the freedom with which they are dressed, and to which the 
term freestone has often been applied. Ot this type are the 
elvans of Newham.t near Truro, at Porkellis, near Wendron, at 
Kerling Downs^ near Chacewater, and many others. 

These rocks have been so extensively quarried that it is unneces- 
sary to enumerate the localities. The stone now being raised for 
building purposes to the south of Nine Maidens is of excellent 
quality, coarse in texture, and grey to pinkish in colour, and 
studded with dark nests of tourmaline. The well-known el van at 
Saveock Water, to the east of Chacewater, is a somewhat similar 
stone, in which the tourmaline nests are exceptionally well 
developed. At Enys a fine-textured c;rey dyke has been 
quarried, which is exceedingly fresh. The stone wrought at 
Towntanna, and at Trevales, is often of a reddish colour. A 
very fine-grained light jrrey el van is quarried at Tresevern Croft, 
and at Cah'adnnck ; while a similar rock is wrought at^ljoining the 
high road to the north of Crelly, and between Little Tre wince 
and Tregolls. The el van that is worked at Green with and 
Pencoose is j)orphyritic, with a fine grey matrix ; at the former 
locality it is fresh, but at Pencoose incipient decomposition has 
set in. At Lower Carnon another large dyke has been ex- 
tensively quarried. The elvan at Kea, near Truro, is greyish 
green in colour, and is beginning to decompose. At Nansavallan, 
near Truro, a band is wrought of the porphyritic type. Near 
Sedrntb a dyke is quarried at Higher Cardew, and on the east 
of Gam Brea Castle a coarse-grained stone is being worked. On 
the northern flanks of Carn Brea a tine -textured grey elvan has 



• Dock and Harbour Works. 

Supplied by 
Total Order. MessrH. Freeman. 
Cubic Fvrt. Cnhic Feci. 

Gibraltar, 1899 1^) 1904 - • I,2rK)/M)() 900,000 

Keyharn, 1897 to 1905 - - 1,891,400 945,000 

Cardiff, 1899 to 1904 - - 142,(XK» 14*2,000 

Portemouth, 1894 to 189<) ■ ■ t)0(),OiM> 606,000 { 

Folkestone, 1897 to 1904 - 14'2,(^H) 142,000 , 

Dover Harbour Board, 1892 to 

1901 118,162 118,162 

Barry, 1892 to 1898 - - - 162,218 162,218 

Bridges. 

Kew, 1899 to 1902 149,000 

Kntherglen, 1893 to 1895 90,643 

Tower Bridge, 1887 to 1889 139,000 

LiGHTUOUSE. 

Fastnet, 1898 to 1902 69,000 

+ Mr. Collins states that a large portion of the city of Truro was built from 
this stone. TVawi. Hoy. GeoKSoc, Cornwall^ vol. ix., p. 226. 



1 10 ECONOMICS. 

been quarried. Good stone is also being raised from the quarries 
at Bolenowe Crofts and Bolenowe Moor, to the east of Troon. 
The dyke which runs through Gregwartha is fine-grained, soft 
and locally known as freestone; it is at present being quarried 
half a mile to the north-east of that locality. A hard durable 
stone is raised at Creegbrose, near Chacewater. At Praze 
Station there is a large quarry of a greyish green elvan of a very 
fine-grained, even texture, and a somewhat similar rock is wrought 
near Trevoole. 

The greenstones and mica traps have only been exceptionally 
used for building purposes, the former on account of their tough- 
ness and cost of working, and the latter from their decomposition. 
In spite, however, of their general unsuitability, the mica traps 
have occasionally been utilised in preference to the killas 
amongst which they occur. When not too decomposed they 
are readily dressed, and are said to be durable. The green- 
stone has been quarried at Flushing, Bissom^ Treluswell, Devis, 
Tuckingmill, and Wheal Trannack. At Camborne it has been 
extensively used for walls, in which huge blocks have been 
laid. 

Notwithstanding the superabundance of excellent building 
stone in the district, the more massive beds of the killas have 
been employed where superior stone is not immediately available. 
Although situated within two miles of the Carnmenellis granite, 
the town of Falmouth is mainly built of killas, and that stone, 
especially the crush conglomerate, is still largely utilised for 
building material. 

BoAD Metal. — The stone mainly employed for road metal is 
elvan, the finer varieties of which produce an excellent surface. 
Greenstone is also made use of to some extent, but notwith- 
standing its excellence this rock is frequently exceedingly tough 
to break, as at Treluswell and Ponsanooth ; nevertheless, at this 
latter locality it is at present being worked. Granite forms an 
inferior road metal, but is often used in the granite Areas. The 
harder sandy beds in the killas, especially the siliceous grits of the 
Lower Devonian area, are likewise wrought. Veinstone from the 
mine heaps is occasionally utilised. Stone is also imported, as the 
Plymouth limestone, and hornblende schist from the Meneage 
peninsula. These are mainly used, however, in the eastern 
district, where igneous rocks are rare, and where the tidal estuaries 
have favoured water carriage. The hornblende schist produces a 
greasy surface, and is, therefore, not so suitable as the greenstone. 
One of the latter type, locally known as "blue elvan," is at 
present being worked at Porthoustock by Messrs. Freeman & Co., 
and yields an excellent road metal.* 

Clays. — China clay, into which some of the Cornish granites 
decompose, is rare in this district. At Lower Kergilliack, how- 
ever, near Penryn, the granite yields an inferior china stone, 
which is mixed with imported china stone from the St. Austell 

* Samples of thig rock submitted to attrition tests yield dust to the low 
percentage of 4*6^^ The specific ^vity of the stone is 2*91 . 



CLAY — WATER SUPPLY. Ill 

district, and worked at Penryn. China clay works of small extent 
formerly existed in Porkellis Moor, in the parish of Wendron. 

Near St. Day the decomposing granite is utilised for the 
manufacture of bricks, and the factory turns out over a million 
annually, ^he granite is decomposed for a depth of about 50 
feet, and was formerly used (or china clay, but was unable to 
compete with the superior clays of the St. Austell district. On 
account of the gritty nature of the clay the individual bricks are 
cut by hand. Those produced from this decomposing granite 
have smooth faces, but their edges are imperfect. 

Some of the decomposed el vans have also been worked com- 
mercially for their clay products. Between Carharrack and 
Lanner clay pits have been formerly opened on an elvan for china 
clay and bricks. Similar dykes have also been worked as clay pits 
at Sparry Bottom, in the parish of Gwennap, at Carnon Downs, and 
at Wheal Baddon. 

The upper part of the Fal estuary is lined with a deposit of 
grey clay brought down by the drainage of the china clay district 
of St. Austell. This clay, which is of a whitish and pale yellow- 
grey colour, is not only used at Trelonck for the manufacture of 
bricks, but works have also been established for the production of 
the coarser varieties of earthenware. The following analysis 
of this clay was made by Dr. Pollard* from a sample taken at the 
ford between Ruan Lanihorne and Lamorran : — 



a .07 

• •• ••• ••• ••• vf 

1-30 
9*64 



HjO 105» 1-30 



HjO above IDS** 1 

+ Some organic matter/ 



100-57 
Less O for CI '17 



100-40 



Air 'dried Sample. 

oiXj^ ... ••. ••• ••• 4a'D7 

Jl i\^A ••• ... ••• .•* Lv 

J\laXj9 .•• ••• ••• "■• «Jo 4»> 

J? f)*vla ... ... ••• ••• 1 tf^ 

v/CbV^ ••• ••• ••• ••• X race 

MnO ... ... ..• ... Trace 

ai^o • • • ... ■ . . ... -37 

J!vm\^ ••• ... ... ... O 0^ 

^1 a«vr ... ... ... ... £if 

I4LO ... ... ... ... Trace 

l3\../tt •■• ••• ■•• ••• vF/ 

The ohlorine aDd sulphuric acid are due to sea water. The soluble salts 
amounted to *83 per cent., the sand + acid silicates to 24*7 per cent« 

Water Supply.— ^The granite and killas, which almost entirely 
make up the geology of the area, both hold water. The experience 
of miners leads to the conclusion that the killas contains more 
water than the granite, which is doubtless due to the excess of 
Assuring and shattering in the slaty rocks. The granite, however, 
appears to furnish the largest springs, and it is from this source 
that the principal towns of the district, viz., Falmouth, Penryn, 
Bedruthy and Camborne, draw their water supply. Truro, on the 
other band, obtains its water from the killas in the vicinity. 
Although there is no lack of water in the slate, the absence of 
large springs is often a serious difficulty in dealing with the water 
supply of the smaller villages that are unable to bear the expense 

• "Summary of Progress of Geological Survey " for 1899, p. 175. 



1 1 2 ECONOMICS. 

connected with storage reservoirs. The average water level is, 
perhaps, aboat 40 fathoms, bat this is sabject to great fluctua- 
tion. At Wheal Yor, for instance, it varied as much as from 
30 fathoms in winter to 45 fathoms in summer. The public 
water supply of St. Agnes and Mount Hawke is obtained from the 
adit of an old mine east of the latter locality. 

Smelting, Arsenic, and Ochre Works. — ^Tin smelting works 
are in operation at Point in Restronguet Creek. Further up the 
valley, at Bissoe, are two arsenic factories, one, situated about a 
quarter of a mile west of Bissoe bridge, employed in 1902 about 
8 men in addition to carters. The crude arsenic calcined at the 
mines is sent there for refinement. Ochre works exist in the 
same locality, which at the time of our survey in 1902 were said 
to have been in continuous operation for over 40 years. The 
oxide of iron carried in suspension, in the waters that discharge 
from the main adit into the Carnon stream, is caught in small 
pools, after which it is pulverized and washed. It is then dried 
into a fine brown ochre, in winter by fires, and in summer by the 
sun. The works are small, and there is no continuous market for 
the product. 



113 



PART II. 



MINING. 

BY 

D. A. MacALISTER. 

CHAPTER XIII. 
GEOLOGY OF THE MINERAL AREA. 

The rock formations, together with their tectonics, have been 
deacribed by Mr. Hill in the preceding pages. The mineral lodes 
of this district are almost entirely confined to those divisions of 
the killas which have been assigned to the Lower Paladozoic system, 
and to the granite, which invaded the killas about the close of the 
Carboniferous period. 

As the metalliferous minerals are very largely concentrated in 
the mutual marginal zone of the granite and killas, and as the 
lodes are frequently influenced by their association with igneous 
sheets and dykes, the following details in connection with the sub- 
terranean occurrence of granite, elvau, and greenstone will elucidate 
the underground geology of the metalliferous region, so far as 
mining operations have revealed it : — 

Sviterrariean Features of the Granite. 

In a geological map constracted by Kichard Thomas and pablished 
about the year 1819, the Kedrath (or Carn Marth) granite mass is shown 
by a sea level contour of its junction with the overlying killas to be con- 
tinuous with the Carnmenellis mass. 

The Carn Brea granite is connected with the Caruineuellis mass under- 
ground, a tact confirmed both by the subterranean dips of the granite and 
from information obtained from the mines. It is, moreover, of identical 
litholQgical character, as described in Part I. It is possible that the three 
of granite are connected, but this conclusion requires verification. 



Note. — In the ensuing paces the f ollowiu>^ publications are so f rea uently re- 
ferred to that for the sake of brevitvthe author's surname alone will be quoted 
in the footnotes : — W. J. Hen wood, ** On Metalliferous Deposits of Cornwall 
and Devon." TV. JR. G.8, Com., vol. v., 1843. Kichard Thomas, '' Report on a 
Survey of the Mining District from Chacewater to Camborne/' 1819. 
De la Beche, *' Geological Report of Cornwall, Devon, and West Somerset," 
1839. Joseph Carne, '* On the Veins of Cornwall." Tr. H.G.S. Com., 1822, 
vol. ii. Clement le Neve Foster, *' On the Great Flat Lode." Q.J. G.^., 1878, 
vol. xxxiv. John Garby, '• On some Cornish Mineral Localities." Vr. Ji, (^.;S. 
Ccrn.y vol. vii., 1847. 



1J4 



GEOTX)GY OF TU£ MIN£BAL AREA. 



Its petrological character and mode of occarrenoe, as already pointed 
out by Mr. Hill, suggests the Gam Marth mass to be an independent 
intrusion, but it may nevertheless be in juxtaposition below the surface 
with the adjacent granite of Oarnmenellis.''' 

The following table gives the dipsj of the junction of the granite and 
killas : — 



Mine. 



From Point. 



In 

direction. 



:ts fid 



Bemarks. 



Carn Bred Granite, 



OamborneVean 



Dolcoath 
Ditto... 



Ditto... 
Ditto.., 



Cook's Kitchen 

Carn Brea ... 

Ditto... 

Ditto... 

East Cam 
Brea 

WhealUny ... 



North Wheal 
Frances 



South Dolcoath 
South Con- 

durrow 
South Tol- 

carne 



South of Engine 
shaft 



South of Stray 
Park shaft 

North of Wil- 
liam's New 
shaft 



On Caunter lode 
On Main lode 
near Eastern 
shaft 
South of Dun- 
kin's shaft 

Providence 

shaft 
Near Tregajor- 

rau 
Druid shaft (on 

east) 
North slope of 

tongue of 

granite 
Southern slope 

of tongue of 

granite 



Deg. 
N.50W. 



Near King's 

shaft 
Near Taylor's 

shaft 



N.20W. 
N.22W. 



W. 5 N. 
W. 32 S. 



N. 37 W. 

N. 11 W. 
N.48 W. 

N 
N. 24 W. 

S.24E. 



S.30E. 



S. 42 E. 
S. 45 E. 

S. 



Deg. 

58 



72 
40 



72 
23 



30 

30 
30 
30 
34 

40 
(approx). 

35 



18 
17 

10 



Becomes flatter in 
depth and is 
thrown up into a 
ridge 

Ditto. 

Becomes steeper 
until it meets 
with Dolcoath 
Main lode at 
about 140 fathoms 
from surface, 
when it is thrown 
up into a ridge 

Becomes steeper 
and then flattens 

Gets flatter and is 
thrown np into a 
ridge 

Ditto. 



Ditta 



Becomes flatter and 
continues into 
the Cammenellis 
mass 

Becomes flatter and 
continues into 
the Cammenellis 
granite 
Ditta 
Ditto. 

Tending to become 
steeper in depth 



* J. 13. Hill. ** Summary of Progress of the Geolojrical Survey for 1903/'p. 26. 
■f The angle of dip is measured from the horizontal. 



SUBTERRANEAN FEATURES OF THE GRANITE. 



115 



Mine. 



From Point. 



In 

direction. 




Remarks. 



Redruth (or Cam Marth) Granite, 



Pedn an Drea 



I>itto 

Wheal Beau- 
champ 
Ting Tang ... 

West Poldice 
Treskerby ... 



Beg. 
East of Bragg*s I W. a few 



shaft 



South of Tre- 
vena's shaft 



deg. N. 



N.15(?)W. 



North of Roach's S. 40 E. 
shaft 

E. 30 N. 



Deg. 

18 



23 
40 to 50^ 

30» 
22^ 



At 75 fathoms from 
surface it is ver- 
tical for 30 
fathoms below 
Street shaft. Then 
dips 32 deg. in 
the same direc- 
tion 



Same dip in Poldice 



Carnmendlis Granite. 



Tresavean 




E.40N. 


36^ 


Below the 60-fathom 


Mine 








level the junction 
of the granite and 
killas is irregular 
and almost per- 
pendicular in 
some places 


Wheal Beau 


— 


N.E. 


60« 




champ 










Wheal Buller 


Point near ... 


N. 24 W. 


58 


— 


Wheal Basset 


South of Mar- 
riott's shaft 


N, 


57 


Gets flatter and 
then steep again 


Wheal Gren- 


South of King's 


N. 45 E. 


30 




ville 


shaft 









From the foregoing data it is possible to form an idea of the shape of 
the granite surface concealed by the overlying slates (see Fig. 2). The 
western portion of the northern margin of the Carn Brea granite dips 

* Henwood, p. 71. 

* Thomas, p. 10, gives the dip of the granite and killas junction from Wheal 
Damsel to Carharrack as 10 deg. and in a direction S.E. towards Ting Tang 
Mine as 18 deg. Henwood, p. 71 , gives the dip from East Wheal Damsel east- 
wards as 14 deg. to 16 deg. ; and at Ting Tang in a S.E. direction as 40 deg. 
to 45 deg. 

' Op. cit., p. 10, gives dip at Wheal Gorland to Wheal Unity as 20 dec:- 
^ Op. pit., p. 10, gives dip as 26 deg. 

* Op. cit.y p. 10. Henwoo<l gives tlie dip as 40 deg., p. 71. 
" Henwood, TaMc Iviii. 

i2 



116 



GEOLOGY OF THE MINERAL AAEA. 



Si 

I 



Sit 



s3 



c5 







cS 



cj 
a 

CO 



1 



2 « 

si 



-S £ 



M o 
•a CS 

1.1 

-♦- 

^ o 



SUBTERRANEAN FEATURES OF THE GRANITE. 117 

under the slates at a high angle (72 deg.)t bat in going eastwards it 
gradually flattens out, and in Cook's Kitchen Mine the dip is only 
30 deg. Further east, near Redruth, it is inclined to the horizontal at 
24 deg. The dip in the western portion of the southern margin is, at 
South Tolcarne Mine, only 10 deg., but in going eastwards the angle of 
dip increases until at North Wheal Frances it is 35 deg. ; and further east 
still, in Wheal Uny, near Redruth, the angle is 40 deg. from the hori- 
zontal. 

The elongate, somewhat curved shape of this mass is perhaps its most 
peculiar feature, as it is, correctly speaking, a ridge rather than a dome. 
On the east this peculiarity is strongly pronounced. 

The Redruth (or Cam Marth) granite presents the form of a more even 
dome, since not only is the exposed surface more nearly circular, but the 
dips around its margin do not vary to such extent. The northern and 
western slopes dip beneath the kiilas at angles varying from 18 deg. to 
23 deg. The eastern margin is steeper, and its slope beneath the kiilas 
varies from 30 deg. to 47 deg., the highest angle of dip being towards the 
south. The southern slope appears to have a maximum dip of about 
50 deg. 

The kiilas which lies in the subterranean basin formed by these three 
granite masses probably exceeds 1,200 feet in thickness in the vicinity of 
East Wheal Basset. Proceeding from thence westwards in a direction 
W. 35 deg. S*j between the two granite hills (of the Carn Brea and 
Cammenellis granites), the kiilas thins out rapidl3% until at South Con- 
durrow it is, at most, 300 feet in thickness, after which it dips away west- 
wards at an unknown angle. 

Underground exploration in the mines has to a certain extent revealed 
the character of the upper surface of the granite concealed by the kiilas. 
It appears to be undulating, but on the north of the Carn Brea mass 
there are two well-marked subterranean ridges^ of granite striking 
in the same direction as the cleavage of the kiilas. The granite plunges 
northwards beneath the kiilas, and after reaching a certain depth it rises 
in the form of an irregular wave trending E. 30 deg. N. This subterranean 
ridge varies in height to a maximum of 40 fathoms, and has been identified 
in Camborne Vean Mine, Dolcoath, New Cook*s Kitchen, Tincroft, and 
Blast Pool. About 150 fathoms further north there is a second but smaller 
ridge, of a maximum height of 30 fathoms, trending in the same direction, 
but only encountered in depth in South Crofty and East Pool.*^ 

In this locality there are also a number of intrusive sheets protruding 
from the main mass of granite which penetrate the kiilas on the north of 
the Carn Brea granite. To the list of such intrusive offshoots encountered 
in mining operations, the particulars of which have been published,* may 
be added those which were met with in the adit level at Kellivose Mine,^ 
and the tongue of granite which was driven through for several fathoms in 
Wheal Uny. At the 10-fathom level in Williams' shaft, in South Con- 
durrow Mine, the junction of the granite and kiilas can be observed, 
where small veins of granite penetrate the kiilas. The 70-fathom cross- 
cut, in Wheal Basset, is driven northwards from the North Basset lode 

* H. C. Salmon. Mining and Smelting Magazine^ 1862, p. 385. 

^ There is diificulty in accuratelv tracing these ridges, and it may be that 
the former really trends from Camborne Vean, through Dolcoath, New Cook's 
Kitchen, and South Crofty to East Pool. 

» W. Phillips, "On the Veins of Cornwall." Tr, Geol. Soc.y vol. ii., 1814, 
p. 152, and plate 7. Thomas ; Henwood ; Joseph Came, ' ' On the Veins ot 
Cornwall." IV. Jl.G.S. Com., vol. ii., 1822. Veins, tongues, or intrusive 
sheets of granite occurred in Kellivose, Dolcoath, Cook's Kitchen, Tincroft, 
Cam Brea, South Condurrow, Wheal Uny, Herland Mine, Wheal Basset, 
Pedn an Drea, East Wheal Sparnon, Wheal Beauchamp, Ting Tang, Wheal 
Damsel, Wheal Gorland, l*oldice, Wlieel Feevor, Cardrew Down Mine, Wheal 
Unity, Wheal Buller, Tresavean, Wheal Trannack, Carleen Mine, Wheal Voi . 

* 1* rom an old report, Pendarves Estate Office, Camborne. Obtained through 
the courtesy of Mr. Vercoe. 



118 GEOLOGY OF TUE MINEEAL AREA. 

towards South Carn Brea Mine and passes alternately, in some places, 
through granite and killas. 

The deeper parts of the more important mines situated in the killas on 
the north of Carn Brea have reached the granite. In Wheal Agar the 
granite is encountered at a depth of from 140 to 150 fathoms. In East 
I\k)1 it is about the 135-fathom level ; in South Orofty it is met with at a 
depth of from 140 to 160 fathoms, but getting deeper westwards ; in New 
Cook*s Kitchen from 120 to 136 fathoms. In Wheal Tehidy, on the east, 
granite was not met with iii the mine, but it is probably about 120 fathoms 
below surface. The granite was never reached in the Koskear or Seton 
Mines. Finally, in no case have the workings of any mine, when once 
fairly into the main mass of the granite, been known to pass through it. 



Svhteiranean Occurrence of Elvan} 

Mining operations have revealed the presence of a greater number of 
el vans, both in the granite and killas, than can ever be discovered at 
surface ; but the available information is scanty, owing to the fact that 
the miners have no interest in recording their occurrence, and conse- 
cxuently each discovery is soon forgotten. It is only in a few cases that 
all the particulars can be forthcoming, since it is only here and there that 
elvans are intersected during the development of the mine. This may 
partly account for the statement so commonly heard from miners that 
elvans occur in patches ; but it is also certain that such intrusions are 
sometimes split up into branches. 

At Wheal Beauchamp an elvan throws off several branches into the 
slates.^ Several irregular ''spots" of elvan occurred in the western 
part of Wheal Unity.'* The elvans in the killas in Barncoose, Wheal 
Druid, and Wheal Basset are greatly branched.^ 

At Wheal Clifford the elvans are considerably branched in depth. 
Elvans sometimes show considerable change in width witiun short dis- 
tances ; thus at Wheal Beauchamp the elvan at the 29-fathom level is 
3 fathoms in width, but at the 69 it is 30 fathoms in width.'' In Wheal 
Unity an elvan varies in width from 6 feet to 60 fathoms.^' 

** The elvan courses are from two or three to twenty or thirty fathoms in 
breadth, some of them larger. ''^ The following are a few selected examples 
of the widths of elvans as discovered in the mines : — In Wheal Beauchamp 
the width of the elvan is as much as 40 fathoms in some places.^ In Wheal 
Bullor an elvan is 25 fathoms in width.'' In Consolidated Mines^° there is 
an elvan 16 to 20 fathoms in width. In Cook's Kitchen an elvan is 17 
fathoms wide ;" another is 20 feet wide.**^ In Chacewater Mine an elvan 
is 6 fathoms in width.^^ In Crenver and Wheal Abraham, 1 to 3 fathoms 
ill width." In East Wheal Crofty (South Crofty) an elvan is 6 fathoms 
wide." In Cardrew, 8 or 10 fathoms.^'* In Creegbrose, 4 feet to 5 fathoms." 
In Wheal Unity, 5 fathoms.^" In Wheal Vor there are two elvans, one 
8 fathoms and the other 2 feet in width.*** In Carn Brea an elvan is 7 
fathoms wide, and another one less than this ;* at the 300-fathom level 

' The angle of underlie is measured from ihe vertical. 

"^ Kenwood, p. 81. * Thomas, p. 66. 

* J. Maynard, *' liemarks on two Cross Sections." ^Ut Rnt. Ray. Carn. 
Pol}/. Soc, 1871. 

•' Kenwood, p. 81. 

" J. Came, '-On the Veins of Cornwall," Tr. R.G.S. Com., 1822, vol. ii., 
p. 93. 

^ Thomas, p. 16. "* Op.eU.^y^.bQ. ^ Kenwood, p. 81. 

^"^ Op. fiit., p. 83. »* Op. cit., p. 63. 

'- W. K. Argall, ** On Elvan Courses." Mines' Assoc, 1875. 
*' J. Came, " On the Veins of Cornwall." Tr. H.G.S. Corn., vol. ii., 1822, 
p. 79. 

" Op. cit., p. 82. »5 Henwood, p. 62. ^^ Op. cit., p. 80. 

^^ Thomas, p. 34. J" Op. cit., p. 65. ^^ Kenwood, p. 62. '^ Op. cit., p. 63. 



SUBTERRANEAN OCCURRENCE OF ELVAN. 119 

there is an eLvan 10 fathoms in width. In Suuth Uoskear there are elvans 
irom 5 to 9 fathoms in width.^ In Ting Tang an elvan is 24 fathoms wide.^ 
In Tincroft, 6 fathoms wide/ In Wheal Grenville an elvan was penetrated 
for 40 fathoms without cutting through it. 

Very few of the elvans underlie south. There are two south underlying 
elvans in the section of ground between South Wheal Basset and South 
Dolcoath Mine ; and at the present time elvans which underlie south can 
be seen in the deep workings of Dolcoath and Wheal Grenville. Hen- 
wood (p. 80) gives two other examples. Elvans sometimes change their 
underlie in depth. In Dolcoath there is an elvan which in the upper part 
of the mine has an underlie north of about 45 deg. In depth, where the 
"country rock" is granite, it is almost perpendicular, underlying slightly 
south. At ClilTord Amalgamated Mines an elvan, outcropping between 
Garland and Hawke's shafts, starts from surface with a northerly underlie 
of 70 deg. as far as the 75-fathom level, after which its underlie is 35 deg. N. 

In the Gwinear district there are two series of elvans : one series 
strikes approximately E. 30 deg. N., and the other series striking nearly 
E. and W.* Now, although two series cannot be identified in this 
district, there appears to be one elvan about 40 feet in width, which 
strikes nearly E. and W. between Camborne and Dolcoath.^ At the 
400-fathom in Dolcoath Mine, about 40 fathoms west of the Old Sump 
shaft, there is an elvan striking nearly E. and W. and underlying 
N. 35 deg. All the other elvans have a strike approximately E. 30 deg. N. 

In the Camborne district it is particularly noticeable that the elvans 
in the killas, on the north of the Cam Brea Hill, are much more highly 
inclined to the vertical than those on the south, situated entirely 
in granite. The information concerning this can be generalised as 
follows : — The elvans cropping out on the north of North Wheal Crofty 
and striking westwards (W. 80 deg. S.) towards the Seton Mines vary in 
underlie (angle from vertical) from 47 deg. to 60 deg. N. The elvans are 
slightly steeper on the west than on the east. An elvan passing through 
South Crofty Mine underlies N. 45 deg. The elvans of West Stray Park, 
Cam Camborne, Dolcoath, Cook's Kitchen, Tincroft, Cam Brea, and Wheal 
Druid (eastern part of Cam Brea), situated along the northern margin of 
the Cam Brea granite, vary in underlie from 30 deg, to 45 deg. In Cook's 
Kitchen an elvan underlies N. 54 deg. In Wheal Druid there are two 
elvans ; the more northerly underlies N. 37 deg. and the more southerly 
N. 15 deg. An elvan in South Dolcoath Mine and West Wheal Basset 
underlies S. 18 deg. to S. 40 deg. The elvans in Wheal Basset are in 
killas, and are perpendicular or inclining north. An elvan between South 
Wheal Basset and Carn Kie underlies S. 8 deg. The particulars of the 
underlies of the elvans between Scorrier Gate and the United Mines in a 
similar manner maybe generalised as follows:— At Little North Downs 
Mine an elvan underlies N. 47 deg. At New Treleigh Consols an elvan 
underlies N. 38 deg. From Treskerby to Great Wheal Busy the elvans 
underlie N. from 28 deg, to 47 deg. In Killifreth the main lode 
accompanied by an elvan underlies N. 58 deg. In Wheal Unity an 
elvan underlies N. 10 deg.*^ In the Consolidated Mines the elvans vary 
in underlie from 30 deg. to GO deg. N. From Ting Tang through the 
United Mines, Wheal Clifford and Nangiles to Wheal Jane the elvans 
underlie N. 35 deg. to G5 deg. (05 deg. in Wheal Jane). In Wheal Clifford 
the elvans becomes steeper in depth. 

Throughout the whole district most of the elvans underlie north — a few 
only (in the granite) underlying south. 

The following table gives the underlies of elvans in various mines : — 

» Thomas, p. 42 ; W. H. Argall, "On Elvan Courses." Tr. It.G.S. Corn., 
Minen* Aisoo,, 1875. 

* Kenwood, p. 71. * ^ Op.cU.,^. 63. 

* Ernest Dixon (II.M. Ueolotrical Survey) Sumviary of Prorjrfss, 1901, p. 25. 
Mr. Dixon considers tlie latter series to be more recent than the former. 

* Henwood (p. 160) quotes from a paper by Professor Sedgewick. Camh. 
Phil. Tram. 7., p. 129. 

" Thomas, p. 65. 



120 



GEOLOGY OF THE MINERAL AREA. 



Mhie. 



Bamcoose 



Basset, Wheal 
Bell Mine - 



Buller, Wheal 

Baddern, 
Wheal 



Underlie 

of 
ELvan, 



Deg. 
N. 15 

N.37 



N. 46 



Nearly 
vertical 



N.45to 

50 

N.59 



Remarks, 






Outcropping about 120 fathoms south of the 
Great Western Railway. 

Two el vans outcropping about 60 fathoms south 
of the Great Western Railway. They are 
greatly branched near the surface. 

Between Miner's shaft and Wheal Tehidy 
(about 180 fathoms north of the Great West- 
em Railway). 

Two elvans, a large and a small one. They 
probably unite in depth. 

Intersected in the mine 40 fathoms from sur- 
face. Tin occurs in it. (A. K. Barnett '* On 
Elvan Courses," Bo|/. Oorn. Poly. Soc, 1873, 
p. 18.) 

25 fathoms in width. (Henwood, p. 81.) 

170 fathoms south of Hillbrother*s shaft. A 
smaller elvan 15 fathoms north underlies in 
the same direction. (Fig. 3.) 



Fig. 3. — Great Wheal Baddem. 



Bosleake 
Busy, Great 

Wheal 
Consolidated 

Mines 

Cook's KLitchen 



Chacewater 
Mine 



i 




S.(?) 
N. 35 

N.45to 
00 

N. 40 

N.60 
N. 47 



Fig. 4, 

In Wheal Fortune at 160 to 200 fathoms below 
adit, 16 to 20 fathoms in width. (Henwood, 
p. 84.) 

20 feet wide. (W. H. Argall **0n Elvan 
Courses,'* Afiners' Aasoc, 1875.) 

Another elvan. 

Part of Great Wheal Busy. Elvan lies between 
** Winter's " and " Chacewater " lodes. 6 
fathoms in width. Carne states that there 
are two elvans uniting in depth. (*' On 
Elvan Courses," Tr. R.G.8. Com., vol. !., 
1818, p. 104.) 



SUBTERRANEAN OCCURRENCE OF ELVAN. 



121 



Mine. 



Grenver and 
Wheal 
Abraham 
Crofty, Wheal 
Clifford Amal- 
gamated 
Mines 



Copper Hill - 
Cam Brea 
Monument 



Cam Cam- 
borne 
Cardrew Mine 

Carn Brea 
Mine 



Underlie 

of 
El/oan. 



N.45to 
75 

N.52 
N. 70 



N.57 

N.38 
S. 40 

N. 15 



N.30 

N.30to 
40 

Slightly 
North 
N.20 
N.40 



Remarks, 



1 to 3 fathoms in width. (J. Came ** On the 
Veins of Cornwall," Tr. R.GS. Com., 1822, 
vol. ii., p. 82,) 

Outcrops near Garland shaft. At the 75- 
fathom level it is directly under Deeble's 
shaft and underlies N. 35 deg. 

Crops out near Moor shaft on the south of the 
sett. 

100 fathoms south of the Monument. 

North of the Monument. (J. Maynard, " Re- 
marks on Two Cross-Sections,** 41st Rep. 
Roy. Corn. Poly. Soc., 1871.) 

[n depth it is vertical. 

Near South lode. 8 or 9 fathoms in width, 

(Henwood, Table Ixviii.) 
At the 300-fathom level it is 10 fathoms in 

width in granite. 

ISeen in upper levels. (Henwood, p. 63.) 



Fig. 4. — Great Wheal Bust/. 

II PI 




tS,^ 



CO 



S. 



-rr 

•l 

•I 



AOIT 



L£ \/ £ L 



Dolcoath 

East Pool - N. 44 
£iiiUy Hen- N. 60 

rietta, 

Wheal 
Jane, Wheal - N. 65 
Little North N. 47 

Downs 
New Cook's N. 44 

Kitchen 



See Remarks on El vans in Dolcoath, in Sec- 
tion on Mines, p. 217. 

Crops out between South and Pearce's shaft. 

Two elvans in south part of mine about 30 
fathoms apart. (Maynard*s '* Cross-Sec- 
tions," ^Ut Rep. Corn. Poly. Soc, 1871.) 

Elvan in the hanging wall of the lode. 



122 



GEOLOGY OF THE MINERAL AREA. 





Underlie 




Mine. 


Elvan. 


Bemarks. 




Deg. 




Naugiles 


N.50 






N.50 


Near Wheal Clifford lode. 


North BuUer - 


N. 10 




New Treleigh 


N.38 


Crops out between Gardner's and Carr*8 


Consols 




shafts. 


New Wheal 


N.47 




Seton 






South Dolcoath 


S. 22 






N.25 


South of Providence lode. 


South Wheal 


N.45 




Seton (Gilly 






Mine) 






Sithney Cam- 


S. 60 


Crops out 100 fathoms south of the Engine 


meal Mine 




lode. (Pig. 5.) 



Fig. 5. — Sithney and Cammeal Mine, 
N. S 




South Roskear 


S. 10 


South Crofty - 
Seton, Wheal 
Squire, Wheal 


N.45 

N.50 


Ting Tang 
Mine 


N.45 


Tincroft 


N.40 


Treskerb}' 


N. 20to 
N.30 
N.30 


Tehidy, Wheal 
Union, W^heal 


N.30 
N.30 
N. 61 
N.45 



(W. H. Argall " On Elvan Courses," Rep. Roy, 
Corn, Poly. Soc, 1875.) 

South of Bickford*8 shaft. 

Crops out 60 fathoms south of Tilly*s shaft. 

Eivans so nearly horizontal that they were 
called ** Floors *' by the miners. (J. Carne 
" On the Veins of Cornwall," Tr. R.G.S. Corn., 
vol. ii., 1822.) 

24 fathoms in width. Worked for tin ore at 
Poldory and Ale and Cakes Mine. It sends 
out branches into killas. (A. K. Barnett 
** On Elvan Courses," Roy. Corn. Poly. Soc., 
1873, p. 15.) 

Crops out between Highburrow and Dunkin's 
shafts. 

6 fathoms in width. (Hen wood, p. 63.) 

A branch from it is perpendicular up to the 

surface. 
Crops out 30 fathoms north of Moyle*s shaft. 

Crops out south of Wheal Union. 

Elvan further north than last. (Maynard's 

Cross-Sections, 41«t Rep. Corn. Poly. Soc., 

1871.) 



SUBTERRANEAN OCCURRENCE OF GREENSTONE. 



123 



Mine. 



Uuited Mines 
Unity, Wheal 



UTiderlie 

«/ 

Elvan, 



Deg. 
N. 60 
N. 10 



Vor, Wlieal - 



S.(?) 

N. 50to 

57 



N. 20 to 
30 

West Wheal Vertical to 
Basset S. 18 



Remarks. 



Two elvans north of Cha|)ers shaft. 

Irregular underlie. 25 feet wide, and con- 
tinues into Creegbrose. (A. K. Barnett ** On 
Elvan Courses," Rep. Corn. Poly. »Voc., 1873, 

p. 12.) 
20 feet wide. Another elvan. {Op, cit., p. 14.) 
Two elvans. The larger 8 fathoms in width. 

(J. Carne **0n Elvan Courses." Tr, R.G.S. 

Corn., vol. i., 1818, p. 103.) 
Another elvan 2 feet wide. (Henwood, p. 52 ) 

Vertical near surface. 



Fia. 6. — West Stray Park Mine, 

N. J S. 




West Stray i N. 35 

Park I 

Weutworth, | N. 53 

Wheal j 

W-est Seton - I N. 58 



Fig, 0. 



SvJbterranean Occu7*rence of Greenstone {^Irestone, Iroiutone^ Iron 

KiUas). 

Pryce* is the first to have mentioned the occurrence of greenstone as 
encountered in mining operations, and states that ** it often keeps a course 
east and west like a lode but is commonly very wide .... it is very 
tedious and chargeable where an adit must be driven through it." Charles 
Thomas,^ who was a prominent mine captain in the Camborne district, 
asserts that greenstone never behaves like the elvan courses but occurs 
in ** embedded masses." Some of the following facts lack confirmation, but 
they illustrate the subterranean extent of this rock, which is the oldest of 
the igneous rocks. 



^ Mineraloaia Comubientis, 1778, u. 75. 

"* *'Kemarka on Mines in Cornwall." Rep, Com. Poly. Soc.^ 1854. 



124 GEOLOGY OF THE MINERAL AREA. 

At Roskear, on the north of Caiubome, a sill of greenstone, 20 fathoms in 
width, was penetrated at the deep adit level (30 fathoms from surface) at 
about 120 fathoms south of the ^uth Roskear lode.^ Another sill was 
encountered In the workings of the South Roskear lode from the 107 to 
the 13U-fathom levels at least.' In North Roskear Mine greenstone was 
met with abont the main lode from a depth of 30 fathoms from surface 
(deep adit) to 100 fathoms.' An old unpublished report states that the 
Doctr>r*s shaft was sunk through greenstone from the 30-fathom level to 
the 80, after which it was in killas until greenstone was again encountered 
at a depth of 150 fathoms. 

Greenstone was encountered in Wheal Seton between the 130 and 140- 
fathom levels at Tilly's shaft, which is sunk on the North Gaunter lode.^ 

Greenstone with a westerly dip of 12 deg. to 16 deg. occurred at the 
108-fathom level in Stray Park, Wheal Gons, and Camborne Vean.'^ In 
the western part Carn Camborne Mine the workings wera in greenstone 
from the 20-fathom level (or adit) to the 50 ; at West Condurrow Mine 
(or Kellivose) greenstone was encountered when sinking was commenced 
on the North lode. 

In South Crofty Mine a cross-cut driven north from Pryce's lode near 
Bickford's shaft at the 120-fathom level (near a granite ridge) encountered 
gieenstone in the killas." In the same mine a greenstone sill, about 100 ieet 
thick, was passed through in Robinson's shaft above the 60-fathom level.*^ 
A little further west in the same mine the Gaunter lode passes through 
greenstx)ne at about the 70-fathora level, and the Copper Tankard lode 
was in greeniitone at about the same level. Other lodes encountered 
greenstone in different parts of the mine from theL30 to the 75-fathoni 
levels.^ In East Pool Mine there are two small sills of greenstone about 
the Engine shaft at the 48-fa thorn level. They have a northerly underlie. 
At North Pool there is a sill of considerable thickness, outcropping about 
60 fathoms south of the main shaft and underlying. north at about 54 deg. 
from the vertical." A greenstone sill 20 fathoms in width was found in 
the upper part of Tincroft Mine.^° Further east there appears to be a sill 
of greenstone at about the 20-fathom level in Barncoose Mine. At Wheal 
Union, near Redruth, greenstone is said to have been encountered at about 
the SO-fathom level. In Trevaskus Mine, Gwinear, greenstone occurs in 
the walls of the lodes at the 33, 51, 66 and 71-fathom levels.^^ 

In the killas, on the north of the Carn Brea granite, there appears to be 
two prominent but irregular sills of greenstone. The sill seen in North 
Pool Mine may be the same as that seen in North Roskear and Wheal 
Seton. The other appears to extend from Barncoose through East Pool, 
South Crofty, to South Roskear, and the sill observed in Tincroft Mine 
probably represents that intrusion. 

» Thomas, p. 18. ' Kenwood, Table liv. 

' M. L. Moissenet, '' FilonH de Coi nouailles/' 1874. 

^ H. C. Salmon, Mining and Smelting Magazine ^ 1862, vol. ii., p. 282. 

^ Hen wood, Table xlix. 

® J. Maynaixl, ** Remarks on Two Cross Sections." Eep. Com, Poly, Soe,, 
1871. Thomas, p. 18. 

' Information from John Penhall, manager of South Crofty, Carn Brea, and 
Tincroft Mines. 

'* Kenwood, Table Ivi. " See ** Cross Sections," by J. Maynard {op, eit.) 

^'' J. Carne, "On the Veins of Cornwall." 2V, Jl.O,i^. Com., vol. ii., 1822. 
p. 61. 

* * Kenwood, Table xxxv. 



125 



CHAPTER XIV. 



NATURAL HISTORY OF THE LODES. 

I. Distribution of the Lodes. 

Tbe lodes of the area are almost entirely confined to the western 
district, and are mainly restricted to the neighbourhood of the 




« 



CQ 









aq 



c 
^ 

g 












c 




121 



NAIVSAT. inSTORY OF TUE LOD£S. 



granite, and more eitppcialljr near its margin ; bat they continue to 
occar for a distance of 4 miles eastward of the granite. Thus the 
country lying between Baldhu (on the east) and Camborne (on the 
weat) and extending for a few miles north to a few miles soutli of 
Redratb includes the principal mining area of this map. (See Fig. 1.) 




For simplicity this district can be roughly divided npiDtoreineralised 
areas without separating the lodes genetically. Thus, the margin 
of the Carn Brea granite is the eite of a remarkable series of tin 
and copper lodes (Etriking N.E, xE., approsimalely parallel to 
the granite margin), extending from Camborne to Redruth. The 



DISTRIBUTION OF THE LODES. 



127 



lodes of thii mineral belt which are situated but little more than 
three-qoarters of a mile north of the granite margin, are of 
no great valae. Near the margin, however, the lodes have been 
enormouBl; prodoctive in tin anJ copper ores for a distance of at 





least 3 miles along their strike. The lodes on the north of the 
Bedrath (or Caro Marth) granite may he considered as being 
in the eastern extension of the same belt. 

Between the Cam Brea and CarDtnenellis granites there occurs 



128 



t§ 



a. 

I 









,8 



I— I 

d 



NATURAL HISTORY OF THE LODES. 



m <t 




9 



\ 



4' 



v 




•s 





ii 



00 

I 



•i^ 




i; 



00 

I 

l-H 



/ 




/ . 



>- x' 



«o 



X >. 



w ' * »^ 



'»^ \' 



I 



o 



^' 



«• 



DISTRIBUTION OF THE LODES. 



129 






a 



^ 









•J 



«o 




i 



'h-9 



^' 




">/*^ 



'- ', 



^.^ V 



00 

s 






I* 



^ 



I 

CO 

d 




^*u ^ 



v»c 



" •'^' 



>-, • 






"•'„ 



■. 





CS4 



I 



u 
o 

Ex 



130 NATUBAL HISTORY OP THE TX)DES. 

a prominent series of lodes, of which the G-reat Flat lode is the 
largest member. The series extends from the west of South 
Condurrow Mine to Gam Marth (on the east) — a distance of 3^ 
miles. (See cross sections. Figs. 7 to 16.) On the west of the 
Carnmenellis granite is the mining district of G-winear and 
Crowan. Here and there^ around the same granite mass and 
in the more elevated portions of the interior, from Wendron to 
Halabezacki are lodes containing both tin and copper ores. 
Finally, there is the Forth Towan group of lodes near the sea 
coast on the north of this map. 



II« Cr£OLOGICAL AgE OF THE LODES. 

In discussing the ages of the lodes, it should not be assumed 
that the mineralisation of a fissure commenced immediately after 
its formation. Carne's classification* of the lodes into six systems 
appears to imply that movements operated successively for the 
production of fissure systems, and that each movement was 
accompanied not only by a series of fissures^ but by a distinct 
period of mineralisation. The fissures of a single zone of fissur- 
ingi or of a whole fissure system such as either of those referred 
to on p. 205, may be assumed to have had a common 
mode of origin. The process which produced the fissures should 
be regarded as a progressive or long-continued one, so that the 
fissures first formed should not be separated from the last. In 
speaking of the age of the lodes, therefore, a period is implied 
during which two operations may have gone on hand in hand — 
(1) fissuring, (2) mineralisation. Reference will be made else- 
where to the order in which the minerals arrived, but it may be 
mentioned incidentally that it appears to be this which accounts 
to a certain extent for the confusion that has arisen regarding the 
relative ages of the lodes. The tin and copper lodes may be 
broadly described as of post-CSarboniferous but pre-Triassio age.f 
In Cornwall and Devon this epoch is characterised by an intrusion 
of granite, which in fact appears to have been the culminating 
effect of great earth movements. The direction assumed by the 
lode fissures formed after the consolidation of the granite appears 
to have depended upon the structures produced by these pre- 
granitic movements. Indeed, lines of weakness so formed do 
not appear to have become fissures capable of the reception of 
minerals until after the intrusion of the elvans. The process by 
which the fissures were mineralised was probably long-continued. 

III. Relative Age of the Tin-C!opper and Silver- 
Lead Lodes. 

Besides tin and copper, other minerals occur in the lodes, and 
of these the ores of silver and lead are among the more impor- 

♦ Tt, M.O.S. Com., 1822, vol. ii.. p. 49. t See De la Beche, p. 283. 



STRUCTtTRE OF THE LODES. 131 

tant Geographically, the distribation of the ores of lead and 
silver in the district is comparatively wide, but their ecoDomic 
importance nnder present conditions is small. They occur in 
districts outside the great tin and copper centres, but they are 
also found in lodes containing tin and copper. 

The arrival of the silver-lead ores appears to have been delayed 
to a late period in the history of the metalliferous veins of the 
district, since although they occur in a number of east and west 
lodes^ they continued to arrive after the lodes of tin and copper 
had been completely formed; and, indeed, these ores were still 
being deposited during the later phase of movement, which re- 
sulted in the production of cross courses (or cross faults). Many 
of these cross courses contain ores of silver and lead and other 
minerals of less economic importance. Tin and copper ores had 
entirely ceased to arrive during the formation of the cross 
courses. 

IV. Structure of the LoDEa 

Many lodes have been formed intermittently by operations 
extending over a lengthened period, with the result that they 
frequently display a variety of structures. The veinstones of the 
lodes show that they have originated in one or more of three 
modes of production : — 

1 . Infilling of a fissure or series of close parallel fissures by 
minerals derived from a distant source. 

2. Alteration and impregnation of the country rock in the 
vicinity of a fissure or fissures by minerals derived from the 
fissure. 

3. Alteration and impregnation of a friction breccia contained 
in a fissure (modification of 1 and 2). (Plates X. and XI.) 

The simplest structure which a lode can have is the comby or 
platy structure. Here the lode is built up of layers parallel to 
the walls, each layer representing a period of deposition and also^ 
possibly, a widening of the fissure. In the *^ tin-copper " lodes 
the comby structure is not rare, but is mainly seen as the linings 
of actual cavities, particularly in the upper parts of lodes. In 
some fissures completely filled with quartz the " combs " are 
clearly seen interlocking in the middle of the vein. 

The Cathedral Mine, near Redruth, shows successive depositions 
of quartz, fluorspar, and copper pyrites in the lode ; and at 
Wheal Julia, near Binner Downs, the layers consist of quartz, 
blende, and copper pyrites.* At Wheal Tolgus a specimen shows 
the order : quartz, blende, and iron pyrites. A table prepared 
by Henwoodf shows that a definite order of mineralisation can 
be made out in the lodes of many mines. The mineral which 
occurs most frequently against the walls of lodes is quartz ; and 
in tin lodes tin is also in this position. When wolfram occurs 
it is likewise here. The next appears to be principally sulphides 
of copper, with occasionally galena, and sometimes iron and man- 

* De la Beche, p. 840. -^ p. 214. 

k2 



132 IrATUBAL HISTORY OF THE LODES. 

ganese miDerals and arsenical ores with blende, associated with 
quartz, fluorspar, chlorite, and other veinstones. 

Another form of banded structure is that produced by the 
infilled fissure and the country rock, which for a short distance 
on each side has been altered into ^'capeL" This alteration 
in the walls is characteristic of the tin lodes, and in some cases 
the country rock in the vicinity of the fissure is worth breaking 
down for the tin ore it contains. Thus the stanniferous deposits 
of East Wheal Lovell consist of altered granite, in the neighbour- 
hood of fissures, impregnated with tin ore.* In some cases the 
lode has a banded appearance, the origin of which is interesting. 
The lode may consist of a series of narrow parallel cracks or 
joints, through which at one time mineralising solutions were 
passing, with the result that the lode consists of a series of narrow 
strings, containing cassiterite or wolfram, quartz, &c., enclosed by 
bands of altered country rock.f In other instances the original 
character of the fissures is obscure, as sometimes the cracks or 
joints are so close together that the intervening layers of country 
rpck are completely altered, while at the same time the fissures 
have been obliterated. Sometimes, where the lode appears to be 
massive, minute lines of rifting can nevertheless be seen, through 
which, no doubt, the changes in the walls of the lode were 
effected4 A microscopic degree of fineness, in which the lines 
are so closely packed that the rock appears homogeneous, is 
sometimes discernible. 

Modifications of these structures are very interesting, as 
accounting for the presence of strings of chloritic material, or for 
veins and plates of ^^ peach " (fine-grained schorl rock) which not 
infrequently occur in the lodes in both granite and killas. Some 
of these cases may be explained as follows : — The first fissure in- 
filling firmly cemented itself to the walls of the fissure, but when 
the fissure re-opened at a later time it did so along a plane of 
weakness parallel to the lode, but in the band of altered country 
rock alongside the original fissure infilling. In this manner a 
plate of altered country rock became detached and enclosed in the 
lode between old and new infillings. In some cases, especially in 
killas, where the lode is parallel to the cleavage, this has happened 
again and again, so that each fresh re-opening of the fissure took 
place on the outside of a thin sheet of country rock, which re- 
mained firmly attached to the lode. A similar explanation may 
be applicable in many eases to the presence of more irregular 
masses in the lodes {e.g,y horses), and to go a step further is to 
arrive at a structure which resembles a breccia. Breccias in lodes 
are not rare, but they also originated in a variety of other ways. 

* C. Le Neve Foster, '* Remarks on the Tin Deposits of East Wheal 
Lovell.*' Tr,R.G.S, Com., 1876, vol. ix. 

t Illustrations of similar structures are to be found in " Mlneralogischen 
Geographie," by J. F. W. Charpentier, 1778. 

X An excellent 
found in "Ore De^ 

Oeol, Survey 22nd' ^ , ^^ 

ture of lodes will be found in the various publications of the U,S. Geol. Sur- 
vey by such authors as Ransorae, Adams, and Spencer, 




STRUCTURE OF THE LODES. 133 

Locally^ the breccias were agaiu brecciated by movements taking 
place in the plane of the lode.* In other places the lode cracked, 
and the walls slid over each other, so that the vein materials were 
sheared oat and crushed. Phillips says that ^^ in many instances 
the original opening would appear to have been a mere comminuted 
fracture of the rock in a given general direction, between the 
several planes of which a deposit of mineral substance has sub- 
sequently taken place through chemical agency. The final re- 
sult in such a case will be a brecciated veinstone of the kind so 
constantly met with in mineral district8."t 

The structure of lodes in the killas is, on the whole, more 
varied than of those in granite. Some lodes are of enormous width, 
and consist of zones of crushed and dragged-out fragments of 
killas, filled with granite and metalliferous minerals. In 
the Dowgas Mine (St. Austell), for instance, the " GrofBn " lode in 
M)me places attains 50 feet in width, and it is difficult to say 
exactly where the lode ends and the country rock begins. In 
the neighbourhood of Veutonwyn Mine (St. Austell), the cleavage 
of slates is nearly horizontal, or dip gently northwards, but 
in the vicinity of the main lode of that mine the dip of the slates 
is greatly increased until it becomes parallel to the lode which 
underlies steeply northwards. In this case the slates were bent, 
dragged out, and broken by the sliding downwards of the hanging 
(or north) wall of the lode. Slickensides are common. In other 
cases the killas in the vicinity of the lode is contorted and 
gnarled, and traversed by irregular lenticular quartz veins, and in 
appearance very like some of the structure depicted in the 
Kingabridge and Salcombe Memoir.X Instances of gnarling 
in the vicinity of the lode have been noticed in the St. Agnes 
di8trict.§ 

Another kind of lode structure is that which depends upon the 
infilling of the interstitial spaces, and the alteration and impreg- 
nation of the crushed material of friction breccias. In the 
Camborne district this type of veinstone is extremely common, 
and many modifications of it are represented. Thus the lode 
may consist of an interlacing network of stanniferous and quartz 
veins, enclosing fragments of altered country rock. This breccia 
may be brecciated again and again, and each time sealed up 
by infiltrated minerals. Thus at Wheal Basset a specimen of 
veinstone shows at least four successive operations of crushing 
and healing up. The lodes of Dolcoatb, South Grofty, and East 
Pool also typify this sort of structure. Lodes in killas generally 
contain a great amount of that material, either as large broken 
masses or small fragments. In granite the lodes very frequently 

• J. H. Collins, "Cornish Tin Stones and Tin Capels." Min, Mag., 1882. 
p. 16. J. S. Flett (H.M. Geological Survey), " Notes c i Some Brecciated 
Stanniferous Veinstones from Cornwall. " Sunnnary of Pi carets, I9(y2t p. 154. 
"Petrography of West Cornwall." Summary of Progresi, 1903, p. 158. 

t J. A. Phillips, '• Lodes of the Mining Districte of Cornwall." Q.J,0,S,, 
▼ol. xxxi., 1875, p. 341. 

t By W. A. E. Ussher, 1904, see pp. 7 and 8, and Fig. 3. 

§ C. Le Neve Foster. Jr. R,G,S. Cornwall, 1877. *' Remarks on Some Tin 
Lodes." 



1 34 NATURAL HISTORY OP THE LODES. 

have what is known as a " granitic structure." In this way the 
lodes vary in composition according to the nature of the country 
they traverse. 

The formation of crash conglomerates is locally characteristic 
of some of the lodes. In South Wheal Frances, at the 82-iathom 
level, or 105 fathoms from surface, near the middle of the copper 
lode, rounded stones (granite) were found, all of them apparently 
moved away from the places originally occupied by them by dis- 
turbances in the lode. Some of them were embedded in copper 
ore. 

Pieces of granite the size of the palm of a man's hand were 
found embedded in the lode in the eastern part of Carn Brea 
Mine,t where the lode was disturbed by a cross course. 

The occurrence of conglomerate in the lodes of the adjacent 
mineral district of Gwinear was more common. At East 
Relistian pebbles cemented by copper ore and iron pyrites 
occurred. 

The infinite variety of stractures presented by some of the 
great lodes of the Camborne district almost defies description. 
The enormous excavations alone remain in many cases as mute 
witnesses of the size and value attained by the deposits of this 
district. In some cases, as for instance in East Pool Mine, the 
country rock for a great distance on either side is highly 
altered by silicification, &c., and, indeed, it is a matter of 
difficulty to see a really fresh piece of granite, except at con- 
siderable distance from the lodes. Alteration of the country 
rock in the vicinity of the lodes is exhibited on a large scale 
in other mines, as for instance Dolcoath, Wheal Grenville, &c. 

Observation in Dolcoath Mine shows that this extensive altera- 
tion of the country rock does not take place from a single fissure. 
It sometimes happens that the lode consists of two or three 
or more cracks or fissures, along which the solutions have flowed 
at the time the lode was being formed ; they may be more or less 
parallel, but very often it appears that the country rock is so 
shattered near the lode that the mass would be better described 
as a breccia. The country on either side of these cracks has 
been completely changed, so that no fresh, unaltered rock remains 
in the space between the cracks. Thus at the 412-fathom level 
in Dolcoath Mine, between the Eastern and New Sump shafts, 
the lode contains two or three parallel fissures which are only 
discerned with difficulty, since they are very narrow and cemented 
up. The lode here, for several feet in width, is a dark, hard, 
schorl rock containing tin in certain parts. The country granite 
near the lode has been taken away for the tin it contains, which is 
generally in the form of strings. At the 375-fathom level very 
numerous small, irregular strings penetrate from the main lode 
into the country rock, and the tin contained in them and their 
neighbourhood has warranted the excavation of a considerable 
piece of ground. These generally are regarded by the miners 

♦ John Rule, ** Notice of the Discovery of Several Rounded Stones in the 
Lode at South Wheal Frances." Tr. R, G,S. Com., 1847-65, vol. vii., p. 161. 
t W. H. Argall, "On theElvans of Cornwall." Miners' Amc.^ 1875. 



STRUCTUBE OF THE LODES. 135 

as droppers or feeders, since they are supposed to feed or eDrich 
the lode. At the 375-fathoin level the main lode is clearly 
seen in a stope on the west of the Eastern shaft At this point 
the lode consists of a small band of soft, light blue peach, on 
the north or foot wall of whi(;h the granite is altered for several feet 
into tough schorl rock (*' peach "). On the south or hanging wall the 
granite is altered, but not to schorl rock. On the south there is 
a dropper (or oflF-set; underlying north, consisting of schorl rock. 
The wedge of ground between the dropper and the main lode at 
this place has been worked away for tin ore. On a much larger 
scale the granite between the South lode and the north part of the 
main lode has been excavated to a great extent. The South lode 
and the north part of the main lode between the New Sump 
shaft and the Eastern shaft converge in depth and unite at the 
400-fathom level. Both these lodes and the country rock 
between them from above the 375-fathom level downwards have 
been worked to an enormous extent, and the size of the immense 
caverns formed by the stoping away of this rich tin ground for 
many fathoms in breadth and height is but faintly appreciated 
by the dim light of the miners' candles. The country rock 
between the lodes above mentioned is traversed through and 
through by small strings, so that the mass is really a breccia 
on a large scale containing tin ore. 

It may happen that the initial fissure in which the lode was 
produced has left some trace of its original form in the occurrence 
of a persistent tin, quartz, or schorl rock vein. In such cases 
these features may act as indicators, or leaders, to guide the miner 
in driving and opening up the lodes. Leaders are, however, 
generally of more recent origin. A smooth wall, a clay flucan, 
or parting filled with clay, quartz, fluorspar, chalybite, <&c., may 
also act as leaders. The leader at Wheal Uny is in one part 
18 inches wide, consisting of a mass of fragments of more or less 
altered killas (capel), with some tin oxide, and it soon dwindles 
down to a mere flucan, or vein of clay, with a little quartz, 
only 2 inches wide. The sides (walls) are very smooth, presenting 
numerous slickeusides ; in fact, the leader has all the appearance 
of being a mere crack, filled, in the main, mechanically, by 
fragments of the sides reduced in places to a clay by the 
attrition of the walls."* At South Carn Brea Mine this leader 
becomes a copper lode 2 to 4 feet wide, and in West Wheal 
Basset the leader of the same lode was frequently reduced to a 
mere ferruginous joint. At West Wheal Frances (on the west) 
the leader becomes a quartz vein 2 or more feet wide, but it 
is generally poor in tin.f 

In Wheal Grenville the leader sometimes consists of a very 
hard, fine-grained schorl rock, of the usual lode type, varying in 
thickness about a foot or so, but occasionally dwindling down 
until it disappears altogether, or changes its character to a 
ferruginous clay or quartz vein. 

• Foster, p. 641. t Op, cit. 



136 NATUBAL HISTORY OF THE LODES. 

At Great North Wheal Seton a flucan, or clay parting with 
some vein qaartz, occurred in the lode. The North Tincroft 
lode in Cook's Kitchen Mine is 3 to 6 feet in width and consists 
of quartz and soft killas. The leader is a vein of crushed fluorspar 
(" can ") 3 inches in width. 

In East Wheal Lovell the lodes are very narrow, " sometimes a 
mere joint or line of division in the rock, but occasionally a couple 
of inches thick ; they consist of quartz, a little clay, and red oxide 
of iron, and 'pw se are utterly valueless." These are regarded as the 
leaders, the valuable ore occurring as impregnations of the country 
rock.* 

A few common types of veinstone or altered country rock near 
the lodes have received special names, as Capel, Peach, Prian, and 
Scovan. 

Cafbl.— The following is from Pryce'a old bookf :— ** The Scovan lode, 
when in decay for tin, will oommonlj degenerate into a caple, which, in 
faot» is mostly of the nature of a scovan lode's walls, or tiiat enclosing 
stratnm, which it is in contact with ; thence called the caples or wails of 
the lode. But there is really such a thing as an original caple lode, 
properly so called ; which abounds with a very stiff, hard atone, some- 
thing like a limestone, except the colour, wherein the tin is sometimes 
veined, and other times very small and disseminated. A primary caple 
lode is promising for tin, though but seldom for copper, unless there 
is a branch of copper ore or gossan that veins downwards in the lode.** 

In the glossary of terms in the same book, Pryce says : — 

Capel is ** a sort of stone something like limestone, but will not burn. 
The walls of most lodes are of this kind of stone, therefore it is 
common to call the walls of a lode by the name of its caple. Also 
i$ome veins which abound in this stone are termed caples, or caple 
lodes." William Phillips): says that *' a vein is termed a caple lode when 
consisting of a hard, compact and unpromising substance which seems 
principally to be quartz intermixed with minute portions of chlorite, 
giving a greenish or brownish-green tinge to the mass. Tin is often 
found in it» copper rarely. But if a branch of copper ore, or a gossan 
be found to take its course down the vein, it commonly makes a durable 
copper mine." 

** Of this word it is almost impc^ssible to give a definition, as it refers 
rather to situation than to substance."§ " The word capel refers rather 
to situation than substance, but it generally appears to be a hard homo- 
geneous stone, of a grey or bluish grey, with no structural peculiarities.'* || 

Phillips states that the hard quartzose altered country material in the 
vicinity of the lode, if not carrying tin, is called " capel." Under the 
microscope it is quartz and chlorite, or quartz and tourmaline with 
unaltered country rock.^ *' Capels are most frequently composed of a 
quartzose base through which crystals of schorl are very thickly 
disseminated either in the form of spheroidal aggregations radiating 
from various centres, or as acicular crystals crossing one another in 
all directions. Sometimes, particularly when they occur in slates, capels 
are a mixture of quartz and chlorite ; in others, both chlorite and 
tourmaline are present. They also often contain innumerable fragments 
of the country rock, and are traversed by narrow strings of quartz into 
which project hair-like crystals of schorl, which are generally attached 
to the sides of the enclosing fissure. In addition to the foregoing, 

* Le Neve Foster, •• The Tin Deposits of East Wheal Lovell." Tr, B, G,S, 
Com., 1876, vol. ix., p. 4. 
t Min. Camub,, 1778, p. 90. 

t Tr. Qeol. Sac,, vol. ii., 1814, p. 119. " On the Veins of Cornwall." 
§ J. Carne, " On Eivan Courses." Tr. R.Q.a, Com., voL i., 1818. 
II Thomas, p. 19. 
U J. A. Phillips and Henry Louis. ** A Treatise on Ore Deposits," 1896. 



STRUCTURE OF THE LODES. 137 

capels frequently enclose crystals and crystalline groups of quartz 
(traversed by belonites of schorl), which sometimes appear to have been 
broken by contraction or otherwise, and afterwards repaired by a growth 
of schorlaceoua matter within the crack."* Foster, speaking of Penhall's 
Mine (St. Agnes), says that " the word capel is applied to a rock which 
appears to me to be simply a highly altered killas— a killas which has 
been greatly acted on by mineral solutions, and changed from a soft, 
slaty rock into a hard, dark-coloured compact mass of quartz and schorl, 
these minerals being arranged in streaks following the original lines of 
stratification of the killas. In addition, the capel is generally full of 
short lenticular veins of quartz, and is intersected by numerous little 
strings of cassiterite and chlorite.''* 

In Wheal Uny, situated on the Great Flat lode, the lode lies 
between granite and killas in one place. Here the leader'* is 18 inches 
wide, consisting of a mass of fragments of more or less altered killas 
(capel), with some tin oxide," while the term "greyback" is reserved 
for the altered granite which is found below the lode, consisting of 
"schorl rock with large grains of quartz in a compact black matrix.*'!: 
In the part of Wheal Uny, where the lode is entirely in granite, the 
word capel has a different meaning. The capel here is found in the 
granite below the lode and is a ** compact " schorl rock, with spots and 
veins of quartz, containing a very little tin, 2 feet thick." The " grey- 
back " lies just beyond, and consists of a ** schorl rock with large grains 
of quartz in a compact black matrix." This shades off into "country" 
granite.§ In South Carn Brea Mine there is formed in the granite, 
below the copper lode, a "more or less stanniferous schorl rock, Le., 
lode or capel," while above the copper lode, in killas, the capel consists 
of " schorl rock derived from killas." In West Wheal Basset the tin lode is 
entirely in granite. Here the stanniferous lode shades off into slightly or 
non-stanniferous schorl rock. In South Condurrow the same lode is 
entirely in granite and has a capel consisting of compact schorl rock 
above and below the lode; that "above the lode is much veined with 
quartz and contains little or no tin." At Wheal Grenville the capel for 
about 2 feet on each side contains 1*6 per cent, of tin ore (30 lbs. of black 
tin per ton), whilst the capels left standing contain ^ to 1 per cent, of 
tin ore. II 

Mr. Ck)llins states that " capels are the silicificd walls of fissures, they 
occur more especially in tin mines, and often, indeed, contain enough tin 
to pay for working, but they are known also in lodes yielding copper, 
lead, zinc acd iron."^ " The substance known in Cornwall and Devon as 
capels may be described as highly altered and usually silicified bands of 
country rock, bordering a more or less distinct fissure or fissure-filling. 
The term is sometimes applied to a silicified or mineralised band at the 
side of a fissure traversing granite or even el van, but most well-marked 
capels occur in killas. Tin capels contain particles of tin oxide in 
notable proportions, though not always in quantities sufficient to pay 
for working."** 

Peach. — Pryceff states that "a peach, or peachy lode, takes its name 
from a kind of stone, which principally abounds in the lode, and is 
generally of a spongy texture, and of a greenish or dark green olive 
colour. It is better for tin than copper ; but is not a desirable lode 
for either, especially the latter, which is always of a poor quality and 
value when found in a peachy lode." 

* J. Arthur Phillips, " Rocks of the Mining Districts of Cornwall. " 
Q.J.6f.8., 1874, vol. xxxi., p. 341. 

t ** Remarks on Some Tin Lodes in the St. Agnes District." Tr. BM.S. 
Com., 1877, vol. ix. 

t Foster, p. 642. § Op, cit. \\ Op, cit, 

IF J. U. Ck>llins, " Origin and Development of Ore Deposits." Joum. Roy, 
Intt, Com., 1892, p. 86, 

♦♦ Op, cit, p, 167. tt Min. Cornub,, 1778, p. 90. 



138 NATURAL UISTOAY OF THE LODES. 

William Phillips* says that '* a vein that contains a great proportion 
of chlorite is termed a peachy lode." 

Carne writes that peach is chlorite ; or mica if it is tinged with green.f 
Professor Foster remarks that the *' green peach of the Cornish tin 
mines is undoubtedly chlorite, but the so-called ' blue peach/ which is 
so large a constituent of the tin lodes of such mines as Dolcoath, Cook's 
Kitchen, Carn Brea, West Basset, &c., is a bluish grey variety of 
tourmaline."! Specimens of peach from Dolcoath and Wheal Basset, 
examined by Dr. Flett, show it to be fine grained and dark green or bluish 
green in colour and '* while in some cases it is so fine as to be crypto- 
crystalline in appearance, in others it is visibly composed of little 
acicular needles." Light-coloured peach from Dolcoath shows under the 
microscope many aggregates of pale mica, which appear to be altered 
remains of felspar, no doubt derived from the country rock," and 
** owing to the abundance of finely-divided chlorite " was green in colour, 
" while tourmaline was present only in small quantity." The blue or 
dark blue varieties from Dolcoath and Wheal Basset are rich in tour- 
malina"§ 

Prian. — "A vein is said to be a pryany lode when the tin or copper 
ore does not occur in a compact state, but when the stones containing 
either of them are found mixed with other substances such as gossan or 
fluccan."!! A term applied to a vein material of tin and copper lodes which 
consists of loose, crumbling ferruginous mixture of clay and quartz grains, 
and sometimes mica. The clay by itself would be called fluccan, while a 
ferruginous loose quartzose vein infilling is known as a **gossany" or 
"sparry" veinstone. 

ScovAN. — Pryce^ says that a " scovan lode is formed of a hard compact 
crystalline stone either of a brown or black hue, according to the colour of 
the tin with which it is mixed. The ore is often rich, ponderous and solid 
in this stone, and when it is worth one half for metal they caU it scove." 

William Phillips states that " when tin ore is intimately mingled with 
quartz and chlorite the vein is termed a soovan lode, which is of a dark 
brown or of a greenish hue, but not very hard or compact. It sometimes 
occurs in a vein the contents of which are not solid, thence by the miners 
termed a sucked stone."'*'* This substance is a "hard blackish stony 
matter."! f Hunt describes it as tin ore mingled with quartz and chlorite 
of a dark brown or dirty green hue, generally loose textured.^! 

Cavities or *'Vdgs" in Lodes, &c. — In the Dolcoath main 
lode, at a depth of 175 fathoms from Eurfaee, a large cavity was 
discovered about the year I8I4. It measured 18 to 20 fathoms 
in length, 3 fathoms in height, and from 4 to 9 feet in width. 
Carbon dioxide was present in quantity sufficient to extinguish 
a candle flame.§§ At the 352-fathom level in the main lode the 
granite is soft and the lode " vuggy."||!| At the 4G2-fathom level 
in the same lode there are several vugs. One of them is an 
irregular cavity of about 12 feet in length, 6 feet in height, and 
4 feet in width. The ground in which it is enclosed is very rotten. 

• ** On the Veins of Cornwall.*' Tr, Geol. Soo,, vol. ii. , 1814, p. 118. 

t *' On Elvan Courses." Jr. R. G.S. Com., toI. i„ 1888, 

t ** New Mineral Localities." Min, Mag,, 1877, No. 3, 

§ J. S. Flett, "Stanniferous Veinstones of Cornwall.'' Summary of Pre- 
greu of Geol. Survey, 1902, p. 156. 

II W. Phillips, **0n the Veins of ComwaU." Tr. Geol. Soo., vol. ii., 1814, 
p. 119. 

1[ Min. Comub., 1778, p. 90, 

♦♦ " On the Veins of Cornwall," Tr. Geol. Soc., Tol.ii., 1814, p. 118. 
ft Thomas, p. 34. tt Robert Hunt, Brituh Mining, 1884. 

g§ John Rule, ''Cavern in Dolcoath Mine." Tr. ILO.S^ Com., 1818, vol. i., 
p. 225. 

lilj K. J. Frecheville, ** Notes on the Great Main Lods of Dolcoath." Tr. 
M.G,S. Com., 1883, vol. x;, p. 147. 



VUGS — HORSES— WALLS OF LODES. 139 

A vug containing phosphate and arsenate of lead with quartz 
occurred in the lode at Wheal Rose, in the parish of Sithney.* 

At the Consols Mine (Gwennap) a '' great cavity or vug was 
found, many fathoms in length and height/' at the bottom of 
which a mass of brecciated copper ore was met with, some of which 
had evidently fallen from the upper part of the cavity .f 

At Great Condnrrow Mine a vug was encountered in the main 
lode at the 155* fathom level ; the length is 36 feet, height 12 feet, 
width 2 or 3 feet. 

Horses. — Large pieces of the country rock, which are entirely 
surrounded by lode matter (that is, round which the lode has 
formed), are called ^' horses." In Dolcoath Mine there are at 
least three '^ horses '' of granite in the main lode. The largest 
is at the 425-fathom level, and measures 40 fathoms in length and 
15 fathoms in thickness. In depth it has not yet been proved. 
Other ** horses " occur at the 210-fathom level, between the Old 
and New Sump shafts, and at the 352-fathom level on the east of 
the New East shaft. 

** Horses** were encountered in Binner Downs Mine, Cook's 
Kitchen, and other mines.^ 

Walls of Lodes. — The transition between the payable lode 
and altered country rock is often gradual, and it is probable 
that the grinding of the walls upon one another, together with 
the corroding or altering action of solutions traversing the 
fissures, have obliterated the original walls in many cases. Thus 
the Great Flat lode has no sharp bounding walls, and, except for 
many faces or joints in the lode running in the same direction, 
the lode gradually dies out laterally in the country rock. Many 
parts of the Dolcoath main lode show similar characteristics. In 
Cook's Kitchen Mine, at the 145-fathom level on the Highburrow 
lode, the lode is 10 feet wide. The granite walls are more or less 
ragged or rough in appearance, and on close inspection the wall 
rock is seen to cleave most readily along irregular planes rudely 
parallel to the walls. These are sometimes narrow cracks filled 
with lode material. The country is occasionally so shattered as to 
be really a mass of impregnated rock, enclosing a number of 
irregular open or closed fissures, situated near to one another. In 
the country rock of the Highburrow lode in Tincroft Mine there is 
occasionally a fairly well-defined cleavage or jointing, which strikes 
more or less in the direction of the lode, but is inclined more 
towards the vertical than the south underlying Highburrow lode. 
These joints do not appear to traverse the lode, and are mineralised 
to a very slight extent with a little tourmaline or quartz, or they 
are simple clean cracks. On the other hand, many of the lodes 
are bounded by sharply -defined walls. The North Entral lode 
at Dolcoath shows clean bounding walls in many places, but the 
walls are nevertheless considerably altered. 

• Hugh Stephens, ** Mineral Phenomena of Wheal Rose." Hep Cam. Poly, 
8oc., 1871, p. 77. 

t De la Beche, p. 324. :: Honwood, p. 176. 



140 



NATURAL HISTORY OF THE LODES. 



V. Gaunter Lodes. 

** Cornish miDers always give the name of a contra-lodei or 
caunter, to those veins which do not hold the directions of their 
main lodes, and therefore what may be termed a oontra-lode in 
one district coincides in direction with the normal lodes of 
another ; thns the lodes of the southern part of the St. Austell 
district coincide with many contra-lodes in Gwennap, Camborne, 
&c., and the direction of some of the contra-lodes in the former 
coincides with the true lodes of Gwennap, &c."* Prycef states 
that Caunter lodes frequently cut through all lodes except the 
cross gossans (cross courses), but points out that lodes which 
intersect are caunters with respect to one another. Bichard 
Thomas^ states that the general course of the lodes in the Cam- 
borne and Redruth districts is from £. 20 deg. to E. 40 deg. N., 
and that the Caunter lodes vary in direction from this course 
from 30 deg. to 40 deg. Joseph Cafne§ says that the contra* lodes 
are metalliferous veins, whose direction is from E. 30 deg. S. to 
E. 40 deg. S.y but that some run in an opposite direction. 

The following relates to the Dolcoath Caunter lodes : — 
The North or Valley Caunter Lode branches off from the main lode 
near the Oossan shaft and strikes E. 60 deg. N. for some distance until it 
encounters the South Entral lode. It is really a branch of the main lode. 
With a southerly underlie of 5 deg. it yielded immense quantities of 
copper ore to the 130-fathom level. 

The Dolcoath Caunter Lode.— Hen wood || states that the Caunter 
lode faults Harriett's lode (which has bearing E. 30 deg. N.) at the 56 and 
76-fathom levels bnt at the 96 and 1 16-fathom levels Harriett's lode fanlts 
the caunter. The Caunter lode passes from killas into granite. It has an 
underlie of 15 deg. S. and a bearing E. 4 de^^ S.^ This lode produced con- 
siderable quantities of copper ore to the l^fathom level ; but recently it 
was intersected in the granite by the 220-fathom cross cut driven south 
from the Old Sump shaft and at that depth is tin bearing. 



Particulars of other Caunter lodes 
table : — 



are given in the following 



Mine, 


Caunter Lode, 


Beari^tg. 


Underlie, 


Remarks, 






Deg. 




Cook's Kitchen 


South Caunter 


E. 20N. 


40 S. 


Contained tin and 
probably copper 
ore. 




Middle Engine 


E. 5N. 


15N.to 


Branched from 




lode 




40 N. 


Chapel's lode at 
the deep adit and 
was productive in 










copper ore until it 
changed its under- 
lie to 40 deg. N. at 
the 52-fathom level. 



• De la^Becbe, p. 365. f Min, Conwb., 1778. t V- ^^' § P- 1^^- 
II Table L., Kenwood quotes the authority of R. W. Fox. PhU, Jr., 1830. 
t Henwood, Table L., states that the bearing is E. 11 deg. S. 



GAUNTER LODES. 



141 



Mine. 



Cam Brea 



Oaunter Lode^ 



Draid Caunter 



Vigur's lode 



Camborne Vean 
West Boskear 



Great North 
Seton 

South Wheal 
SetoQ 

Wheal Seton - 




Deg. 
E.20S. 



E,20 8. 



B. and W. 
? 



XJnderlie, 



Deg. 
Nearly 
vertical 

Nearly 
vertical 



North Caunter 
lode 



B. and W. 



£.and W. 



S. 
? 



15 N. 



North Wheal 
Crofty 

South Crofty - 



South Caunter 
lode 



Reeves' Caunter 
lode 



E.3S. 



45 N. 



Longclose 
Caunter 



Copper Tank- 
ard lode 

Trevenson 
lode 



E.30S. 



E. 24S. 



E.2S. 



10 N. 



Nearly 
vertical 
to N. 13. 



BemarkB, 



14to40N 



An ore-bearing lode 
from adit to 50- 
fathom level. 

South of Druid lode, 
to which it is con- 
nected by short 
branches. Con- 
tained copper ore 
to the IC^-fathom 
level and then tin 
ore. 

Probably copper. 

Caunter branched 
from main lode at 
about 12-fathom 
level. Both lodes 
contain lead, 
blende, copper and 
iron pyrites, and 
tin. 

Branched off from 
the main lode at 
the 70-fathomlevel. 

Branched off from 
main lode in deep 
levels. 

Worked upon in 
North Roskear and 
East Wheal Seton. 
It contains copper 
and iron pyrites. 
(Harry Tilly, 
** Particulars of a 
Thermal Spring at 
Wheal Seton." 
Mtners* Assoc, 
1873.) 

Contains some tin 
ore. 

A Caunter lode in 
west end of mine 
of no value. 

Contained copper 
ore to the 90-f athom 
level. Recognised 
in North Roskear 
and Wheal Seton. 

Vertical to the 35- 
f athom level. Cop- 
per ore abundant 
to the 115-fathom 
level. (Henwood, 
Table Ivi.) 

Contains copper, 
zinc ores, and iron 
pyrites. 

Yielded copper ore. 
(Henwood, Table 
Ivi.) 



142 



NATURAL HISTORY OF THE LODES. 



Mine. 



Wheal Crofty - 



Gustavas 
Wheal Tehidy 
East Pool 



Park an Bowan 
(Roskeamoweth) 

Wheal Harriet 

Qreat Condur- 
row 

West Basset - 

Wheal Basset - 

Wheal Gorland 

Soath Wheal 
Hawk 




Middle lode 



Deg. 
K25S. 



E. a few 

degs. N. 

Kand W. 

E.24S. 



E.24S. 



East Wheal 
Chance 



Wheal Basset 
and Grylls 

Crenver (and 
Wh. Abraham) 



Gaunter 



B.aodW. 



E.20S. 



Underlie, 



Deg. 
8 to 25 S. 



S. 

N. 



S 



8. 



20N 



2or3N 



2or3N. 



Remarks, 



Contains copper, 
lead and zinc ores, 
and iron pyrites. 
(Henwood, Table 
Iv.) 



Copper and iron 
pyrites. 

Branched off from 
the south of 
Pryoe's lode. A 
Gaunter at the 170- 
fathom level in 
granite is a brec- 
ciated lode, con- 
tains tin and other 
minerals,with later 
yein of chalybite. 
This lode is being 
worked. 

Copper to the 70- 
fathom lerel. 

(Part of North 
Roskear) contains 
copper and zinc 
ores. 

Copper ores. This 
mine is in granite. 

Gaunter at 10- 
fathom level con- 
tained copper ore. 

Contains copper and 
tin. It intersects 
Williams' lode. 

Faultn the Great 
Flat lode. 

Lodes counter to 
one another. 

Contains copper. It 
intersects the 

South Wheal Hawk 
copper lode. 

(Thomas, p. 43.) 

The Gaunter lode 
intersects the 
main lode which 
underlies south 
and faults it 12 
feet. Both con- 
tain copper. 
(Thomas, p. 37.) 

A Gaunter lode 
5 feet wide con- 
taining tin ore. 

A Gaunter lode 
intersected and 
heaved by the 
Great lode 70 
fathoms. (Game, 
p. 98.) 



INTERSECTION OF LDDES. 



143 



Mine. 


Oaunter Lode, 


Bearing, 


Underlie, 


Remarks. 






Deg. 


Deg. 




Herland - 


Fancy Gaunter 
lode 


E.35S. 


8 to 18 S. 


(Henwood, Table 
xxiv.) 


North Downs - 




E.28N. 


7 to 10 N. 


Contains copper 
pyrites. Forms a 
junction with the 
Tenp^nny lode 
and is with it for 
8 fathoms. (Uen- 
wood. Table Ixix.) 


United Mines - 


Bawden's South 
lode 




S.10to24 


Two lodes have an 
east and west bear- 




Nicholls' Branch 




S. 12 to 30 


ing but are not 
called Gaunters. 
Both contain cop- 
per ores. (Uen- 
wood. Table Ixi.) 




Gaunter lode 


N.B. 




(Game). 


KiUifreth 




K34N. 




The main lode has 
a nearly E. and W. 
bearing and the 
Gaunter branches 
off from it on the 










north side. 



The foregoing list is far from complete, and there are probably 
errors in the few details which it has been possible to collect. On 
the whole the Gaunter lodes are far more common in the killas 
than in granite, and although some of them contain tin ore, they 
more generally contain copper or other ores. As a whole 
Henwood's statement that '^ Gaunter lodes have no distinctive 
character but that of direction " is true. 



VI. Intersection of Lodes. 

The question here concerned is largely that dealing with fault- 
ing, and whether or not there is any justification for the view that 
the lode fissures were formed successively by distinct epochs of 
movement. The information of the precise mineral phenomena 
of the intersections of lodes is very meagre, but in view of the 
diverse opinions of different writers* the case requires a very 
careful examination of the facts. The question is complicated by 
the probable processes of secondary concentration of some of the 
ores in the lodes, their unequal mineralisation^ and by the move- 
ments that have taken place in the lodes long after they were 
formed. The facts recorded by early writers must sometimes be 
treated with caution ; thus there are somewhat disturbing state- 

* In 1778 Pryce classified the lodes under twelve heads (Mineralogia 
Comubieniis, p. 88). In 1822 Came divided the fissures into eight successive 

rhs of formation {Tram. Geol. Soc. of ComrvoUl, vol. ii., pp. 85-119). In 1897 
Collins classified the lodes under nine heads, each representing a distinct 
epoch of movement {Journal Roy. Imt, Cornwally 1897, p. 196). 



144 NATURAL HISTORY OF THE LODES. 

ments in one of Carne's papers, in which it is said that '' in some 
copper lodes tin is so plentiful in some parts as to give them, for 
a short space, the appearance of tin lodes."* And, again, ^^ it is con- 
sidered a favourable symptom to find, on the back (of the ^ oldest 
east and west lodes') tin ore/'f Carne states that " it appears 
probable that previous to about A.D. 1700, the copper ore produced 
in Cornwall was principally, if not wholly, from tin mines, or at 
least from mines originally wrought for tin."t Kichard Thomas 
says that the *' Chacewater lode at Wheal Daniell is called a tin 
lode ; at Chacewater Mine, a tin and copper lode ; and at Treskerby 
a copper lode/'§ Phillips states that the old miners frequently 
worked a lode for copper, entirely ignoring the presence of tin ore, 
considering it to be not worth working, or ehe thinking the lode 
was of no more value after the copper ore had been eztracted.|| 
There are many cases where a number of lodes are proved in 
depth or in their direction of strike to be really branches of one 
lode, although each is treated by the miners as a separate lode and 
called by a special name. In the following are a few particulars 
of the intersections with one another of what appear to be inde- 
pendent fissures : — 

Cook's Eitohbn Minb.— The Oreat lode, which has a southerly under- 
lio, intersects and heaves Toy's lode, which underlies north, to the extent 
of 18 fathoms at a depth of about 105 fathoms below adiL Above this 
place the Great lode was only copper bearing, but the part of the lode 
between the intersected portions of Toy's lode contains both copper and 
tin. Below the intersection the Great lode only contained tin ore. Thus 
it contained no tin above the intersection and no copper below.^ The 
Great lode is that which is known at the present time as Dunkin s lode. 
Exploration in the deeper parts of the lodes since Came made the above 
observations shows that copper occurred in Dunkin's lode to the 222- 
fathom level. Thomas states that Toy's lode contains both tin and 
copper ores and that it crosses the Great lode at the 90-fathom level.*"" 
Henwood says that the junction consisted of ** a mass of earthy red iron 
ore, quartz and vitreous copper ore 10 feet wide. They continue mixed on 
the line of Dunkin's lode for 9 fathoms " after which there is black and 
vitreous copper ore, crystallised red oxide of copper, and some tin ore.|| 

Wheal Bassbt.-— The intersection of the Great Flat lode by the 
numerous more or less perpendicular lodes which heave it is characterised 
by a great widening of the Flat lode near these places. The lodes which 
fault the Great Flat lode contain mainly copper ore, but copper ore also 
occurred in the upper part of the Great Flat lode itself, while some was 
also only recently taken from it at the 250-fathom level in Wheal Basset. 
The tin ores in this mine are mainly obtained from the Great Flat lode, 
but tin also occurs in smaller quantities in the lodes which intersect it. 
The lines of intersection are not distinct, but in West Wheal Frances 
(further west) a copper lode containing some tin ore is stated to have 
actually passed through the Flat lode as a distinct vein. 

North Roskbar and Whbal Cropty. — The Engine lode is possibly 
traversed by the Gaunter lode which underlies south. The intersection 

* Carne, p. 103. t Op. cit., p. 93. 

t ** Copper Mining in Cornwall.*' Tr. R, O. 8. Cornwall, vol. iii., 182S, p. 44. 
§ Tliomas, p. 20. » » r 

II '* On the Veins of Cornwall." Tr. Geol. 8oe., vol. ii., 1814, p. 122. 
IT Carne. •♦ Thomas, p. 33. ff Henwood, Table li. 



INTERSECTION OF LODES. 146 

r 

of the Camiter lode with the South lode, which has a variable underlie, is 
simply a confused lode, and at a lower level these lodes are together for 
7 fathoms with no sign of a heave. They all carry copper.* 

South Condubrow. — The Engine, Middle and West Basset lodes, which 
are more or less vertical, all heave the Great Flat lode. All of them con- 
tain tin and copper, but the Great Flat contaius very little copper and the 
other lodes not much tin. 

South Frances Mink. — The Basset lode and two other lodes heave the 
Great Flat lode between the 134 and 205-fathom levels. The Basset lode 
underlying north intersects one of the copper lodes which underlies south. 
They all contain tin and copper ores. The Great Flat contains but little 
copper, while the other lodes contain more copper than tin. 

South Crofty. — The Middle lode drops from the south \\»all of Prj'ce's 
lode Into the North lode. The lodes cannot be distinguished at the 
junctions and are of similar conipi>sition« containing tin and copper ores. 

Trehkkrby.— The Flat North underlying copper lode crosses the north 
underlying Chacewater lode at the 6(Kfathora level. The Chacewater 
lode in Chacewater Mine contains tin and copper ; in Wheal Daniel 1 it is 
called a tin lode, t 

United MiXB8.~The South lode and the Great lode (in the Ale and 
Cakes part of the mine) intersect each other at the 170-fathom level. Both 
underlie north and contain co])per.t The Mundiclode underlying north 
intersects, but does not heave Bawden's lode, which underlies south. 
Both lodes contain tin and copper.§ The Cargruel lode, containing both 
tin and copper, traverses the Rapsey copper lode.| 



Wheal Gorland. — Dennis's lode, which is a vertical copper lode, inter- 
sects Green's lode, which underlies north and contains tin and copper.^ 

Wheal Unity. — The Solid tin lode underlies north and forms a junc- 
tion with Francis copper lode, which underlies south. The lode so 
formed carries both tin and copper, and is known as Green's lode in 
Wheal Gorland.** 

Carzibe Mine. — The Gaunter lode joins the Carzise lode and they 
continue as one lode for 20 fathoms and then separate. Both carry tin and 
copper and underlie south.j ) 

E1A8T Wheal Chance.- See p. 226. 

POLDICE. — The Great ore lode underlying north and containing copper 
intersects and heaves to the extent of about two fathoms the Poldice tin 
lode and the Bissoe tin lode, which underlie south, j \ 

SooRRiSR Mine. — Two eopi>er lodes underlying north are intersected 
by a Gaunter lode underlying north and containing copper. The Gaunter 
is the same as that seen in p]ast Wheal Chancc.§§ 



Wheal Hawke. — The Wheal Hawke copper lode underlying south 
intersects the tin lode which underlies north. Similarly, the Pendarves 
copper lode crosses a south underlying tin lode in Wheal Messar.|||| 

Nangilbs. — Two copper lodes heave a tin lode.*[*i^ 

Dolcx)ATH. — See p. 140. 

East Wheal Crofty. — The Lougclose main lode intersects the Long- 
close Gaunter lode at the 30-fathom level. At the 54 and 65-fathom levels 
the main lode heaves the Gaunter lode 3*5 and 5*5 fathoms respectively. 
Both lodes imderlie north and both contain copper and zinc.*** 



* HenwtKKl, Table Iv. + Thomas, p. 20. * Op. cit., p. 49. 

§ Henwood, Table Ixi. l] Carne. IF Thomas, p. 56. 

*• Thomas, p. 65. ft Henwood, Table xli. Xt Thomas, p. 40. 

§§ Op. cit.y p. 42. ,.ii Op. cit., j). 57. H^l Carne, p. 88. 

*•• Henwood, Table Ivi . 



146 NATURAL HISTORY OP THE LODES. 

Ting Tang. — The middle lode unites with the main lode westwards 
and forms one lode \\ith it. Both lodes contain copper and underlie 
north,* 

CoNSOLiDATBD MiNBH. — 61oTer*s and Eitto's lodes both underlie south 
and intersect Paul's lode which underlies north ; all contain copper. 
Taylor's and Tregonning's lodes unite eastwards.t 

South Wheal Towan.— The Slide lode is thrown up 25 fathoms by the 
South Icde. Both are copper lodes.}; 

The above list, together with that of the Caunter lodes, includes 
the cases upon which systems of classification according to the 
different ages of lodes have been based. It appears that in these 
instances the intersecting lodes do not differ from each other, 
except in a few cases, in the actual minerals they contain. In 
some lodes, however, copper predominates, while in other lodes tin 
ore is more abundant than copper. The case at Cook's Kitchen 
Mine (page 144) shows how easy it is to be misled as to the pre- 
cise meaning of these intersections. In Poldice it appears that a 
tin lode is heaved by a copper lode. On the whole those lodes 
containing much more copper than tin sometimes intersect those 
containing more tin than copper. Joseph Came§ endeavoured to 
classify the lodes into distinct systems, but the data upon which 
he based his classification were incomplete. Thus he refers to the 
Dolcoath lode as being one of the *^ oldest east and west copper 
lodes," whereas it is known at the present time that in depth it is 
an exceedingly fine tin lode with no copper in it 

Before the lodes can be classified in this manner it must be 
shown that there are two or more distinct fissure systems, each of 
which contains characteristic minerals, separating it in some way 
from the others. The formation or re-opening of a fissure giving 
rise to a lode is not necessarily followed immediately by infilling 
of minerals. 



VII. Paultinq by Lodes. 

De la Beche pointed out long ago that most of the lodes are 
faults. The evidences of faulting are based upon direct observa- 
tion, which can be classed under three heads : (1) Dislocation of the 
walls of the lode ; (2) Form of the fissure ; (3) Brecciation of the 
walls of the fissure. 

On account of the similarity in dip and strike of the lodes and 
elvans it is only in a few cases that the elvans are clearly seen to 
be faulted by the lodes which cross them. 

At Herland Mine (Owinear) an elvan is heaved six feet by a 
Caunter lode.|| Another elvan in the same mine is thrown some 
fathoms by a lode (op, ciL), At Duffield Mine there is a similar 
instance.1I The Great Flat lode, south of Camborne, is faulted by 
several more or less vertical lodes in South Condurrow, South 
Frances, West Basset, and Wheal Basset. At Wheal Basset the 

• Henwood. Table Ix. t Op. clt., Table Ixii. t Op. oit.. Table Ixxii. 
§ Carne. il Henwoud, Table xxxiv. IT Op.cit,, Table xxxvii. 



FADLTINCf BY LODES. 147 

Flat lode is heaved 20 {ieithoms by the Old lode.* In Camborne 
Vean Mine the granite is heaved 20 fathoms by the lode, and in 
Dolcoath the hanging wall of the Caunter lode is lower than the 
footwall. At South Crofty Mine the granite is faulted down 
southwards by Pryce's lode to the extent of 9 fathoms. The 
sheet -like intrusions from the granite in Cook's Kitchen Mine and 
Tincroft are dislocated by the Highburrow and other lodes.f The 
granite is faulted (10 fathoms) at Wheal Beaucbamp by a lode,t and 
at Tresavean§ and Wheal Trannack.|| Cases where one lode faults 
another are common. At South Wheal Towan the south under- 
lying lodes are dislocated by the north underlying lodes to the 
extent of 25 fathoms (see page 146). 

The form of the fissure frequently shows that faulting has taken 
place, as the infilling is often made up of alternate wide and 
narrow parts produced by the movement of the walls of an 
irregular crack along one another. Any of the larger lodes 
exemplify this. 

Brecciation of the lode materials indicates crushing by move- 
ment of the walls either during dislocation or by vibration, such 
as those arising from earthquake shocks. ^^ Fragments of slate 
cemented by quartz and yellow copper ore " were obtained from 
the principal lode of the Consols Mine, Gwennap. Angular pieces 
of slate cemented by yellow copper ore were found at the United 
Mines, Gwennap. At Wheal Jane (Helston) similar veinstones 
occur. At Binner Downs Mine (Crowan) angular portions of slate, 
yellow copper, and zinc blende cemented by pearl spar or carbonate 
of iron occurred.^f Brecciated veinstones from the deep levels of 
the lodes can be identified in East Pool, South Crofty, Dolcoath, 
and Wheal Basset. Slickensides occurring in a lode already 
supposed to be a fault are confirmatory evidence. " Slickensides " 
may, however, be produced by the squeezing of a soft substance 
such as moist clay between hard walls, or by a vibratory move- 
ment of the walls upon one another, or it has been suggested that 
etching of the walls by corrosive gases may produce the appear- 
ance of a slickenside. In Cook's Kitchen Mine the footwall of 
the Highburrow lode at the 270-fathom level is a hard granite 
scratched up and down for several fathoms. At the 210-fathom 
level in the main lode of Dolcoath, on the west of the North 
Valley shaft, there are horizontal striations. Numerous slicken- 
sides occur also in Wheal Uny.** Slickensides on iron and copper 
pyrites occurred in the walls of lodes in Great Wheal Fortune, 
South Crofty, and Consolidated Mines. ft In conclusion, it may be* 
stated that movements appear to have taken place in the plane of 
the lode both before and after mineralisation, and of those lodes 



* J. Maynard, ** Remarks on Two Cross Sections. ' Hep. Corn, Poly, Soc^ 

1871. 

t Thomas, p. 43. Kenwood, Table li. and p. 60. 

X Kenwood, p. 199. § Op. cU,, p. 71. II Op. cit,, p. 197. 

H De la Beche, p. 323. 

*• R. H. Thomas, " Some Observations on the Great Flat Lode in Wheal 
Uny." Rep. Com. Poly. Soc, 1886, p. 184. 

ft Kenwood, p. 181. 

l2 



148 NATURAL HISTORY OF THE LODES. 

in which both can be shown to have occurred the principal are 
found at the margin of the granite, which is a position of 
structural weakness, and may be described as the focus of the 
metalliferous area. It is a position very favourable to the produc- 
tion of breccias. It i& more than probable that the largest ore 
lodes are generally to be found at the edge of the granite where 
the lodes are parallel to the granite margin. 

Lodes in which the Faulting is Insignifijca/rd. — Mr. Hill states* 
that in the parish of Wendron there is ^' an extremely attenuated 
set of mineral veins which have been extensively worked for tin." 
He traces a connection between these fissures and the E.N.E. system 
of joints (tougbway joints of the granite), and concludes that they 
originated in' the continued operation of the same stress with which 
the intrusion of the granite is connected. It is not improbable that 
the tin deposits of Wheal Lovell and East Wheal Lovell and many 
other mines afford some instances of this nature.f 

In many cases the lodes of this region each consist of a series 
of close parallel cracks. The intervening layers of country rock 
have been so completely changed, and the fissures themselves so 
obliterated by the action of the vapours which once traversed them, 
that the original structure of the lode is altogether lost, and may have 
the appearance of a massive fissure infilling. Sometimes there are 
two or more systems of cracks intersecting each other at a narrow 
angle, and seeming to form conjugated systems such as those 
lererred to by Daubree. " But," as Mr. Hill points out, " when 
the granite is followed into the districts of Kedruth and Camborne, 
the magnitude of the fissure lodes and elvans have reached their 
maximum, and the marginal zones of the granite constitute the 
heart of the mineral are&"| 

With regard to the origin of the jointing in its relation to lode 
fissures. Professor Crosby's hypothesis that parallel jointing is due 
to earthquake movements is one worthy of consideration.§ 



VIII. Trend of the LoDEa 

The metalliferous fissure veins or lodes in any particular part 
of this district, in common with the elvan dykes (and ^' toughway " 
joints of the granite), have a certain more or less definite bearing 
which varies slightly for each locality from the bearing common 
to the whole. Henwood|| states that the mean strike of the lodes 
In the Camborne district is E. 20 deg. N., and that in the Bedruth 
district it is E. 22 deg. N. The mean strike of all the lodes in any 
particular locality is, however, not the same as the mean strike of 
the principal lodes ; in Camborne, for instance, the mean bearing of 

* J. B. Hill, K.N. (H.M. Geol. Survey), Summary of Progreu^ 1903, p. 31. 

t See ** Tin Deposits of East Wheal Lovell," by C. Le Neve Foster. 
Tr, R.Q.S, Cornwall, vol. ix., 1876. 

X Summary of Progress, 1902, p. 31. 

§ W. O. Crosby, Proo, Boston mt. Hist, Soc., 1882, vol. j^xiL 77ie 4meH^n 
Otologist, vol. xii., 1893. 

II p. 250, 



TREND OF THE LODES. 



149 



the principal lodes is E. 30 deg. N. There are, therefore, certain 
lodes which have a bearing differing from that of the majority ; 
and in Camborne there is a marked series of lodes having a bearing 
nearly £. and W. called Caunter lodes. These lodes '^ have no 
distinctive character but that of direction/'* and are comparatively 
few in number. 

The following tabular statement is an attempt to give for each 
locality the mean bearings of those lodes that have the same 
general trend : — 



LOOEH. 



Camborne District. — 
Dolcoath, &c.,and the 
lodes on the north. 

Lodes in the granite on 
the south of above, 
excluding the Great 
Flat lode. 



Redruth District.— 
Round the margin of 
the Redruth granite. 



District on the north 
of the Redruth 
granite. 

Oammenellis granite. 
Round the N. and 
N.K margin. 



Gwennap District. — 
Between St. Day and 
Twelve Heads. 

District between 

Twelve Heads and 
Newbridge. 

Wendron Dis'rict. — 
Southern part of Carn- 
menellis granite 



Bearing. 



E. 30 deg. N. 



E. 32 deg. N. 



Remarks. 



E. 22i deg. N. 



Forth Towan lodes. 



E. 21i deg. N. 



E. 30 deg. N. 



E. 20 deg. N. 



E. 34 deg. N. 



E. 36 deg. N. 



E. 20 deg. N. 



Lodes along the margin and on the 
north of the Carn Brea granitei 
excluding Caunter lodes. 

Great Flat lode. (From South 
Condurrow to West Frances E. 
31 deg. N. From West Frances 
to South Carn Brea E. 35 deg. N. 
From Wheal Uny eastwards 18 
deg. N.) 

The lodes on the northern margin 
have a bearing greater than this 
number ; those on the south less* 
Some have a nearly E. and W. 
bearing. 

The bearings vary from E. 15 deg. N. 
to E. 35 deg. N. Some lodes run 
nearly E. and W., and are not 
included. 

The bearings vary from E. 16 deg. N. 
to E. 30 deg. N. the latter being 
the Tresavcan main lode, the 
former those lodes on the north 
and north-west of Tresavean. 

Some of the lodes not included bear 
nearly E, and W. ; others bear E. 
30 deg. N. to E. 40 deg. N. 

One lode, at least, has an E. and W. 
bearing, and is not included. Lead 
lodes not included. 

The lodes vary in direction from 
E. 15 deg. N. to E. 53 deg. N. 
The latter are round Garlidna 
and Ilalabezack district. There 
appear to be several series of lodes 
corresponding with directions E. 
5 deg., 17 deg., 28 deg., 35 deg., 
and 48 deg. N. 

Some lodes not included strike 
nearly E. and W. 



IX. Underlie of the Lode8. 

As a rule, the principal lodes underlie north, and in this their 
behaviour is similar to that of the elvans. 



• Hen wood, p. 253. 



150 NATU&AL HISTORY OF THE LODES. 

Taking the Camborne district first, and traversing the district from 
north to south, the following general average underlie of the principal lodes 
is obtained. 

The most northerly series of lodes in the Camborne district is that 
extending from Wheal Tolgus (on the east) through West Wheal Tolgus 
westwards. Situated entirely in the killas, the average underlie is from 
26 deg. to 30 deg. N. The next series, on the south, includes the lodes of 
the Seton Mines through to North Pool and South Wheal Tolgus ; the 
average underlie is 40 deg. N., but the lodes on the west are flatter than 
those on the east. 

The next series includes the lodes of the Roskear Mines, South Crofty, 
East Pool, and Wheal Tehidy. In South Crofty and East Pool the lodes 
pass into granite in depth. The average underlie is from 20 deg. N. to 
perpendicular, but some lodes underlie south. 

A single lode lying between the last series and the next is known in 
Dolcoath as the North Entral lode, and eastwards as the North Tincroft 
lode. It underlies N. 34 deg. (average). 

The next series is that situated along the margin of the Cam Brea granite, 
and extends from West Stray Park, through Dolcoath, Cook*s Kitchen, 
Tinoroft, and Cam Brea. The lodes vary from vertical to S. 18 deg. ; 
but in the deep levels of Dolcoath, over 300 fathoms in the granite, the 
underlie is S. 45 deg. Numerous lodes in the upper levels of these mines 
underlie north. South of this series is a lode situated in granite extending 
from Cam Camborne to Wheal Providence, and it underlies a few degrees 
north to vertical. The lodes from Great Condurrow to South Dolcoath Mine 
underlie a few degrees S. Along the southern margin of the Cam Brea 
granite is a series of lodes situated mainly in granite extending from 
South Tolcarne through South Condurrow, West Francis, West Basset, 
and Wheal Basset (in killas). These lodes are more or less vertical, but 
some underlie north and others south. The Great Flat lode, which belongs 
to this series, is exceptional, and has an average southerly underlie of 
51 deg., but is steeper on the east and flatter on the west. 

There are a few lodes extending from Grillis to South Wheal Basset, 
situated in granite. The underlie is a few d^rees to the north. 

The district from Scorrier Gate to the United Mines in Gwennap can be 
dealt with in a similar manner as follows : — 

The lodes of Wheal Mary and Little North Downs intersect each 
other, some lodes underlying south and others underlying north. They 
appear to follow no particular direction as regards underlie. Some of 
the lodes of New Treleigh Consols, Wheid Peevor, and North Downs 
underlie north at about 19 deg., but some underlie south or are vertical. 
The main lodes of Treskerby and Great Wheal Busy (Chacewater Mine) 
underlie north from 34 deg. to 40 deg., but some lodes underlie south. 
The lodes of Killifreth underlie north at 58 deg. or less. The Unity Wood 
series underlies north. The Wheal Gorland lodes underlie north or are 
perpendicular. The lodes from West Wheal Damsel to the Consolidated 
Mines underlie north from 20 deg. to 25 deg. There are numerous south 
underlying branches in the Consolidated Mines. The lodes from Ting Tang, 
through the United Mines, Wheal ClifiFord, and Nangiles to Wheal Jane 
underlie north from 20 deg. to 65 deg. A few lodes in Nangiles are 
nearly perpendicular. 

" Flat " * Lodes. — ^There are many cases of lodes underlying at 
about 45 deg.y but in a few eases the lodes approach more nearly 
to a horizontal than to a vertical position. The following examples 
indicate those of low hade : — 

At West Wheal Seton (on the north of Camborne) the underlie of the lode 
(which is accompanied by an olvan) is 58 deg. N. At Wheal Jane the 
main lode underlies north at about 05 dog. (Fig. 17.) At Killifreth the 
middle lode underlies north at 58 deg. (Pig. 18.) The Great Plat lode 

* The term •• Flafc Lode " is commonly applied in Cornwall to a lode with a 
characteristic low hade. 



UNDERLIE OF THE LODES. 



151 



(along the soathem margin of the Cam Brea granite) is the only south 
underlying Flat lode. At South Tolcarne its underlie is 80 deg. S. (10 
deg. from the horizontal), but eastwards the lode becomes gradually 
steeper, until at Wheal Uny it is 45 deg. S. There are several places in 
which the lode is almost vertical, but only for short distances. At Wheal 
Squire the Flat lode underlies N. 54 deg.* At Wheal Peevor the Flat 
lode underlies north at 53 deg. There are also Flat lodes in Wheal Music, 
United Hills, Wheal Busy, &c. 



Fig. 17,— Wheal Jane. 




SCALE -TatttOTTLS 



O 



lOO 

I 



zoo 

I 



The Relative Underlie of Lodes and Elvans. — There are 
a great many cases in which the lodes underlie in the same direc- 
tion as the elvans in their vicinity. 

The flat, north underlying lode in the Seton Mines, on the north of 
Camborne, is contiguous to an el van. The lodes of Dolcoath Mine in the 
deep workings are associated with el vans. Some parts of the Great Flat lode 
in Wheal Basset are mineralised elvan, which underlies south at about the 
same angle as the lode. At Wheal Wentworth (near Redruth) an elvan 
underlies in the same direction as the lode. At North Wheal Crofty a 



Fig is.— KUlifreth Mine. 




lOOF^I.evel 



SCALC-FajtJxornS 

o too 



north underlying elvan is intersected by north underlying lodes which are 
slightly steeper. In the Clifford Amalgamated Mines two north under- 
lying elvans are intersected by slightly steeper north underlying lodes ; 
and in Nangiies, Treskerby, Wheal Busy, Killifreth, and Wheal Jane the 
lodes and elvans are more or less parallel or occupy the same fissure. At 
Copper Hill an elvan underlies north with the lodo. At Wheal Moyle 
Ting Tang, an elvan underlies northwards towards the granite, and is 
Intersected by north underlying lodes which are slightly steeper. At 
Wheal Jennings (Parbola-Gwinear), Bissoe Bridge (near the United Mines 

• J. Came, **0n the Veins of Cornwall." Tr, ll.G.S. Corn., vol. ii., 1822, 
p. 98. 



152 KATUaAL HISTORY OF THE LODES. 

Gwennap), Ohacewater Tin and Copper Mine* and Wheal Unity,! much of 
lode material is only mineralised olvan. Thus, many of the lodes underlie 
in the same direction as the el vans, and either at the same angle or more 
steeply. 

The angular difference between the amount of underlie of the 
lodes and elvans occurring in the same mine in a few selected cases 
is as follows : — 

In West Stray Park Mine the difference in underlie of the el van and lode 
is about 25 deg., in Wheal Clifford from 35 deg. to 50 deg., in the United 
Mines about 30 deg., in Ting Tang Mine about 20 deg., in Wheal Emily 
Henrietta (near Tolvaddon) about S deg. ; in all these cases the elvans and 
lodes underlie towards the north and are in killas, and in no case is the 
el van steeper than the lode. Similar differences are observed in the granite, 
but where, as in Dolcoath, the lodes and elvans are south underlying, the 
elyan is steeper than the lode or is parallel to it. 

Cases in which lodes underlie in a direction opposite to that of 
the elvans are not so numerous or striking. 

The Engine lode at East Pool Mine is a steep south underlying lode, 
and intersects an el van which underlies north. Similarly, in Cook's 
Kitchen Mine the main lode (Highburrow) underlies southwards into the 
granite, and intersects an elvan which underlies northwards. Finally, 
there are numerous cases where the lodes of a mine underlie in different 
directions and, consequently, intersect each other. Thus : at Little North 
Downs Mine, one set of lodes underlies north in the same direction as 
an elvan, while another set underlies south. Similarly, at Chacewater Mine, 
the ore-bearing, north underlying, elvan is intersected by south under- 
lying lodes. 

X. Length of the Lodes. 

The length of a lode is the length of a more or less continuous 
fracture which may be subject to the irregularities of ordinary 
faults. Most of the lodes have not as a rule been completely 
explored from end to end, owing to their poverty or other causes ; 
but the lodes of one mine can be frequently identified in a neigh- 
bouring mine into which they pass. '^ Whether explored hori- 
zontally or as they descend in depth, they are seen often to be 
wavy and irregular, to go off from and return to their usual 
direction, and to present so many anomalies, that whilst on a 
map we may be obliged to take a straight line as an average, the 
real course is usually such as not only to complicate the workings 
but to make us slow to accept some of the brilliant theories which 
have connected lines of fissures with actual dates asserted to be 
discoverable in the elevation of mountain chains." t Iq a general 
way, however, the important lodes, whether as single fissures or 
mineralised zones, have been traced for considerable distances 
across the country. 

The Great Flat lode extends continuously from South Tolcarne, through 
South Condnrrow, West Francis, West Basset, South Carn Brea, and 
Wheal Uny to Cal Downs (on the western margin of the Redruth Granite), 
a distance of 3^ miles. It becomes steeper as it goes eastwards, and so 
loses its chief peculiarity, making it a matter of difficulty to identify it in 
that direction. The Dolcoath main lode extends from Carn Brea Mine, 

J. Carne, **0n Elvan Courses.'* Tr. H.O.S. Corn., 1818, vol. i., p. 104. 



BRPIADTH OF THE LODES. 153 

where it is known as the Highburrow lode, through Tincroft^ Cook's 
Kitchen, Dolcoath, Camborne Vean and West Stray Park, to near Kams- 
gate. Total length nearly 3^ miles. The Carn Cainl)orne main lode 
extends from Kellivose through Cam Camborne and Wheal Providence to 
Wheal Druid, a distance of over 2J miles. The Wheal Briggan main lode 
extends from Wheal Mary, on the "west, through North Dowis and Wheal 
Briggan to East Downs.* Distance 2f. miles.* The Great Wheal Busy 
lode has been traced from Wheal Danieil (on the east) through Great 
Wheal Busy, Scorrier Old Mine, Treskerby to Cardrewj and possibly runs 
Into Treleighwood Mine. In the United Mines the old lode has been 
traced from Camborne Parish through Carnkic to Baldhu, a distance of 
7 miles.]: 

No information is forthcoming of the way in which a lode dies 
out in the direction of strike, since if the lode is poor it has been 
abandoned ; and, as William Phillips states, " the most experienced 
miner never satisfactorily witnessed the termination of a vein 
either on the east or west."§ Where a lode in killas is coincident 
with the cleavage, it probably dies out gradually along these 
planes. Mineralised joints in granite will die out into a mere 
line of rifting. 

XI. Breadth of thk Lodes. 

The breadth of a lode includes the width of the infilled fissure 
and the altered rock on each side of it. As both these factors are 
Jiable to considerable variation it is almost impossible to determine 
what is the true width of any single lode. But by means of a 
number of measurements^ Uenwood|| found the mean width of the 
lodes in the Camborne district to be 3*68 feet, and in Redruth 
3*36 feet ; and generally that the width of the lodes in slate is 
greater than that in granite. He also noted that, on the whole, 
the lode containing both tin and copper ores are wider than those 
oontaining copper only. Since Henwood's time the workings have 
been carried to a much greater depth, and the information so 
obtained casts considerable doubt on the conclusions he arrived at, 
more especiaUy since many of the lodes are not single fissures. 

A few examples will illustrate the difficulties in the way of 
any attempt to calculate an average for the width of the lodes. 

DOLOOATH. — The lodes whore principally worked vary in width from a 
mere parting to 20 feet, but the average is 3 or 4 feet.^ The widest parts 
of lodes occar principally where there is an abrupt change in the strike of 
the lode. From the 200 to the 300-fathora level (in granite) the lode varies 
in width from 1 to 9 feet. At the bottom of the mine, near the 400-f athom 
level, nearly 300 fathoms in the granite, tho lode consists of a hard breccia, 
42 feet in width. The junction formed by the Main and South Entral lodes 
i8 60 feet wide. The South lode— which is a bninch of the main lode- 
varies from 6 inches to 2 feet iu the upper levels. The Silver lode is 
aboat 2 feet wide. The Gaunter lodo varies from 6 inches to a foot. 

The Obeat Flat Lodk.— The part of the lode left standing in Wheal 
Granville is 1 foot to 8 feet in thickness, and in South Coudurrow the tin- 
bearing part is 5 or 6 feet In breadth, but the total width of the lode 
inoluding the barren capel in either wall, is 12 to 20 feet. In West Wheal 
Basaet the lode and altered country rock at the MO-fathom level are 

• Thomas, p. 30. t Op. cit., p, 82. 

X J. Came, ''On the Veins <>f Cornwall." V'/-. //.^^.^'. ('/>/•/*., vol, ii., p, 96. 

§ "On the Veins of Cornwall." Tr, G. 'S<u'., vol. ii., 18U, p. 113. 

II p. 24.3. 

% Josiah Thomas. Journ. Hoy. In*t, Cora,, ISOS, vol. iii., p. 192. 



154 NATTJRAI. HISTORY OF THE LODES. 

together 40 to 50 feet in thickness.'*' In Wheal Uny the same lode varies 
from 4 to 10 feet in thickness, and in one place near a cross course is 72 
feet wide.t 

MisoELLANEOus LoDES. — In Tincroft Mine, on the north of the Cam Brea 
granite, some parts of the Highburrow lode are 3 or 4 feet wide, while 
other parts are 30 to 40 feet. The E ngine lode at North Roskear 
varies from 1^ to 18 feet. In Wheal Vor the main lode varies from 3 to 
30 feet. The Bor lode in Polladras Downs Mine varies from 1 inch to 
4 feet.j: In Nangiles the main lode reached a maximum width of 30 feet. 

Observations on the Width of Lodes. — If the original fissure 
in which a lode is formed is irregular, the relative displacement of 
its walls by faulting results in the formation of open and closed 
parts as was shown by De la Beche,§ Le Neve FosterJI and other 
writers. During the act of dislocation the walls of the fissure are 
crushed or ground together so that the original walls are obliterated. 
In this manner the fissure becomes largely filled with breccia* 
These breccias may also originate in the swift vibratory move- 
ments accompanying earthquake shocks, or may result from, direct 
pressure without faulting. 

Again, the width of lode is largely determined by the extent of 
the alteration in the vicinity of the fissure by active agents con- 
tained in solutions traversing the fissure. It will be seen, then, 
that in nearly all cases where the width of a lode is given it much 
exceeds the amount of opening in the original fissure. In this 
way the walls of those parts of a fissure which have afforded a 
passage for mineral solutions for a lengthened time must (other 
conditions being equal) be altered more completely, and for a 
greater distance on either side than in a case where access of 
solutions was only limited. 

Finally, every movement, which is not one of shearing under 
great lateral pressure, serves to further increase the width of the 
fissure, so that in this manner a lode is always tending to increase 
in size. Where, as is often the case, the lode consists of a series of 
close parallel joints or cracks, the width of the lode varies oon- 
siderably, according to the number and proximity of the cracks. 



Xn. Veinstone of the Lodes* 

In hand specimens the veinstones in any particular lode are 
considerably varied. Broadly speaking, the miner recognises 
certain types to which special names are given (see page 136). 
The miners' terminology, although rough and ready, is expressive 
enough. The characteristic veinstones of any part of the lode 
area vary almost imperceptibly in passing from one place to 
another, owing to the preponderance of different minerals over 
one another in different parts of the district. Certain types of 

• C. Le Neve Foster, "On the Great Flat Lode." Q.JM,S., 1878, 
vol. xxxiv., p. 640. 

t K. H. Thomas, ** Some Observations on the Great Flat Lode.'* H^, Com» 
Poly, Soc, 1888, p. 184. 

t Hen wood, p. 240. § Geological Report previously cited. 

II ** Remarks upon the Tin Deposits of East Wiieal Lovell." Trans, JIM^S, 
Corn., vol. ix., 1876. 



VEINSTONE OF THE LODES. 165 

veinstone are regarded as good or bad signs of the value of the 
lodes. A soft or " plumb " lode containing quartz and ohlorite, 
or a little clay or prian is supposed to be a good lode. The hard 
blue-black rock (schorl rock) which is commonly met with, 
eFpecially in the deeper parts of the lodes, is a good sign, par- 
ticularly if it is brecciated, although tin ore may only occur in it 
in small quantities. The schorl rock of a somewhat lighter blue 
colour, frequently modified by the presence of kaolin, rendering 
the rock more or less pulverulent, and especially if associated with 
chlorite, is an excellent indication of a good lode. The presence 
of oxide of iron, or the existence of cavities or vugs, are sup- 
posed to be indications of a good lode. A quartz (sparry) vein, 
unless accompanied by other minerals such as peach, chlorite, 
&a, is considered valueless as an indication of the presence of 
ore* 

William Phillips^ makes mention of the miners' saying that 
*' Black Jack rides a big horse," from the fact that a lode con- 
taining blende in the upper part is often rich in copper in depth ; 
an instance of this being Wheal Towan. 

Microscopic Structures of some Tin Stones. (Plate Xll.) 

The microscopic structure of the veinstones of the Camborne 
area, from material collected at Dolcoath, Wheal Basset, 
South Crofty and Cam Brea, was described by Dr. Flett in 
the Summary of Progress of the Geological Survey for 1902 
(pp. 154-159). 

The descriptions that follow illustrate the micro-photographs 
depicted on Plate XII. : — 

Fig. 1, — Veinstone from Cam Brea Mine. The material is a 
breccia consisting mainly of quartz, tourmaline, and cassiterite. 
In the tissue sketch over the plate the cassiterite is represented 
by (1), cassiterite and tourmaline needles by (2), quartz by (3). 
(E. 3,601). 

Fig. 2. — Cam Brea Mine, 300-fathom level. The slide shows 
large crystals of tin (*'Zinngrauper,") with usual zonary banding, 
set in a matrix of quartz and chlorite with abundant oxide of iron 
(haematite) which occurs among the chlorite. The part of the 
figure marked (1) represents cassiterite, (2) is chlorite and oxide 
of iron largely interstitial, (3) is quartz. (E. 3,603). 

Fig, 3. — South Crofty Mine. The figure shows cassiterite (1), 
radiate green chlorite (2) which are intimately associated, and 
quartz (3), also quartz crowded with tourmaline needles (4). 
(R 3,604). 

Fig. Jh — South Crofty Mine. The figure shows a veinstone 
consisting of cassiterite and chlorite traversed by a vein of fluor- 
spar. In another part of the slide there is a quartz tourmaline 
vein. (1) consists of cassiterite with a little chlorite, (2) of 
chlorite, (3) of fluorspar, and (4) of quartz. (E. 3,605). 

Fig. 5. — Wheal Buys. A brecciated veinstone. The fragments 

* "Onthe Veins of Cornwall." Tr, QeoL Soc^ vol. ii., 1814, p. 121, 



156 NATURAL HISTORY OF THE LODES. 

in the slide consist of cassiferite, which in some places, owing to 
its yellow colour, appears almost black in the photograph, and 
some quartz. The whole mass is traversed by veins of quartz in 
which topaz occurs. (1) consists of brecciated cassiterite, (2) 
quartz frequently crowded with tourmaline needles, particularly 
where near the cassiterite. Bows of inclusions and of erains of 
oxide of iron show a zonal arrangement in the quartz. (E. 3,858). 
Fig, 6. — Dolcoath Mine, 475-fathom level. The shde shows 
several periods of disturbance of the brecciated lode. (1) consists 
of quartz-tourmaline veinstone, and is possibly itself a breccia. 
(2) infilling consisting of cassiterite, quartz, chlorite, and dusty 
undetermined inclusions, (3) cassiterite, (4) quartz. (E. 4,278). 



157 



CHAPTER XV. 
CROSS-COURSES, CROSS-FLUCANS AND SLIDES. 

The lodes are intersected by a system of fissures probably pro- 
duced in Tertiary times. These fissares traverse the district in a 
direction approximately at right angles to the lodes, from which 
fact the term " cross-course " is no doubt derived. Although the 
cross-courses are frequently faults, sometimes sufficiently large to 
affect mining operations, they have no important effect on the 
geological structure of the district. Excepting those cases cited 
in the section dealing with the general distribution of the ores, 
the cross-courses are unproductive from the miners' point of view. 
It is impossible to separate them geologically, however, from 
similar fissures which in some parts of Cornwall have yielded so 
much iron and silver-lead ore. 

In 1778 Pryce defined a cross-course (cross bar, cross gossan, 
cross lode) to be '^either a vein of a metallick nature, a cross 
gossan, or else a soft earth, clay or flookan like a vein, which un- 
heads and intersects the true lode."* 

Elsewhere in the same work ** flookan " is defined to be " an 
earth or clay of a slimy glutinous consistence, in colour, for the 
most part blue or white, or compounded of both." The same 
word is now used loosely where the term '* cross-flookan " should 
be employed. According to Pryce, "a cross-flooken runs across 
through a lode, unheads it and throws it on one side out of its 
place. There are flookans also which run parallel with metallic 
lodes and take the name of course-flookans." When clay occurs 
throughout an ordinary lode it is called a flookan lode. A slide 
is defined as being " a course-flookan or course-gossan, that either 
inclines faster or in direct opposition to a metallick lode." There 
is here no attempt at classification as regards age. Richard 
Thomas, however, stated that cross-courses and cross-fiookans 
appear to be more recent than lodes or slides, and pass through 
them without interruption.f He called a cross-course which 
contains clay a " fluccan." In 1822, Came distinguished two 
kinds of cross-courses, the difference between them being both in 
bearing and underlie. Most of those which have a bearing E. of 
N. underlie west, and those with bearing W. of N. underlie east4 
With regard to slides, he states that they traverse every other 
kind of vein — a statement directly contradicting that of Richard 
Thomas. The slides, although generally parallel with lodes, may 
run in any direction. Hen wood does not make any statement on 
the relative ages of the cross-courses and slides, but he remarks 
that the slides never contain metalliferous minerals, and that they 
never occur in granite. " Their whole substance consists of soft 

• Mln, Cornub., p. 319. t Survey, 1819, p. 21. 

; J. Came, ** On the Veins of Cornwall." Tr, I{,G,8, Corn., vol. ii., 1822, 



158 CBOSS<H)UBS£S, CROSS-FLUCANS AND SLIDES. 

clay, similar in mineral composition to the rocks which they 
traverse. So close, indeed, is this resemblance, that even the 
lamination of the slate is often as perfect in them as in the con- 
tiguous rock," and " the softness of the slide is frequently the 
only character distinguishing it from the neighbouring 
country.' "* 
The slides are few in number, seldom exceed a foot in width, 
and their average underlie is about 45 deg. or 50 deg. Slides are said 
to occur in Treskerby, Wheal Squire, Wheal Vor, Wheal Friendship, 
&c. In the districts of Camborne and Redruth the directions of 
the principal cross-courses and cross-flucans, with their average 
widths, were tabulated by Hen wood, and the results may be pre- 
sented as follows :— « 

Bearing. 
N. to N 10° W. 
N. 10° to 20« W. 
N. 20° to 30° W. 
N. 30° to 40° W. 
N. Wto50»W. 
N. 50^ to 60' W. 
N. 60^ to 70" W. 
W. 20° to 30° S. 
W. 50° to 60° S. 
V7. 60« to 70° S. 
W. 70" to 80° S. 
W.80°S. toS. 
Average bearing 
Average width 

Henwood says that the material principally filling the cross- 
veins consists of quartz and clay, and according as one or other of 
these constituents predominates they are called cross-courses or 
cross-flucans, and it is owing to the impervious nature of these 
flucans that they are sometimes selected as the boundaries 
between different mines.f The Great cross-course, which can be 
seen in the adit between Cook's Kitchen and Dolcoath Mines, is 
a case of an impervious barrier between two mines. The structure 
of cross-courses is variable,but they have, as pointed out by Mr.Hill, 
an intimate connection with the ^' cleaving way " jointing of the 
granite.} They are not characterised by the presence of breccias 
as a rule ; are generally more or less vertical, and are not infre- 
quently faults of considerable magnitude. The larger of them 
contain quartz with fragments of country rock, while the smaller 
are mere cracks, that may or may not contain quartz, but along 
which there has generally been a little faulting. Henwood states 
that some cross-courses consist of several parallel cracks filled with 
quartz or other materials. The tabular statements contained in 
his book have much detailed information concerning the cross- 
courses in the mines. 

Mr. Came says that there is no connection between the size of 
cross-courses and the amount of faulting they produce,§ and gives 

• p. 282. t Henwood, p. 258. 

t Trans. Hoy, Oeol, Soc, Corn., vol. xii., part vii., 1901. 

§ " On tiie Veins of Cornwall," 1822, p. 117. 





Number. 


Camborne. 


Redratlu 


9 


4 




6 


4 


6 


2 


G 


1 


4 


1 


— 


— 


1 


— — 


r 


.^ 


1 


— 


4 


2 


— > 


._ 


2 


N. 34? W. 


W. 35« N. 


1*48 feet. 


1-62 feet 



CB0SS->00UBS£3, CKOSS-FLITCAKS AND SLIDES, 159 

seVeral examples of considerable faulting by cross-courses which are 
comparatively narrow, and vice-versa. In Wheal Virgin (Consoli- 
dated Mines) a cross-course 2 feet wide heaves the lode 6 fathoms ; 
in Wheal Peevor another of the same width heaves the lode 
18 fathoms ; at Sparnon a cross-course 8 feet wide heaves the 
lode only 2 fathoms. In Wheal Unity a flucan 18 inches wide 
heaves the lode 5 fathoms. In Wheal Squire a flucan 2 feet 
wide heaves the lode 19 fathoms. A small flucan in Wheal 
Paniell heaves the lode 14 fathoms, while lodes in the United 
Mines are heaved only 1 fathom by a flucan over 2 feet wide. 
The principal cross-courses and cross-flucans of the Camborne and 
Bedruth district are indicated on the map published by Richard 
Thomas in 1819. The facts relating to a few of the principal 
cross-courses of this district may be briefly stated as follows : — 
The Great or County cross-course has been referred to by Berger, 
Thomas, Came, and Henwood. Thomas says that it starts from 
Tolben rock, near Forth Towan, 2^ miles N.E. of Portreath, and 
goes through to Wheal Jewell. From here southwards it is divided 
into four branches, each of which is a fault of about 20 fathoms. 

Although Berger* states that this cross-course continues its way 
southwards to Pedn Boar Point, the statement iH not proven. 
Game remarks that there are two cross-courses seen at some 
distance from each other in the cliff at Porth Towan, and that 
they intersect and heave all lodes as far as Wheal Peevor, at which 
place they run into one another. The eastern one heaves the lodes 
54 fathoms and the western one 18 fathoms to the right hand. 
From Wheal Peevor to Wheal Jewell the heave is 74 fathoms, but 
further south still, at Wheal Damsel, it runs into confused ground, 
and heaves the lodes only IG fathoms. 

Henwood appears to disagree with both views, and says that 
although there are several flucans in Wheal Damsel, Wheal 
Squire, and Poldory, none of them can be shown to run into the 
Great cross-course, while the only considerable heave north of 
WhealPeevor isin Cliff Down (western part of Wheal Towan),where 
the heave is to the left hand. Another important cross-course is 
that which separates Cook's Kitchen from Dolcoath Mine, and is 
known to dislocate the main lode to the extent of 74 fathoms. 
Northwards, it passes between North Koskear and East Wheal 
Crofty, and is the same as that exposed in the cliffs near Samphire 
Island. At the present time it can be seen in the adit between 
Dolcoath and Cook's Kitchen, where it is of a clayey or flucany 
nature, while at Samphire Island it is a quartz vein. 

Some cross-courses have, on account of their special interest, 
received notice from several writers. A north and south cross- 
course called Skewes flucan, with a slight heave to the left, 
traverses the mines of Ting Tang, Wheal Damsel, Wheal Jewell, 
and Wheal Gorland. Between Wheal Jewell and Wheal Damsel 
it passes through the Great cross-course. A cross-course, designated 
the Caunter cross-course, separates Wheal Prussia and Wheal 
Boys, and southwards passes through Wheal Derrick. In Wheal 

* Ocul, Tra/ns^f vol. i., p. 165, 



160 CROSS-COURSES, CROSS-FLUCANS AND SLIDES. 

Prussia it is traversed by Butcher's cross-course, aud in 
Wheal Derrick by Wheal Boys' cross-course, both of which are 
parallel with the County cross-course, the Gaunter cross-course 
bearing about W. 40 deg. N. Tiddy's cross-course contained some ores 
of copper. It passes from Poldory (United Mines) through Wheal 
Virgin (Consolidated Mines) and Poldice, where it is called 
Trus&ars cross-course. At the Garras Mine (Gwarnick) there is a 
silver-lead lode striking approximately north and south. It is 
2| feet wide, and is heaved twice by two slides, each to the extent 
of about 6 fathoms.* 

In the south-western part of the map some remarkable cross- 
veins have been noticed. WoolPs cross-course, at Great Wheal 
Vor, consists of quartz. It intersects the old Wheal Vor and the 
Wheal Metal lodes, and is considered to be the same as that which 
yielded grey copper ore in the Godolphin Bridge Mine, and lead 
ore, with oxide of iron, in Wheal Rose.f 

♦ J. Carne, "On the Discovery of Silver in Cornwall,*' Tr, B,G,S, Com., 
vol. i., 1818, p. 120. 

t H. Stephens, Hep, Com, Poly, Sac,, 1871, p. 77, "Mineral Phenomena of 
Wheal Rose." See also R. Hancock, "On the Mineral Deposits of the Old 
Wheal Vor." Hep. Koy, Poly. Soc, Com,, 1870, p. 101. 



161 



CHAPTER XVI. 



NATURAL HISTORY OK THE ORES. 

I. The Ore Bodies. 

The profitable parts of the lodes (containing anything over 1 per 
cent, of tin) alternate with poor or barren parts. That the ores do 
not occur uniformly disseminated throughout the lodes is a point 
which cannot be too strongly emphasised. Grenerally speaking, 
the conditions aflFecting the shape of the ore bodies depended 
upon (1) the shape of the cavity or brecciated mass in which the 
ore was deposited, and (2) the nature and jointing (or fissuring) 
of the country rock in the neighbourhood of the lode. In this 
district there is no evidence for differentiating the origin of the 
more remarkably-shaped ore bodies from that assigned to those of 
ordinary lodes, since all the deposits are connected with fissures. 

Impregnated masses formed in the open parts of an irregular 
fault-fissure, or in a friction breccia of a fissure, together with 
the metalliferous altered country rock in their vicinity, are known 
as bunches or pipes. A succession of such bunches makes up a 
" chute " or " course *' of ore. The word '^ chute " refers to a 
succession of bunches in more or less vertical arrangement. 
A *' course " refers to a succession of bunches in a more 
or less horizontal direction. The lodes of the Grwmear 
district were termed ^'bunchy" by the miners, but used in 
that sense the word means that the bunches were un- 
certain in occurrence. A ^' pipe " is an elongate bunch 
within the lode, with its longer axis lying in the direction of 
underlie of the lode, or "pitching" slightly to one side or the 
other; or it may be the infilled line of junction of intersecting 
lodes, or the line of bifurcation of a branching lode. The dis- 
tinction between the terms " chute," ** course," and ** bunch " is 
not very definite, and the use of the terms is a matter of con- 
venience only. " The masses or shoots of ore in any given lode 
have, generally speaking, a prevailing dip (pitch), and whether 
they occur in granite or in slate, whether on the eastern or 
western side of granite tract, this inclination is invariably towards 
the great body of the slate."* 

In Wheal Uny the ore bunches pitch westwards.! The lode is very 
large, and yielded great quantities of low-grade tin ore.t 

In Wheal Grenvllle the ore pipes in the lode pitch slightly eastwards. 
The three chutes of ore in Dolcoath Mine and the chute of ore in Cook's 
Kitchen Mine, although almost vertical, iiave a slight easterly pitch in 
depth. The individual bunches of which these shoots are composed are 
ill-ndefined. In Great Wlieal Fortune and Great Wheal Vor the shoots 
incline in the direction of the granite and kilhis junction, or where 
associated with el vans they follow the dip of the latter. § 

* Hen wood , p. 195. 

t R. H. Thomas, ** Some Observations on the Great Flat Lode in Wheal 
Uny." liej). R. Corn. Poly. Soc, 1886. 

X H. C. Salmon. Miuhig and SmeUhuf Magazine, 1862, p. 318. 
§ Op. cit., 1862, vol. ii., p. U. " ' 

M 



NATUBAL HISTORY OF THE OHES. 




THE ORE BODIES. T6 

In Dolcoath, the main lode can be divided vertically into three chutes- 

(Fig. 10.) The lode regarded as the main lode strikes from the western 

boundary of the mine to Harriett's shaft at E. 30deg. N. Thence to the Old 

Samp shaft it strikes E. 50 deg. N. (at the 190-fathom level near the junction 

of the granite and kiilas). Thence to the Gossan shaft, in the eastern part 

of the mine, the strike is E. 30 deg.N. The lode then splits into two branches 

known as the Valley lode and the Valley Caunter lode. The main chute 

of ore is situated between the Gossan shaft and the Old Sump shaft. This 

chute is made up of more or less connected bunches which have been 

worked for copper down to the 190-fatbom level, and (after passing 

through a zone of mixed copper and tin ores) for tin, down to the deepest 

point of the present workings, which are 490 fathoms below adit, or over 

.500 fathoms from surface. The width of the bunches varied from a few 

feet to 60 feet. Thus, the junction of the main lode and South Entral 

lode is 60 feet wide. From the 150-fathom level to the 200-fa thorn level 

the lode varied in width from 7 to 12 feet, and from the 200 to the 

300-fathom levels from 1 to 5 feet. At the 3.38-fathom level the 

lode was from 6 to 9 feet wide, and at the 485-fathom level the width of 

the lode, including the altered country rock, is 42 feet in width, carrying 

25 lbs. of black tin per ton of stuff. 

Another chute of ore occurs in the same lode in the section of ground 
between Harriett's shaft and Wheal Kiilas shaft (on the west). This chute 
is made up of disconnected bunches of ore, showing the same change in 
mineral contents in depth as that of the chute just described, but has only 
been explored to the 338-fathom level. In the western part of the mine 
there is another chute of less importance. The section of ground between 
Harriett's and Old Sump shaft,striking E.50deg.X.,is almost barren,and the 
lode here is wrung up between the first and second chutes above described. 
The lode was extremely rich in tin ore above, and on the eastern slope of 
the large " horse " of granite, occurring about the 425-fathom level. (See 
page 139.) Tin ore also occurs in small strings and veins in parts of th» 
" horse " itself. 

In Cook's Kitchen Mine the chute of ore is in the continuation of the 
same lode as that worked upon in Dolcoath, but is here known as the 
Highburrow lode. The chute is made up of connected bimches, and has 
been worked upon from surface to the 4.*i0-fatlu)ni level. The width of the 
bunches varied from to 20 feet ; at the 400-rathom level the lode is 
30 feet wide, and at the 450-fathom level is Wi feet wide. The width of 
the bunches is always greatest where the lode was branched. Further 
east an important chute of ore was shared by both Tincroft and Carn 
Brea Mines. This chute was worked from surface to the 330-fathom 
level. In the eastern part of Cam Brea Mine the lode is split up into 
branches. 

On the south of the Carn Brea granite is situated the Great Flat lode, 
which affords some interesting examples of ore bunches. Thus, at Wheal 
Grenville, the lode underlies 60 deg. S.* (dip 30 deg. S.), and the ore occurs 
chiefly in pipes separated from each other by intervening portions of poor 
lode. Observation shows that this lode undulates very gently in the direc- 
tion of its strike, so that the levels driven along the lode zig-zag slightly 
from left to right. In West Wheal Frances a chute of tin ore was worked 
on the same lode. In West Wheal Basset, between Granville's and Pascoe's 
shaft, there was a chute of tin ore extending to great depth. Part of this 
chute was known as Pascoe's pipe. Further east in the same minn 
Thomas's shaft was sunk through a chute. In Wheal Basset some parts of 
the Great Flat lode are as much as 150 feet wide, but these are at noints 
pf intersection of the bunches of the Great I'lat lode with other lodes, 
resulting in the production of a large body of ore of ellipsoidal shape at 
the jnnetion.| 

In Wheal Uny the tin ore occurs in pipes pitching west, the intervening 
ground being poor. [ 

♦ Foster, p. 640. 

t Information from Captain W. James, manager of Wheal Basset. 
X' R. H. Thomas, *' Some Observations on the Great Flat Lode in Wheal 
Uny." Bejf. Ray. Corn. Poly. Soc, 1886. 

if9 



164 NATUHAL HISTORY OF THE ORES. 

iRREorLAR BuxcHES OR Masse^s. — An abnormal development 
of the lode may form an irregular bunch or mass. In some cases 
ore bodies occur which bear some resemblance to carbonas. The 
carbonas of the St. Ives district have, however, given to this 
term a special meaning. In that region the carbonas are irregular, 
more or less horizontal ** pipes,'' passing into the country rock 
along cracks, making a large angle with the lode. Typically, 
they contain a large amount of schorl. The term '^ Carbona " as 
used in the Camborne district does not appear to have received 
recognition. 

In Wheal Basset the carbonas are impregnations of the country rock in 
the vloinity of small fissures which run ** counter" to the lodes and so 
sometimes connect them. These deposits are somewhat irregular and of a 
soft or ** plumb " nature (decomposed granite). As a rule they are 
uncertain, widening out into a body 6 feet across, or narrowing down 
to a small string in a short distance. The largest occurred at the 113- 
fathom level on the west of Carnkie shaft, and contained from 14 to 28 lbs. 
of black tin per ton of stuff. The veinstone is chlorltic and highly 
ferruginous. The manager of Wheal Basset* considers these bodies to 
be branches from some of the nine or ten more or less vertical lodes which 
traverse the mine. Where these branches cross each other the line of 
intersection contains tin or copper ores, and the pipe-like deposits so 
formed are more or less horizontal. The carbonas occur mainly in the 
neighbourhood of Carnkie shaft. The carbonas on the west of the shaft 
produced mainly copper ores, and those on the east mainly tin ores. Both 
the lodes and carbonas were richest above the l!IO-fathom level. 

In PoLDiCE Mine, in G wen nap, a fissure branched off in a south-westerly 
direction from Singer's tin and copper lode. The body of ore associated 
with it was known as a carbona. 

Balmynhekr Mine (Wendron). -The deposit consists of a large irregular 
mass of stanniferous altered granite. A vein or slide about 6 inches in 
thickness, consisting of white clay and a little quartz and mica, underlies 
N. 60 deg., and bears E. 32 deg. N. Below the slide the irregular mass of 
tin-bearing rock varies in thickness from 30 to 50 feet, and underlies in 
the same direction as the slide. Between this mass and the granite there 
is no regular plane of separation. Occasionally there is some tin ore 
above the slide. This mass, which consists of quartz, chlorite, gilberlite, 
iron pyrite^s, zincblende, and tin ore, and occasionally a little wolfram, 
extends for 30 fathoms along the strike of the slide, the lowest workings 
being at 30 fathoms from surface. \ In 1876, 2,200 tons of tin ore were 
stamped yielding over 1 [)er cent, of black tin per ton. 

Halabezack Farm (Wendron). — There is a vein of clay about 2 feet 
wide which underlies N. 26 deg. A mass of granite about this vein has 
been worked as an open quarry for the tin ore it contains. The breadth of 
the deposit is possibly 20 fathoms. In addition to the tin ore there was 
micaceous iron ore and iron pyrites.^ The produce varied from 10 to 
56 lbs. of black tin per ton of ore. 

South Wendron Mine.— The deposit here is a very irregular cylindroid 
of stanniferous rock, merging gradually on all sides into granite, with its 
axis dipping at 49 deg. from the horizon in a direction N. 25 deg. W. The 
longer axis of the oval section of the pipe varies from 20 to 60 feet in 
length, while the shorter is about 10 feet. The mass consists of quartz, 
mica, gilbertite, a little iron pyrites, and tinstone, and is traversed by a 
few irregular joints ; the stuff is cavernous or honeycombed, and in little 
cavities there are fine acicular crystals of tourmaliue.§ 

* Captain W. James. f Foster, p. 648, 

X Charles Fox, " A Deposit of Tin in Wendron," Miru-ri Assoc. Corn 
and Devon, 1868, p. 47. ' 

§ Foster, p. G50. 



THE ORE BODIES. 



165 



Ix)VELL Mine.— The South lode is traversed by naraerous joints. The 
principal joints dip and strike with the lode. On one or both sides of the 
lode there is an altered band of ** country " rock, 6 to 12 inclies thick, con- 
sisting of quartz, mica, gilbertite, chlorite, iron pyrites, copper pyrites, 
and a little schorl. The lode itself is a dark mixture of quartz, gilbertite, 
mica, zincblende, chlorite, iron pyrites, and a little copper pyrites, fluor- 
spar, and tinstone. When one of the aforementioned joints diverges from 
the lode it carries 'Modey stnff" with it. Tlie North lode, which is very 
** bunchy," is 10 to 15 feet wide, and consists of quartz, gilbertite, some 
iron pyrites, tourmaline, and tinstone.* 

Eaht WiiKAL LovELL (\Vendron).~The main "chute" of ore in this 
mine " is in the shape of a long irregular cylindroid or cylinder with an 
elliptical base generally from 12 to* 15 fe^t long by 7 feet wide." This 
chute has been followed down from the 40-fathom level to the 1 10-f athom 
level as one continuous pipe. There were several other pipes and bunches 
of si miliar character. ** The East Wheal Lovell pipes and bunches resemble 
in their mode of occurrence some of the carbouiis of St. Ives, but differ in 
the absence of tourmaline, which is so very abundant at St. Ives."| 

Pedn an Druv. — A curious deposit of tin ore, called a "carbona," 
occurred in the killas not far from its junction with the granite, at the 
68-fathom level. It consisted of ii mass of small veins penetrating the 
killas. These veins branched oil from a lode 4 fathoms in thickness. The 
mass so formed was 25 fathoms long and 11 fathoms wide, the richest 
portion being in the country rock between the Engine and Martin's lodes. [. 

Whjlvl Vyvian. — The deposit has the ** character of an enormous granitic 
lode, bearing 20 to 30 deg. S. of W.," and dipping N. 40 to 55 deg. 
It is 5 to 10 fathoms wide, or even more in some places, and the composi- 
tion is similar to that of the country rock. ** The whole substance of the 
lode is thinly interspersed with tin ore, copper j)yrites, and also spots of 
iron pyrites,'* &c., but these minerals occurred chiefly in small veins and 
strings running in the same direction as the lode and having a northerly 
underlie. " The joints of the rock seem to coincide with the veins both 
in bearing and dip, and where there are crevices in them their faces are 
commonly coated with fine crystals of tin ore."§ 

Wheal Musrc (St. Agnes). — The lodes which had been worked for many 
years were at length " split up into minute strings and branches, none of 

Fig. 20. — l/fheal Mime. 




which were, Singly, worth pursuit. The whole rock was then removed and 
the copper ores extracted. An excavation of an irregular elliptical form 
of about an acre in area and 25 fathoms in depth " was left.|l (Fig. 20.) 

* Foster, p. 649. 

t C. Le Neve Foster, ** The Tin Deposits of East Wheal Lovell." Tr, 
RM.S, Corn., vol. ix:, 1876- 

t M. H. C. Salmon. Minimj and Snu'ltlay Mcu/azine, vol. ii., 1862, 
p. 143. 

§ Kenwood, p. 72* I Op. eU.,\).^^ 



166 NATUEAL HISTORY OF THE ORiES. 

Chackwateb Tin and Copper Mink — The elvan in Ibis mine is "full 
of small strings of copper ore which cross the elvan at 45 deg." The ore 
does not enter the killas at all. There are also small unconnected beds 
of " red elvan " called " floors *' by the miners, which, although quite dis- 
tinct from the other, are intersected by the copper reins in the same 
manner.* 

Consols Mine (Gwennap).— Near Frances* shaft at the 135-fathom level 
** for more than 25 fathoms in length and 15 fathoms in height, the lode 
was from 8 to 12 feet wide, and full of fragments of copper ore, some of the 
fragments of slate weighing several tons, and occurring, as to the position 
of their lamina?, in all directions.*' ** Many of these masses and smaller 
stones had the appearance of having been washed by a flow of water. 
Above this mixed mass, and in the level above, a great cavity or vug was 
found many fathoms in length and height, from whence it was conjectured 
the fragments beneath had fallen.*' [ 

Wheal Vor, — The lode produced ore in killas, but was richer in elvan. 
The lode was 2 feet wide, but in elvan was 5 feet, and |in some places 
branched into it so as to impregnate the whole elvan and render it profit- 
able for 20 feet in width.j ** Unconnected ** masses of tin ore occurred in 
the elvan as small veins and irregular bodies.§ 

At the 180-fathom level, the lode from being 2 feet wide suddenly 
broadened to 6 feet, and consisted of chloritic products aud tin ore, either 
separately segregated or more or less " mixed.** Wood tin ore occurred 
in scattered grains, in small isolated masses, or in very fine veins, often no 
thicker than paper, but always with the fibrous structure. || 

At Rast Pool Mink there was a somewhat remarkable occurrence at 
the junction of the granite and killas, a position highly favourable for the 
production of irregular deposits. The Engine lode underlies south 13 deg. 
to 27 deg., and strikes the granite at about the 135-fathom level. At this 
place there is a ridge in the granite some 35 fathoms in height, which 
trends in much the same direction as the lode (see page 117). The £ogine 
lode coming down from surface follows down the southern flank of this 
ridge and enters the granite near the foot. On the other flank (northern 
side of the ridge) the Great Wolfram lode, over 12 feet in width, under- 
lying north, emerges from the granite in its upward course and following 
the junction of the granite and killas on the northern flank of the ridge 
bends over it at its apex, and^nally joins the Engine lode. The ore in the 
Wolfram lode, near the junction of the granite and killas, consisted of 
mundic, copper, tin, and wolfram.* A solid branch of wolfram ore 4 feet in 
width was found in the lode below the 140-fathom level. 

Floors. — In the Camborne district the term " Floor " is applied 
to a more or less horizontal roughly-sheeted deposit, branching off 
from the lode into the country rock. Thus, a deposit in a ** bed- 
ding plane " or horizontal crack in the granite would be regarded 
as a floor. The term is loosely applied and refers to the general 
shape of the body, but it is not used for stookwork deposits. 

Phillips regards ** Floors ** or ** Carbonas " as stockwork deposits.** 
The ** tin floors," in the parish of Madron, were made up of small flssures 

or veins containing tin ore, which follow the inclination of the strata and 

appear to be branches from a central body.jt 

• J. Carne, **0n Elvan Coui-ses." Tr. li.O.S., vol. i., 1818, p. 104. 

+ De la Beche d« 324. 

t J. Came, *' On Elvan Courses." T?\ Jf. G.S. Corn., vol. i., 1818, p. 238. 

§ Hen wood, p. 238. 

il W. Arjrall, " On the Occurrence of Wood Tin." Jonm. li^y. Imt, Corn.. 
vol. iv.. 1873, p. 255 

1!" H. C. Salmon. Mining aiid Smelting Magazine^ 1862, p. 385. 

♦* J. A. Phillips and H. Louis, **A Treatise on Ore Deposits," 1896. 
p. 169. 

ft John Hawkins, "On Tin Floori, &c." Tr, RM.S. Com,, vol. ii., 1822, 
p. 36. 



GENESIS OP THE ORES. 167 

In Wheal Vor floors containing tin ore, and of a composition similar to 
that of the lode, branched off from the lode nearly horizontally into the 
killas.* In South Crofty Mine the main lode in the killas, near the junc- 
tion of the granite and killas, branched off into fl<x>rs. The killas was 
greatly disturbed and mineralised. At the 50-fathom level in West 
Roskear Mine, the divisional planes of the adjacent slates were infilled 
with copper pyrites and ranndic, thus forming? floor deposits as branches 
from the main lode. 



IT. Gknesis of thf Ohks. 

The limited number of types of ore deposit in the region 
ander consideration enables the discussion of their genesis to 
be confined to a mode of origin the explanation of which was 
first suggested by Elie de Beaumontf and Daubree.t 

Daubree's results were based largely on experimental researches 
carried out by him in 1849, although the principle was first sug- 
gested by him in 1841. § 

In reference to the tin lodes of Cornwall, the works of the late 
Sir Clement le Neve Foster stand pre-eminent for the examples 
brought forward by him, which have become classic, as illus- 
trating the connection of the tin deposits with lines of greisen 
action ; a fact entirely supported by Mr. J. H. Collins, author of 
many well-known works relating to the geology of Cornwall. 

Although the tin and copper deposits are without doubt con- 
nected with the granite, yet since they occur in fissures, gener- 
ally about the peripheral portions of the granite masses, they 
should not be regarded as being immediately connected with the 
country rock in which they are enclosed. The ores are now sup- 
posed to have originated by " extraction " of metalliferous solu- 
tions emanated during the final phase of consolidation of the acid 
magma from which the granite was formed. The secretion of the 
ores depends upon the principle known as ** raagmatic extraction," 
by which is meant the extraction in solution of metalliferous 
minerals from a still completely fluid or partially consolidated 
magma, by means of other materials which combined with them, 
and may be termed *' carriers." The precise chemical and 
physical phenomena are still only vaguely known, but the ex- 
planations oflFered by Professor Vogt, of Kristiania, form a land- 
mark in the field of ore deposits of the kind here considered, and 
the conclusions arrived at by him are the most satisfactory 
hitherto formed.|| Professor Vogt has clearly stated his views in 
an ingenious argument, in which is shown how tin veins in 
granite may be compared with rutile-apatite veins in gabbro.** 

* Henwood, Tabic xlv 

t **Note sur Ics Emanations Volcanique et MeialUf^res." Bull, de la 
Soc, Geol.de France, 2e Serie, Tome iv., 1846, p. 1^5. 

X " Etude Synthetique de Geologie Experinientale,** 1879, p. 29 

§ ** Memoire sur le Gisenient, la Constitution et I'Origine ties Auias dc 
Minerai d etain. Ann. des Miaes, 3e Serie, Tome xx., 1841, p. 65. 

I J. H. L. VoL't, Znt, f. Praht. Geol., 1894-9.')-98-99. See also Professor 
Kemp's pa[)ei-, **Tlie Role of the Igneous Kocks in the Formation of Veins," 
T)\ Am. Imt, Min, En{/.y 1901, wliich is a recent valuable contribution to 
the science. 

•♦ Op, cit., 1895, pp. 447, 474. 



168 NATURAL HISTOEY OF THE ORES. 

In both cases ihe extraction process is mainly dependent on the 
nature of the compounds formed with halogens present in the 
magma. Both magmas contain phosphoric acid, which forms 
compounds readily soluble in acids, but it is present in larger 
quantity in gabbro than in granite. The metals forming com- 
pounds with the halogens (fluorine and chlorine) are able to pass into 
fissures along with phosphoric and hydrofluosilicic acid. The 
former is characteristic of gabbro, but only accessory in the case 
of granite. Hence rutile with phosphates, possibly a little silica 
and some alkaline earths, are concentrated in fissures mainly 
through the agency of chlorine in the case of gabbro. In 
granite, cassiterite, wolfram and silica, together with a little phos- 
phate and also lithia and potash, are extracted by Uuorine. Each 
rock has its characteristic extraction products ; and possibly they 
existed as dissolved gases, which on relief of pressure at any 
point, as by a fissure in the consolidated crust, were permitted to 
vapourise and escape. It is this assumption that gases and not 
liquids formed the main part of tbe emanations that prompted 
the use of the terms " pneumatolytic " and " fumarole." This 
implies that gas was the principal agent in the secretion of tin 
ores at least. The only difference in the meaning of these words 
is that " pneumatolysis " refers to the action of gases above 
critical temperature (and hence generally of deep-seated origin in 
connection with bulky igneous intrusions), while " fumarole " 
refers to gases considerably below their critical temperature. 

The whole history of the actions which finally resulted in the 
deposition of the metalliferous minerals of the cassiterite veins is 
very complex, but the elements which took part in these opera- 
tions are discovered in the secondary minerals, which commonly 
occur in the altered country rock, in the vicinity of the fissures 
which form parts of the lodes. The minerals of the " tin-copper " 
lodes of Cornwall can be broadly divided into two classes, corre- 
sponding with the minerals of the infilled fissures and those of 
the altered country rock. To the former class belong such 
minerals as cassiterite, wolfram, scheellte, mispickel, copper 
pyrites (and other sulphides), mundic, arsenical pyrites, and 
other metalliferous minerals, together with quartz, apatite, schorl, 
chlorite, fluorspar (occasionally in great quantity), &c. These have 
been introduced into the lodes by gases or solutions traversing 
them. To the second class belong tourmaline, axinite, topaz, garnet, 
and various secondary micas, chlorite, &c. These minerals hkye 
been formed by the action of vapours on the country rock, e.ff., 
tourmaline in granite, and axinite in lime-bearing rock .by addition 
of boric acid ; garnet veins in greenstone by addition of silica 
during metamorphism by granite. To these may also be added 
iron pyriies, which results in many cases from alteration of oxide 
of iron in the country rock by sulphur vapours. 

As a whole, then, the materials brought up in solution were 
composed of the elements — tin, wolfram, arsenic, copper, iron, 
&c., silicon^ chlorine, fluorine, boron, phosphorus, oxygen 
sulphur, hydrogen, and carbon, together with lead, silver, zinc, 
nickel, cobalt, manganese, &c., which, as Vogt points out, may or 



GENESIS OF THE ORES. 169 

may not be present but often are, in small qaantities, charac- 
teristic of cassiterite veins. 

The early history of the metalliferous minerals is intimately 
bound up with the more general petrological problems concern- 
ing rock magmas. In all probability the metallic elements were 
diffused uniformly throughout the magma when it was intruded. 
As the mass cooled the basic materials of the magma crystallised 
out first, while the more siliceous material (which resulted from 
their withdrawal), as crystallisation proceeded, drove out the 
active gases, gradually concentratiug them in a siliceous 
" residual magma." 

It is in the latter that the gases and the metals extracted by 
them are concentrated, but *' so long as they remain in the magma, 
they must be regarded as belonging to it and playing their part 
along with the other constituents in producing the final result."* 
Fluorine, chlorine, boron, phosphorus, and steam are common 
characteristic constituents of granite magmas, and assist in keep- 
ing some of the free silica fluid to a late stage in the history 
of the consolidation, and possibly even decompose the first formed 
minerals, with, for instance, the production of tourmaline from 
ferro-magnesian minerals, &c. In this manner they are concen- 
trated in the fluid part of the consolidating mass and carry with 
them tin, wolfram, and other metals, and in fact it is possible that 
the extraction of these compounds does not take place until the 
magma is actually consolidating. 

The silica or silicic acid combined with fluorine is carried up into 
the veins as SiF^ (silicon fluoride), or bydrofluosilicic acid, from 
which quartz is derived hy decomposition in contact with water. 
Fluorine, and possibly also chlorine in the same way extract 
lithium, potash, &c., which go to form secondary mica. Most of the 
other bases are also attacked in the same way by fluorine, with 
which in all cases steam co-oj^erates powerfully. The reaction in 
the case of tin may be represented by the equation — 

SnF, + ^H.O = SnOz + 4 HF. 

The fluoride of silicon may be supposed to be decomposed in the 
same way. 

In the case of the iron and titanium of basic rocks, each re- 
action is represented by a similar equation in which, instead -of 
fluorine, chlorine is the carrier. 

While tin is a characteristic accessory of granite, it has been 
pointed out long since that copper frequently occurs in cassiterite 
veins, and in Cornwall the association of stanniferous and cupri- 
ferous minerals is so striking that the term ** tin-copper " veins 
applied to the lodes is quite appropriate. They are cassiterite 
veins characterised by the presence of copper sulphide and tour- 
maline.f 



♦ J. J. H. Teall, '• The Evolution of Petrolcgical Idoas." Q,J. G S., 1901, 
vol. Ivii., p. 76. 

t J. H. L. Vogt, *' Zur Clas^ifi cation der Erzvorkoiiiuiun. ' ZeH.f. Vraht. (k'ol, 
1895, p. 152. 



170 NATUEAL HISTORY OF THE ORES. 

The general relations of the deposits of copper to those of tin 
have already been pointed out It will be seen that both are 
associated with minerals derived from the granite. Dalmer has 
shown that in the Erzgebirge, the sulphide zinc and lead deposits 
are^ in common with the tin lodes, connected with the consolida- 
tion of the granite, but while the tin ores were deposited in or 
near the granite, the zinc and lead ores were only deposited at a 
distance from the granite.* 

A similar peculiarity is noticeable in the relations of the tin 
and copper deposits of this region. Dalmer, in reference to the 
Altenberg, supposes that the tin ores were extracted and deposited 
while the interior of the magma was still fluid ; and with regard 
to the position of the deposits in reference to the granite he 
states that the zone-like arrangement cannot be regarded as 
accidental. It seems probable that part at least of the sulpho- 
compounds in the lodes were extracted at the same time as the 
tin, but whether through the action of fluorine or not is uncer- 
tain. In addition to the mineralisers already mentioned, there 
are boric acid, sulphuretted hydrogen, carbon dioxide, &c. The 
part which the boron plays in the extraction of the metals is at 
present unknown. The simplest explanation is that sulphuretted 
hydrogen helped largely in the actual secretion of copper and 
other sulphide ores ; but it is not improbable that fluorine, and 
even boron, had something to do with their extraction from the 
magma. In acid magmas sulphur is not generally present in such 
quantities as in basic magmas. In the later stages of the con- 
solidation of the acid magma the sulphur compounds are driven 
out and play their part in the secretion of copper and ether 
metals. 

The reactions connected with the extraction of cassiterite and 
wolfram to<)k place at high temperature and pressure. Those 
connected with the extraction of copper and the other sulphides 
took place under the same conditions, but the ores continued to 
be deposited in the lodes after the deposition of tin and wolfram 
had practically ceaeed. The connection of the lead and silver 
ores with those of tin and copper is obscure ; but from their 
general distribution and relations to the tin and copper deposits it 
seems probable that some, at least, were derived from the granite 
in a manner similar to, but at a later date than, the copper ores. 
Unlike copper and tin, the ores of lead and silver have not been 
found in lodes in granite, but, on the other hand, the greatest 
lead lodes in Cornwall occur in the killas, and have a strike similar 
to that of the cross-courses of the district in which they occur. 
The minerals so characteristic of the " tin-copper" lodes are gener- 
ally wanting in the "lead-silver" lodes, except in those cases 
where the lead and silver occur in the ordinary cassiterite lodes. 
In the latter the lead and silver is generally accompanied by zinc, 
copper, and cobalt ores, iron pyrites, or mispickel, and carbonates. 
In two instances in the Camborne district lead occurs in cross- 

• « 

* K. Dalmer. "Der Alten1»erg-Graupener Zinnerz lagerstiitten District/' 
Zeit. /. Prakt. Qeol^ 18W, p. 321. 



DISTRIBUTION OF THE ORES. 171 

courses. In one case it is associated with silver, and in the other 
with copper and antimony. The facts point to the conclusion 
that the ores of lead and silver arrived at a late period in the 
history of the lodes, but not so late as in some cases to pre- 
clude their extraction in the later stages of the actions connected 
with the deposition of tin and copper ores. Their deposition con- 
tinued to take place for some time after the processes connected 
with the extraction of tin ore and the bulk of the copper ore had 
ceased. 

The chemico-ph} sical aspect has been worked out by Svante 
Arrhenius,* who shows how metals such as tin, copper, lead, zinc, 
and iron can exist together as sulpho-salts in an aqueous extract, 
while their behaviour is mutually independent of one another. 
In the aqueous extract are also sulphuretted hydrogen, hydro- 
chloric, hydrofluoric, boric and carbonic acid^, and silica. Hence 
it 'appears that at high temperatures the liberation of the active 
compounds of tin and tungsten, &c,, with fluoric and silicic acids 
and copper, &c., takes place ; and it is only at low temperatures 
that the more soluble, less active lead, zinc, &c, compounds are 
liberated, so thfit their deposition as sulphides does not occur until 
a late stage. It is also possible that some of the materials were 
even brought up as solid particles, mechanicaUy suspended in 
water. 

III. Distribution of the Ores. 

The general distribution of the lodes has already been described. 
In this section the general distribution of the ores, together with 
a more detailed statement of their vertical arrangement in the 
lode, will be considered. Between Camborne and Truro the lodes 
and elvans have a similar geological occurrence and geographical 
range. With respect to the granite, the richest mines are those 
situated along the granite margins and in the altered killas 
beyond. It has already been seen, however, that the granite had 
consolidated to a considerable depth, and, indeed, the elvans were 
intruded before mineralisation of the lode fissures began. The peri- 
pberal portions of the granite itself, therefore, were very favourably 
situated for the formation of important ore bodies in it. Speak- 
ing generally, the more important tin deposits of this district 
have occurred within the granite margin, and not infrequently in 
the altered killas beyond, particularly where the lodes are parallel 
to the granite margin. In some instances the chutes of tin extend 
to tK>nsiderable depths in the granite, as for example in Dolcoath 
Mine, where but little tin ore of value was encountered until the 
granite was struck; but after this, for 300 fathoms within the 
granite (down to the ■i90-fathora level), the lode has yielded 
enormous quantities of tin ore. At the bottom of the mine the 
lode is 42 feet in width, and contains 25 lbs. of black tin per 
ton of stuff (r008 per cent.). On the other hand, there are many 
deposits of tin occurring in close proximity to granite but which 

• ** Zur Physik dea V\ilkanLsiiius." (jfcol. ForcnhtfjcfUft 1900, p. Ho. 



172 NATUEAL HISTOEY OF THE OEES. 

are not actually in that rock. That is to say, the lode, although 
passing from the killas into the granite, was only worth working in 
the part enclosed by the killas. In the parish of Breage, for 
instance, there are two mines situated near one another which 
show remarkable and instructive diflFereuces. The lodes of Wheal 
Vor were of enormous value while in the killas, but in granite 
were utterly worthless. Great Work Mine, not far distant from 
Wheal Vor, appears to have been very rich in granite but poor in 
the killas. The great ore chutes of both mines plunge away 
eastwards approximately parallel to the subterranean surface of 
the granite.* 

Similarly, the principal courses of tin ore in Pedn an Drea 
Mine plunged westwards with the granite margin. At the St. 
Day United Mines the ores occurred principally in the killas, but 
near the granite, which here plunges eastwards. The ores of 
copper and tin occurred in a course of ore extending in the 
direction of strike of the lode for over 700 fathoms, from surface 
to the 130-fathom level. Below this, and roughly parallel to it, 
was a course of tin ore which was worked to a depth of 205 fathoms 
below adit. 

In West Poldice and Unity Wood Mines, a course of tin and 
copper ores extends from the granite margin into the killas for 
about 300 fathoms to a depth of 125 fathoms below adit. Similar 
instances are not lacking from other districts, as for instance at 
St. Just, where the richest mines are situated round the granite 
margin. This apparent selection of horizon is brdught out forcibly 
when the case is viewed on a larger scale. Thus, instead of taking 
a single great ore chute, a succession of them may be selected in 
any single series of lodes traversing the district. For example, 
the series of lodes upon which are situated Camborne Yean, DoL- 
coath. Cook's Kitchen, Tincroft, and Cam Brea Mines, have been 
of enormous value for a length of two miles. Some of these 
mines are already exhausted in depth, and under any circum- 
stances it would be improbable that these lodes should be as rich 
for a depth of two miles as they have been for a length of two 
miles in the direction of strike. There appears to be an explana- 
tion for this. The continuation of some of the larger lodes in 
depth is a matter of certainty, but that they will prove as rich at 
great depths within the granite is another question. Supposing 
that at the time the lode was being formed the solutions cpntain- 
ing tin were rising; through the fissure. A little titi ore was 
deposited regularly in the fissure at points from the greatest 
depths reached by the fissure to the higher levels. At any par- 
ticular place, however, say the margin of the granite, the con- 
ditions might have been such that the whole of the tin still 
remaining in solution arriving there was deposited. In fact, it is 
unlikely that the tin could be carried in solution much further, 
owing to the low temperature at the margin of the granite. This 
explanation does not suggest that it is impossible for the tin ore to 
be deposited at great depths, and all it points out is that at certain 

^ * U«nwood, p. 54. 



DISTRIBUTION OF THE ORE^S. 178 

horizoBS, snch for instance as the granite margin, the ore bodies 
of greatest commercial value are hkely to be forotied. With. 
different conditions, such as a greater depth of cooling of the 
gnmite before the arrival of tin, the horizon at which the great 
ore bodies will be formed will also be different. 

There appears to be some analogy to the tin deposits of the 
Alton berg (Erzgebirge). In these deposits the tin ore began to be 
deposited shortly after the intrusion of the granite ; the peripheral 
portions of the granite were scarcely consolidated before Assuring 
commenced. The tin deposits were formed mainly in the over- 
lying rocks or in the portions of the granite which were the first 
to solidify and crack. As the crust grew thicker, Assuring in the 
deeper portions took place less easily, and was not so i*eadily 
accessible by " tin-bearing superheated gases of the magma/'* 

With regard to the copper ores it appears that similar observa- 
tions might apply, with this exception, that the copper ore was 
arriving after the arrival of tin ore had ceased ; and, again, copper 
ores are liable to reconcentration by being dissolved and re- 
deposited. Copper ore as a rule has been more abundant in the 
parts of the lodes in killas than in granite. Thus there are the 
upper portions of the lodes in Dolcoath, Cook's Kitchen ^ &c. ; 
South Crofty, South Roskear, East Pool, &c. ; the United Mines, 
Consolidated Mines, and other places in Gr wen nap, and the lodes 
in Wheal Basset. In all these mines the copper ore occurred 
in great quantities in the killas, but in granite were much poorer. 
There is an important exception in the once magnificent ore chute 
at Tresavean Mine. Tresavean Mine is situated on the margin of 
the granite. The lode has an east and west strike, and is nearly 
vertical. The copper ores occurred from surface in an immense 
chute within, but parallel to, the subterranean surface of the 
granite, which here plunges eastwards below the slates. This 
chute, in the part of the lode in granite from surface to ohe 310- 
fathom level, was of great value, but in the killas the lode was not 
worth working. Trethellan Mine, situated entirely in the granite 
on the west of Tresavean Mine, worked the upper part of this 
chate. Treviskey Mine, situated in killas on the east of Tresavean 
Mine, did not strike the chute except at great depths. 

Certain areas, on account of the ores for which they were par- 
ticularly celebrated, have come to be regarded as tin districts or 
copper districts. Thus Gwennap fs regarded as a copper district ; 
Wendron and Porkellis as tin districts ; Camborne and Redruth 
as tin and copper districts. Broadly speaking, the districts 
situated entirely in the granite have produced mainly tin ore ; 
those entirely in killas mainly copper ore ; and the marginal areas 
have, as far as this district is concerned, yielded both tin and 
copper ores. 

In describing the general distribution of the ores it is convenient 
to speak of them in their relation to the granite masses. The less 
common ores will be treated of elsewhere. (See Fig. 1.) 

* KarlDalmer, " Altenberg-G raupener Zinnerz Lagerstiitten." Zflt.f, Praht. 
Otol, 1894, p. 317. 



174 NATFRAt HISTORY OF THE ORES. 

Oahn Brea GrRANiTE Regiqn. — The richest ore deposits of the 
whole district under consideration, and indeed of the whole of 
Cornwall, occur on the northern margin of the Cam Brea granite. 
The lodes near the granite boundary enter the granite in depth, 
and from yielding large quantities of copper in the upper levels 
became exceedingly rich in tin ore in the underlying granite. 
The deposits in the lodes to the north have similar characteristics, 
but the granite was struck at greater depths in these mines, which 
are now yielding considerable quantities of tin ore. Further north 
8tiil, the deposits contained bat little tin, while they have yielded 
considerably less copper than those nearer the granite, and they 
have not been explored to the same extent. Along the southern 
margin of the Cam Brea granite, and in the strip of country repre- 
sented by the killas occurring between the Cam Brea and Carn- 
menellis granite masses, the district has been of enormoas value, 
and, like the district on the northern margin of the granite, con- 
tinues to yield tin ore. These deposits occur in lode^ outcropping 
in the killas situated In a shallow trough-shaped hollow in the 
granite which deepens as it goes eastwards to Wheal Basset. 
Copper occurred in the upper parts of the lodes, but was particu- 
larly plentiful in Wheal Basset and the neighbouring mines. 

Carx Marth Granite Region. — The Cam Marth granite is 
situated in the heart of the great mining area. In the middle of 
this mass the mines worked chiefly for copper, but not to great 
depths. Lodes containing tin also occur. In the killas on the 
north of the Cam Marth granite there is an important mining 
district now idle which yielded both tin and copper ores. The 
lodes in which the deposits occur may be regarded as the eastward 
continuation of the lodes on the north of the Carn Brea granite. 
This great mineral belt is over a mile across, and from Gilbert's 
Coombe to Wheal Daniell its length is over 3 miles. On the 
western margin of the Carn Marth granite the most important 
mine was Pedn an Drea (near Redruth Station), which yielded 
both tin and copper orea On the eastern margin the mines con- 
tained both tin and copper ores, but they were particularly noted 
for their wealth of copper. The districts eastwards are those of 
St Day and Gwennap. The St. Day district yielded both tin and 
copper ores. The Gwennap district, situated in killas, is famous 
for the copper ores it has yielded. Eastwards from Gwennap 
towards Baldhu and Newbridge the mines have yielded both tin 
and copper ores, but tin was proportionately more abundant than 
copper. 

Carnmenellis Granite Region. — No deposits of importance 
occur on the eastern margin of the Carnmenellis granite. On the 
northern margin Tresavean Mine has yieldedT great quantities of 
copper ore and but little tin. From Tresavean Mine, westwards, 
along the margin of the granite as far as Wheal Buller and Basset, 
the mines produced both tin and copper ores. Westwards, between 
the Carn Brea and Carnmenellis granites, is the important mining 
district referred to under Carn Brea. On the western margin of 
the granite there are some important mines near Crowan^ and on 
the south. Crenver and Wheal Abraham, which is a mine situated 



DISTRIBUTION OF THE ORES. 17.5 

in the killas west of Crowan Church town, yielded tin and copper 
ores, but chiefly the latter. On the south of Crowan Church town 
there are some tin mines from Polcrebo Downs to Prospidnick, 
situated along the granite margin. Finally, from the margin of 
the granite near Wendron into the interior of the granite mass, 
there is quite an extensive tin mining area, in which tin ores with 
occasionally other minerals such as copper, zinc, &c., occur on the 
east of Coverack Bridge, near Laity, Porkellis Moor, Garlidna, and 
Halabezack. 

In the south-east corner of the map there is part of the mining 
district of the parish of Breage. In this district Wheal Vor and 
other important mines yielded tin ore to great depths and but 
little copper. 

The group of mines on the north of this district, near Perth 
Towan,have yielded mainly copper ores, and belong to the mineral 
district extending northwards towards St. Agnes Head and Cligger 
Head, which at St. Agnes has yielded such immense quantities of 
tin ore. 

DoLCOATii AND Cook's Kitcuen DISTRICT. — The following 
account is a more detailed description of the geological position of 
the ores in the lodes in a few selected cases : — 

In the Doleoath and C(K>k's Kitchen series of lodes, situated near the 
northern margin of the Cam Brea granite, the granite is encountered 
below the slate at various dei)ths in the different mines. At Stray Park 
(the western end of Doleoath Mine) the granit*' was encountered in sinking 
on the main lode at about 250 fathoms from surface. ?]astwards, from 
Stray Park shaft to Dunkin's shaft, the granite rises to from 250 fathoms 
to 215 fathoms from surface, and at the eastern end of the Doleoath sett is 
roughly about 30 fathoms from surface. In Cook's Kitchen Mine the 
granite was struck at about 1)0 fathoms from surface ; in Tincroft Mine at 
about the 105 ; and in Cam Brea at about 135 fathoms from surface.* At 
the western end of Doleoath Mine (inStra^- Park), coi)i)er ores occurred in 
the lode from surface to about 230 fathoms ]>elow surface, or to within 
20 fathoms of the granite. At Dunkin's sl»aft (Doleoath) copper ores 
occurred in the lodes from near the surface to about 215 fathoms below 
surface ; that is to say, the lodes yielded copper from surface to the junction 
of the killas and granite. At the eastern end of the same mine, copper ore 
occurred to about the same depth, but here the coi>per is at a depth of 
185 fathoms within the granite. In depth copi)er ore is entirely absent. 
In Cook's Kitchen Mine the copper ore occurred from surface to 185 
fathoms below surface, or 95 fathoms in the granite, but it continued to 
occur in less quantity to a depth of 345 fat bonis below surface, or 245 
fathoms below the junction of the granite and killas. In Tincroft Mine 
copper ores occurred to a depth of 175 fathoms from surface, or 70 fathoms 
in the granite. In Cam Brea Mint^ the copper ores occurred from near 
surface to a depth of 160 fathoms, or 25 fathoms in the granite, but some 
lodes yielded copper ores to a depth of 221 fathoms below surface, or 90 
fathoms below the granite and killas junction. In Wheal Druid there 
was not much copi)er below a depth of 95 fathoms from surface, but it 
continued to occur in small quantities to 140 fathoms from surface. 
The position of the tin ore in this series of mines is ns follows : — 
In Stray Park (Doleoath) tin ore commenced to occur in quantity at a 
depth of 224 fathoms from surface, and the lode continued to yield tin ore 
to a depth of 380 fathoms ; thus tlie lode yielded tin ore from 25 fathoms 
above the granite surface to 130 fathoms below. In the eastern part of 
Doleoath Mine the great ore chute commenced to yield tin ore at a depth 
of 170 fathoms below surface, and has continued to yield tin to a depth of 
about 510 fathoms below surface, or about 320 fathoms in the granite. At 

* These figures are approximate only. 



176 NATTTKAL HISTOHY OF THE ORES. 

this depth tho lodo is of wide low-grado stuflf containing very fine-grained 
tin ore. 

In C(>ok*8 Kitchen Mine the distribution of the ores was more irregular, 
but the greatest amount of tin ore commenced to make its appearance in 
the lode at a depth of about 200 fathoms below surface, and the lode con- 
tinued to yield tin ore to a depth of 455 fathoms from surface, or from 110 
fathoms below the junction of the granite and killasto .*i65 fathoms below. In 
Tincroft and Cam Brea Mines tho tin ore occurred from surface, where it 
was worked in olden times,* to a depth of 415 fathoms below surface, or 
from about 120 fathoms above the granite to about 280 fathoms within the 
granite. Tin ore did not occur in great quantity above a depth of 80 
fathoms below surface. 

Greneralisiog the facts coDcerning this range of mines it will be 
seen that the copper ores occur in abundance from near the sur- 
face to depths varying from 160 to 345 fathoms below surface; 
or, stating this in another way, they occur from surface down to 
the granite, and passing into the granite may continue to occur 
for distances of from 25 to 170 or even to 245 fathoms below the 
junction of the granite and killas. Tin ore, on the other hand, did 
not generally occur in abundance near the surface, and as a rule 
the lodes did not yield much tin ore until they were worked in 
granite. A.fter striking the granite the tin ore occurred in the 
lodes to the deepest points attained in mining. 

In sinking through the lodes copper ores are first encountered ; 
then comes a very ill-defined, discontinuous zone in which both 
tin and copper ores may be profitable, and, finally, in depth, only 
tin ore occurs. 

Mispickel or arsenical pyrites occurred chiefly in the upper 
workings, but is not absent from the lode in depth. 

The silver ores of Dolcoath were all raised from the Silver lode 
above a depth of 100 fathoms. In this lode arseniate of cobalt 
and copper ores also occurred.t Some of the Dolcoath tin ore 
contains cobalt in quantities up to '5 per cent.t Pitchblende and 
bismuth occur in the same mine.§ Wolfram and pitchblende occur 
in one of the lodes of Tincroft Mine.|| 

District North of Dolcoath and Cook's Kitchen. — The 
series of lodes situated on the north of the Dolcoath — Cook's 
Kitchen series, may be dealt with in a similar manner. 

This group of lodes has been worked by the following mines : — North 
and South Roskear, Wheal Knight and North Crofty, South Crofty 
(including the old Longclose Mine, Dudnance and Penhcllick), East Pool, 
Wheal Agar, and Wheal Tehidy. The granite was never struck in depth 
in North or South Roskear or in Wheal Tehidy. 

In South Crofty the granite was first met with at a depth of about 
140 fathoms, but westwards it was not encountered. In East Pool the 
granite was met with at a depth of from 135 to 150 fathoms from surface. 
In Wheal Agar it is a little nearer the surface, while in Wheal Tehidy it 
may be about 120 fathoms below surface. 

In North and South Roskear Mines the copper ores appear to have been 
particularly abundant from tho upper levels down to about 180 fathoms 
from surface, but they continued to occur to 285 fathoms from the surface. 

♦ Hen wood, p. 205. f Carne, p. 105. 

+ R. Pearce, *' Note on the Occurrence of Cobalt in connection with Tin 
Ore." Journ.Roy, Inst. Corn,, vol. iv., 1872. 

§ R. Pearce. »* Note on Pitchblende." Tr. IIM.S, Com,, vol. ix., 1864 
II Carne, p. 104. ' 



DIOTBIBUTION OF THE ORES. 177 

Zineblende and galena oeenrred in some quantity in the upper levels. 
Anenieal pyrites was abundant in South Roskear between the depths of 
100 and 182 fathoms below surface. 

l^n ore occurred in the upper parts of the lodes at the western end of 
these setts (particularly in North Roskear) associated with lead, zinc, and 
copper ores. It was first met with in any quantity at depths from 100 to 
150 fathoms below surface, and was of some value to the bottom of the 
mine. In Wheal Crofty (Wheal Knight) the lodes contained copper, zinc, 
and lead ores above a de])th of 100 fathoms from surface. 

In the two mines North and East Wheal Crofty (part of South Crofty) 
the copper ores appear to have ceased to be of great value below a depth 
of 130 fathoms from surface, but they continued to occur in smaller quantity 
to greater depths, where they were accompanied by tin ore. In Kast Crofty 
(part of South Crofty) zinc occurred in Reeves' lode at a depth of 140 
fkthoms from surface. In South Crofty copper ores and mispickel occurred 
in quantity from near the surface down to 140 or 150 fathoms from surface, 
or6om surface down to the killas and granite junction, and a little way in 
the granite. Copper ores are not of much value below this. Zinc occurred 
in this mine below adit level. Tin ore was first met with in quantity at 
about 80 fathoms from surface, or 60 fathoms above the granite and killas 
Junction ; but it continues to occur down to the deep levels, well within 
the granite. 

In East Pool Mine copper ores occurred in quautity in the lodes from 
near the surface to about 166 fathoms below surface, or to about 30 
fathoms in the granite. Tin ore appears to have been of value from a 
depth of about 90 fathoms from surface to the bottom of the mine, but 
in Wheal Agar, at least, the outcrops of the lodes were worked by the old 
miners presumably for tin ore. Wolfram occurred in quantity frt^m a depth 
of 146 to 196 fathoms from surface, or from about the junction of the granite 
and killas to about 40 to 55 fathoms in the granite, and continued to occur 
down to near the 300-fathom level in quantities sufiicient to warrant the 
erection of a magnetic separator able to treat 10 tons of concentrates a 
day for the separation of wolfram and tin ores. Silver, nickel, cobalt, and 
arsenic also occur in this mine. In Wheal Tehidy, tin, copper, and zinc 
ores occur. 

Generalising these facts, it may be said that in this series of 
lodes the upper parts were copper bearing, and where granite was 
encountered the lodes continued to yield copper ores for some 
distance in it. In depth the lodes are tin bearing. Wolfram 
occurs in large crystalline masses with quartz and arsenical pyrites, 
principally in the granite near the junction of the granite and 
killas. 

District Occupied by the ** Great Flat " Lode. — ^The Great 
Flat lode and the nearly vertical lodes which intersect it form an 
important series extending from South Condurrow to Wheal Uny. 

The Great Flat lode crops out along the southern margin of the Cam 
Brea granite. Between South Condurrow Mine and West Wheal Basset it 
is practically wholly enclosed iu granite, but on the east of the latter it 
strikes out of the granite, and for the rest of its course eastwards through 
Wheal Uny it lies near and parallel to the junction of the granite and 
killas. The Great Flat lode has been principally wrought for tin ore from 
surface to a depth of over 300 fathoms in the granite. The other (more or 
less vertical) lodes which intersect and heave the Great Fiat contain 
principally copper ores* but tin ore is also present in them, as for instance 
in the case of the Middle lode at South Condurrow Mine, where tin ore 
occurred in payable quantity near adit level, which is 50 fathoms above the 
line of intersection of the Middle and Great Flat lodes. The lodes in 
South Wheal Frances also contained tin ore in the upper levels. Several 
of the lodes in West Wheal Basset also produced both tin and copper ores.* 

♦ J. Maynard, ** Remarks on Two Cross Sections." Rep, Oorn. Poly. Soc, 
1871, p* 202. 

N 



178 NATURAL lUSTOEY OF THE OEES. 

Copper ores occurred in all the lodes of this series. At South Ck>ndurrow 
there is a little copper ore and native copper in the upper levels of the 
Great Flat lode. In going eastwards all the lodes became richer in copper 
ores. At South CarnBrea Mine and Wheal Uny copper ores occurr^ in 
the upper part of the Great Flat lode.* In Wheal Uny it continued to occur 
with tin ores to a depth of over 220 fathoms from surface. Only recently 
in Wheal Basset about 10 tons of grey copper ore have been broken from 
the Great Flat lode at a depth of over 250 fathoms from surface, and in this 
mine it is no uncommon thing to find copper ores at this depth in small 
quantities. The other lodes in Wheal Basset yielded immense quantities 
of copper ores to a depth of 150 fathoms from surface, but below this were 
poor. 

Throughout this range of mines the upper part of the Great Flat lode 
contained copper ores, but to greater depths and in much larger quantity 
eastwards, where it is near the junction of the granite and killas» than on 
the west, where it is almost wholly in granite. This lode contains mainly 
tin ores. The other lodes contain chiefly copper ores, and in these they 
were particularly rich in the neighbourhood of Wheal Basset. 

Q-WENNAP District. — In the Gwennap district an important 
group of lodes extends from the United Mines to Wheal Jane. In 
none of its mines has granite been encountered in depth. From 
the United Mines to Nangiles the lodes yielded immense quanti- 
ties of copper ores down to considerable depths. Eastwards, tin ore 
is more abundant than copper. Hence in proceeding along this 
series of lodes from west to east the copper ores gradually become 
less abundant, while the tin ore, although not very abundant, 
becomes of greater importance. Zinc occurs in the lodes from 
Nangiles to Wheal Jane but not in great quantity. West Wheal 
Jane has only been explored to the 70-fathom level. 

Distribution of the Subordinate Ores. — ^The following occurrence 
of less common ores illustrates their distribution : — 

SiLVSB AND Lead Obeb. — See ''Distribution of the Silver and Lead 
Ores," p. 181. 

Wolfram. — At Balmynheer Mine (in the parish of Wendron) wolfram 
occurs in association with zincblende, tin ore, iron pyrites, &c.| Wolfram 
also occurred in Wheal Druid (eastern part of Carn Brea Mine).:}^ In Cam 
Brea Mine with copper pyrites and mispickel. 

Several tons of wolfram have recently been taken from the North Tin- 
croft lode in Tincroft Mine.§ The occurrence of wolfram in East Pool 
Mine has been referred to above. Some of the wolfram in this mine is 
traversed by strings of copper pyrites ; wolfram ochre also occurred. 
Wolfram also occurred in Wheal Harmony |{ (on the north of Redruth) 
and in Poldice^ and in the main lode at Wheal Busy, where it is associated 
with tin, copper, and arsenical ores. It occurs at Penzilly, in Breage, mixed 
with manganese. Wolfram ochre occurs in Wheal Friendship (Gwennap) 
and Poldice.** 

ZiNa — Although occurring in small quantities, this ore has a compara- 
tively wide distribution throughout the area, and is associated particularly 
with ores of copper, lead, &c. It occurs in Binner Downs Mine, Wheal 
Crofty, Camborne Vcan, South Crofty, Wheal Falmouth, Wheal Andrew, 
North Roskear, Wheal Towan, Trevaskus, United Mines,] f Wheal Ann,:(}: 

♦ Foster, p. 641. t Op. cit, p. 641. 

t Garby. Tr. B. O.S. Com,, vol. vi,, 1846, p. 84. 

§ Information from J, Penhall, manager of Carn Crea and Tincroft Mines. 

II J, Garby. Tr. IIM,S, Com,, vol, vi., 1846. 
IT Came, p. 94. ** Klaproth, p. 31. 

t+ Henwood, Tables, xxxix., Iv^ xlix.| Ivi., Ixvii., Ixi., Ixxiii., xxxv. 
^ Thomas, p. 60. 



DI8TBIfiUnON OF THE ORES. 179 

Wheftl Ann* Mariay Swanpool,^ Wheal Julia,* Wheal Lovell, Balmynheer,' 
Nangilesp^ TrethellaD,^ Violet SetoD,< Great Wheal Vor (associated with 
copper pyrites),^ North Downs,** Tresavean, Wheal Briggan." The Crane 
Mine» Wheal and South Wheal Ellen, Wheal Emily Henrietta, Wheal 
Music, South and West Wheal Seton, Wheal Tehidy, West Koskear, Wheal 
Jane, GkwnhaTern, and in Wheal Jewel, where it is associated with copper 
and arsenical pyrites. 

Bismuth. — Native bismuth and bismuth sulphide occur with cobalt ores 
in Dolooath, Herland Mine, and in Wheal SparnoD (in a cross-course).^^ Bis- 
muth occurred in **Mr. Beauchamp*s Mine,*' Gwennap.^^ 

Antimony. — Antimony was found in cross-courses with cobalt ores and 
iron pyrites in Wheal Falmouth, Herland, and Vor.^^ Antimony is said to 
have been found at Carclew in Mylor," where remains of ancient mine 
workings were seen by Mr. Hill. 

Nickel.— In East Pool nickel ore occurred with cobalt ore.** In South 
Tresavean Minekupfernickel occurred with uranium, silver and lead ores.^^ 
Sulphide of nickel occurred at Wheal Sparnon ;^^ and at Hoskrow United 
Mines (near Ponsanooth) nickel was found with silver, copper and uranium 
ores and sulphide of iron. In lloskrow United Mines granite is said to 
occur at 70 fathoms below adit level. 

Cobalt. — Arseniate of cobalt occurred in a lode containing copper in 
Dolcoath ; it is associated with grey and native silver ore. At Wheal 
Sparnon, cobalt and arsenic occur in a cross-course.*^ Cobalt ores occur at 
Wheal Unity" and East PooP^' (see under " Antimony "). 

Mamoanese.— Wad and other manganese ores occurred in Pedn an Drea 
Mine, Wheal Tolgus, and Wheal Buckets" (near Wheal Sparnon). Man- 
ganese also occurred in Wheal Ellen. Grey oxide of nmngaiiese has been 
found at Veryan.^ 

Uranium.— Pitchblende was found in Tresavean Mine and atlioskrow 
United Mines (see under ** Nickel "). At South Trosavean Mine pitch- 
blende was accompanied by kupfernickel, silver, aud lead. The pitchblende 
of Wheal Buller and Carharrack is said to have been phosphorescent, 
Uranite also was found in the mines at Ting Tang, Tolcarne, Wheal 
Gorland, Wheal Unity, Tincroft, Wheal Buller, and Pedn an Drea. Com- 
pounds of uranium with phosphorus and copper occurred in South Wheal 
Basset. Uranium ochre occurred at Carharrack and in Wheal Buller. Pitch- 
blende was found in Ting Tang and Tolcarn Mines." Phillips states that 
oxide of uranium and pitchblende was found at 30 fathoms from surface in 
Tolcarn Mine.^ Uranium ores occurred in Tincroft Mine with wolfram 



* F. J. Stephens, ** On Recent Discoveries of Gold." Tr, R,G,8. Com. 1899.. 

* De la Beche, p. 340. ' Foster, p. 641. *• Came. p. 95. 

• J. Garby. Tr. 11.G8. Corn., 1847. p. 92. 

• Brenton Symons. ** A Sketch of the Geoloj^ of Cornwall," 1884. 
' R. H. Sollv. Min. Mag., vol. ix.. 1891, p. 208. 

Pryce. Min. Comub., 1778, p. 136. 




Kenwood, p. 271. 

*' Courtney, " A Treatise on the Statistics of Cornwall." 6M Ann, Hep, Hoy 
Corn,Polt/t.8oc,,lS3S, 

" Brenton Symons. " A Sketch of the Geology of Cornwall," J 884, p. 128. 

"R.JPearce, "Note on Pitchblende." Tr. liM.8. Com., vol. ix., 1864, 
p. 102. 

»• J. Garby. Tr. E.G. 8. Com., vol. vi., 1846. p, 87. 

" Came, pp. 105, 113. 

^■* J Garby. Tr ii. 6^.8. Torw., 1846, vol. vi., p 87. 

'• Brenton Symons. ** A Sketch of tlie Geology of Cornwall, g 1884. 

^ J. Garby, Tr. It.G.S. C<>rn., vol. \\i., 1847, p. 85. 

" J. Garby. Ov. cit., p. 84. " J. Garby. Op. cit., p. 86. 

" ** On the Oxidesof Uranium," Tr. Qeo. Soc, 1816, vol. iii., p^ 112. 

N 2 



180 NATUBAL HISTOEY OF THE OEES. 

and copper.^ At Dolcoath pitchblende occurred with bismuth and cobalt 
ores and fluorspar.' Uranite (phosphate of uranium and lime) occurred in 
West Wheal Basset, Uranium ore with arsenical and cobalt ores were 
found in Herland Mine' (Gwlnear). Pitchblende occurs at Wheal Basset, 
Wheal Unity, Wheal Gorland, and Tincroft. Its occurrence at East 
Wheal Lovell has been remarked by Mr. Cunnack.^ 

Gold. — Although no deposits containing gold in quantity sufficient to 
warrant their being worked have been found in the district, its occurrence 
has been recorded in several places. Its frequent presence as traces in 
pyrites, &c., accounts for its having been found in the gossans of the lodes 
of several mines. The gossan of one of the lodes in Naiigiios is said to be 
auriferous,' while some gossan from Wheal Gorland when assayed by Cap- 
tain Uambley was found to contain 6 dwts. of gold and 2 dwts. of silver per 
ton and also 15'5 per cent, wolfram.^ Gold was detected in a silver-lead 
lode at Swanpool Mine and in a lode containing blende and argentiferous 
galena at Wheal Clinton.^ Gold was found on a burrow and in a cross-course 
at WJieal Sparnon'*; it also occurs in Woolfs cross-course (Breage).'* 
According to Mr. Collins gold is also found in traces in copper ores and also 
in ores of tin, lead, and zinc. Gold has been obtained in greater quantity 
in alluvial deposits, and Borlase states that nuggets have often been found 
in tin stream works, particularly those of the parishes of Probus, Kenwyn, 
St. Stephen, &c. Restronguet Creek^^ and Carnon Valley have yielded 
nuggets of considerable size, one weighing nearly 2 ozs. The district near 
Grampound was particularly celebrated for the gold found in the alluvial 
tin, the miners preserving the gold dust in quills.^^ Carew says that 
** Tinners do also And little hopps of gold amongst their ore which they 
keep in quills and sell to the goldsmiths oftentimes with no better gain than 
Glaucus exchange."" Mr. Stephens makes the following remarks with 
regard to the presence of gold in this region.^' On the Roscarrack estate, 
near Falmouth, there is in an old quarry a quartz reef associated with a 
black siliceous rock. The reef contains pyrites, galena, and blende, which on 
assay yielded gold, and in some cases over 1 oz. to the ton was found. 

In the Red River Valley near Gwithian a siliceous schistose rock is 
traversed by two sets of joints. The joints contain dusty oxide of manganese 
which was found to contain gold. At the north cliffs, near Camborne, quartz 
occurs in large lenticular masses with '* green and decomposed chlorite.*' 
Some of the quartz is drusy. '* Occasionally pure gold can be seen," while 
assays revealed as much as 1 oz. of gold to the ton. Mr. Stephens also 
states that gold has been detected in raised beaches. Thus at Godrevy 
gold was found in a black part of the raised beach, which contained in 
addition to ^ dwt. of gold per ton, 13 per cent, of oxide of manganese. 
Raised- beaches at Falmouth and Gerrans Bay are stated to have yielded 
on assay similar results. 

1 Carne, p. 104. 

» R. Pearc«, "Note on Pitchblende in Cornwall," Tr. ll,Q.S. Cam. ^ vol, ix., 
1878, p. 103. 

' Dr. Berger, " On the Physical Structure of Devonshire and Cornwall.*' 
Tr. QeoU 8oe., vol. i., 1811, p. 170. 

* Discussion on Foster's paper, '* New Mineral Localities.*' Min* Mag, , 1877, 
No. 3. 
« J. Garby,1848, vol. vii. Tr. 11.0,8. Com. p. 90. 

« F. J. Stephens, "Recent Discoveries of Gold in West Cornwall" Tr. RQ.8. 
Coim,, 1899. 

■^ Op cit. 

8 J. Garby, " Notice of the Occurrence of Gold in a Cross-Course/' Tr. R.Q.8 
Com., vol. vi., 1846, p. 265. 

» J. H. Collins, ''Precious Metals in the West of England." Joym. Roy, Inst. 
Corn.,yo\. xvL, part i., 1904, p. 103. 

^° W. Kenwood, " On Detrital Tin Ore of Cornwall." ./<mr?i. Itoi/. Inst Com , 
1874. p. 191. 

" Borlase, p. 213. " Survey of Cornwall, 1811, first published in 1602. 
" F. J. Stephens, " Recent Discoveries of Gold," Tr. R, 0.8. Com., 1899. 



DISTRIBUTION OF THE LEAD AND SILVER ORES. 181 

Mr. Ck)lliiis* notes Mr. Hamblev*s statement that gold was found in the 
West Wheal Tolgus lode in 1854.f Samples of ore from Wheal Jane, West 
Wheal Jane, and Wheal Tremayne are also said to have yielded on extraction 
by amalgamation over 2 ozs. of gold per ton. 

Distribution of the Lead and Silver Ores. — In the Camborne 
and G-wennap district it was noticed that the tin and copper 
lodes of the richest area were more or less suddenly terminated by 
a line of lodes extending from the United Mines to Wheal Jane, 
on the south of which no lodes of importance appear. On the 
eastern margin of the Carnmenellis granite no lodes of importance 
occur on the south of the Tresavean lodes ; and in the Camborne 
area lodes are absent on the south of the series of lodes that occupy 
the tract between the Garn Brea and Carnmenellis granites. Pro- 
ceeding westwards, it is not until the parish of Gwinear is reached, 
or the western margin of the Carnmenellis granite is followed south- 
wards, that any lodes of importance again appear. 

These observations apply equally well to the distribution of the 
lead-silver as to the tin-copper lodes, with this modification, that 
in proceeding northwards from the G wen nap district towards 
Newlyn the lead-silver lodes become of ever-increasing importance. 
Silver and lead ores occur in a number of the ordinary east and 
west lodes, as follows ; — 

At Dolcoath a nearly vertical lode, having a bearing similar to that of 
the Dolcoath main lode, yielded in the year 1810 from ^62,000 to -63,000 
worth of silver ore at about the 160-fathom level.J This lode contained 
copper and cobalt. Silver ores occurred in East Pool,§ and argentiferous 
arsenical iron occurred at Wheal Mary (Redruth) with cobalt ores.|l At 
Wheal Falmouth, lead, zinc, and copper occurred in a lode bearing 
E.40 deg. N.^|[ At Swanpool Mine,*Dear Falmouth, lead, tin, and copper occur 
in a lode striking E. 28 deg. N. At Wheal Clinton, near Trefusis Point, 
Falmouth, a little argentiferous lead ore was raised.** 

The Crane lode in the Crane and Bejawsa Mine, Camborne, contained 
lead, copper, zinc, and iron pyrites. Similarly, in the South Wheal Seton 
Jdine the North lode, at the 60-fa thorn level yielded zinc, copper, and lead; 
and in North Wheal Seton lead and copper occurred. In West Koskear lead, 
zinc, and copper occurred in a lode bearing E. 10 deg.N., and in a Caunter 
lode of the same mine lead, zinc, copper, and tin and some iron pyrites were 
present. In North Wheal Busy lead and tin occurred in the same lode, and 
also in North Wheal Jane, where zinc was also present. In Roskrow United 
Mines, near Ponsanooth, silver, nickel, uranium, and iron occurred. At 
Wheal Baddem, near Bissoe, a lode yielded galena while in elvan but was 
unproductive in the killas.jt 

At West Wheal Towan a lode containing lead, tin, and some iron pyrites, 
intersects the Tye lode. At South Wheal Ellen (Old Wheal Basset), zinc, 
copper, and lead occurred. In Wheal Crofty lead, zinc, and copper occurred 
in the Caunter lode.^ [ Mr. Collins states tliat 235 tons of silver ore were 

• "Precious Metals in the West of England." Journ. Hoy. ItisI, Corn., vol. 
xvi., parti., 1904, p. 103. 

t Jiep. IL Corn. Polyt. Soc, 1897, p. 100. 

t J. Came, '*0n the Discovery of Silver.'* Tr n.O.S. Com., 1818, vol. i. 

§ Brenton Symons, ** A Sketch of the Geology of Cornwall," 1884. 

II J. Garby, ** A Catalogue of Minerals found in Cornwall." Tr. R.O, Soc, 
Com., vol. vii., 1848, p. 82. 

H Henwood, Table Ixvii. 

** Information obtained through the kindness of Mr. D. K.Crawfurth Smith, 
of the Woods and Forests Office, from a Report by Warington Smyth, dated 
1857. 

tt A. K. Barnet, " On Elvan Courses." Hoy. Poly. Soc. Corn., 1873, p. 17. 

Ji^Henwootl, Table Ivi. 



182 NATUBAL HISTORY OF THE OEES. 

raised from North Dolcoath in 1859-1860, and that in 1827 small qnantities 
of silver ore were raised from Treskerby and North Downs ; and in 1878 
from Treleigh Consols.* Several of the mines in Uie Owinear district as, 
for instance, Wheal Brook, Wheal Herland, and also Trevaskus and Dinner 
Downs Mines, yielded silver ores. At Tresavean,f Silver Hill, and the New 
Barra Burra Mine, lead and copper occurred. At South Tresavean Mine 
native silver and galena with tin ore and kupfer nickel occurred4 Silver 
and copper ores occur in Trumpet Consols Mine, Wendron.§ Galena 
occurred with copper and arsenical pyrites at Poldory.|| 

The lead and silver ores sometimes occur in cross-courses as follows : — 
In Wheal Basset a cross-course contains silver and lead, as also at Gwamick 
(the Oarras) on the north of Truro,^ and at Silverwell. In 1720 the Garras 
Mine yielded lead ore which contained 100 ozs. of silver per ton of lead.'*'* 
, There is a North and South lead lode in Wheal Falmouth. 



rv. Order of Arrival of the Ores. 

The granite had consolidated and the elvans were intnided 
before the lode fissures were impregnated with metalliferoas 
minerals. Assuming that the ores and their characteristic mineral 
accompaniments were extracted from an igneous magma^ the ores 
must be regarded as being later products of the same magma 
which gave rise to the elvans^ the elvans in their turn being 
intimately related to the granite. 

Many of the silver-lead ores were being deposited after the arrival 
of tin and copper ores had ceased, yet from their frequent associa- 
tion with the ores of tin and copper it is difficult to assign other 
than a common mode of origin to both classes of ores. The 
question of the order of deposition of minerals in the lodes is not 
quite the same as their order of arrival. The occurrence of cx>pper 
pyrites moulded on cassiterite is not absolute proof that cassiterite 
arrived at that place before copper ore, and there appears to be 
some grounds for the view that the oxidic and sulphidic minerals 
are practically contemporaneous. 

Joseph Came, in 1822, collected a number of facts which 
appeared to indicate that a classification of the lodes into distinct 
epochs of formation was possible. The objections to his method 
of dealing with the lodes, brilliant as it was for his time, have 
already been pointed out ; but Came established the general fact 
that tin ores were deposited before copper ores, and that the latter 
continued to arrive after the arrival of the tin ore had practically 
ceased. 

Hen wood showed that the mineral most commonly found against 
the walls of lodes is quartz, and occasionally cassiterite, ^r fluor- 

* "Precious Metals in the West of England." Journ, Boy, Inst. Com., 
vol. xvi., part i., 1904, p. 115. 

t M. U. Klaproth, ** Observation^^ Relative to the Mineralogical and Chemical 
History of the Fossils of Cornwall," 1787. Translated by J. G. Groschke,D. 30. 

t R. Pearce, " Note on Pitchblende in Cornwall." Tr, 11.0,8. Com., vol. ix., 
1878, p. 102. 

§ J. H. Collins, " Origin and Development of Ore Deposits " Journ. B, Intt, 
Com., 1892, p. 66. 

II Klaproth* Op. cit 

IT J Came, ** On the Discovery of Silver in the Mines of Cornwall." Tr, ll.0,8» 
Com., vol. i., 1818, p. 120. 

•♦ Pryce. Min, Comub,^ p. 58, 



ORDER OF ARRIVAL OF THE OREa 183 

spar. These are followed by wolfram, oxide of tin, and chlorite. 
When sulphides, carbonates, or oxidised minerals occur they are 
generally next in order, and in no case does the cassiterite and 
wolfram succeed the solphides.* 

Mr. Collins confirms these facts,! and distinguishes two broad 
classes : (1) the minerals associated with cassiterite, such as quartz, 
felspar, mica, tourmaline^ wolfram, stannite, topaz, apatite, scheelite, 
fluellite, Tavistockite, churchite, molybdenite ; (2) the minerals 
** which have been observed in immediate contact with cassiterite 
and mostly deposited upon it," such as quartz, mispickel, pyrites, 
chalcopyrite, smaltite, blende, bismuth, bismuthinice, hsematite, 
limonite^ native copper, pitchblende, uranium ochre.J 

The history of the tinstones from Dolcoath, South Crofty, Cam 
Brea, and Wheal Basset has been described in detail by Dr. Plett, 
who finds that in all cases the copper ores belong to the later 
period of infilling, while tin belongs to the earlier,§ and the 
history of the veins as indicated by the structure of the veinstones 
is highly complex. 

The conclusions to be drawn from the mutual relations of the 
ores as viewed on a large scale only will here be dealt with. 

The similarity in the mode of occurrence of the ores of tin and 
copper may be thus summarised. Their geographic distribution is 
practically the same. They are common associates in the lodes, 
and all the greatest lodes of this district have yielded both tin and 
copper ores. The differences are as follows : — While tin and copper 
ores occur in the same lodes, the copper ores occupy a higher posi- 
tion in the lodes than the tin, or else the ores are mixed, but, 
generally speaking, where both tin and copper ores occur in abun- 
dance in a lode, the copper is not far distant from tin ore 
Again, the copper ore, with a few important exceptions, generally 
prefers the part of the lode which is in killas. Tin ore occurs 
either in granite, or in the killas not far from granite ; copper ore 
is sometimes entirely absent from the lodes in the bottom of deep 
tin mines, e.g. Dolcoatb. From these considerations only it would 
be impossible to conclude which ore had arrived first. Indeed, 
the circumstances point to the fact that copper and tin ores must 
have arrived together. 

The facts advanced by Thomas, Carne, Henwood, and others re- 
garding the intersections of lodes show that a lode containing tin 
ore may be intersected by a lode containing sulphidic ores. Here, 
at any rate, is evidence that tin with its characteristic minerals 
arrived before copper ores. A clear and instructive example occurs 
in West and Wheal Basset. There the Great Flat lode, which 
from its apparent mode of origin and its mineral contents is dis- 
tinguished from the more or less vertical lodes which intersect and 



• Table C, p. 214. 

+ J. H. Collins. *• On the Origin and Development of Ore Deposits in the 
West of England." Journ. Hoy. Inst, Corn., 1898, vol. xliv., p. 221. 

X J. H. Collins, ** On Some Cornish Tinstones and Tin Capels." Min. Mag,, 
1883, p. 121. 

§ John S. Flett, " Note on Some Brecciated Veinstones from Cornwall." 
Summary of Progress (U.M. CJeological Survey), 1902, p. 155. 



184 NATTJEAL HISTOEY OF THE OEES. 

heave it. The periods of the arrival of the different ores appear 
to have overlapped — especially in the case of tin and copper ores. 
Briefly, the order appears to have been : (1) tin, wolfram, and 
arsenic and also copper ores* ; (2) copper ores and other sulphides, 
such as zinc — and possibly some lead and silver; (3) lead and 
silver ores and carbonates. 

V. Local C!onditions Influencing Ore Deposit. 

Certain rocks appear to be more readily altered and impregnated bJ 
ores than others. Thus granite and manyelvans very commonly con- 
tain tin ore in the vicinity of lodes. On the other hand, some kinds of 
killas are probably only mineralised with difficulty. The texture 
of the rock is an important factor. In speaking of the local con- 
ditions affecting the deposition of ores the operations which are 
particularly dependent upon changes of temperature and pressure 
dre not included. 

'^The connection between bunches of tin and copper ore in 
fissures and those places where the latter traverse the elvans is, 
viewing the subject on a large scale^ of the most marked kind."t 
A lode in passing from the killas into elvan may become poorer, 
but in some cases this is due solely to the fact that the lode is split 
up into strings and branches in the elvan which^ taken together, 
may be as rich or even richer than the lode in killas. 

In the Crenver and Wheal Abraham tin and copper mine the lode some- 
times became poor and hard, and was ** often divided into branches " in the 
elvan, and yet the lode appears to have consisted partly of impregnated 
elvan.| In the western part of Wheal Busy, at about 60 fathoms from the 
surface, near Lobby's shaft, the tin and copper lode is 12 feet wide, but very 
much broken up in the elvan through which it passes ; in the main part of 
the mine, however, the lode was richest when in elvan. 

In OamBrea Mine the Highburrow lode, as it approached the 310-fathom 
level (which is at a considerable depth in the granite) changed from a fairly 
productive tin lode, 15 feet in width, to a poorer and thinner lode, until it 
cut across an elvan 60 feet in width, where the lode was utterly valueless.§ 
On the other side of the elvan the lode was only 2 feet wide and became 
larger in depth but never regained its former productiveness. 

Miners, as a rule^ say that the softer or ** plumb " parts of the 
rocks (particularly granite and elvan) through which the lode 
passes are signs of a rich lode.|| It should he observed that as the 
elvans were probably still in a heated condition at the time the 
ores were being deposited important reactions promoting deposition 
of ore are certain to have taken place near them. 

In Nangiles Mine the lodes were rich when they intersected soft (de- 
composed) elvan % ; thus the Nangiles coppei^ lode was poor in killas but 
rich in elvan. Tho country granite of the Great Flat lode in the upper 
levels of South Condurpow Mine is very soft and kaolinlzed ; especially so 
in the hanging wall. The numerous lodes in Wheal Basset were all more 

* Cassitcrite moulded upon mispickel and blende has been found in the 
deposits of Willeder (Morbihan, France). Fuchs and DeLaunay. "I^t^des 
Gites Mineraux," 1893, p. 139. 

i* De la Beche d. 329. 

t J. Carne, "On Elvan Courses." Tr, JtG.S. Com,, vol. i., 1818, p. 101. 

§ Captain White, manager of the mine, states that the lode was ^uite wrung 
up in tne elvan. 

II Dc la Beche, p. 336. II Thomas, p. 17» 



LOCAL CONDITIONS INFLUENCING ORE DEPOSIT. 185 

• 

or less productiye, bat were especially rich in the vicinity of elvans.'*' At 
Penstrathal mine the tin and coppei lode was tried in both the hard and 
soft (decomposed) parts of the granite ; it was poor in the former and rich 
in the latter.f In the granite at Tresavean Mine the lode is associated 
with elvan.J In East Pool Mine the Engine lode in killas became very rich 
in tin ores where it intersected elvan. 

In Dolcoath Mine the South lode in the upper levels was of greater value 
where it was in elvan. In West Wheal Seton the old North or main lode 
situated in killas was much richer in copper ore in the vicinity of elvan 
than away from it Many parts of the Great Flat lode in Wheal Basset 
are simply highly altered elvan impregnated with tin ore. At Wheal Unity 
Wood large quantities of tin ore were obtained from elvan. Thus at the 
60-fathom level an elvan 4 fathoms in width contained tin ore " sprinkled" 
throaghoat.§ Another case is that of the well-known Bissoe Bridge elvan, 
where large quantities of tin ore occurred in the elvan, which can be traced 
through to the United Mines. The cases of such association of the richer 
parts of lodes with the elvans near them are bound to be frequent, since the 
geological conditions of their occurrence is similar. 

It appears, as a whole, that the local deposition ~ of the ore 
in the rocks depends upon the texture and chemical conditions 
relative to composition of the enclosing rock. In the case of 
the sedimentary rocks it is not improbable that certain organic 
minerals contained in them have exercised a considerable pre- 
cipitating action. Some of the killas beds are distinctly 
carbonaceous or graphitic; and in some cases mineral pitch 
(petroleum) has been discovered in the vu^s of lodes traversing 
the killas, e.g,y South Wheal Towan, East Wheal Damsel, North 
Roskear, East Wheal Crofty (at the 120-fathom level in Reeves' 
lode)J| Cook's Kitchen, Wheal Unity,! Treskerby, Carharrack,** 
Wheal Jewell, and Poldice.ft In banded sediments forming the 
country rock of lodes the ore often replaces certain of the bands 
for a short distance, while the others are unaffected. 

At Poldice and Wheal Fortune the lodes were of value in the killas, 
until a stratum of hard blue killas was encountered in the workings which 
•• cut out " the riches. In Wheal Squire the lodes were valuable in soft 
light blue killas, until a stjratum of hard black killas was encountered in 
one lode, at the 44-fathom level, and in another lode at the 120-fathom 
level, with the result that both became poor.Jt Similarly, the slate which 
the miner prefers for tin ore is duller, darker, and harder than that con- 
sidered good for copper ore.§§ A clay slate " of a very pale greyish hue, 
passing into dull white," accompanies the richer portions of the copper 
lodes at Ting Tang, Wheal Virgin, Wheal Jewell, Wheal Unity, and through 
most of the Gwennap Mines. Some of the lodes passing from this into 
that of a deep blue colour maintain their productiveness, as at Wheal 
Fortooe (Consolidated Mines) and Ale and Cakes ( United Mines); for the most 
part, however, the lodes are impoverished, as at Wheal Virgin (Consolidated 
Mines j, &c.|l || In some parts of Gwennap a reddish slate is regarded with 
disfavour.^ •[ Wherever tin ore abounds the slates are of uniform character, 

• J. Maynard, "Remarks on Two Cross Sections." Kcp. Corn, Pohj. Soc.^ 
1871, P. 192. 

t I)e la Beche, p. 337. t Op, cit„ p. .33,3. § Henwood, Table Ixvi. 
II Op. cit„ p. 214. % J. GaHiy. Tr, JUIS, Com., vol. vi., p. 76. 
*• Came, p. 214 .Klaproth(l787), p. 32, states that mineral pitch in this mine 
was found in granite at 45 fathoms from surface, 
tt Greg and Lettsom. '* Mineraloo:y," 1858, p. 15. 
tt De la Beche, p. 337. §§ Op, cit. |{ll Henwood, p. 223. 
V^ Carne. Tr, 11,0, S. Com,, vol. iii., 1828. 



186 KATUEAL HISTOEY OF THE OEES. 

thickly bedded and deep blue, ** with here and there a somewhat greenish 
tinge, and rather a greasiness or gloss on the surfaces of the cleavage 
planes."* Generally, the miners find that a change in the character of the 
country rock is accompanied by a change in the productiveness of the 
lode. 

Conditions Relating to Greenstone. — Lodes traversing 
greenstone are hardly ever of great value while in it. Although 
" the fissures traversing it are often large, and its condition as to 
the proximity of the granite, the intermixture with elvan dykes, 
and the intersection of cross-courses is equal to that of the slates 
with which the greenstones are for the most part associated," they 
seem as a whole to be unfavourable to the ores of tin, copper, and 

lead."t 

Pryce states that '^ it is this stratum that is uppermost through 

great part of the middle of Camborne and Illogan parishes, where 

many of the principal copper mines are enclosed in it (greenstone 

or diabase)."^ 

Conditions at Lode Intersections. — The lodes are often rich 
where they intersect one another. The precise effect which such 
junctions have in promoting deposition of the ores is not certain. 
In many cases the junction of intersecting lodes affords a good 
ore body^ because there was a considerable opening in that place in 
which ores could be deposited. The question is complicated, 
because some of the minerals, such as tin ore, have remained 
where they were first deposited, while others (copper ore) can 
migrate under certain conditions with ease, and so are liable to a 
secondary concentration. ^'As a leading fact, however, it is 
understood that the meeting of two lodes at a small angle is pro- 
ductive of good."§ On the other hand, two poor lodes intersecting 
one another will not have a rich junction. 

At Wendron Consols Mine the junction formed by Liddeeoat^s and 
Flander*s lodes was rich in tin ore. 

In West Wheal Damsel the intersection of the New North lode with 
Tremayne*s lode was rich in the deeper parts of the mine. 

At Wheal Basset the junctions formed hy the intersection of the Great 
Flat lode by the nearly vertical lodes, which cut throngh and heave it, 
were generally productive in tin ore. The nearly vertical lodes do not 
themselves contain much tin, while below their intersection with the Great 
Flat lode they are generally very poor. 

The Dolcoath main lode at the junction with the South Entral lode is 
60 feet wide, and was very rich in that place. The junction of the Gaunter 
lode and the main lode in the same mine was also rich. 

CONDITIONS WHERE LODES ARE OF IRREGULAR BEARING. — If a 

lode changes its bearing slightly in different parts, it is generally 
found that the richest parts have a common bearing. The relative 
movement of the walls of an irregular or wavy fissure result in 
the production of open parts, having a common hearing, which 
have been filled with veinstone. The closed parts have a common 

• Henwood, p. 224. f De la Beche, p. 337. 

t Pryce. Mm. ComubicniU,n7S, p. 76. § De la Beche, p. 334. 



DECOBfPOSITION AND REDISTRIBUTION OF THE OREa 187 

bat slightly different bearing. Dolcoath main lode affords an 
instance of this,* and the Great Flat lode may be taken as 
another instance. Moissenet endeavoured to form an estimate of 
the amount of movement that had taken place in the wails of the 
fissure necessary for the formation of the open parts of the lodes 
in which the ores were deposited. The form of the fissure he re- 
garded as being intimately connected with the hardness of the 
rocks through which the fissure passed. Taking Kenwood's data 
and basing his calculations on the relations which existed between 
the angle of general underlie of the lode and the angle of underlie 
of that irregular part which contained the ore (open part), 
Moissenet arrived at the conclusion that for most of the lodes of 
Cornwall a fall of 2*75 to 3'75 metres would produce an opening 
in the lodes of one metre. It should be remembered, however, 
that many of the Cornish lodes are the result of in-filling and 
alteration in the vicinity of a series of close parallel cracks, so 
that the width of an ore body does not necessarily represent the 
width of the original open part of a fissure. 

VI. Decomposition and Redistribution of the Ores. 

Since tin districts are connected with plutonic rocks, it follows 
that tin-mining districts are situated as a rule only in extensively 
denuded areas. As a rule also, tin alluvial deposits nearly always 
occur where there are tin lodes. Simultaneously with the re- 
moval of the surface deposits the upper parts of the lodes are 
being greatly affected by the action of water containing various 
dissolved substances, such as oxygen, carbon dioxide, and organic 
acids. The surface water, percolating the crust, penetrates 
cracks in the lodes and attacks the sulphides and other oxidisable 
or soluble materials, so that not only is the lode considerably 
changed in appearance and composition, but redistribution of 
certain of the minerals takes place. It is upon this principle, 
taken in conjunction with the assumption that water is able to 
descend through interstitial spaces and capillary openings in 
porous rocks to great depths, and reascend through larger cracks 
or other channels, that various theories have been advanced 
accounting for the secretion of ores in fissures by the leaching out 
of metalliferous minerals from the surrounding rocks. In great 
mining regions this process is supposed to have been particularly 
stimulated by association with plutonic intrusions, and conse- 
quently was mainly active in the contact rocks of the meta- 
morphic aureole. 

Some excellent treatises dealing with the origin of certain ore deposits 
of America have been written from this point of view by American 
geologists.! Posepny'sl view is, that from surface to ground water level, 
there is an active circulation of waters, called the vadose or shallow-undeiv 
ground circulation, resulting from the descent of rain or surface water 
through the rocks. Below this is the deep-underground circulation pro- 

• K. Hunt. "British Mining," 1884, p. 439. 

t eg, C. R. Van Hise, *' Preliminary Keport on the Lead and Zinc Deposits 
of the Ozark Region." 22nd Ann. lUp, U.S. QeoL Survey, 1900-1901. 

X ** The Genesis of Ore Deposits." Ir, Avi. Inst, Min, Eng. (Chicago 
Meeting), 1893. 



188 NATUEAL HISTOEY OF THE OEES. 

moted by differences of temperature in the upper and lower rocks through 
which it passes. The water, as it descends through capillary openings in 
the rocks, is gradually warmed, and is able to ascend through other 
channels. Daubr^* actually supposed that steam emitted from natural 
Tents was produced by actions analogous to those in an experiment carried 
out by him showing the behaviour of water In passing through a slab of 
porous material (sandstone), one side of which was heated. Water was 
able to flow continuously from the cool to the warm part, where it was 
vaporised. In nature the subterranean water was supposed to find its way 
down and come in contact with large heated rock masses — intrusive or other- 
wise. Van Hisej has elaborated the arguments favouring the view that 
" the greater number of ore deposits are the result of the work of under- 
ground waters." 



Crenerally speaking, the distribution of the undergroand water 
has constantly changed with the elevation or depression of the 
district and with denudation. Locally^ the arrangement or 
structure of the rocks, their porosity or imperviousness, and also 
the extent of Assuring, has a great deal to do with the distribution 
and circulation of the water^ and hence, in all probability, upon 
the distribution or position of some of the secondarily concentrated 
minerals. In Cornwall the circumstances do not permit of any 
extensive application of the principle of circulating waters in 
regard to the origin of the ores, but it does apply in the case 
where soluble metalliferous minerals already present in the lode 
have been dissolved and redeposited in other parts of the lode. 

The upper parts of lodes, and especially those lodes containing 
copper ores, are characterised by the presence of oxide of iron, 
which is the main constituent of the ''Iron Hat" or Gossan, a 
term by which the weathered ferruginous upper portion of the lode 
is designated. The iron oxide is derived from copper and iron 
pyrites by oxidation. Emmons was one of the first to show how 
sulphides decomposed in. this way are dissolved, carried down the 
fissures, and regenerated ; and, indeed, he states that the '* native 
metals and their oxides and chlorides (except, perhaps, gold, tin, 
and the platinum group of metals) " are generally the result of 
secondary alteration from sulphfdes.^ The general vertical distri- 
bution of the ores bas been referred to, but in addition to this it 
will be observed that there is a vertical arrangement of the 
metalliferous minerals brought about by the action of water, a 
fact known to miners from early times.§ 

Emmons distinguishes three zones in the part of the lode affected by 
percolating waters. An upper zone, near the surface, of recently oxidised 
ores, gossan, in which may occur some residual masses of sulphide not yet 
oxidised. Below this is a second zone in which carbonates, oxides, or 
native metals occur ; these are the less soluble or more readily precipi- 
tated compounds. Below this is the zone of sulphide-enrichment in which 
minerals brought in solution are deposited as sulphides. Here occur 
sulphides, sulph-arsenides, sulph-antimonides, or native metals, in contact 
with original sulphides of the lodes which have not yet been altered. 

• ** Geologie Experimentale," vol. i., 1879, p. 241. 

t C. R. Van Hise, ** Some Principles Controlling the Deposition of Ores." 
Tr, jUru Imt. Min. Ertg,, 1900. 

t S. F. Emmons, ** the Secondary Enrichment of Ore Deposits." Tr. Am. 
Inst. Min, Eng, (Washington Meeting), 1900. 

leg. See Pryce, Min. Ctfrnub,^ 1778, p. 6. 



DECOMPOSITION AND REDISTRIBUTION OF THE ORES. 189 

Van Hise states'*' that there are three zones. Above the level of ground 
water there is a belt composed lai^ely of oxidea, carbonates, chlorides, and 
associated products which may contain enriched sulphides. Above and 
below ground water level is a transition belt, consisting of sulphides rich 
in valuable metals, such as gold, silver, copper, lead, and zinc, and some 
oxides. Below this are the ** lean sulphides," containing small amounts of 
valuable sulphurets commonly passing into sulphide of iron. 

De Launayj says that near the surface there is a zone of oxides or 
carbonates, sometimes chlorides. Below this is a zone of argentiferous 
grey copper with copper gladce and uativo copper. Still lower tliere is 
copper pyrites. Vogt|: has shown that in tlie San Domingo Mine, in 
Southern Spain, the amount of copper in tho pyrites of these deposits 
diminishes with depth. He also dLstiufjuishes three zones : (1) the oxidised 
zone, gossan ; (2) the small zone containing gold and silver ; and (3) below 
this the principal sulphide zone in which tho percentage of copper 
diminishes with depth. 

Penrose§ states that in Arizona the upper parts of copper deposits con- 
sbt of black and brown ferruginous masses with oxidised copper minerals, 
such as cuprite, malachite, azurite, chrysocolla, &c. ; while at depths vary- 
ing from a few feet to several hundred feet the deposits are a mixture of 
copper and iron sulphide in which the latter is in excess. Penrose has also 
noticed that the decomposition of country rocks in the vicinity of ore 
deposits is more extensive than in similar rocks in which ore deposits do 
not occur, " The explanation is, doubtless, in many cases, that the rock 
has decayed under the influence of the same waters that originally con- 
centrated the ore. When subsequently the ore body is aifected by surface 
influences, sulphuric acid is liberated from sulphide, and carbonic acid 
from carbonates, as well as other acids from other minerals, and all these 
materials have an active effect on most rocks," || 

The relation of the underground water to the distribution of the ores 
has recently received the attention of Mr. Finch,*[ who distinguishes 
three important zones. Zone I. includes '* all depths near the surface in 
which water is accumulated and conducted to a saturated zone. If there 
is no saturated zone it terminates with the cessation of downward percola- 
tion. It is the *belt of weathering.*" Zone 11. is the zone of discharge. 
It is the upper part of the belt of saturation of Van Hise, and " embraces 
that part of the belt of saturation, in any region, which has a means of 
horizontal escape and discharge. Tho upper part of Zone II. is very 
variable. The bottom of Zone II. is the lowest limit of notable movement of 
water, and is controlled by lowest limit of discharge. If impervious 
"barriers intervene the bottom of the zone may be the crest of the 
barrier and much higher than the line of lowest escape." Zone III. The 
transitory or static zone. " The movement of the water found below 
the level of the lowest point of discharge is for normal conditions in- 
finitesimal," but convection currents may be set up by heat. Finch 
believes that Zone III. is rarely extensive,except where there are deep open 
fissures ; and that rocks below 1,000 or 1,500 feet are commonly dry. He 
divides the upper part of a vein in which secondary enrichment has taken 
place into two zones : (a) the upper is the zone of oxidation, in which are 
oxides, sulphates, chlorides, bromides, carbonates, silicates, native metals, 
and loose open veinstone materials ; and {b) the lower zone (zone of reduc- 
tion), in which are sulphides, arsenides, antimouides, &c., tungstates, 
molybdates, &c., and dense veinstone material. 

♦ "Some Principles Controlling Deposition of Ores." 7r, Am. Inst. Mln. Eng,, 
1900, p. 365. 

t E. Fuchs and L. De Launay. ** Trait<S des Gltes Min6raux et M6tal- 
Uf6re8,''vol.u., p. 233. 

t •* Das Huelva-Kiesfeld in Siid-Spanien nnd dem angrenzenden theile von 
Portugal." Zcit.f. prakt. Ovol, 1899, p. 241. 

} R. A. F. Penrose, junr., *' Superficial Alteration of Ore Deposits." Joum, 
Geology t vol. ii., p. 307- 

II up, eit., p. 295. 

IF J. W. Finch, " Aqueous Solutions and Lode Ores." Proc. Col. Sci. SoCy 
1904, vol. vii. 



190 NATTJEAL mSTOHY OF THE OEES. 

These general results have been supported recently by Mr. 
Hill in regard to Cornwaii, who asserts that " before the upper por- 
tion (of a lode) shares in the disintegration and denudation that 
are going on at the surface^ it has already parted with its metal- 
liferous contents, which have gone to enrich the lode below. Con- 
sequently, according to this view, the enrichment of lodes must be 
descending at a corresponding rate with surface denudation."* As 
early as 1778 this general principle wa6 recognised by Fryce, who 
wrote at some length on the subject. 

With regard to the occurrence of cassiterite in the upper por- 
tions of lodes, it has occasionally occurred in the gossans of mines 
wrought for copper in such quantity as to jnake the outcrop of 
the lode worth treating for cassiterite. Thus, some of the 
^' backs " of the lodes in the Grwennap district, as well as those 
near Carn Brea and other places^ are typical cases, e.g.^ Cook's 
Kitchen, Wheal Unity,t Wheal Daniel), Wheal Spinster, &c. 
Cassiterite is so insoluble under ordinary conditions that this 
occurrence is not remarkable, and is explained by the fact that 
the more readily decomposed minerals have been washed away 
from a matrix originally carrying cassiterite and decomposable 
sulphide ores. De la Bechef says ^ it has been found that the 
percentage of cases is considerable where an iron ochreous sub- 
stance, named gossan, prevails and copper ore is connected with 
it, and it may be said that the instances are very rare where 
copper ore is found in fair quantity in a lode without gossan 
having been discovered on the ' back/ This gossan is generally 
mixed with quartz and other mineral substances, among which 
the oxide of tin frequently occurs.*' Henwood states that the 
greatest number of rare and curious minerals are found in the 
upper parts of lodes, and particulaily where gossan is plentiful.§ 
In Hen wood's great work on Cornwall the term ^' earthy brown 
iron ore" is very commonly used in the descriptions of the 
metalliferous contents of the lodes. This no doubt refers to the 
iron oxides resulting from the decomposition of pyrites. This 
observer found that in the ^' superficial " portions of the lodes 
much iron pyrites (mundic) occurs in East Wheal Crofty, 
Pennance, United Mines, and Baldhu. Blende occurred in the 
upper portions of the lodes in the United and Consolidated Mines, 
Baldhu, Wheal Hope, &c., and that the shallower portions of the 
lodes yielded earthy black copper ore in gossan in Wheal Jewell 
and the Consolidated Mines. Native copper and red oxide of 
copper, with carbonates and arseniates, were also found in 
Dolcoath, Wheal Buller, Penstruthal, Ting Tang, Wheal Gorland, 
Wheal Unity, and Wheal Charlotte. Where the lode has a gossan 
the ferruginous ingredients diminish with depth, while the 

♦ J. B. Hill, R.N. (H,M. Geo!. Survey), ** The Plutonic and other Intrusive 
Rocks of West Cornwall in tlieir Relation to the Mineral Ores." Jr. Royal 
Qeol. 8oc, Cornwall^ vol. xii., part vii., 1901, p. 686. 

t W. Pliillips, *'0n the Veins of Cornwall." TV. Oeol. Soc, vol. ii^ 1814. 
p. 122 ' 

t p. 326. § p. 204. 



DECOMPOSITION AND REDISTRIBUTION OF THE ORES. 191 

copper becomes more abundant.* The table of the metalliferous 
contents of the lodes given on page 195 includes those minerals 
which have been deposited long after the arrival of the ores in the 
lodes. Of particular interest in this connection are the Cornish 
pseudomorpbs described by Professor Miers, Evidence of the 
work of meteoric water is plentifully seen in the upper parts of 
lodes at the present time. Incrustations of basic copper car- 
bonate, carbonate of iron, and pigotitef occur in the drivages of 
the Entral lode of Dolcoath Mine, to some distance below adit 
level. These deposits are comparatively recent, as the drivages 
wore made little more than 150 years ago. In the deeper levels 
the incrustations are not so plentiful, the levels are drier, and the 
lodes generally cease to bear much oxide of iron. In North 
Boskear chalcedony occurs as replacement of calc-spar. Observa- 
tions in Cook's Kitchen Mine confirm the general results as to 
the dying out of the oxides in depth, although this mine is an 
old one and the working places have been exposed to the oxidising 
influence of air and moisture. Chapple*s lode, in Cook's Kitchen 
Mine, consists in the upper parts largely of red oxide of iron, 
clay, and chlorite, stained by iron oxide. The granite down to 
below the 100-fathom level is considerably decomposed. Cracks 
and vugs in it are filled with oxide of iron and clay. Chalybite 
occurs in small crystals on the sides of the levels^ and there are 
stalactites of pigotite and oxide of iron in the levels about 72 
fathoms below adit. The oxide of iron staining diminishes with 
depth, until at about the 190-fathom level it is only in small 
quantity. Copper carbonate occasionally occurs as thin incrusta- 
tions. From the 85-fathom level to the 258-fathom level the lode 
is traversed by small veins of quartz here and there. From 
above the 200 to the 345-fathom level, below which the mine was 
filled with water at the time these observations were made, 
the lode consists mainly of peach, chlorite, and quartz (or capel), 
with a little kaolin. Most of the ore of value has, of course, been 
extracted from the workiug places, but old reports state that the 
ores of copper were principally chalcocite and copper pyrites, 
which were abundant to below the 160-fathom level. The 
minerals occurring in the upper parts of lodes which may be 
regarded as being derived by alteration of pre-existing minerals 
are cuprite, melaconite, native copper, malachite, chrysocoUa, 
chalcopyrite, Redruthite, erubescite, chalybite, limonite, &c., and 
even mispickel, iron pyrites, copper pyrites, vitreous copper ores, 
and other minerals: although some of them are not necessarily 
derived by alteration but may represent original deposit. 

The chemistry of the actions l)y which these compounds are derived has 
received attention from various writers, who have shown in the form of 
chemical equations the reactions involved in their production. Iron 

• W. Phillips, ** On the Veins of Cornwall." Tr. Oeol. Soc, vol. ii., I814 
p. 207. ' 



192 NATURAL HISTORY OF THE ORES. 

pyrites in the presence of oxygen and water is converted to sulphide of 
iron and sulphuric acid, which react with the production of ferrous 
sulphate and sulphuretted hydrogen : — 

FeSa + O3 + H,0 = FeS + HaSOi = FeSOi + H^S, 

Iron pyrites is likewise acted upon by the sulphuretted hydrogen of this 
reaction as follows : — 

FeS, + Oa 4- 2H,S = FeS -f 2HaO 4- 3 S 

but by further oxidation sulphuric acid is formed, which acts upon iron 
pyrites : — 

S + Oa + H,0 « HaSO^.* 

By reaction between ferrous sulphate, sulphuric acid, and oxygen, the 
ferric sulphate is obtained : — 

2 FeSO, + O + H^SO, = Fe8(S0,)a + H^O 

which may react with sulphide of iron with the production of ferrous sul- 
phate again : — 

FeS + Fe8(S0 Jb = 3 FeSO, + S. 

By reacting with the oxygen of the air and water sulphuric acid is pro- 
duced, which is capable of converting ferrous sulphate into ferric sul- 
phate. It was shown by Emmons that the sulphides written in the follow- 
ing order represent the order of the ease with which their decomposition 
is effected by ferric sulphate : — Iron pyrites (FeS^) pyrrhotite (FeiiS,a), 
copper pyrites (CusFaiSJ, bornite (CusFeSs), millerite (NIS), copper 
glance (Ou,S), galena (PbS), and zincblende (ZnS). 

If copper pyrites or bornite are present the part of the compound con- 
sisting of iron sulphide is attacked by ferric sulphate, ** leaving Cu,S as 
an amorphous, sooty material.'^t The copper sulphide molecule is next 
attacked by ferric sulphate, with the production of copper and ferrous 
sulphate, as follows : — 

Cu^S + 2 Fe,(S0j8 = 2 CuSO^ + 4 FeSO, + S.^: 

The copper sulphate is soluble, and is carried down the lode until it is 
decomposed by meeting with iron pyrites, pyrrhotite, or copper pyrites, 
as follows : — 

4 CuSO» + 3 FeSa 4- 4HaO = 2 Oa,S + 3 FeSO* + 3H4SO4 + H^S 

2CUSO4 + 2FeS = Cu,S + 2FeS04 + S 

2 CuSO* + OuaSFejSa + H,SO* = 2 Cu^S + 3 FeSO^ + HaS.§ 

• W. H. Weed, '* Enrichment of Mineral Veins by Later Metallic 
Sulphides." BttU. Qeol, 80c, America, vol. ii., 1900, p. 184. 

t Op, cit, 

t AV. H. Weed gives a formula Cu-S + 5 Fe<SO,), + 4 Rfi = 2 CuSO* + 
10 FeSO* + 4 H.,S04. * • Enrichment of Gold and Silver Veins. " 7>. Am. Jntt. 
Min. JSng., 1900, p. 478. 

§ According to Van Hise the reactions involved in the regeneration of copper 
pyrites may oe represented as follows : — 

CuSO^ + 2 FeS = CuFeSj + FeS04 
or CUSO4 + 2 FeSa + 04 = CuFeS^ + FeSO^ + 2 SOa- 

In passing up from lowest level at which copper pyrites occurs it becon 
more abundant until bornite becomes an important mineral, thus : ^ 

CU2SO4 -h CuS04 + 3 FeS = CujFcSa + 2 FeSO^ 
CuaSO^ + CUSO4 -h 3 FeSa + 0- = CujFeSj + 2 FeSO^ + 3 SO- 
or CuFeSa -h CuSO* + 02 = CuaFNeSa + FeS04 + SO^ 

At a still higher level copper gUnce may be produced as follows : — 

Cua SO4 + FeS = Cu.,S + FeSO, 
or Cu.^S04 + FeSa + O^ = Cu^S + FeSO* + SO,, 

or according to the equations — 

CuFeS. + CuSO* + 03= Cu.S 4- FeS04 + SO- 
CuaFeSa + CUSO4 4- (5, = 2 Cu^S + FeS04 + SO^. 

At still higher levels come oxides and carbonates. 



DECOMPOSITION AND REDISTRIBUTION OF THE ORES. 193 

In these reactions copper glance is prodaced owing to the greater 
affinity of the copper than the Iron for sulphur. Sulphates of lead and 
zinc may also be prodaced by similar reactions, and may be precipitated 
in the same way as sulphides. The carbonates produced in the upper 
parts of lodes are capable of reduction by contact with sulphides of iron, 
and Van Hise represents this reaction as follows : — 

PbCOa + FeS = PbS + FeCO^ 
or PbC03 + FeS, + O^ ^ PbS + FeCO« + SO,. 

Similar eriuations represent the reactions forming zinc sulphide. He 
shows also that zinc sulphide itself is capable of reacting with. the sul- 
phate and carbonate of lead, with the formation of lead sulphide and zinc 
sulphate or carbonate thus : — 

PbS04 + ZnS = PbS + ZUSO4. 
PbCO, 4- ZnS = PbS + ZnCOa. 

With regard to the production of carbonates, oxides, or hydrates from 
metallic sulphides, Dr. Evans states that free carbonic acid gas is unable 
to effect this change directly, and as a rule the formation of such com- 
pounds from sulphides is accomplished by carbonates.* This is probably 
owing to the fact that carbonates would be decomposed in the presence of 
the free acid which would result from this reaction if it were possible. 

The production of basic copper carbonate, for instance, above the 
ground water level, is probably effected by some such compound as 
ammonium, sodium, or calcium carbonate, thus : — 

2 CuSO, + 2 CaCO, f^ H.O = Cu(H0),CuC03 + 2 CaSOi + CO,. 

The oxide of copper and native copper are produced above ground water 
level by reactions similar to those represented in the following equa- 
tions: - 

2 CuSOi + 2 CaCO, --^ 2 CuO + 2 CaSO, + 2 CO,. 

The CuO is reduced to CuoO, and may be acted upon either by ferrous 
sulphate or free sulphuric acid ; — 

Cu,0 4 H.SO, = Cu + CuSOi + H,0 

3 Cu,0 + 6 FeSO.^ = 6 Cu + Fe^O, + 2 Fe, {HO^h 
or 3 Cu,0 + 2FeS04 = 4Cu + Fe-A + 2CUSO4. 

The oxidation of the iron salt is carried out by abstraction of the 
oxygen from the copper oxide, which is reduced in consequence, and, as 
pointed out by Penrose, this reaction may take place at comparatively 
considerable depths below the oxidised zone in the lodes* 

In the oxidised zone the production of oxides of iron which characterises 
the gossan takes place according to the equations ; — 

12 FeSOi +60 + 2 H,0 = 4 Fe,(S04)8 + 2 Fe^OgH^O 

or to limonito (2 Fe^Oa 3 H,0). 

Ferric sulphate may also be oxidised to limonite and free acid. 

The reactions involved in thedecomposition and regeneration of the rarer 
metals are capable of expression in the form of equations. The question 
of secondary deposition of silver has received attention from Vogt,| who 
shows how native silver is a secondary product derived from silver glance. 
Weed shows how silver sulphate acting upon copper sulphide results in 
the production of silver sulphide and copper sulphate. Similarly, pyrites 
decomposes impure pyrites containing antimony, arsenic, and silver, with 
the production of antimony sulphide. Native silver may result from the 
action of ferrous sulphate on silver sulphate, thus : — 

Ag,S04 + 2 FeS04 = Ag2Fe,(S04)8. 

According to Bischoff, silver sulphide acted upon by steam yields native 
silver : — 

4 Ajr^S + 4 11,0 --8 Aff + H,SO, + 3 H,S 



* J. W. Evans, J///i. J%., vol. xii., 1898-19!)0, p. 377. 

t '* Ueber dicBildang des gedie;^eaen Silber-J, clurcli secundar processe aus 
Silbertjlanz undandercn Sill>ererzen." ^eit. f. Pya^^ Groi., 1899, p. 113. 



194 NATUIIAL HISTORY OF THR ORES. 

The reaction represented by this equation is, however, not an accom- 
paniment of surface action.* 

The presence of gold in gossan, in rather larger quantity than is found 
at greater depths in the lodes, is accounted for by the action of ferric and 
ferrous sulphates. The gold is dissolved by ferric sulphate and precipi- 
tated by fenous sulphate, a sulphide, a native metal, or by organic 
matter. Many sulphides contain gold in the form of a mechanical mixture 
of free gold and the sulphide. The decomposition of the sulphide results 
in the formation of oxide of iron, in which the gold remains. 

The variety of ores Id the upper parts of the lodes is accounted 
for by the complicated set of reactions resulting from the effect 
of surface water containing a few simple substances in solution. 
The depth to which these effects extend in the Cornish mines 
cannot be stated with accuracy. With regard to the gossan, the 
tabulated statements of the lodes in the different mines of Corn- 
wall show that oxidising influences in the Camborne region have 
been at work from surface to a depth of at least 1 ,000 feet, and 
in all probability below this. The distribution of this oxidised 
zone is by no means regular^ so that no definite assertions can be 
made. 



VII. Minerals of the OHEa 

Cassiterite. — (SnOj) in the lodes presents a variety of struc- 
tures and modifications, occurring in minute embedded grains 
(Zinn-zwitter), or in small or large crystals either embedded 
or encrusting (Zinn-grauper)^ and as the fibrous variety known 
as wood — or Toad's-eye tin. Wood-tin occurred in some abun- 
dance in the Metal lode in Wheal Vor in scattered grains, 
small isolated masse?, or in veins of varying but small dimen- 
sions, at a depth of about 180 fathoms from surface*! In this 
mine the tin ores were all obtained from the lode in killas^ 
which in some places, in 1867, was worth £1 ,000 per cubic fathom^ ; 
in granite, the lode was a noiere string and was almost barren of 
tin.§ As seen by the naked eye, the tin ore commonly occurs 
filling or encrusting the walls of minute cracks in the granite or 
killas, or it may form small strings in quartz tourmaline rock, or 
in quartz with chlorite, and not infrequently in masses consisting 
almost entirely of tinstone and chlorite with a little quartz and 
tourmaline. Occasionally, it is abundant in china clay or occurs 
in decomposed granite in the neighbourhood of the lode. The tin 
ore frequently occurs in the same crack with arsenical and copper 
pyrites, but in these cases crystals of tin are idiomorphic and were 
the first of the minerals to crystallise. In brecciated masses of 
lodestuff the tin ore is clearly seen to be associated with the earlier 
fragments of the brecciated material, and is itself frequently broken 
and crushed. Wolfram, with occasionally arsenical and copper 

♦ Seo ** Elements of Chemical and Physical Geology,** by G. Bischoff. 
Translated by B. H. Paul, 1859, vol. iii., p. 636. 

t W. Argall, **0n the Occurrence of Wood-tin at Wheal Vor." Joum, Roy. 
Inst, CWn.y vol. iv., 1873, p. 255. 

t Charles Thomas, " Mining Fields of the West," 1867, p. 24. 

\ Carue, p. 93. 



MINERALS OP THE OREa 



195 



pyritesy with quartz^ tourmaline, chlorite^ and sometimes fluorspar, 
appear to be the principal minerals associated with the tinstone, 
(^issiterite crystals taken from the 314-fathom level at Dolcoath 
in 1878 are very fine and of a jet black colour '^ shading into brown 
with adamantine lustre/' Some associated with limpid fluorspar 
and chlorite from the Wheal Harriet part of Dolcoath were deeply 
striated on the prism faces. In Great Wheal Vor jet black crystals 
of cassiterite show polysynthetic twining^ while others are brown 
and often highly modified, and occur with chlorite and sometimes 
limpid crystals of apatite. Blende, copper pyrites, mispickel, iron 
pyrites, and pearl spar (Dolomite) also occur with tinstone in this 
mine.* An extensive series of tinstones are exhibited in the 
Museum at Jermyn Street. 

The following table enumerates the other metallic products, 
together with their mineral associates: — 



— 


Mine. 


Accom- 
panied by. 


Remarks. 


Authority.+ 


Stannite 


Cam Brea - 


• • • 


Sparingly 


Garby, p. 85. 




South Croftj- 


• • • 


• • • 




East Pool - 


• • • 


In some < 








quantity 






ScorrierMine 


• • • 


In small 

quantity 


De la Beche, 
p. 584. 




Barrier Mine 


• • • 


• • • 


Hall, Min. 




(Owen nap) 






Directory, 
1868, p. 38. 


Copper 


Tolgus, Wheal 


• • • 


One of the 




pyrites 


Jewell, Dol- 




principal ores| 




coath, Cook's 




of the mines 




Kitchen, 




1 




North Kos- 








kear, Eant 








Wheal Crofty, 




i 




East Pool, 








&c., &c. 








Consolidated 


Iron pyrites 


Catalogue of 




Mines 




Mineral Col- 
j lection at 
Jermyn St., 










1864. 




Tresavean - 


Fluorspar - 


• • • 






Cam Brea - 


Specular 
iron ore and 
carbonate 


• • • 






North Ros- 


Fluorspar - 


• •• 






kear 










Buller - 


» 


... 





♦ R. H. Solly. Mi^. Mag,, vol. ix., 1891, p. 207. See also William Phillips, 
•*0n the Oxide of Tin.'' Tr, Geo. Soc, 1814, vol. ii., p. 336. Also *' Speci- 
mens of British Minerals from the Cabinet of Philip Kaslileigh/* 1797* 

t The references to Garby and Rashleigh relate to the following:— 
J. Garby. Tr, li.G.S. Corn,, vol. vii., 1848, p. 71, et *«y. P. Rashleigh, 
*' Specimens of British Minerals ^3elected from the Cabinet of Philip Rash- 
leigh." 1797. 

o2 



XATCBAL HtSTOEY OF TIIE OBES. 





Mine. 
Cum Brea, 


Accom- 
panied by. 


Remarks. 


VitrcouM 




Abundant in 


coiiporore Rant BaasOt, 




lodes rich in 


South Baaset, 




copper 








1 Trcsavoan, 






1 Dolooath, 






; Wheal Jowcll 






' Abraham 






Redruthite - Cam Brea • 


CopiKT py- 


Inupiierparts 




ritea, wol- 


of lode 




fram, tin, 






chlorite, 






quartz, &c. 




enniborne 






Vea.1, Ccxjk'a 








Kitchen, 








Wheal Biiller 






Grey copper 


Great Work - 


Copper py- 


In South 


ore 




rit«!i, tin 


Wheal Brcage 
lode 




Trtuavean 








Mine 








C(H)k's Kit- 








chen, Tin- 






croft,, Con- 






diirrow.Tres- 






uvcan, Car- 






harriLCk, 






South Bnsset 


1 


Bornitp, 


Cum Brea, 


With copper Commuu ia 


l->ul*8eit» 


Dolciiith, &c 
Wheal Bullor, 
North Wheal, 


pyrites | Curu Brea 




Kortuno 








Wheiil Fal- 




1 




mouth 








Camborne 








Vcan. &c. 








South Tolgiis 


... 




Indigo copper 


Cam Brea - 






Arsenate of 


Wheal Buller 






copper 


and Beau- 

champ 

TiDK Tans - 
Cnrliarrack - 








norland 


(See '" Tile 
ore and red 
oxide ot 
copper) 






Pedn an Drea 







See " Observa- 
ti..i,« relative 
ti) Winorali)- 
gical History 
ot the Fossils 
of Cornwall," 
KJaproth. Tr. 



by Grc 



dike. 



1787. p. 20. 
R. H. Solly, 
Mill. M„g., 
1801, vol. ii., 
p. IW. 



B. Kitto, Hep 




Poly 




I8C0, p 






Garby 


p. 88. 



1828, p. 338. 
Hen wood. 
Table Ixvii. 



Garby, p. 88. 
Kenwood, 
Table Iviii. 



A. W. Tooke, 
Mtn. Rev., 
1830, p. 23«. 



MINERALS OP THE ORES. 



197 



1 


Mine. 

1 


Accom- 
panied by. 

• • • 


! 
Kemarks. 


Authority. 


Arsenate of i 


Herland 




• • • 


Symons, ** A 


copper — 










Sketch of the 


cant. 


. 








Geologv of 

Cornwall," 

1884. 


Wood copper 


Wheal Unity- 


• • • 




• • • 


Came, p. 93. 


Libethinite 


South Wheal 


• • • 




« • • 




(phosphate 


Frances 










of copper) 












Condurriteor 


Condnrrow, 


• • • 


An 


a lysis by 


CJarby, Tr. 


pitch cop- 


Wheal Druid 




Di 


'. Faraday 


U.(i.S. Corn., 


per 






in 


1827. Cu. 


1846, vol. vi. 




1 




60'5 per cent., 










As. 1*51, 










As..Oh 25-94, 










S. 


306, 










Water 8-99. 




Tile ore 


Wheal Gor- 


Chlorite, 




• • • 


W. Phillips, 




land 


blue and 
green cop- 
per car- 
bonate, 
arseniato of 
copper and 
; iron, and 
native cop- 
per 






Tr, Geol. Soc, 
vol. i., 1811, 
p. 30. 




Wheal Jewell 


Fluorspar 




• • • 


Op, cit. 




Tolcarne 


« • • 




• • • 






Tincroft 


Copper 
oclirt*, red 
crystal- 
lised cop- 
per ore,and 
malachite 


D,. 


composing 


Kashleigh, p. 
17. 




Wheal Unity 


• • • 




• • • 




Cuprite- 


Cam Brea - 


ChrysocoUa 


In a small vein 


W. Semmons, 












3ftfi. ^fag,f 












vol. ii., 1878. 




Gorland 


• •• 




• • • 






South Frances 


• • • 




• • • 




Ked oxide of 


Ting Tang - 


Vitreous 




• • • 


llenwood, 


copper 




copper ore 
and earthy 






Table Ix. 


• 




brown iron 
ores 










Wheal Buller, 


With native 




• • • 


Catalogue 




Treskerby 


copi)er 






Min. Collec- 
tion, 1864. 




Wheal Damsel 


• • • 




■ • • 


Carne, p. 121. 




Tincroft 

1 


Native cop- 
per 




• • • 


W. Phillips, 
Tr. Geol. Soc.^ 
vol. i., 1811, 
p. 31. 




Dolcoath 


With black 
oxide 




• • • 


• 




West Wheal 


Vitreous 


In 


a cross 


Henwood,p.92. 




Virgin 


and native 


course 








copper 


(" 


Tiddy's ") 





198 



NATXJEAL HISTOay OF THE ORES. 



— 


Mine. 


Accom- 
panied by. 


Remarks. 


Authority. 


Red oxide of 


Wheal Gor- 


Fluorspar, 


IntheMuttral 


W. Phillips, 


copper — 


land 


vitreous 


and Great 


Tr.Geol.SoCy 


COHt, 




copper, 


Gossan lode 


1811, p. 23. 




• 


black oxide about 66 and 








of copper, 86-fm. level 








arseniate of in Gossan 








copper, 










mispickel. 










quartz,and 










native cop- 










per 






Capillary red 


United Mines 


Native cop- 


In a cross- 


Henwood, 


oxide of 




per 


course 


p. 270. 


copper 






(" Tiddy's '•) 




Green car- 


Ting Tang - 


Blue car- 


• • • 


Henwood, 


bonate of 




bonate. 




Table Ix. 


copper 




copper py- 
rites, and 
vitreous 
copper 








Dolcoath 


Red oxide 
of copper 


• • • 


Catalogue 
Min. Collec- 
tion, 1864. 




Duller - 


* . • 


• • • 


Henwood, 

p. 214. 




Wheal Virgin 


With grey 
copper ore 


• • • 


Klaproth {op, 
cit,), p. 28. 




Oarharrack - 


... 


• • • 






Binner Downs 


Blue carb. 
copper 


• • • 


Henwood, 
Table xxxix. 




Wheal Gor- 


(See Tile 


• • • 






land 


ore) 








Trefusis 


• • • 


« • • 




Blue carbon- 


Bas-set, BuUer, 


• • • 


• • • 


Garby, p. 89. 


ate of cop- 


Ting Tang 








per 


Virgin - 


• • • 


« • • 


Klaproth (op. 
cit.)f p. 28. 




Oarharrack - 


• ■ • 


• • • 


Klaproth (op. 
ctt.), p. 28. 




East Pool - 


« « ■ 


• • • 


W. Borlase, 
Nat. Hi8t, of 
Com,f 1757, 
p. 196. 




Gorland 


• • • 


• ■ • 






Cook's 


Ochre 


• 1 • 


Rashlelgh, 




Kitchen 






p. 22. 




Nanterrow 


• • « 


In the gossan 






Mine (Gwi- 










thlan) 










Dolcoath 


• • • 


Ripple marked 
encrustation 
on the walls 
of old levels 
in the Entral 
lode 






Wheal Tre- 


• • • 


• • • 






fusis 








Teunautite - 


Tresavean 


With Born- 
ite 


• ■ • 





MINERAI^ OF THE ORES. 



199 



I 

1 


Mine. 

1 

1 


Accom- 
panied by. 


Remarks. 

i 


Authority. 


1 

Tennantite— 


Wheal Jewell, 


. • • 


i J. H. Collins, 


cont. 


West Jewell, 


Min, Corn. & 




Dolcoath, ! 


Devon, 1871. 




North Ros- 1 




. 




kear, Cook's 


1 
1 






KitcheD,TiQ- | 






croft. Cam 


1 
1 






Brea, Wheal 










Unity, Tre- 










vaskas, &o. 








Chrysocolla - 


Ting Tang - 


Copper py- 
rites,vitre- 
oos copper 


(See Cuprite) 


Henwood, 

Table Iz. 




Gorland 


... 


.. • 


Hall, Min. 
Directory, 
18(58, p. 39. 


Native 


Cook's Kit- 


. • • 


Several tons 


Pryce, Min, 


copper 


chen 




obtained 


Conitib., 1778. 




Wheal Virgin 


••• 


... 


M.H.Klaproth, 






1 
1 


**Observations 










on Minera- 










logy of Corn- 










wall," 1787. 










p. 25. Tr. by 










Groschke. 


Cam Brea - 


• • • 


In large 


Garby, p. 88. 








quantity 






Wheal Gor- 


... 


(See Red oxido 






land 




of copper and 
tile ore) 






Carharrack - 


... 


... 






Poldory 


With red 
vitreous 
copper ore 


... 


Klaproth {op. 
ciL), p. 26. 




United Mines 


... 


... 


Rashleigh, p. 
31. 




Tincroft, Dol- 


Vitreous 


In small quan- 


Henwood, p.CVS. 




coath 


copper 


tity in strings 






Wheal Music 


. . > 


... 






Consolidated, 


Oxide of 


In a cross- 


IIenwood,p.92. 




United, W^st 


copper 


course ("Tid- 






Wheal Virgin 




dy's ") 






Treskerby - 


... 


• • • 


Carue, Tr. 
R.G.S. Coi-n., 
vol.vi., 1840, 
p. 20. 




South Frances 


(See Red 
oxide of 
copper) 


• • • 






Condurrow 


Clayey, pri- 


In a pipe 18 ft. 


E. \W. \y. Pen- 




Mine 


any load 


long, 8 ft. 
high, 3 in. to 


darves, Tr. 
EXiJi. Corn., 


« 






5 in. wide 


vol. iii., 1828. 
(See also De 
la Beche, p. 
591.) 




Tresavean 


... 


Pseudomorph 


H. A. Miers, 




Mine 




after cuprite 


Min. Mag., 
vol. xi , 1897. 



200 



NATXTEAL HISTOEY OF TITE ORES. 



— 


Mine. 


Accom- 
panied by. 


Remarks. 
Common in 


Authority. 


Mispickel - 


In|many mines 


... 






in the dis- 




lodes. Its 






trict 




presence ne- 
cessitates the 
roasting of 
ores 






Dolcoath 


Cobalt and 
nickel ore 


• • • 


Catal. Min. 
Coll., Jermyn 
Street, 1864. 




Great Wheal 


B1ende,cop- 


• • • 


R. H. Solly, 




Vor 


per pyrites, 
iron py- 
rites, tin- 
stone 




Min, Mag,, 
vol. ix., 1891, 
p. 208. 


Leucopyrite- 


Pedn an Drea, 
&c. 


• • • 


• • • 


C. Le Neve 
Foster, Min. 
Mag., 1877, 
No. iii. 


Oxide of ar- 


Wheal Spar- 


• • • 


In a cross- 


Garby, Tr, 


senic 


non 




course 


R,G^, Com,, 
vol. vL, 1846, 








p. 86. 


Native 


Dolcoath 


Cobalt ores 


1 Garby, p. 86. 


arsenic 










Wolfram 


Pedn an Drea, 
&c. 


• • • 


(See under 
** Distribu- 
tion of Ores," 
p. 178) 




Scheelite 


East Pool 


• • • 


As partial re- 


J. H. Collins, 




Mine 




placement of 
wolfram. At 
Wheal Maud- 
lin, near St. 
AubtelljMiers 
records wol- 
fram after 
scheelite 


"On Cornish 
Mineral Lo- 
calities,"Afitt. 
Mag,, 1878, 
p. 92. 

(Mtn. Mag,, 
1897) 


Phosphate of 


Wheal 


Carb. and 


••• 


Henwood, Ta- 


lead 


Falmouth 


phospb. of 
iron 


• 


ble Ixvii. 




Wheal Rose - 


• • • 


• • • 




Arsenate of 


Wheal Rose - 


• • • 


(See Phosphate 




lead 






of lead) ' 






North Downs 


• • • 


• • • 






Wheal Unity 


• • • 


• • • 


Henwood, p.87. 




Gorland 


• « • 


• • • 


A. W. Tooke, 
Mining !?«♦., 
1836, No. viii., 
p. 253. 


Carbonate of 


Wheal Rose 


(See Phos- 


Some crystal- 




lead 


(Helston) 


phate of 
lead) 


lised on hae- 
matite 




Galena 


•* * 


(See Distri- 
bution of 
Silver-Lead 
ores p. 181) 


• ■ • 





MINERALS OF THK ORES. 



201 



Native silver 



Mine. 



Wheal Basset 



Accom- 
pauied by. 



(.iaiena 



Remarks. 



Authority. 



Ilerland 



Dolcoath 



South Trosa- 
vcan 



Vitreoas sil- 
ver (glance) 

Ked silver ore 



Dolcoath, Her- 
land, Basset, 
South Basset 

Dolcoath 



Chloride of North Dol- 



silver 



Blackjack - 



Bismathinite 



coath 



East Pool 



Ilerlaiid 



Dolcoath 



Sparnon 



Arseuiate of 
silver, vi- 
treous and 
capillary 
silver ore, 
mispickel, 
and iron 
pyrites 

Vitreous and 
red silver 
ores. Some 
associated 
with che- 
nocoprolite 

Argenti- 
ferous pi- 
lena, kup- 
fernickol, 
and pitch- 
blende 

(See under 
Nativo sil- 
ver) 

(See under 
Native sil- 
ver) 

I 

Horn silver, 
crystallised 
and mas- < 
sive 

Copper and 
lead ores, 
&c. 

(See Distri- 
bution of 
ores, p. 178) 



In cross-course 
near its in- ' 
tersection 
with a lode 

In a cross- 
course strik- 
ing N. 30 deg. 
W. Only 

rich near a 
copper lode. 
£8,000 worth 
of silver ore 

South Kntral 
lode 



Came, Tr. 
li.dJi. Corn., 
vol. i., 1818, 
p. 123. 

Came, Tr., 
li,G.S. Corn., 
vol. i., 1818, 
p. 123. 



HenwoodyP.65. 



Found in 1803 | R. Pearce, 

" Note on 
Pitchblende," 
Tr. i?.OJS., 
Corn., vol. ix., 
1804-78, p. 
102. 



Some crystal- 
Used <»n ar- 
senical py- 
rites 

8 tons cwts. 
in 1858. 



Mineral 

statistics 



Cobalt ores i 
and nativo j 
bismuth 
Nativo bis- 
muth. Some 
native bis- 
muth asso- 
ciated with 
fluorspar 
Native bis- 
muth and 
cobalt ores 



Acicular coat-! 
ing. Needles | 
lying on face \ 
of joint 



: Garby, p. 86. 



Garby, p. 80. 



Garbv. Tr. 
lt.G!S. Corn., 
1846, p. 86. 



202 



NATUEAI. HISTORY OF HIE ORES. 



— 


Mine. 
Beauchamp - 


Accom- 
panied by. 


Remarks. 


Authority. 


Bismuthinite 


Cobalt ore 


• • • 


W. Borlase, 


^-^ont. 








Nat. Hist, of 
Cornwall^ 
1758, p. 129. 


Native bis- 


•• • 


(See under 


• • • 




muth 




Bismuth- 
inite) 






Stibnite 


Dolcoath 


(See under 
Red silver 
ore) 


• • • 






Falmouth 


Cobalt ore 


In a cross- 


Henwood, 


# 




and iron 
pyrites 


course 


Table Ixvii. 




Herland 


Cobalt ore. 


In a cross- 


Henwood, p. 






iron py- 


course 


271. 






rites, and 










quartz 








Wheal Vor - 


Cobalt ore, 


In a cross- 


Henwood, p. 






iron py- 


course 


271. 






rites, and 










quartz 




• 


Cobalt bloom 


Wheal Unity- 


. • • 


• • • 


Garby, p. 87. 




Sparnon 


•• . 


• • • 




Smaltite (tin. 


Dolcoath 


Native ar- 


« • « 


Garby, p. 87. 


white co- 




senic 




(See also 


balt) 








Pryce, p. 50.) 




Sparnon 


• • • 


In veins and 
small bunches 
(one mass 
weighed 
1,333 lbs.) 


Garby, p. 87. 
Came, p. 113. 




Elizabeth - 


• •• 


... 


Hall, Min. 
Directory, 
1868, p. 50. 


Cobalt ore - 


Wheal Bean- 
champ 


(See under 
Bismuth- 
inite) 


... 






East Pool - 


. • • 


• ■ • 


Symons, " A 
Sketch of the 
Geology of 
Cornwall,** 
1884, p. 128. 




South Crofty 


• • • 


... 


Pryce, p. 50. 




(Dudnance) 










Wheal Gal 


With"cal" 


... 


Pryce, p. 50. 




(Ponsanooth) 


(Gossan) 
and tin ore 








Falmouth and 


(See under 


... 






Vor 


Stibnite) 






Kupfernickel 


• • • 


(See Distri- 
bution of ores 
p. 179) 


. • . 




Sulphuret of 


Wheal Spar- 


(See under 


... 


Garby, Tr. 


nickel 


non 


Distribution 


1 
1 


K.GJS. Corn,, 


(Millerite) 




ofores,p.l79) 


1 

1 

1 


vol. vi., 1846, 
p. 87. 


Molybdenite 


Wheal Crofty, 


... 


t • • 


Gilbert, Hist. 


(" Molyb- 


Wheal Unity, 






of Com., vol. 


^denum ") 


Gorland 






L, 1817, p. 268. 



- 


Mine. 


Aooom- 

p«nIedbT. 




ADthortty. 


Wad - - 


Wheal 

Wheal Tolsutt 
PedB an Drea 








Garb)-, p. 85. 




Spamlck - 


With small 


In live 


nSin. 


A. K. Barnett, 






veins of 


wideii 


elvan 


"On Elvan 






galena 






Courses," 
Hoy. Corn. 
Poly. Soe., 
1873, p. 17. 


Rtchblende- 




(See under 










Distribution 










joforeap.170) 








Uranito 


... 


<See under 
DUtributioii 


■ ■ 








otores p. 171)1' 




Johannlte - 


South Basset 


Other uran- 


Lemim 


and Garbf, p. 86. 






sulphu 










j-eilow 




BarTtes 


Mines and 

Wheal 

Friendship 






Sytnons,Gase(- 
1 teer of Corn^ 
p. 212. 


Specular iroD 


Wheal Beaii- 

cfaamp 
Tlnoroft, Oarii 

Brea. 

Tresavean 






Garby, p. 83. 

' J. H. Collins, 
Min. Loc, 
1 1871. 


Magnetic iron 


Wheitl Ilar- 

rooiiy worited 
fttTroluswell 
and found ij> 
Other places 








Garby, p. 82. 
De la Heche, 
p. 618. 


LimoDite • 




Common in 












many minen 






Aiaenate ot 


Wheal Druid, 






Oarby, p. 84. 


iroD 


GotUnd 








Carbonate of 


Wheal Beau- 


(See under 


Common as a | 


iroa 


champ 


Phosphate 


late incrusta- 1 






ot lead) 


tiou i 
levels 
workjn 


n old 
and 

g 






places 


e.g.. 






Cook's 


Kit^l 






chcn 






Tlnoroft 








Dolcoath - 








Wheal Towan 




Kail, Min. 
i Directorg, 
1 1868, p. 32. 




Caru Brea - 




'h. a. Miers, 
Min. Mag., 
vol. xi., 18y7, 
p. 260. 




Wheal Basset Tin and 










copper 









^04 



NATFBAL IHSTORY OF THE OHES. 



Phosphate of 
iron 



Sulphuret of 
molybdena 



Native sul- 
phur 



Mine. 



In Gwennap, 

Wheal 

Friendship, 

Wheal Gor- 

land, and 

Wheal Unity 
Nangiles 



Accom- 
panied by. 



(See under 
i^hosphate 
of lead) 



Remarks. 



In Wheal Jane: 
crystallised | 
on iron py- | 
rites ! 



Authority. 



Garby, p. 85. 



Garby, p. 92. 



Cornish PseudOxMORphs.* 

Chalcopyrite after bismuthine, boumonite, calcitc, Redruthite, tetra- 
hedrite. 

Redmthite after galena, iron pyrites, erubescite. 

ErubcMscite after chalcopyrite and Redruth ite. 

Iron pyrites after calcite, barytes, fluor, pylrhotite, quartz. 

Chalybite after fluor, calcite, barytes, dolomite, pyrites, bismuthine. 

Limonite after fluorspar (Cook's Kitchen). 

Professor Miers describes a hollow drusy pseudomorph of the form of 
mispickel in a matrix of chlorite and accompanied by a later deposit of 
chalybite and tarnished erubescite (Cam Brea Mine). 



* H. A. Miers, ** On some British Pscndoniorplis." Min. Miuj , vol. xi., 1897' 



205 



CHAPTER XVII. 



THE MINES. 
I. Linear Distribution of the Prinxipal Mines. 

The principal mines are situated side by side along important 
mineralised belts or zones, so that in a diagrammatic manner the 
mines on any particular zone can be represented on a map by a single 
line. (Fig. 21.) Thus in the Camborne district a line on the 
northern margin of the Carn Brea granite represents the important 
lode belt upon which are situated — Camborne Vean Mine, Dolcoath, 
Cook's Kitchen^ Tincroft, and Carn Brea Mines. A line parallel 
with it but further north may represent the important lodes of 
South Boskear, South Crofty, and East Pool Mines. The Great 
Flat lode on the southern margin of the Carn Brea granite, and 
the vertical series which intersect it, can in like manner bediagram- 
matically represented as an important mineral belt by two lines 
upon which are situated South Condurrow Mine (and Wheal 
Grrenville),West Frances, West Basset, South Carn Brea (and Wheal 
Basset), and Wheal Uoy. Similarly, in the Crwennap district, the 
important mines are situated along a line extending from the 
United Mines through Wheal Clifford, Wheal Andrew, Nangiles, 
Wheal Widden, and West Wheal Jane to Wheal Jane. A branch* 
of this series of mines runs from the Consolidated Mines to Wheal 
Andrew, and another branch* runs through Ting Tang to the 
United Mines. Wheal Damsel, Wheal Maid, and Todpool are 
again in linear arrangement. North of this are several series of 
lodes upon which important mines are situated, as follows: — Wheal 
Jewell iind Poldice ; Wheal Gorland, Unity, and Creegbraws ; West 
Poldice ; Unity Wood ;* Killifreth.* These lines are short. Near 
Scorrier Crate there is a mineralised zone along which Treskerby, 
Scorrier Old Mine, Great Wheal Busy, and Wheal Daniell are 
situated. North of this there are two more series of important mines 
— New Treleigh Consols, Wheal Peevor, Great North Down?, Wheal 
Rose and East Downs; and Wheal Mary, North Downs, Wheal 
Briggan, and Boscawen. 

Each of these zones is made up of several important lodes which 
have a bearing similar to that of the zones themselves. Hence 
these lines represent the linear arrangement of the principal mines, 
the position of the principal mineralised belts or zones, and the 
bearing of the principal lodes of which the belts are composed. 
In this manner the confusion which is sure to arise from any 
attempt to work out the lode systems by consideration of the par- 
ticulars of individual lodes is largely eliminated. It should be 

" * See Noto at the end of this Seobion. 



THR UltTB!;. 




observed that the couDtry separating these great lode series is also 
fissured and mineraliEed, but the importance of the lodes in it is 
leas. 

Heference to the diagram or geological map shows that these 
lode lones can be divided into two main ByBtem8,acoordiDg to their 



PAKTICULABS RELATIN'g TO THE MINES. 207 

directional characters, which may have been determined bj 
the nature of the folding in the sedimentary rocks, pioduced by 
the pre-Devonian and post-CSarboniferous movements. In the par- 
ticulars given above, those series marked with an asterisk (*) have a 
bearing of a few degrees north of east, and in some cases they 
appear to fault the other series, wnich has a bearing of about 
E. 30 deg. N. The latter make up the more important system. 



II. Particulars Relating to the Mines. 

Miscellaneous information relating to individual mines may be 
obtained in the following publications, much of which it is un- 
necessary to reproduce ; so that the descriptions which follow are 
largely confined to unpublished information, together with scattered 
facts not already referred to in the previous pages : — 

The West Briton (since 1805). 

The Ettgifieering and Mining Journal (since 1830). 

The Mining Review. '* Survey of Carameuollis District," vol. iii., 1835. 
{^ Descriptive notice of the Oonsolidated and United Mines/' voL ill., 
1835). *' The Mining District of Redruth/' vol. ii., 1832. 

1819. Thomas, Richard, '* Report on a Survey of the Mining District 
from Chacewater to Camborne." 

1843. Henwood, W. J., *' On the Metalliferous Deposits of Cornwall and 
Devon." Tr. R.G.S. Corn., voL v. 

1843. Watson, J. Y., '*A Compendium of British Mining, v^ith Statistical 
Notices of the Principal Mines in Cornwall." 

1860. Pike, J . R., *' Britain's Metal Mines." 

1862. Salmon, H. C, ''The Seton Mining District." Mining and 
Smelting Magazine^ vol. ii., pp. 277 and ^2. Also descriptions of 
prominent mines, pp. 74, 84, 8(9, 140 and in vol. i., pp. 314, 384. 

1863. ''The Condurrow District." Mining and Smelting Magazine^ 
vol. iii., p. 82. 

1865. Spargo, T., " The Mines of Cornwall and Devon." 
1867. Thomas, 0., '• Mining Fields of the West." 

1873. J. H. Collins, Inst. Mech. Eng. " On the Mining Districts of 
Cornwall and West Devon." 

1874. Maynard, J., " Mines of the Dlogan District." 42mi Ann. Sep. 
Boy, Corn. Poly. 8oc.f p. 84. 

1876. "Note on a Cross Section from Cook's Kitchen to Wheal 

Emily Henrietta." Bep. Miners' Assoc. Corn, and Devon, p. 65. 

1CU84. Symons, Brenton, " Gazetteer of Cornwall." 

1890. Collins, J. H., '' Origin and Development of Ore Deposits in the 
West of England." Journ. Roy. Inst. Com., p. 109. 

1892. Do. do. p. 111. 

1893. Do. do. p. 327. 

1897. Do. do, p. 195. 

In the following particulars relating to the mines precedence 
has been given to those which are now working. The abandoned 
undertakings, however^ do not imply the exhaustion of the local 
mine-fields, and it may be regarded as certain that many will be 
again opened up in the future. 

The AcrrivE Mines. 

WHEAii Bah8ET.- -There are a number of lodes in this sett, but in recent 
yearb the ore has been obtained principally from the Oreut Flat lode, which 



208 THE MINES. 

has bcjeu explored to a depth of 260 fathoms from adit measured vertically- 
The lode in some places is of enormous width. The Flat lode was first 
discovered in 1876 in this mine, and during the following years it was exten- 
sively explored. From September, 1883, to October, 1884, over 17,000 tons of 
ore were taken from the stopes, averaging 34 lbs. of black tin per ton. From 
October, 1884, to May, 1885, 10,809 tons were raised, averaging 46 lbs. per 
ton ; and in 1887, 400 to 450 tons were raised weekly, yielding 7 tons of black 
tin a week. The lode is traversed by numerous quartz strings. It consists 
mainly of blue peach, which in some places is brown or dull red owing to 
presence of ferruginous material. In many cases the peach shows the 
original structure of the granite from which it was formed. The other 
lodes have yielded copper ores to a depth of about 150 fathoms from sur- 
face. Between the years 1815 and 1833, 17,416 tons of copper ore yielding 
577 tons of metallic copper, were raised.* 

The Great Lode underlies north and varies in width from 2 to 7 feet. 
At the 120 and 130-fatbom levels the lode consists of quartz, ilucan, tin 
and copper ores, and a good deal o( ferruginous matter. 

Giesler'a Lode is situated on the north of the Great lode and under- 
lies north. Near the Old Sump shaft it is 1 to 2 feet in width at the 120- 
fathom level and contains both tin and copper ore. 

Paddon*8 Lode, — Situated north of Giesler*s lode and underlies north. 
At the 120-fathom level near the Old Sump shaft the lode contains copper 
ore and is 1| feet in width. 

Paddon*s North Branch, — Varies in width from IJ- to 1 foot and yielded 
good copper ore. 

Theaker*8 Lode branches off from the Great lode on the south side below 
adit level. It has a southerly underlie. 

William*8 South or Gaunter Lode.— Nearly vertical. It crosses William's 
lode. At the 110-fathom level it is 1 foot wide and yielded copper 
ore. 

IVilliam's Lode, — It has a good gossan and underlies S. 10 deg. It Is 
about 4 feet in width, and consists largely of quartz, clay, and ochreous 
materials. 

Viuian*8 Lode is north of the New lode, which is situated below Vivian and 
Paddon's lodes. It underlies south and yielded copper ores. 

North Basset Lode. — Situated on the north of Vivian's lode and explored 
for copper ore to considerable depth. At the 185-fathom level it is 18 feet 
wide and yielded tin ore to the value of £10 per cubic fathom. 

North Lode, — Situated north of the North Basset lode. It underlies 
23 deg. N. and varies from 1 to 12 feet in width. The lode has yielded 
good copper ores and consists of quartz, peach, and killas, with some 
mundic. 

Garnet described the mode of occurrence of sUver in Wheal Basset. 

A grey silver ore accompanied by galena which did not itself contain 
much silver, yielded as much as 600 ozs. of metallic silver per ton of stuff. 
The ore was found in a cross-course about 4 inches in width, near the place 
where it intersects a copper lode. At 6 fcei on either side from the lino of 
intersection of the cross-course and the lode the cross-course ceased to con- 
tain silver ore. 

Carn Brea and Tincropt United Mines.- The sett includes Tincroft 
Mine (formerly Wheal Fanny), Carn Brea Mine, and Wheal Druid. The 
lodes wrought by these mines belong to the same series as those worked in 
Cook's Eitchen, Dolcoath, and Camborne Vean. It is almost impossible to 
give a complete account of the relations of the various lod€« and their 
branches ; and the available data are not easily reconcilable with one 
another. 

The principal lodes can be identified in the mines situated along this 
series of lodes. The Barncoose lode in Carn Brea Mine is known in Tin- 
croft Mine and Cook's Kitchen as the North Tincroft or East Pool lode, 

* Phillips and Darlington. ** Records of Mininj? and Metallurgy," 1857. 
t "On the Discovery of Silver in tho Mines of Cornwall." Tr. Il,Q,;S. 
Com., vol. i., 1818, p. 123. 



THE ACTIVE MINES. 209 

and in Dolcoath as the North Entral lode. The Hif^hbarrow lode in 
Cam Brea and Cook's Kitchsn is known as the main lode in Dolcoath. 
Chappie's lode of Tincroft and Cook's Kitchen is recognised in Dolcoath as 
Harriett's lode. Teague's lode in Carn Brea is the same as Dnnkin's lode 
in Tincroft and Cook's Kitchen and Richards' lode in Dolcoath. The South 
lode of Cook's Kitchen is known as the South lode in Dolcoath. The 
Druid South lode in Cam Brea Mine is the same as the Providence lode 
in Tincroft and Cook's Kitchen and the Brea lode of Dolcoath. 

Druid Lode. — The underlie is from 15 deg. to 40 deg. north. The lode 
Taries in width from 1 to 2 feet. In depth it is 4 feet wide. The eastern 
part of the lode is in killas and is split into two parts. Westwards, the 
lode is in granite and is split into three north-underlying branches. In the 
eastern part the lode was not of much value in the upper levels. In the 
granite the lode has a good gossan with clay and " prian." Black, grey, 
and yellow copper ores occurred in horizontal bunches from adit to the 36- 
fathom level. At the 112-fathom level there was both copper and tin ore, 
and from the 145 to the 204-fathom level the lode varied in width from 4 to 
6 feet, and contained tin ore. On the whole there was not much copper 
below the 70-fathom level. The back (outcrop) of the lode was worked 
away in olden times. 

Druid Gaunter Lode. — Bearing E. 20 deg. S. Nearly vertical and varies 
in width from 1 to 3 feet. It runs into the Druid lode on the north side 
at about 30 fathoms east of Druid New shaft, and is 24 fathoms north of 
Vigur'g lode. The copper ore in this lode extended for 80 fathoms in the 
direction of strike between adit and the 50-fathom level, but below the 60- 
fathom level it was poor and very quartzose. 

Jenkins' Lode. — Underlie 10 deg. N. About 2 feet wide. It is situated 
40 fathoms south of the Druid lode and is one of the most southerly lodes In 
the sett. In granite it is ferruginous and clayey. 

Vigur'a Lode. — A Caunter lode running into the Druid lode on the north 
side about 15 fathoms east of Druid New shaft. It is nearly vertical, and 
roughly parallel with the Druid Caunter. In width it is about 3 feet. 
Vigur's lode has a good gossan and was rich in copper ore in the upper 
levels. At the 105-fathom level it yielded a fair amount of tin ore. 

Druid North Lode— Much the same bearing as the Druid lode. Under- 
lie is slightly north and it drops into Teague's lode below the 200-fathom 
level. Yielded tin ore. 

Teague^s Lode. — Underlie at Old Engine shaft is 13 deg. south. At 
Barker's shaft the underlie to the 50-fathom level is 15 deg. south. From 
the 50 to the 80-fathom level the underlie is 10 deg. north. From 
the 80 to the 150-fathom level the underlie is 10 deg. south. The changes in 
underlie did not affect its productiveness. It is from 2 to 7 feet in width, 
and converges with the Highburrow lode in depth. At the 141-fathom 
level it is 20 feet in width.* The veinstone is ** priany," quartzose and 
ferruginous. From the 34 to the 105-fathom level for 100 fathoms in direc- 
tion of strike the lode yielded good copper ore ; and from the 80 to the 
135-fathom level some tin ore. Known as Dunkin's lode in Tincroft 
Mine. 

Dohree*s Lode. — It is a branch of Teague's lode on the south side. It 
underlies north from 18 de^. to 30 deg. The lode contained copper ores 
from the 20 to the 70-fathom level for 80 fathoms in direction of strike. 

North or Dmoe's Lodes. — Branches of Teague's lode on the north side. 
Underlie from 27 deg. to 40 deg. They yielded copper ore from the 34 to 
105-fathom level for about 50 fathoms in direction of strike, but they 
became unproductive at a distance from Teague's lode. From 2 to 6 
feet in width. 

Hichen*8 Lode— Underlie north 20 deg. to 40 deg. Width from a few 
inches to 1| feet. Yielded copper ore from 34 to 70-fathom level but was 
poor below. 

Hiqhhurrotu Lode.— BoiXTiug E. 30 deg. N. In the upper levels it is 
nearly vertical but gradually underlies south. The width varies from 2 to 
12 feet. The main part of the lodo is in the western part of the sett. 

* Hen wood. 



210 THE HINZS. 

From the 60 to the 105-fathom level lai^e qnantitlesof tin ore were extrac- 
ted for a dUtance of 150 fathoms in direction of strike. At the 200-fathom 
level there was both copper and tin ore. At the ^0-fathom level it was 
very rich in tin ore, but at the 310-fathom level the lode was wrung up in an 
el van and became valueless. Phillips states that about the 100-fathom level 
the lode yielded both tin and copper " either mixed or running down the 
lode side by side."* 

Bamcoose Lode, — ^This lode runs into the Bamcoose Mine. The lode is 
about 3 feet wide. It is very quartzose and yielded tin ore at adit level. 
At the 100-fathom level the lode is 4 to 10 feet in width. At the 136- 
fathom level the lode yielded rich tin ore. Further west in Tincroft Mine 
the lode is known as the North Tincroft lode. In this part of the mine 
wolfram and tin ore occur. It is possibly this lode to which Oarne refers 
when he states that wolfram and uranium oxide were found in an "east and 
west copper lodo."| 

There are a number of other lodes which have received notice from 
Thomas and Henwood ; but some of them cannot now be identified. 

All the lodes in the upper parts contained copper pyrites and vitreous 
copper ore. Native copper]: as well as purple and indigo§ copper or(« 
occurred. A mineral called condurrite (pitch copper) was found in the 
east part of Cam Brea Mine (Wheal Druid), within 10 fathoms of a 
cross-course. The lode yielded condurrite for a width of 3 to 4 feet, 
with a vein in the -middle of native copper from i inch to 2 inches 
wide. The lode was soft and reddish, and the condurrite was taken from 
it in small nodules. The rest of the lode is iron oxide, quartz, chlorite ; 
with a little tin ore and mispickel.|| 

In Wheal Druid the lodes contained specular iron, arsenlate of iron, 
wolfram, and tin pyrites, in addition to tin ore.1[ 

ChrysocoUa occurred in Carn Brea, and small veins of cuprite 2 mm. 
in width. The felspar crystals of the granite in which they occur are 
partly converted to chrysocolla.** 
The mine was first worked on a large scale in ISSO.tt 
Between the years 1830 and 1856 the mine sold by public ticketing 
161,593 tons of copper ore yielding 12,039 tons of copper. j:f 

In Cam Brea Mine the average yield of** black tin" from 1872 to 1881 
was 35 lbs. per ton. In Tincroft during the same period the yield was 
53 lbs. per ton.§§ The mining cost per ton during the same period was 14s. 3d. 
The cost of dressing was 3s. 9d. Mr. Collins states that there was a poor 
zone in the main lode near the 238-fathom level. |||| 

Henwood states that in sinking on Dunkin's lode, in the Tincroft 
part of the Carn Brea Mines, the first 26 fathoms was in granite. 
Below this to 84 fathoms below surface the lode is enclosed by killas ; 
and below this again is the main mass of granite. 

Near Martin's lode there are several irregular patches of granite, 
all heaved by the eastern cross-course. There is a third mass of granite 
extending from the main mass to within 25 fathoms of the surface. No 
granite veins have been encountered north of these places.iriF 

• " On the Veins of Cornwall." Tr. Qeol. 8oe., 1814, vol. ii., p. 164. 
t J. Carae, "On the Veins of Cornwall." Tr. R.GM. Corn., 1822, vol. ii., 
p. 61. 

X Henwood, p. 65. 

§ J. Garby. Tr. B.O.8., Cam. vol. vii.. 1847, p. 86. 
II J. Garby. Op. eit., vol. vL, 1846, p. 194. 
IF Op. (fit,, p. 83. 
♦• W. Semmons. Min, Mag., vol. ii., 1878, p. 200. 

ft J. Maynard, ** Remarks on Two Cross Sections," &c. Hep. Roy. Corn. Poly. 
Soc, 1871, p. 193. 
XX Phillips and Darlington, " Records of Mining," p. 857. 
§§ R. J. t rechcville, "Notes on the Great Main Lode of Dolcoath," &c vol. x., 
1879 to 1887. Tr. R.G.S. Com.,x>. 147. 

II II J. H. Collins, ** Origin andf Development of Ore Deposits, &c." Joum. 
Boy. Inst. Com., 1892, p. 75. 
^f Henwood pp. 60, 198. 



THE ACrnVE MINES. 211 

Ck)OK*s Kitchen Mine. — Maynard in 1874 states that the mine had 
worked continuoiisly for 130 years,"** and that the lodes yielded copper 
ore to the Ill-fathom level, below which they have yielded mainly tin 
ore. In 1814 this mine was one of the most productive tin mines in Corn- 
wall.! The average yield of black tin per ton of ore from 1872 to 1881 
was 43 lbs. The cost of mining for the same period was about 16s. 4Jd. 
per ton, while the cost of dressing was 4s. 5^^. Between 1815 and 1856, 
43,606 tons of ore were sold by public ticketing, yielding 1,484 tons of 
copper.j: The mine has been worked to a depth of at legist 430 fathoms 
below adit. 

Chapple^s Lode, — The underlie is south 15 deg. to 20 deg. Eastwards it 
drops into the Highburrow lode, which is the main lode of Cam Brea and 
Tincroft. The lode has yielded immense quantities of copper pyrites and 
rich grey copper ore and tin, and especially at the junctions with its 
numerous branches. The ore shoots follow the lines of intersection of lodes 
and pitch eastwards.§ 

In width it varies from 6 to 20 feet. At the 332 and 345-fathom levels, 
just below the point whore Dunkin's lode drops into Chappie's, the lode 
varies in width from 15 to 20 feet.|{ 

At the 400-fathom level it is *iO feet wide. The lode yielded a great 
deal of copper ore from the 16-fathom level to below the 100-fathom 
level ; grey copper and copper pyrites mixed with " peach," " prian," 
and capel occurred down to the 160-fathom level. The greatest wealth 
began below the 200-fathom level, the lode varying in width from 5 to 
8 feet, and contained good tin ore down to the 400-fathom level (below 
the junction of Dunkin's and South lode). Here the lode is 30 feet wide 
and consists of peach and capel with 4 feet of chlorite and flucan, which 
contained about 40 lbs. of black tin per ton of stuff for a distance of 
over 60 fathoms in the direction of strike. At the 320-fathom level the 
lode was divided into two parts (by a smooth wall) the total width of 
which is 12 feet. The south part (or hanging wall) consisted of peach and 
tin ore ; while the north part (or the foot wall) yielded copper ore. 
Chalybite is common in the lode. 

Dunkin*8 Lode, — This lode had a fair gossan and yielded copper ore from 
the 30 to the 100-fathom level, in killasand granite alike. The veinstone 
was mainly a ferruginous chloritic mass of crushed quartz. From the 1 70- 
fathom level where a little copper was found down to the 222-fathom level 
the lode yielded tin ore. It varied in width from 2 J to 8 feet. The lode 
contained quartz, fluorspar, carbonate and oxides of iron, cupreous and 
arsenical pyrites, and tin ore. In the upper levels it varies from 1 to 12 feet 
in width. 

At the 48-fathom level in Dunkin*s lode the north wall is granite, and 
the south wall is slate traversed by several granite veins. At the 52, 55, 
and68-fathom levels the north (or foot) wall is slate and the south wall 
granite. At the 73-fathom level the south wall is slate and the opposite 
wall granite. 

Eddy* 8 or Etideijs Lod<».— This lode yielded copper pyrites down to the 100- 
fathom level, while below that, at the 121-fathom level, good tin ore was 
found. 

Richard Thomas (1819) gives a brief account of the lodes being worked in 
his time, but some of the names he gives to the lodes have long since been 
forgotten, or the lodes have been renamed. 

The lodes yielded copper ore down to the 150-fathom level. Pryce states 
that several tons of native copper were sold from Cook's Kitchen Mine.*[ 
Vitreous and other copper ores occurred in abundance. The occurrence of 

* J. Maynard, " Mines of the Illogan District." B^, Com. Poly, Soc,y 1874, 
p. 86. 

t Daniel and Samuel Lysons. Ma^. Britt. Com.^ vol. iii., 1814, p. 206. 

:J: Phillips and Darlington, '* Records of Mining and Metallurgy." 

§ R. J. Frecheville, •'Notes on the Great Main Lode of Dolcoath," TV. R.G.S, 
Com., 1879 to 1887, vol. x., p. 149. 

II Op. cit. ^ Min. Cornub., 1778. p. 61. 

p2 



212 THE umrBs. 

mineral pitch has already beea referred to elsewhere. The average yield 
of black tin from 1872 to 1881 was 43 lbs. to the ton. 

It is in this mine that alternations of granite and killas were encountered 
in sinking on the lodes. Hen wood"** gives the following particalars : — At 
the 54-fathom level in the South lode, granite occurs in the south wall, 
and slate in the north, tn Toys lode at the 54-fathom level the foot wall 
is granite while the horse of ground between two branches is partly granite 
and partly killas. 

Middle Engine Lode. — At the 33-fathom level the north wall is slate and 
the foot wall granite, but at the 73-fathom level both sides are granite. At 
the 54-fathom level the north wall of the Hard shaft is slate and the south 
wall granite. 

The Cropty Minbb. — The largest mine in the Crofty group is South 
Wheal Crofty, which formerly was divided into several properties of which 
North Crofty (or East Seton), South Crofty, East Crofty, and the Old Pool 
Mine were the principal. The area was divided into three sections. The 
western section was known as Longdose ; the middle section as Dudnance ; 
and the eastern section as Penhellick. 

Pane's Lode (in Longclose section of the mine), bearing E. 8 deg. N.f 
The underlie is north from 14 deg. to 20 deg. Varies in width from 2 to 3 
feet. The lode joins Reeves' lode as it runs westwards, and although exten- 
sively explored, is comparatively poor. It has yielded a little copper 
pyrites, and at the 71-fathomlevel it is in greenstone and is of a quartzose 
nature. 

Another lode 25 fathoms north of Fane's, contained copper but was value- 
less in depth. In width this lode was about a foot. The underlie is 10 deg. 
N. Another lode called the Red Lode is situated (at the 80-fathom level) 
40 fathoms north of Fane's lode. It is 1 foot wide, has a southerly underlie 
and consists of quartz and peach. 

Beeves* Lode, — Bearing E. 3 deg. S.| Underlie 15 deg. N. It is a large 
well-deQned lode which yielded copper ores from 20 to the lOO-fathom 
levels. The lode has a splendid gossan, and copper ore occurred to the 90- 
fathom level for a distance of 350 fathoms in the direction of strike. 
It joins the Trevenson lode in depth. Henwood states that the lode varies in 
width from 1 to 6 feet and contained in addition to copper ore — iron pyrites, 
blende, mineral pitch, earthy brown iron ores, chlorite, and fluorspar to 
a depth of 125 fathoms below adit. It also yielded tin ore, and at the 205- 
fathom level the lode intersected an elvan and was richer in tin ore below 
the elvan than above it. It was very rich in copper in the Old Pool Mine, 
and was productive also in Wheal Crofty (now part of North Roskear 8ett)§ 
where it is known as the Great Caunter, and it passes into Wheal Seton 
where it is the main lode. 

Trevenson Lode, — Situated south of Beeves' lode. Henwood states that 
the bearing is E. 2 deg. S. Underlie is from 14 deg. to 40 deg. north. In 
width it varies from 1 to 3 feet. The lode yielded some copper ore but 
was poor below the 110-fathom level. 

Cherry Garden Lode.—Situated south of Trevenson lode. Underlie is 
10 deg. to 15 deg. north, to a southerly direction. The lode varied in width 
from 1 to 4 feet. Henwood states that the lode contained copper and iron 
pyrites and blende to the 88-fathom level. May nard states that the lode 
yielded good copper ore at shallow levels ; below the 110-fathom level 
there was no copper in the lode, but there was a little tin ore.|| 

Longclose Lode, — Situated south of Cherry Garden lode. The lode is 
nearly perpendicular from surface to the 35-fathom level, but is not so 
steep in depth ; the underlie varies from 8 deg. to 20 deg. north. The 
lode has a fine gossan and it yielded copper ore from adit to the 35-fathom 
level for 100 fathoms in direction of strike. Below this down to the 115- 
fathom level the lode was not of great value. The lode also contained 

• p. 198. 

+ H. C. Salmon. J/m. and Smelt, Mag., vol. ii., 1862, p. 17. 

Z Op. cit., p. 74. § Ojf, cit. 

;| "Mines of the Dlogan District." Rep, Com, Poly. Soc, 1874, p. 86 > 



THE ACTIVE MINES. 213 

blende and fluorspar. At the 126-fathom level it is 1 foot wide and still 
in killas. 

South Lode.— South of Longclose loda Underlie sonth 10 deg, and 
varies in width from 1 to 6 feet. Yielded copper ores to the 70-fathom 
leveL Bearing approximately E. and W. 

Longclose Caunter Lode, — Situated on the south of Longclose lode. 
Bearing E. 30 deg. S. (Henwood). Nearly vertical to the 35-fathom level 
after which it underlies N. 13 deg. It varies in width from 1 to 3 feet. 
The lode branched off from the Cherry Garden lode near the Engine shaft, 
and yielded copper ores down to the 125-fathom level. Blende, iron pyrites, 
fluorspar, and quartz were also present in the lode. 

Penhellick Lode.— Situated in the south-east part of the sett. Bearing 
approximately east and west. It underlies south at a varying angle. In 
width it is from 1 to 6 feet. There is a good gossan ; and from the adit 
level to the 50-fa thorn level copper ore occurred for 100 fathoms in 
direction of strike. At the 100-fathom level it still yielded copper ore ; 
at the 110-fathom level it was very watery. 

Copper Tankard Lode. — This is a Caunter lode situated in the south-west 
corner of the sett. The bearing is about E. 20 deg. or 30 deg. S. At 
adit level the lode is 6 feet wide, and contains quartz, iron pyrites, zinc- 
blende, and copper ore, near an elvan. At the 24-fathom level the lode is 
1 foot wide in places, and the bunches of ore of no great extent. At the 
70-fathom level the lode is 3 feet 6 inches wide but valueless. The country 
rock at this level is diabase. 

Dudnance, — A lode explored at the 16-fathom level is 1 foot wide. 

Wheal Knight Lode, — In the western end of the sett. Bearing E, 33 deg. N. 
Underlie north 16 deg. to south 10 deg. In the Wheal Crofty part of the 
sett there are several lodes the particulars of which have been given by 
Henwood. Most of the lodes contained iron and copper pyrites and other 
copper ores. Blende and galena were also found in some quantity. At 
the present time o/ily the central and eastern part of the South Crofty sett 
is being worked. The lower part of the mine is well within the granite 
and extends below the 260^fa thorn level. The mine yields tin ore and a 
little wolfram. 

The North Lode underlies south at about ao deg. at the 225-fathom level, 
and forms a junction with the middle lode below the 260-fathom level. The 
lode varies in width up to about 7 feet and yields good tin ore. 

Pryce*s Lode, — The bearing is about E. 15 deg. N. In the upper levels 
the lode is nearly vertical, but its average underlie in the lower levels is 
about 20 deg. south. At the 205-fathom level it joins the South lode. (It 
forms a junction also with Palmer's lode at about 80 fathoms west of the 
Engine shaft. This lode underlies south about 10 deg.) At the 112-fathom 
level the lode is from 8 inches to 8 feet in width near Palmer's shaft. At 
the 260-fathom level the lode is from 3 to 5 feet in width. Pryce's lode 
has yielded mainly copper ores down to the 100-fathom level. Below this 
in the granite the lode yields mainly tin ore. At the 112-fathom level the 
lode divided into two parts. The north part at the 260-fathom level is 
3 to 5 feet in width. The lode consists of blue capel and peach, quartz, 
chlorite, and fluorspar. Some of the cross-courses intersecting the lode 
contain quartz made up of zoned crystals. 

The Middle Lode is situated between Pryce's lt)de and the North lode. 
It branches off from the north side of Pryce's lode below the 100-fathom 
level, and joins the North lode below the 260-fathom level. It varies in 
underlie but is nearly vertical. Not a very rich lode. 

The South Lode is situated south of Pryce's lode and underlies north, 
joining the latter at the 205-fathom level. 

East Wheal Crofty sold by public ticketing, between the years 1832 and 
1854, 100,952 tens of copper ore containing 7,280 tens of metallic copper. 
South Wheal Crofty between 1854 and 1856 yielded 2,209 tens of ore con- 
taining 104 tens of copper. North Wheal Crofty in the same time yielded 
3,713 tons of ore containing 233 tens of copper.* 

* Phillips and Darlington. ** Records of Mining and Metallurgy," 1857. 



214 THE MINES. 

DoLCX)ATH Mine.— Mach of the following iDformatlon has been extracted 
from the unpublished annual reports of the mine, while the rest of the 
detail was obtained by personal inspection rendered possible by the 
courtesy of the mine manager, Mr. Arthur Thomas, and the generous 
assistance of the staff. The workings of the Dolcoath main lode extend 
to a greater depth than those of any other tin mine in the world. The 
deepest workings are in the eastern part of the mine, and reach 3,120 
feet from surface, or about 2,940 feet below adit, the distance being 
measured along the underlie of the lode. The mine has held a pro- 
minent position in the mining world ever since the introduction of the 
pumping engine in the eighteenth century, and is mentioned by Pryce and 
other early writers. In the old days the Dolcoath Mine formed ocJy part 
of the present property, which comprises the old mines of Wheal Harriet, 
Dunkin's Garden, Stray Park, Wheal Gons, Dolcoath, &c. The details of 
the mineral output of the mine prior to 1815 are practically unprocurable, 
as the information is either altogether lacking or is scattered through the 
pages of weekly papers published about the beginning of the nineteenth 
century. The total yield of metallic copper from this mine between the 
years 1815 and 1836, in 1838, and between 1845 and 1903, was 16,100 tons. 
Phillips and Darlington state that for all the years between 1815 and 1856, 
241,522 tons of ore were sold by public ticketing containing 17,478 tons of 
metallic copper. In 1841, copper ore, sold at £5 a ton, realised £18,529. 
The total output of black tin is 77,500 tons between the years 1853 and 
1905. 

The Main Lode has been worked westwards in Camborne Vcan Mine, 
and eastwards in Cook's Kitchen, where it is called Chappie's lode, 
and in Tincroft and Carn Brea, where it is known as the Highburrow 
lode.* 

There are at least three elvans in the settj which underlie north, but 
the most southerly of them probably underlies south in dc^th. 

There are over a dozen ore-bearing fissures, each of which has received 
a distinctive name by the miners; 

The main lode in the eastern part of the mine is in killas to the 80- 
fathom level (adit about 30 fathoms below surface). In the western part 
of the mine it does not reach the granite until a depth of 230 fathoms is 
reached. From surface to about the 80-fathom level the lode is vertical ; 
thence to the ] 25-fathom level it is 6 or 7 deg. south underlie. From the 
125 to the 216 it is about 15 deg. south ; and at the bottom of the mine, 
near the 485-fathom level, it underlies south at 44 deg. In the eastern part 
of the mine, near its junction viith the South Entral lode, it is 60 feet 
wide, but in descending it thins off to about 3 feet at the 145-fathom level. 
Near the surface the lode is 3 to 6 feet wide. From the 150-fathom level 
to the 200-fathom level near the Engine shaft the width is from 7 to 12 
feet. From the 200 to the 33S-fathom level it varies in width from 1 to 9 
feet. 

The lode had a very fine gossan containing a little tin ore, and was 
exceedingly rich in copper ore down to the 150'fathom level and a little 
below. From this to the 190-fathom level there was both copper and tin 
ore, and Mr. Collins states that between the 170 and the 190-fathom levels 
there was a poor zone in the lode which at the time it wjs encountered 
discouraged the adventurers.^ Below the 190-fathom level no copper has 
been found in any quantity. 

In the eastern part of the mine where it encountered the South Entral 
lode (and was so wide) there was a good deal of quartz and fluorspar. 
The north or main part of the main lode, at the 180-fathon) level, also con- 
tained fluorspar, while the remainder of the lode was chlorite and peach. 
At the 3C8-fathom level rich ground worth over £*105 per cubic fathom for 

• K. J. Frecheville, ** Notes on the Great Main Lode of Dolcoath." Tr. 
Jt.G.S, Corn., 1879-87, vol. x., p. 146. 

+ DelaBeche, p. 1/6. 

+ J. H. Collins, ** Origin and Development of Ore Deposits." Joum,R, Inst, 
Corn., 1892, p. 75. 



DOLCOATH MINE. 215 

tin ore was eDCOuntered. At the 364-fathom level, near the Engine shaft, 
the lodestuff yielded 10 per cent, of tin ore in some parts of the lode which 
is here 20 feet wide.* 

South Branch, — This lode breaks off from the main lode towards the 
south at about the 60-fathom level, but curving round it drops into the 
main lode again at the 125-fathom level. It was never an important lode, 
but contained copper ore from the 70-fathom level to the 120-fathom level 
for a distance of 60 fathoms in direction of strike. 

Harriett's Lode. — In the upper levels it has a bearing of about E. 20 deg. 
N., but from the 70-fathom level to the 180-fathom level it gradually 
changes its strike until its bearing is E. 40 deg. N., and in the eastern 
part of the mine joins the main lode at a place where large quantities of 
copper ore were obtained. Where it changed its strike from E. 20 deg. N. 
to E. 40 deg. N., it was poor. At a point a little below where Harriett's 
lode joins the main lode there is a branch from the north side of the 
main lode which is considered to be a continuation of Harriett's lode, 
and to be the same as is known in Cook's I Kitchen Mine as Eddey's lode. 
Harriett's lode had a poor gossan, and yielded no copper ore until opened 
up at the 110-fathom level, after which it produced copper ore down to the 
180-fathom level, especially eastwards, and a few bunches of tin ore near 
the main lode. 

Sotith Lode. — This is an important branch of the main lode and has a 
general strike of about E. 30 deg. N. It is very nearly vertical to the 190- 
fathom level, after which it underlies S. 15 deg. to about the 290-fathom 
level, and, after underlying a little more, it drops into the main lode at 
the 375'fathom level. It varies in width from 6 inches to 2 feet in the 
upper levels, but is much wider and more productive in depth, and was 
extremely rich in tin ore near the junction with the main lode. In the upper 
levels it has a peach and quartz veinstone. 

Richard*8 Lode. — This is situated between the South and Harriett's 
lodes. Its strike is about the same as that of the main lode. Starting 
from surface it underlies northwards at 13 deg., but in depth it reverses 
its underlie and drops into the South lode near the 242-fathom level. 
Westwards it forms a junction with Harriett's and the main lode. It has 
an average width of 2 feet, and contained a little copper ore from the 100 
to the 140-fathom levels. 

North {or Valley) Cauvier. — The main lode branches at the Gossan 
shaft, near the eastern boundary of the sett. One part runs northwards 
and is known as the Valley Gaunter. At the point where it branches from 
the main lode it has a bearing E. 60 deg. N., but meeting with the South 
Entral lode and Silver lode (situated on the north of the main lode) its 
bearing became E. 30 deg. N. The underlie is 5 deg. S. Before it 
encounters the South Entral lode it varies in width from 6 to 10 feet, 
but at its junction with this lode it is from 20 to 60 feet in width. It 
contained immense quantities of copper ore from the 20 to the 130-fathom 
level, but was very poor below. It was very hard near the Great cross- 
course. 

The Valley Lode, — Situated to the south of the main lode east of the 
Gossan shaft. The bearing is similar to that of the main lode, but as it 
approaches the eastern boundary of the sett it turns more northwards. 
In depth it is this part of the mine which is now principally worked. It 
has always been a good lode. 

South Entral Lode.— Situated on the north of the main lode, and has a 
bearing of about the same amount, but it varies slightly in the eastern 
and western parts of the mine. The underlie is about 13 deg. S. It varies 
in width from 1 to 3 feet. The walls in some places are sharply defined, 
and occasionally in the killas the capel is still to be seen. There was a 
fair gossan, and the lode was productive in copper ore from adit to the 50- 
fathom level for a distance along the strike of 160 fathoms. 



• R. J. Frecheville, ** Notes on the Great Main Lode of Dolcoath." Tr, 
R.G.S. Com., 187d-87, vol. x., p. 149. 



216 THE MINES. 

Silver Lode, — Situated on the north of the South Entral lode. Bearing 
E. 30 deg. N. Its underlie is 13 deg. N. In width about 2 feet About 
£3,000 worth of silver ore was obtained from this lode between deep adit 
level and 15 fathoms from surface. Eastwards and in depth it was unpro- 
ductive."** The silver was vitreous and ruby ore. The lode contained a good 
deal of flucan (clay). 

North Entral Lode, — Situated to the north of the Silver lode. Bearing 
E. 30 deg. N. Underlie 27 deg. to 30 deg. N., and is about 4 feet wide. 
Another lode on the north of this is 1 to 3 feet in width, underlies south 
at 30 deg., and intersects it. It had only a moderate gossan, and yielded 
copper ore about adit level. At the 42-fathom level there was mundic. 

The Gaunter Lode, — This lode breaks off from the Dolcoath main lode 
on the south side at Wheal Bryant shaft. Bearing E. 4 deg. S. Underlie 
is 15 deg. S., but it is steeper in depth. In width it varies from 6 inches 
to 1 foot. The lode encounters the South lode at about 50 fathoms west 
of Bryant shaft. It had fine bunches of gossan to within 20 fathoms from 
surface, and was very rich in copper from adit level to the 80-fathom level 
for 150 fathoms east of its junction with the main lode. The veinstone is 
quartzose and chloritic. It was recently intersected by the 220-fathom 
level cross-cut, which was driven south from the main lode, and at that 
depth it contained a little cassiterite. At the 70-fathom level there are a 
few branches from the Gaunter lode. 

The main lode has several small branches which are of insignificant 
importance. One is named Rulers Lode, which branches off at the 70-fathom 
level. It contained copper ore from the 70 to the 100-fathom level for a 
distance of 60 fathoms along its strike. The other is called the OtUvert 
couraet which branches off from the main lode at the 50-fathom level, and 
contained copper from the 50 t^o the 80-fathom level. Another lode of small 
importance, known as Martinis Lode, starts from surface between the main 
and South Entral lodes. It underlies north and intersects the South 
Entral at the 40-fathom level. This lode had very little gossan but con- 
tained copper neaV the Great cross-course. 

The Brea or Plantation Lode, — ^This is the most southerly lode in the 
sett. It is nearly vertical, and was recently intersected by the William's 
New shaft, which was sunk vertically to meet the 220 cross-cut. The lode 
contains cassiterite, mispickel, and chloritic materials. The strike is 
E. 30 d^. N., and in width it is about 1^ feet. 

General Remarks on Dolcoath Mine, — In addition to the ores of tin, 
copper, and silver, there occurred bismuth, arsenic, cobalt, and pitch- 
blende. Thus, arseniate of cobalt was found in one of the lodes containing 
copper,t and in some places in the main lode it was intimately mixed with 
tin ore to the extent of about ^ per cent.| Native bismuth and bismuth 
sulphide with pitchblende, arsenical cobalt, quartz, and fluorspar also 
occurred.§ (See also Index of Minerals, p. 195.) 

The character of the veinstones has been described by several writers. 
Henwood states that in granite the lode is brecciated.|| Mr. Collins exam- 
ined some of the ores with the microscope. A specimen of veinstone from 
the 314-fathom level shows veins of quartz cutting through an " acicular 
mass of blue tourmaline, and are themselves traversed by veins of cassi- 
terite.'* Another stone " is evidently a breccia ; it consists of angular 
patches of fine-grained green or bluish green material, which is apparently 
composed in the main of a network of fine needles, embedded in a crystalline 

* Information obtained from unpublished Mine Records. De la Beche states 
that £2,000 worth of silver ore was obtained, p. 288. 

t J. Carne, "On the Veins of Cornwall." Tr. If.G,8. Com., 1822, vol. ii., 
p. 105. 

X R. Pearce, " Note on the Occurrence of Col)alt in connection with the Tin 
Ores of Cornwall. " Joum, Boy, Inst, Com., vol. iv., 1872, p. 81. See also Josiah 
Thomas, op. cit., vol. iii., 1868, p. 142. 

§ R. Pearce, •* Note on Pitchblende in Cornwall." Tr. R,O.S, Com., 1864 to 
1878, vol. ix.,p. 103. 

II p. 212. 



DOLCOATH MINE. 217 

mass ot cassiterite, which exhibits distinct crystals in a few places. A 
little quartz occupies the interspaces which are few — and this encloses 
many fine needles of tourmaline." Another stone from the 260-fathom 
level contains 60 per cent, of tin. It " is a mass of rather large grey 
ctystals." ''With the cassiterite is a little quartz and some fringed 
crystals of tourmaline. Some of the crystals contain embedded needles 
which are probably schorl."* Dr. Flett has also described some of the 
Dolcoath veinstones. (See p. 138.) Killas obtained from the 215-fathom 
level has been microscopically described by Phillips. It is "exceedingly 
hard with an imperfect cleavage, and is of a dark grey colour. Under the 
low power (400 diam.) small grains of magnetite are distinguished from 
which as a centre indistinct fan-like aggregations of perhaps some variety 
of chlorite diverge in all directions." **It also contains broken and rounded 
plates of mica and a few fragments of brown semi-transparent mineral, 
mechanically embedded in slate." | A large mass of slaty rock was encoun- 
tered in the main lode on the east of the Eastern shaft at the 352-fathom 
level. At this place the main lode is well within the granite and about 
240 fathoms below the junction of the granite and killas.t A piece of 
striped hornfels was recently discovered in the lode at the 375-fathom 
level, near Stray Park shaft, at which point the lode is in granite. 

Elvans are seen at the 375-fathom level in Stray Park ; in the 220 cross- 
cut between Sump shaft and William's New shaft underlying north a few 
degrees ; ac the 220-fathom level at Sump shaft between Richard's and 
the main lode ; also at 375, 388, 400, and 412-fathom levels near the Old 
Sump shaft in the vicinity of the main lode. At the 400- fathom level 
near Old Sump shaft an elvan underlies in a north-easterly direction 
55 deg. ; at 266-fathom level there is an elvan below Harriett's lode. At 
352-fathom lev^l on south of South lode, at 100 and 160 fathoms east of the 
Engine shaft, an elvan is seen underlying south in the same direction as 
the lode which is situated on its foot wall. An elvan is seen at the 
254-fathom plat at Valley (or Eastern) shaft and is again seen in a cross- 
cut on the west of the shaft. Another in the same cross-cut is again seen 
at the 302-fathom level between the main and South lode. An elvan 
crops out at the margin of the granite and underlies N. 45 deg., but 
becomes perpendicular and then south underlying in the granite. An 
elvan on the north of the Engine shaft underlies N. 40 deg. ; another 
cropping out about 170 fathoms north of the engine shaft underlies 
N. 40 deg. 

Dolcoath Mine has been worked for well over a century and a half. 
Josiah Thomas states that the depth of the mine in 1758 was 88 fathoms. 
In 1788 it was 183 fathoms. In 1824, 240 fathoms, and in 1868, 340 
fathoms.§ At the present time the deepest workings are 490 fathoms 
below adit level. 

The cost of driving an end 8 feet high and 6 feet wide was, in 1868, 
about £20 a fathom in hard ground. The cost of breaking the ore and 
sending it to surface is about 5s. 6d. per ton.|| 

The average yield of black tin per ton from 1872 to 1881 was 59 lbs., 
while during the same period the cost of mining was 16s. lid. per ton, and 
of dressing 3s. lOjd. per ton.^j 

The following notes are extracted from the Report of the Directors 
issued in June, 1906, to the shareholders in the mine : — 

The profits earned in the half-year (January to June, 1906) amount to 
£40,165. 

The following table shows the progress of the present company's opera- 
tions since its commencement : — 

* J. H.Collins, "Cornish Tinstones and Tin Capels." Min. Mag., 1882, 
vol. iv., p. 11. 

f J. A. Phillips. Q.J.O.S., 1875, vol. xxxi.,p. 323. 

X J. A. Phillips, " Ore Deposits. ' 2nd edition, p. 213. 

§ Josiah Thomas. Joum. Roy. Irist. Cornn-all^ vol. iii., 1868, p. 192. 
Op. cit. 

f R. J. Frecheville, ** Notes on the Great Main Lode of Dolcoath." TV. R, G.S, 
Com., vol. X., p. 147. 



THE HIKES. 



Six HontllB 
ending. 



II 



Dec. 3lBt. 
June 30th, 
Dee. 31at, 
Jnne 30tb, 
Dec. 31st, 
June 30th, 
Dec. Slat, 
June 30th, 
Dec. 31st, 
Jnne 30th, 
Deo. 31st, 
June 3fltb, 
Dec. 31 Bt, 
June 30tb, 
Deo. 31 at, 
June 30th, 
Dee. 31 Bt, 
June 30th, 
Dec. a 1st, 
June 30th, 
Dec. 31st, 
Jane 30th, 



1,021 1 
,1.073 
11,140 

1,162 



Tons. Tons, 
189528.7171,015 

189630,0151.029 
1896|33,712 "MK> 
1897.36379 
1897:37,"" 

189a!3P. 

1898,40,608.,- — 
1899141.101 1.037 
1699:41,6301,040 
1900 45.102|1, 043 
190043.254 960 
1901147,603 1,001 
1901148.9751,033 
190248.155 934 
190252,295 893 
190347,899 863 
190351,011 876 
190450,196 810 
190450.353' 894 
1905 49.9741 829 
190518.473 860 
190649,934 920 



g.£ 



Averse^ 
price per 
Mm of Ore. 



i-78 
6707 1 

64-10 1 
56-571 
56-001 
5I-8OI1 18 . 
1149-76- "" • 



5 6-33 
110-2 
1 7-27 
L 1 






39 3 
37 4 

36 9 

37 18 



113 : 



18 1 547-14 

13 1 18 47-281 

15 2 2143-481 

13 2 19 38-281 

14 3 13 40-391 
2 2 12 38-471 

15 23 36-181 
8 3 0!39-791 

18 2 23 37-201 

18 3 2l!40-0ei 1 



1 15 1: 



1 10 J 



6-78 


37 17 440,636 19 8 


8-94, 39 16 4145,221 15 I 


10-09, 46 18 0M,497 6 3 


8-21 


66 12 7^9,222 12 8 


H-3f 


79 7 11'82,651 16 


3-51 


82 15 483,364 1810 


M-4 


80 18 2,77,750 U 4 


8-61, 


7219 1073,132 11 


10-35, 68 7 670.676 2 6 


IO-7f 


71 17 167,168 6 6 


St 


72 8 4:64.716 7 4 


11 


80 3 6l69,251 5 


■^o^ 


73 5 864,206 15 6 


l-2^ 


7412 660,504 10 2 


;r42 


77 5 569,114 16 4 


ll-2f 


81 2 167,311 !6 11 


0-4( 


91 17 1179.669 13 1 


U'^ 


105 13 497,208 9 



The 


Keoelpts 


Expenditure, »ad Froflts for 17 halt-Tetrs on 


Profit knd 


Loss Acconnt were as bllcnn :— 




— 


Eeceipts. 


Working 
Cost. 


Grow 
Proflta. 


Lord's 
Bo7aIt»es. 


Net 

Company's 

Proflta. 






£ 8.(1. 


£ fud 


£ ». 


d. 


£ s. d. 


£ B. d. 


First Half of 1898 


46,007 17 8 


37,019 18 6 


8,987 19 


2;1.721 18 3 


7,266 on 


UMer 


of 1898 


55,28413 2 


38,862 7 1 


16,422 6 


1|2,27014 5 


14,151 11 8 


First 


of 1899 


60,983 13 10 


42.910 16 8)27,072 17 


2.4,614 16 10 


22,458 4 


Latter 


of 1899 


83,492 15 11 


46,915 3 1 


36,577 12105,511 7 5 


31,066 6 5 


First 


of 1900 


87,038 12 2 


48,866 8 7 


38,172 3 


7,5,757 16 


32,414 7 7 


Latt«r, 


of 1900 


78,626 3 5 


50,898 U 10 


27,727 1 1 


7,5,183 7 7 


22,544 4 


First 


of 1001 


73,727 1 10 


51,949 3 10 


21,777 18 


04,875 9 4 


16,902 8 8 


Latter, 


otl901 


71.723 2 5 


50,737 8 11120,985 13 


014,711 14 10 


16,273 18 8 


First 


of 1902 


87,926 8 10 


49,054 17 9,18,871 11 


1^,477 17 9 


14.39313 4 


Latter, 


of 1902 


65,281 17 1 


48,928 12 116,353 5 


0,4314 8 5 


12,03816 7 


First , 


of 1903 


69,762 11 3 


19,031 8 320,731 3 


0,4,61615 


16,114 8 


Latter, 


of 1903164,812 18 9 


49,52810 615,284 8 


3,3,280 9 


12,003 19 3 


First , 


of 1904|61,143 3 5 


50.182 14 410,960 9 


1 12,951 5 


8.009 8 8 


Latter, 


of 1904169,699 4 4 


53.67413 9:16,024 10 


7,2,303 16 6 


13,720 14 1 


First , 


ofl905'«7,934 8 


S3350 4lu,584 


4,2,243 14 6 


12,340 5 10 


Latter , 


of 1905179,733 5 4154,69117 7125,041 7 


92,65513 I 


22,385 14 8 


First , 


of 1906 


87,910 18 


54,502 18 9 


43,407 19 


3 


3,242 5 4 


40,165 13 11 



THE ACTIVE MINES. 



219 



Cksst of Baising and Treating the Ore Per Ton.— 







Charges. 


Six Months ending — 


Receipts. 












Working 


Lords' 






Costs. 
£ s. d. 


Roy 
£ 


alties. 




£ s. d. 


s. d. 


31st December, 1895 - 


17 6 


1 4 4 





11 


30th June 1896 


1 5 10 


1 3 1 





10 


31st December, 1896 - 


1 2 6 


1 10 





9 


30th June, 1897 - 


1 2 2 


1 2i 





8} 


3l8t December, 1897 - 


12 


19 





9 


30th June, 1898 - 


14 2 


19 5 





11 


31st December, 1898 - 


1 7 3 


19 1 





1 H 


30th June, 1899 - 


1 14 1 


1 11 





2 3 


31st December, 1899 - 


2 1 


1 2 7 





2 7 


30th June, 1900 - 


1 18 7 


1 1 8 





2 6i 


31st December, 1900 - 


1 16 4 


1 3 6 





2 5 


30th June, 1901 - 


1 10 llj 


1 1 9| 





2 Oi 


31st December, 1901 - 


1 9 3J 


1 8J 





1 11 


30th June, 1902 - 


1 8 2J 


1 4J 





1 lOJr 


31st December, 1902 - 


1 4 Hi 


18 8i 





1 7^: 


30th June, 1903 - 


1 9 IJ 


1 5J 





1 11 


31st December, 1903 - 


1 5 4| 


19 5 





1 3J 


30th June, 1904 - 


1 4 4i 


19 111 





1 2 


31st December, 1904 - 


1 7 8 


1 1 31 





lOj 


■ 


30th June, 1905 - 


1 7 21 


1 1 4 





10: 


■ 


31st December, 1905 - 


1 12 lOf 


1 2 6| 





1 1; 


■ 


30th June, 1906 - 


1 19 2* 


1 1 10 





1 3 



East Pool and Wheal Agar United.— This sett is situated on the 
eastern extension of the same series of lodes which are worked in the adja- 
cent mine of South Crofty. Borlase mentions the Old Pool Mine, and 
describes the mode of working the mine in his time. 

Tne ** backs " (outcrops) of the lodes in Wheal Agar were worked for tin 
by the ''old men."! 

The upper part of the mine is in killas to about the 135-fathom level ; 
below this the lodes are in granite, and are being worked at the present 
time. The mine has yielded enormous quantities of both copper and tin 
ores, and in addition has proved to be an important repository of wolfram. 
Between 1847 and 1856, Wheal Agar sold by public ticketing 3,022 tons of 
ore yielding 390 tons of metallic copper ; East Pool between 1835 and 1856 
yielded 38,780 tons of ore containing 2,911 tons of metallic copper. J 

Main or Engine Lode. — The underlie to the 36-fathom level is 15 deg. S. 
At this level the lode is in contact with an elvan which underlies north, 
and below it to the 60-fathom level the lode is perpendicular. From 
the 60-fathom level downwards the underlie is about 15 deg. south. The 
lode had a good gossan and yielded copper ore in abundance. At the 
150-fathom level the lode is 10 feet wide, and yielded both tin and copper 
ores. It was wrought for wolfram below the 135-fathom level. 



• Borlase. Nat, Hist, Com,, l^SS, p. 167. 

T J. Maynard, '< Remarks on Two Cross Sections," &c. Rep. Roy, Com. 
Poly,Soc., 1871, p. 195. 
X Phillips and Darlington. " Records of Mining and Metallurgy," 1857. 



220 THE HIKES. 

Ths Great Lode.~lt u from this lode Uiat moat ot the wolfrmm of the 
mine has been obtained. This lode vas first encountered at aboat the 
140-Iathoiii level. It baa been worked upon to below the 300-fathom level, 
and has yielded good tin and wolfram ore with miapickel, &c. 

Prycc'a Lode.— Situated on the north of the main li>de and underlies 
north. It ia the same lode that is being worked in South Croft; at the 
present time, 

Middle Lode. — Situated north ot the Qreat lode, and has a slight 
southerly underlie. 

Palmer's Lode.— Vertical to the 50-fathom level, and then underlies 
south 13 deg. Varies from 1 to 3 feet in width. Near the western end of 
the sett, close to South Crofty, it forms a junction with the main lode at 
50 fathoms west of Engine shaft. The veinstone consists ot quartz and 
killas in the upper level, and the lode contained copper from the 26 to 
the 48-fatham level for 30 fathoms in direction of strike. 

North (or Reeve't) Lode.— Underlies north 20 deg. Varies iu width up 
to 2 feet, and containa quartz and copper pyrites. 

South Lode.— Parallel with the main lode. Underlie N. 20 deg. At 
adit level the width is about 1 foot, but below the TO-fathom level It ia I^ 
to 4 feet wide, and at the ISO-fathom level it ia 7 feet wide In places. Near 
the western boundary, at the lOO-fathom level, the lode is 30 feet wide. 
At adit level the lode consisted mainly oF fluean (clay) and quartz. It 
yielded copper from the 40 to the 70-fatbom level. From the 70 to the 
100-fathom level there was both copper and tin. Copper ore was again 
abnndant at the 130-fathom level, at ^hich place the lode also contained 
tin, wolfram, and arsenic. 

North Tincroft Lode.— Underlie N. 27 deg. At the 70-fathom level 
the lode ia 1 foot wide and whs poor. 



Fig. 22. — West Basset North Lode, Longitudinal Section. 




el? §;; i • 

I'* \ * scAi,e -FaiJiomt 

i • I f lep t 

» n t '-^ ^ -■ ' 1. 1 I . 



below the 100-fathom level. The lodes on the south were not so rich, hut 
yielded both tin and copper ores. The Plat Lode is heaved by the "Old 



THE ABANDONED MINES. 221 

Lode " from the 134 to the 114-fathom level. Both the Gaunter lode and the 
New Lode have yielded copper and tin.* 

The Main or North Lode was not rich in copper ore eastwards 
(Fig. 22.) 

Gaunter Lode, — The ore bunches dip eastwards. The width of the lode 
at the 60-fathom level is 1^ feet, and it was a fairly good lode. Below 
the 114-fathom level it was 3 feet in width. 

Middle Lode, — A good deal of tin ore was extracted from this lode near 
the place at which it cut the junction of the killas and granite. 

The Chreat Flat Lode was intersected in depth while working on a north 
underlying copper lode. At the 140-fathom level the width of the capel 
and lode is 40 or 50 feet, and the whole is more or less tin bearing. The 
leader is frequently a mere ferruginous joint. f Between the years 1852 
and 1856 the mine yielded 22,135 tons of ore containing 1,541 tons of 
copper.}: 



The Abandoned Mines. 

Wheal Ann. — The Wheal Ann lode is the easterly prolongation of 
Wheal Trumpet Lode,— From the 122 to the 142-fathom level the lode 
has smooth walls and is enclosed in schorlaceous or decomposed granite. 
The lode yielded black tin ore associated with ** brown iron ore."§ 

Balmynheek Mine. — In 1876, 2,200 tons of tin ore were stamped 
yielding over 1 per cent, of black tin per ton.|i 

Barncoose Mine. — A quantity of rich copper and tin ore was raised 
from this mine, but it was suspended in 1872 owing to poverty. At the 
50-fathom level the lode is 3 feet wide, and consists largely of mundic 
and quartz. 

The MouJhay Lode underlies north, and is thought to be a continuation 
of Dunkin's Lode (in Cook's Kitchen). The Barncooae Lode underlies north 
about 15 deg.^ 

Wheal Basset and Grylls. — Tyack*8 Lode.— The lode varies in width 
from 2 to 3 feet, and has yielded tin ore from surface to the 64-fathom 
level. 

Wheal Fat Lode.— Varies in width from 3 to 10 feet Has yielded tin 
ore. 

Brenton*8 Lode, — From the 22 to the 52-fathom level the lode varies in 
width from 2 to 6 feet, and has yielded tin ore. 

Furgenson'8 Lode, — 4 feet in width. From the- 23 to the 50-fathom level 
the lode yielded good tin ore. 

South Tymorgie Lode.— 3 feet in width at the 30-fathom level. 

Tymorgie Branch, —From the 34 to the 44-fathom level the lode varies 
in width from 1 inch to 2 feet. 

Gaunter Lode, — At the 30-fathom level the lode is 5 feet in width and 
yielded tin ore. A horse of ground occurred in this lode. 

Wilkin's Lode.— From the 20 to the 60-fathom level the lode is 2 feet 
wide. 

Gope*8 Lode, — From 1 to 2 feet in width at the 35-fathom level and 
yielded fair tin ore. The lode at the 65-fathom level is 3 feet in width. 
North branch is 1 foot wide, but yielded no tin ore. 

Garlidna Lode, — At the 11-fathom level the granite was encountered in 
the south wall. 

* J. Maynard, ** Remarks on Two Cross Sections." Bep. Corn. Poly. Sec, 
1871^. 202. 
+ Foster. 

t Phillips and Darlinj^ton. '■ Records of Minin;4 and Metallurgy," 1857. 
Henwood. | Foster, p. 648. % Thomas. 



222 THE MINES. 

Harvey*8 Lode, — At the 20-fathom level the lode is 2 feet in width and 
yielded poor ore. 

Wheal Foster Lode, — From the 15 to the 35-fathom level the lode 
is 1 or 2 feet in width, with a little tin ore. 

Wheal Beauchamf.— There were five lodes worked about the year 1819. 
The most northerly underlies north and yielded copper. The next was 
wrought for both tin and copper. Underlies N. 15 deg. The two next 
yielded copper ore. They underlie north. The southernmost was wrought 
for tin ore and underlies N. 13 deg.* 

Bell Mine. — A copper lode underlies N. 23 deg. (Thomas.) At the 
20-fathom level the leader is 18 inches wide. 

Wheal Boys. — ^A copper lode underlies S. 15 deg. (Thomas.) 

Wheal Bcller. — Charles Thomas states that the dividends from the 
sales of copper ore since its discovery in quantity at the 20-fathom level 
up to the year 1867, were £270,000.1 In 1820 and 1821, 972 tons of 
copper ore were raised yielding 97 tons of copper.^ 

Wheal Bcller and Beauchamp. — Henwood gives the follo^ng 
particulars of the lodes of this mine : — 

South Lode.— Bearing E. 25 deg. N. Underlie 15 deg. to 30 deg. N., 
varies in width from 1 to 2 feet. Black copper ore with quartz, febpar, 
and earthy brown iron ore. 

North Lode.— Bearing E. 25 deg. N. Underlie N. 10 deg. to 30 deg. 
Yielded black and vitreous copper ores to the 50-fathom leveL 

Davejfa Lode— E. 27 deg. N. Underlie vertical to 45 deg. N. Varies 
in width from 1 to 20 feet. The lode contained quartz, slate, black and 
vitreous copper ores, copper pyrites, oxide, carbonate and arseniate of 
copper, fluorspar, and chlorite. At the 99-fathom level there were veins 
of quartz and copper pyrites. 

Cardrew Downs Mine. — Henwood makes the following statement in 
regard to the lodes : — 

South Lode.— Bearing E. 17 deg. N. From the 50 to the 120-fathom 
level the underlie is N. 10 deg. to N. 30 deg., and the width is from 6 inches 
to 6 feet. The lode consists of quartz, earthy brown iron ore, black copper, 
and iron and copper pyrites, chlorite, and fluorspar. 

North Lode.— E. 17 deg. N. The underlie is from 8 deg. S. to 22 deg. S. 
The lode varies in width from 8 inches to 2| feet, and consists of quartz, 
chlorite, slate, and iron and copper pyrites. 

Phillips and Darlington state that the Cardrew Mine yielded between 
1826 and 1838, 17,143 tons of ore containing 1,141 tons of copper.} 

Carharrack.— The Wheal Virgin Lhde underlies N. 16 deg. 

Another lode situated further south is said to be a continuation of 
Wheal Maid lode. (Thomas.) 

Between 1820 and 1852, Wheal Maiden and Carharrack yielded 23,552 
tons of ore containing 1,542 tons of copper.} 

Carleen Mine. — The lode is wide and productive in killas, but Imme- 
diately it enters the granite it is reduced to a mere string.§ The lode is 
a continuation of one of those in Wheal Vor. 

Carqueen Mine.— There is a great cross-course 60 fathoms east of the 
Engine shaft. 

* Thomas. 

t "Mining Districts of the West,** 1867, p. 63. 

t Phillips and Darlin^n. "Records of^Mining and Metallurgy," 1867. 
§ J. Came, "On the Veins of Cornwall." Tr. H.G.S, Com,, 1822, vol. ii., 
p. 93. 



THE ABAin)ONED MINES. 223 

The Chaoewater Minis (or Wheal Easy).— TFtHiam's Lode.— Underlie 
S. 15 d(^. This lode is known eastwards in Wheal Daniell and westwards 
in Wheal Chance. It is the South lode of Wheal Chance, Treskerby, 
Wheal Boys, and Wheal Pjrussia. 

Ohacewater Lode. — ^A tin and copper lode having a northerly underlie 
of 47 deg. The lode is known in Wheal Daniell, Treskerby, and 
Cardrew. 

Winters Lode. — A tin and copper lode underlying N. 47 deg. The 
" black el van ** is situated between this and the Ohacewater lode. 

Wlusal Vor Lode, — Underlies N. 22 deg. A tin and copper lode.* 
Between 1815 snd 1822, 30,140 tons of ore containing 1,882 tons of copper 
were sold by public ticketing ; in 1823, 198 tons containing 16 tons of copper, 
and between 1823 and 1856, 33,486 tons of ore containing 1,669 tons of 
metallic copper.j Tin, copper, wolfram, and arsenic occur. 

Wheal Charler. — The North Lode has a bearing E. 25 deg. N., and has 
an irregular northerly underlie from the 30 to 70-fathom level. In width 
the lode is 2 to 10 feet. It consists of quartz, slate, copper and iron 
pyrites, and earthy brown iron ore. At Bateman's shaft the lode is 3 feet 
wide but barren. 

Stacey's Lode— Bearing E. 25 deg. N. The underlie is north. The lode 
consists of copper and iron pyrites, quartz, and slaty clay.J Between 1821 
and 1834, 4,360 tons of copper ore were sold by public ticketing, con- 
taining 283 tons of copper.§ 

Wheal Clinton. — Situated near Trefusis Point, Falmouth. Mr. F. J. 
Stephens states that the mine was started in 1854 and wound up in 1858, 
but that prior to this a little work was done on the same lode towards the 
east. The adit level driven in a long way on the S juth lode showed traces 
of lead in many places. In the No. 1 cross-cut " a fine course of ore com- 
posed of spar, flucan, and frequent bunches of galena " occurred, but the 
lode was disordered near greenstone. || The same writer states that some 
ore containing blende and galena was assayed and found to contain silver 
and ** gfenerally a little gold."*[ Sir Warington Smyth in 1857 remarked 
that Wheal Clinton has been worked beneath the sea between the 20 
and 30-fathom level, and that lead ore was raised from the mine at this 
place. A cross-course at the 20-fathom level made the workings 
dangerous.** 

CoNSOLiDATEn MiNBS. (See Figs. 23, 24, 25, and 26.) — The following 
notes are from Henwood ; — 

Patd'8 Lode.- Bearing N.E. and S. W. Underlie 14 deg. to 40 deg. N.W. 
From the 70 to the 12^fathom level the lode is 2 to 4 feet wide, and 
contained black and vitreous copper ore, copper and iron pyrites, slate, 
and quartz. 

Glover*8 Lode or Kitto*8 Branch.— Bearing E. 25 deg. N. From the 70 
to the 215-fathom level the lode has an irregular southerly underlie, vary- 
ing from 10 deg. to 45 deg. Black, vitreous, and yellow sulphide of copper 
in slate. 

MichelVB Lode.— E. 25 deg. N. Underlies 80 deg. S., and is about 2 feet 
in width. It consists of quartz, slate, and iron and copper pyrites. 

Taylor*8 Lode. — The bearing from the 150 to the 290-fathom level is 
R 27 deg. N. In the upper levels, down to the 240-fa thorn level, it has an 
underlie of N. 76 deg. At the 240-fa thom level it is vertical. Below this 
it varies from !6 deg. N. to 20 deg. N. Varies in width from 1 to 16 feet. 

♦ Thomas. 

t Phillips and Darlington. '* Records of Mining and Metallurgy," 1857. 

Henwood. 
§ Phillips and Darlington. ** Records of Mining and Metallurgy," 1857. 
II "The Mineral Resources of Falmouth.'' Jiej?. Corn. Poly, Soc, 1886, p. 189. 
% Ir, R.G.S. Corn., 1899. 
** Information obtained from an unpublished report througli the courtesy of 



Mr. Crawfurth Smith, of the '^Ottice of Woods," Whitehall. 



I report 
," WUit 



224 



THE UIKES. 



At tbe 150-fatbom leml there was a vug 25 tathoms in length. The Inde 
contains quarts, alate, iron and copper pjrltes in detached maases, and in 
the deeper levels copper pjrites, fluorspar, and quartz. 

Etvan'B South Lode.- B. 18 d^. S. at the 190-fathom level. It varies in 
underlie [rum S. 26 deg. to S. 40 deg. It is 4 to 6 feet in width, and 
contained quartz, alate, and some copper sulphide. 



Fig. 23. — Clifford Amalgamated Mines. 




Great Consolidated Mioes. 



United Mines. 



Trejjottniiiij'ii tod«.— Bearing N.E. and S.W. Prom the 1© to the 228- 
fathom level the lode underlies S.B. 20 deg. to N.W. 12 de^. Varies in 
width from 3 to 6 feet, and contains quartz, copper sulphide, and slate. 



Fig. 24. — Pddiee. 



Fig. 25.— United Minea. 




DeebU's North Lode.— Bearing N. 3& deg. £. Prom the 250 to the 2C0- 
fathom l(!vcl the lode vurleH in underlie from 10 dog. to 22 dog. N., and in 
width from 1 to 4 feet, couHisting of copper sulphide, chlorite, and quartz. 
It uuitCH with Deeble's lode westwards. 

Deeble'a Lode.— From the 40 to the 285-fathoBi level the lode varies in 
underlie from N. 20 deg. to S. 10 deg. From 2 to 6 feet in width. At 



THE ABANDONED BONEa 



225 



the 40-f»thoni leyel the lode oontalns earthj brown ores, quartz, copper 
pyrites, and black copper ore. In depth it is mainly copper pyrites with 
qnarts. The lode joins the Wheal Fortune lode eastwards. 

Wheal Fwtune Lode.—E. 36 deg. N. From the 160 to the 285-fathom 
level the underlie is N. 30 deg. to yertical, and the lode contains iron and 
copper sulphide and some earthy brown iron ore at the 250-fathom leyeL 
The shoots of copper dip east. In the eastern part of the mine the lode 
has the same bearing, and from the 145 to the 215-fathom level the under- 
lie is N. 4 deg. to N. 30 deg., varying in width from a few inches to 14 feet. 
At the 160-fathom level the lode contains earthy brown iron ores and some 
copper pyrites, and quartz in some places mixed with schorl. There is also 
chlorite in vuggy quartz. 

Ousvey Lode, — Bearing E. 32 deg. N. The underlie is 10 deg. to 
32 deg. N. from the 33 to the 173-fathom level. The lode varies in width 
from 6 or 7 inches to 3 feet, and contains copper and iron pyrites, quartz, 
chlorite, and schorl. The ore shoots dip east. 

Between 1815 and 1856, the ore sold by public ticketing from this mine 
amounted to 441,286 tons containing 37,402 tons of metallic copper.* 



Fig. 26. — ConsolidaUd Mines. 







C&ANE AND Bejawba Mine. — The Wheal Seton main lode as well as 
that of South Boskear Mine traverses this sett. 

The Bejawsa Lode underlies north from surface to the 20-fathom level, 
but below that it uoderlies south. It varies in width from 2 to 4 feet, and 
has a fair gossan with quartz and mundic. 

The Crane Lode varies in thickness from 18 inches to 3 feet. The lode 
generally is poor, but yielded blende, copper ores, and some lead with iron 
pyrites in the higher levels. It was explored to the 60-fathom level. 

The Briggan Lode contains copper ore with quartz and chlorite. 

Charles Thomas states that the West Seton main lode was worked to 
the 100-fathom level in this mine but only yielded a little copper ore. 
The elvan which traverses the West Seton Mine passes through this sett 
and is in contact with the lode.j Between 1851 and 1853, 671 tons of 
copper ore containing 61 tons of copper were sold by public ticketing.:)^ 

Cbenveb and Wheal Abraham and Sarah.— The lode is 24 to 3 feet in 
width and has an east and west bearing. It underlies south 15 deg. It 
becomes poor and hard and often diridcd into branches In tho elvan, and 



* Phillips and Darlington. ^* Records of Mining and Metallurgy," 1857. 

t '* Mining Districts of Cornwall," 18G7, p. 47. 

X Phillips and Darlington. ** Records of Mining and Metallurgy," 1857. 



226 THE MINES. 

in fact *' an elvan appears to be one of the components of tlie lode/** In 
some parts of Crenver and Wheal Abraham the ore shoots have a 
westerly pitch, j The mine has been worked to a depth of 220 fathoms at 
the Old Sump (or Middle Engine) shaft. Between 1815 and 1827, 85,851 
tons of copper ore containing 6,061 tons of copper were sold bj public 
ticketing from Wheal Abraham, Oatfleld, and Crenver. Wheal Abraham 
in 1854 yielded 324 tons of ore containing 5 tons of copper.^ 

Wheal Cupid. — The Wheal Cupid lode is copper bearing and underlies 
S. 13 deg. Another copper lode situated on the south underlies N. 13 deg. 
On the north of the Wheal Cupid lode there is a lode underlying north. 
(Thomas.) 

Wheal Damsel. — The Main Lode has been traced for over 2 miles, 
and is the same as the Wheal Maid lode.§ All the lodes have yielded 
copper ore. 

The Pressure Engine Lode underlies N. 13 deg. 

The Old North Lode underlies N. 27 deg. 

The Old South Lode underlies N. 23 deg. 

Gabert*8 Lode underlies N. 13 deg. 

Turtle's Lode underlies N. 12 deg. 

Wheal Hope Lode underlies N. 15 deg.|| 

Between 1815 and 1842, 25,111 tons of ore containing 3,176 tons of copper 
were sold by public |<icketing.^ 

Wheal Daniell. — The upper part of the lode was worked for tin for 
at least 10 fathoms. The lode did not yield copper near the surface."^* 
It has been worked to the 48-fathom lev^. Thomas has recorded the fol- 
lowing particulars regarding the lodes : — 

OhaceuMter Lode underlies N. 40 deg. Wrought for tin ore. 

Winter's Lode situated north of Chacewater lode underlies N. 40 d^. 
Wrought for tin and copper. 

William's Lode underlies S. 32 deg. Wrought for copper. 

South Lode underlies N. 17 deg. Wrought for tin and copper. Thirty 
fathoms south of the South lode is the Fat Sow Lode which under- 
lies north ; tin bearing. Thirty fathoms south of the Fat Sow lode is the 
Wheal Doit Lode which underlies north ; tin and copper bearing. 

Wheal Derrick.— The North Carquean Lode underlies N. 27 deg. The 
lode yielded both tin and copper. There are three other lodes which haye 
been wrought for copper ore. They underlie north or are perpendicular. 
(Thomas.) 

East Ale and Cakes Mine.— The United Mines Great lode passes 
into this sett. Itunderlies N. 15 deg. The South Lode underlies N. 37 deg. 
(Thomas.) 

East Wheal Chance.— A copper lode underlies south 13 d^. A 
Gaunter Lode bearing copper ore underlies N. 4 deg. and heaves the main 
jode 2 fathoms to the left. (Thomas.) 

East Downs.— Tretiwn North Lode {Briggan Lode) underlies S. 
15 deg. The South Lode underlies south at the same angle. (Thomas.) 

East Wheal Damsel.— The North Lode strikes E. 17 deg. N. From 
the 80 to the 150-fathom leyel it varies in width from H to 12 feet, and 
underlies N. 6 deg. to 22 deg. The veinstone is composed of quartz, 
felspar, clay, iron pyrites, and vitreous and black copper ores. 

• J. Carne, **0n Elvan Courses." Tr, R.O.S. Com,, 1818, vol. i., p. 101. 
t Hen wood, p. 41. 

X Phillips and Darlington. " Records of Mining and Metallurgy," 1857. 
§ J. Carne. ** On the Veins of Cornwall.'* Tr, R,G.8, Corn,, 1822, vol. ii., 
p. 121. 
II Thomas. 

% Phillips and Darlin^n. *' Records of Mining and Metallurgy," 1857. 
** W. H. Argall. Miners' Association (Breage Meeting), 1872. 



THl ABANDONED BONES. 227 

Middle Lode.—IL 17 d^. K. From 100 to 180-ftithom level the lode 
Tftries from 2 to 7 feet and underlies 10 deg. to 30 deg. N. It oonsists of 
decomposed granite, yitreons and black copper ore, copper snlpliide, iron 
pyrites, and earthy red iron ore. (Hen^rood.) 

Eaot Wheal Lovell. (Fig. 27.)— Mr. CoUins has described some of the 
lode material from this mine. He remarks that it was originally granite, 
but the felspar is changed to a dosty-looking material, which under high 
powers of the microscope seem to be imperfectly formed crystals of gil- 
bertite and perhaps a little tourmaline. In places, In the neighbourhood 



Fig. 27.^Ea8t Wheal Lovell. 



n: 






70r^Le^yel 



of these greyish spots, there are very distinct needles of tourmaline and 
radiating flakes of gilbertite. There is quartz, with fluid cavities, which 
includes a little black opaque mica with Irregular crystals and granules of 
cassiterite.* Two lodes appear to form a junction westwards. The upper 
part of the lodes for 17 fathoms were worked by the old men, but it was 
since worked to the 127-fathom level. 

East Wheal Seton and Wheal Emily Henrietta.— Before 1860, 
Wheal Emily Henrietta was known as Tolvaddon Old Mine. Copper ore 
was raised from the 40 to the 70-fathom levels.! 

Coefc's Lode, — At adit level, this lode is 1 to 2 feet in width, and con- 
sists of quartz and muudic. At the 40-fathom level, it is 5 feet wide 
and was fairly rich in copper ore. 

The Main Lode of Wheal Emily Henrietta underlies N. 15 deg., from 
surface to the 30-fathom level, but is not so steep in the western part of 
the mine. It varies in width from 1 to 4 feet. At adit level the lode is 
2 to 4 feet wide and contained blende and copper ore with quartz. 
From the 44 to the 70-fathom level the veinstones were chloritic and 
quartzose, with fair to poor copper ore. 

East Wheal Sparnon.— irhea{ Spamon Lode underlies south 15 deg. 
and intersects an elvan. It is a copper-bearing lode 4 or 5 feet wide. 
The Cal Lode carries tin and underlies south at 23 deg. (Thomas.) 

Eaot Tbxbayean. — ^A copper lode underlies north. (Thomas.) 

• J. H. Collins, ** Cornish Tinstones and Capels." Min. Mag,, 1882, vol iv,, 
p. 10. 

t J. Maynard, "Mines in the Illojran District." Hep. Roy. Com, Poly, Soc,, 
1874, p. 84. 

q2 



228 



THE MINES. 



Wheal Falmouth.— The lode strikes E. 40 deg. N. and nnderlies SJS« 
20 deg. to 46 deg. From the 30 to the 70-fathom level the lode oonflistB 
of cUorite, decomposed slate, and earthy brown iron ores, copper and 
iron pyrites, and at the 50-fathom level phosphate of iron. Also blende, 
purple copper ore, galena, &c. (Henwood.) Between 1S29 and 1833, 1308 
tons of ore containing 87 tons of copper were produced.* 

Wheal Fanot.— Abandoned in 1850. In adit the lode is 4 feet wide 
and contains copper and iron pyrites and qiiartz. In shallower parts of 
the lode ore was obtained. 

Wheal Forebt. — The lode has an underlie 13 deg. S. to the 45-fathom 
level and varies in width from 6 inches to a foot, but is 2 feet wide in 
some places. The lode is an altered elvan on the west of the Engine shaft 
and is richer here than in other places. The ore extracted was lai^ly 
mundic, associated with quartz and flncan, which was very ferruginous. 

Wheal Fortune (Breage). (Fig. 28.)— Tin ore occurred in killas. Collins 
states that the dark greyish brown killas is spotted and banded with 
white quartz, with light yellowish grey macled crystals of cassiterite in 
the Joints, varying from j: to ^ of an inch across, and mingled with gll- 
bertite.j 

Fig. 28.— Great Wheal Fortmu. 




SCALe -FauKoftta 

so I too 



Tfcc OarnTTMd Lode underlies south. The best piece of ore ground on 
this lode is between Hoskin*s and Painter's shafts about the 68-£athom 
level. The lode is 4 feet wide consisting of peach and quartz. The 
Wheal Vor lode also traverses the sett but underlies north.:t 

Wheal Friendship (Wh. Andrew).— The Great Lode underUes north 
13 deg. It is a continuation of the lode which traverses the United 
Mines. 

The North Lode underlies N. 5 deg. It is a branch of the Great lode. 
There are two other copper lodes further north. 

Wheal Fortune Lode traverses this sett. In Wheal Fortune it was 
worked for zincblende. 

South Lode underlies N. 13 deg. and contains tin ore. It is a south 
branch of the Baldhu lode. (Thomas.) 

Garlidna Mine.— -Worked to the 70-fathom level. 

! ™yi^ »n<l Darlinjrton.*' " Records of Mining and Metallurgy," 1857. 
\r' ^^^*°**» " Cornish Tinstones and Capels," Mm, Mag,, vol iv., 1882, 



p. 16. 



H. C. Salmon. Min. <md Svielt. Mcuj., 1862, vol. ii., p. 17. 



TBI ABANDOXED MINEa. 



329 



Wheal OoBLUiD. (I1g.2fli}—GouaM Lode <Bopper)DiiderUwN.2Tdeg. 
It WH known w CUn's lode in Wbtml VxMy. 

VnttK Lo4a (eo^pei) nndarlln N. 27 Oeg. 

O r mm 't Lode (wxppn) imclerileB N. 27 deg. 

DmMtte Lode (aoppar). VertloftL It ofomm Onen's lode. 

Tike Jlfttttral Lode Ib a tin lode situated 10 fsthomB dofUi of Unitr 
Iod& It nnderlieB N. 23 de«. 

Worth Lod« (copper) underlies N. 13 deg. 



Fig. 29.— Wheal Gttrland. 




PoHl'a Lode (copper) nnderliea N. 6 deg. Situated N.W. of the Nortb 
lode. (Tlioaaa.) 

Tke prinoipal lode of Whe^l Oorlaod baa been traced for 2 miles and 
paMea thzongh WIteal Unity and Creegbraws.* Flnorepar has been raised 
in groat qoantitj. In 1884 It realised £1 a ton vhen sold to Swansea 
smeitera.t Captain Hamblej aasayed some of ttie gossan ot Wbeai Oorland 
and (onnd that it contained 6 dnts. of gold and 2 dwte. ot ailver per ton, 
also 15^ per oent. of wolfrun.f Between 1815 and 1851, 40,751 tons of ore 
oontalning 3,2M tons of copper were sold by public tfcketing.§ 

Whbai. Qbambler. — Tlie mine contains the eaatorly extension of the 
lodes fonnd in Pedn an Drea Mine. Some ot the lodes have been vnirked 
alcHig their outcrops tor tin ore. The Grambler Lode has a rich gossan, 
below which good copper and tin ores were wrought- The water level in 
the mine la abont 13 fathoms from snrfsce. Between 1843 and 1856, 7,261 
tou of ore containing 569 tons of copper were sold from Grambler and 
St. AnbTD b; pnblic ticketing.lj 

OBKA.T NOBTH Sbton.— The lode Doderiies N. 13 deg. It is 2 to 3 feet 
In widtb and has a fine gossan. Copper and tin ore with mundic were 
WTODght. In depth the veinstone Is a dark, hard, heavy capel with 
quarts. 

Oreat Sodth ToLGoa,— The Main Lade at lOO-fathom level was from 11 
to 2 feet wide and contained copper and mundic in a quarti veinstone. 
At the I2S-fatfaom level the copper lode is supposed to have been thrown 
W Cathoms to the right. In 1855 and 1856, 1,770 tons of ore were Bold 
• 110 tona ot oopper.^ 



• J.Came, "On the Veinsof Cornwall." Tr. S.(i.S, Com..\%8Z. 
t Brenton Symons. " A Slietch of Geol. uf Cornwall," 1884. 
t F. J. Stephens, " Recent Discoveries of Gold in West Cornwall." !1 
R.a.8. Com., ISM. 
g Pliitlips and Darlington. " Recoids of Mining and Melallnrgy," 1857. 
ii Ibid. q IHd. 



230 THE MIKES. 

GuAUNBCK Mine (Garras).— The mine was worked Id 1720 and some of 
the lead ore yielded 100 ozs. of silver per ton.* It was again worked 
in 1814 and in two years produced 800 tons of silver-lead ore containing 
13 parts of lead in 20 of ore. The lead contained 70 ozs. of silver per ton. 
The lode runs N.N.E. and S.S.W. and is about 2^ feet wide. It is heaved 
twice by two slides each of which throws the lode 6 fathoms. The ore 
richest in silver was found near these slides at the 70-f athom leveLt 

GusTAVus Mine. — The south underlying lode was intersected in the 
shaft about the 35-fathom level. The lode varies in width from 2 to 4 feet 
and is quartzose. At the 76-fathom level it was so poor that it was 
abandoned. In 1853, 89 tons of ore containing 6 tons of metallic copper 
were sold by public ticketing.:|: 

Halabezack Farm.— The^ produce of black tin varied from 10 to 56 lbs. 
per ton.§ 

Hallen BEAGLE MiNE. — Hollehbeagle Lode (copper) underlies S. 15 deg. 
It is recognised in Wheal Rose, Hawke, and Messar. 

South Lode (copper) underlies S. 13 deg. 

Between these are two other lodes :— Eahy*8 Lode (copper) imderlies 
N. 13 deg. William's Lode (copper) underlies S. 23 deg. (Thomas.) 
Between 1835 and 1846, 30,576 tons of ore containing 1,803 tons of copper 
were sold by public ticketing. || The mine is worked to the 70-f athom level. 

Wheal Habmony (or Tbeleighwood) Mine.— Wolfram occurred in 
this mine.^ 
Great Lode (tin) underlies N. 41 deg. 

Another tin lode on the south of the Great lode underlies N. 54 deg. 
Wheal Bray Lode (copper) underlies N. 13 deg. 
Butler's Lode underlies S. 15 deg. 
Butler's North Lode contains tin and copper. 
Polkitihome*s Lode (tin) imderlies S. 10 deg. (Thomas.) 

Wheal Habbiet. — The mine was abandoned in 1866. 

Main Lode.— The Engine shaft is vertical to the 77-fathom level (adit 
40 fathoms from surface), but after this it follows the underlie of the lode, 
which is about 15 deg. N. The lode was not very rich and was poor from 
74 to 00-f athom level. At the 115-f athom level it was about 1| feet wide, 
and contained tin ore, but at the 130-f athom level it was poor. Cross-cuts 
were driven from the main lode, both north and south, at the 90-fathom 
level. 

North Lode, — This is 7 fathoms north of the main lode at the 90-fathom 
level. It was thin and poor but yielded copper ore at adit level. At the 
130-fathom level it is 1 to 1 1 feet wide and contains tin ore. Between 
1835 and 1848, 9,030 tons of ore were yielded containing 496 tons of copper.** 

Wheal Hatchet.— This mine is situated in the south-west part of South 
Boskear Mine. The lode runs under the main road leading from Tucking- 
mill to Hayle, and has an irregular but nearly perpendicular underlie. 
The Engine shaft, which is just north of the rcMid, is perpendicular to the 
170-fathom level, and at this place is 2} feet wide, and contains copper 
pyrites and fluorspar. The lode varies in width from 1| to 3 feet. 

Wheal Hawke.— TT/teai Hawke Lode (copper) underlies south 23 deg. 
The lode is recognised in Wheal Rose, Hallenbeagle. 
Tenpenny Lode (copper) underlies south 13 deg. 
Pendarves Lode (copper) underlies north 23 deg. 

♦ Borlase. Nat. Hist. Corn, 

t J. Carne, "On the Discovery of Silver in the Mines of Cornwall." Tr. 
R.G.S. Corn.^ vol. i., 1818, p. 120. 

X Phillips and Dftrlington. ** Records of Mining and Metallurgy,*' 1857. 

§ C. Fox, **A Deposit of Tin in Wendron." Miners* Assoc. Com, and 
Devon, 1868, p. 47. 

I! Phillips and DarliDgton. *• Records of Mining and Metallurgy," 1857. 

f J. Gar by, p. 84. 
Phillips and Darlington. " Records of Mining and Metallurgy," 1857. 



♦♦ 



THE ABANDONED MINE& 



231 



Tin Lode underiiet iMvth 13 deg. and is oxoned bj the Wheal Hawke 
Lode at the 00-f athom leveL (ThomaB.) 

Whbal Jkwkul.— Between 1815 and 1858, 58,160 tona of ore containing 
5,222 tona of copper were sold. 

Mahi Lode.— Bearing E. 20 deg. K. Underlie N. 10 deg. to 23 deg. 
The lode varies in width from 1 to 4 feet from the 20 to the QO-fathom 
leyel. It consists of decomposed granite, quartz, felspar, clay, blade 
solpliide of copper, and copper pyrites. 

Raw*» Loda.— Underlies N. 10 deg. to 20 deg. and varies in width from 
10 inches to 1^ feet. It consists of quartz, sulphides of iron and copper, 
and fluorspar. (Henwood.) 

Thomas records the following notes in regard to ** Wheal Jewell and 
Wheal Quick":— 

Wheal Quick Lode or Wheal Jewell North Lode is the same as the 
IPoldice Great ore lode. In this mine it is split up into Wheal Quick 
North and South Branches. 

The Middle Lode (copper) underlies N. 23 deg. It is situated south at 
Wheal Quick lode. 

South Lode (copper) underlies N. 23 deg. 

Figs. 30 and ^l.—The LoveLl Mine. 





ST^Uk^ 



» . ' 



^ KILLAS 



GRANITE 
Longitudinal Section of South Lode* 



N.W. 



Fig. 32. — Wheal Lushingion. 



St.^. 




LovELL Mine.— There are two lodes. The North Lode strikes E. 37 
deg. to 45 deg. N. and underlies N.W. 20 deg. The South Lode strikes 
E. 48 deg. N. and underlies N.W. 30 deg. The lodes unite as they go 
east, as also in depth.* (Figs. 30 and 31.) 

• Foster, 



232 



THB ICINGS. 



Wheal Lushinoton (Nbw Doixx>ath). (Figs. 32 and 33.)— TTIieca Fox 

Ijode. An adit has been driven on the lode from Forth Towan Valley. 

The lode is poor, although extensively explored along the outcrop. It 
varies in width from 1 to 2 feet. 

Fig, 33. — Wheal Vincent {paH of Wheal Lushingion). 




Whxal Maid. ~ The Wheal Maid Lode (copper) nnderlies south to 
the 30-fathom level, after which it underlies N. 13 deg. (Thomas.) 

Wheal Mabia.— The Good Suecesn Lode for John's Oo99an) is a lode 
containing copper ore and underlying N. 23 deg. Situated to the north, 
there is a copper branch underlying south 10 deg. (Thomas.) 

Wheal Mart. — The North Lode (copper) underlies S. 13 deg. 

The Middle Lode (copper) imderlies 8. 10 deg. 

The South Lode (copper) underlies S. 13 deg. (Thomas.) 

Medltn Moor Mine.— Worked to a depth of 33 fathoms. 

Nangilvb. (Fig. 34.)— The Baldhu Lode (tin) underlies N. 45 deg. The 
lode splits as it goes west. The north part westwards is the main lode in 
South Ale and Cakes Mine. The south part is the South lode in Wheal 
Friendship. 

Fig. 34. — Ncmgilea, 




N. 



flT^. 



WO FajtAornJ 



NavgiJes Copper Ijode is situated north of the Baldhu lode. The 
lode splits as it goes eastwards. The north part underlies north 13 deg* 
and was rich where it traversed a soft elvan but poor in killas. The 
south branch underlies N. 27 deg. (Thomas.) The gossan of one of tiiese 
lodes is said to be auriferous.'*' 

• D. Forbes, "Researches in British Mineralogy." Phil. Mag., 1869, 
vol. xxxvii., p. 322. J. Garby, Tr. R.G.8, Com., vol. vii., 1848, p. 90. 



THE ABANDONED MINES. 



233 



1846 wad 1848, 1,440 torn of ore ocmtainiiig 110 tons of copper 
ipsie Mldbgr pablio tieketiiig from Andvew and Nangiles.* 

New Wheal LoTSLL.—Worlred to the TO-fttthom level at Hlirs Engine 
abaft 

Nxw Wheal Sbton. — The Main or WestSeton Lode has a good goasan 
and near the surface it is 6 feet wide. At the 62-fathom leyel the lode 
is 2^ to 3 feet in width. The yeinstone consists of chlorite, quartz, oopper 
ore, and nrandic The lode lies next to an ^van which underlies north- 
wards, with the lode on the foot wall side. 

New Wheal Viboin.— Neio Wheal Virgin Lode (copper) underlies 
N. 10 deg. 

North Lode (copper) underlies N. 13 deg. 

One hundred and fifty fathoms furUier north there is the Olyjah Lode 
(tin) which underlies N. 13 deg., while 20 fathoms further noith there 
is a oopper lode which is said to be a continuation of Wheal Virgin and 
Wheal Hope lode. (Thomas.) 



Fig. 35. — North Damns, 




N 



Se F'T^Level 



North Downs. (Fig. 35.)— The mine was worked to the 143-fathom level 
or 110 below adit at the Water Engine shaft 

John^s Gostan Lode.—K 21 deg. N. Underlies N. 18 deg. to 30 d^. The 
lode is li feet wide at the 30-fathom level, and consists of quartz, earthy 
brown iron ore, and iron pyrites. 

Wheal Peevor Lode.- E. 12 deg. N. Underlies S. 12 deg. to 20 deg., and 
consists of quartz, clay, and slate. 

Main Lod€.~E. 14 deg. N. Underlies S. 8 deg. to 20 deg. Consists of 
copper pyrites, llmonite, iron pyrites, blende, slate, and granular quartz. 

Tenpenny Lode.— E. 30 deg. N. At the 30-fathom level the lode is verti- 
cal and 1^ to 2 feet in width. Copper and iron pyrites, quartz, and earthy 
ircMi ores. 

Counter Lode, — E. 28 deg. N. At the 30-fathom level the lode underlies 
N. 7 deg. to 10 deg. It varies in width from 1 to 2 feet, and consists of 
earthy iron ore, iron and copper pyrites, and slaty clay. 



* Phillips and Darlington. '* Kecorda of Mining and Metallurgy," 1857. 



2S4 



TH£ UINES. 



Pendaroea Lode.—E. 22 d;^. N. At the SO-fstbom lerel the lode is 
vertical and U aboat 1 to U feet in width. ContaiHB tin ore with iron 
pyrites and earthy brown iron ore and slate. (Henwood.) 

Between 1815 and 1855, 19^8 tons ot ore oontalaing 1,600 tons at 
oopper were sold bj public tiolceting.* 

n the tin lode, 

NoBTH Pool. — Yielded copper ore, bnt was never worked tor tin. 

North Roskkab.— Between 1816 and 1856, 151,707 tons ol copper ore 
containing 11346 tons of copper were sold by public ticketing. In 1841, 
oopper ore, sold at £7 5s. a ton, realised £28,^a 

At the 205-ratbODi level, west ot Doctor's shaft, the lode is 2^ feet wide, 
and counts ot qoartz with copper pyrites and tin ore. At the 216-fathofli 
level the lode was from 1 to 8 feet wide and contained quartz, fluorspar, 



Fig. 36. — Pedn cm Drea Mine. 




7M,';GRANirE 



chlorit4t, tin, and oopper. At the 208-tathoni level there was tinstone and 
miapicbel, but little or no oopper. In the eastern part ot the mine, on the 
east of the Engine shaft at the 100-totbom level, the lode la 4 feet wide and 
oontains copper and tin ore. A hot spring ot temperature 102 deg. F. 
made the " end " at this level too hot to work in, the temperature of Uie 
air being about 100 deg. F. The Engine shaft is sunk below the 110- 
fathom level. Charles Thomas states that good tin and copper oie 
occurred in the mine in scattered bunches.f 

Henwood remarks that the North Roakear Lode bears K. 32 deg. N. and 
underlies N. 8 deg. to 22 deg. It varies in width from a few Inches to 
5 feet. The lode contained copper sulphide, fluorspar, qnartz, chlorite, 
and iron pyrites. The South Lode has a bearing E. 32 deg. N. At the 

* Phillips and Darlington. " Records of Mining and Metallargy," 1S57. 
t "Mining Districtu ot Cornwall," lS67,p, 49. 



THS ABANDONED MINES. 235 

37-ffttlioiii level the underlie is N. 45 deg. to 50 deg. At the 57-fathoiii 
level it Ib 6 d^. to 96 deg. soath. It oontains qoftrti, blende, copper, and 
Iron pyrites. 

The Maht Lode^ in the Park an Bowan part of the mine, nnderlies 
N. 35 deg. to 40 deg., and is about 1 foot wide. The veinstone is a soft 
klllas with oinndic. The Oaunter Lode was fair in copper and blende, 
at 70 fathoms west of its Junction with the main lode, and varies in width 
from 1 to 3 feet. 

Pbdn an Dbka. (Fig. 3d.)— Thomas makes the following observations : — 
North Tin Lode.— Underlies N. 30 deg. 

The next lode on the south yielded copper. It underlies N. 15 deg. 
Pedfi an Drea Lode (tin).— Underlies N. 30 deg. 
MichelVg Gossan (copper).— Underlies S. 23 deg. 

In 1821, 14 tons of copper ore containing 1 ton of copper were sold by 
public ticketing. Yielded mainly tin ore. (See p. 165.) 

Pbndabveb United (or Camemough).— The sett includes the old 
Ti^phena Mine, Tolcarne (or West Wheal Grenville), and Condurrow 
Mine. 

Oondurrow Mine Main Lode.— From the 140 to the 155-fathom level 
the lode is 6 feet wide, 3 feet of which consists of flucan. At the 266- 
fathom level it is 2 to 3 feet wide. The leader of the lode varies from 
10 inches to 2 feet in width and contains fluorspar, copper, and tin ore. 
At the 165-fathom level at Pryce's shaft the lode is 5 feet wide and 
consists of fluorspar, quartz, peach, and some iron and tin ore in capel of 
north walL* 

Pryce's shaft was sunk on a lode 2^ to 3 feet in width. At the 
140-dithom level it is 3 feet wide, and consists of capel, peach, and flucan, 
with yellow copper ore and tin. At this level a great deal of water was 
met with possessing an acrid taste, owing to the presence of copper salts, 
which, reacting upon metal work in the shaft, caused the precipitation of 
copper upon it. At the 20-fathom level a ** pipe " of malleable copper was 
found which was 18 feet in height, 8 feet in length, and 3 to 15 inches in 
width.! 

At Woolfs shaft at the 200-fathom level there were branches of copper 
pyrites and grey copper ore in the tin lode. Salmon states that at the 
140-fathom level the leader is 10 inches in width. The remainder of the 
lode is made up of ferruginous capels, plentifully speckled with quartz. 
These capels have no re^ilar walls, but pass insensibly into the granite 
of the *' country,*' and as they are stanniferous they are considered to be 
** lode " by the miners.^ At the 155-fathom level a large vug occurred 
in the lode ; its dimensions were 36 feet in length, 12 feet high, and 2 
to 3 feet wide. 

Llandower Lode, — The lode yielded both copper and tin ore at the 
30-fathom level. Copper ore was plentiful at the 50-fathom leveL It 
varies in width from 1 to 4 feet. 

Robert's Lode. — ^Hope's shaft from 100-fathom level to the 177-fathom 
lev^ is sunk on Robert's lode, which varies from 2 to 4 feet in width, and 
yields tin ore. A Caimter lode branches off at the 90-fathom level in a 
north-westerly direction. 

Oaunter Lode. — At deep adit it is 15 inches in width. The lode has 
a good gossan extending below the 10-fathom level and yielded grey 
copper ore. It is 2^ to 4 feet wide. 

South Lode.— Yielded copper ore at the 60-fathom level. 

Field's Lode (in Tolcarne).— Has a good gossao.g 

Between 1818 and 1856, 20,095 tons of ore containing 1,498 tons of 
copper were sold by public ticketing. | 



• H. C. Salmon. Afiii. and Smelt. Mag,, 1863, vol. iii., p. 82. 
t E. W. W . Pendarves, *' Notice of the Native Copper at Condurrow Mine." 
Tr, Ji.G,S. Com., vol iii., 1828, p. 333. 
t Min. a/nd Smelt, Mag., 1863, vol. iii., p. 82. 
§ H. C. Salmon. Min. and Stnelt. Mag., 1863, vol. iii., y. 82. 
li Phillips and Darlington. *' Kecorda of Mining and Metallurgy,'* lb57. 



236 THE lilMRS. 

Pennange Mink.— Situated about 1^ miles west of SwanpooL Tin, 
copper, and lead were found, but although sereral lodes were out tliere 
was nothing of value disooyered. In one trial the lode was 6 inches wide, 
irregular and yery gossany, with quartz and traces of lead ore.* 

Whsal PEByoB. — JokrCa Qoaaan Lode (copper), underlies N. 30 deg. 
This lode is recognised in Grood Success Mine and Wheal Maria. 

Wheal Peevor Lode (tin), 8 to 10 feet in width.! Underlies S. 23 deg. 
This lode is faulted hj John's Gk>s8an lode to the extent of 8 fathoms.} 

Diamond Lode (tin), underlies south 5 deg. (Thomas.) 

Wheal Peeyor lode is also traversed by two slides both underlying 
north. It is faulted by them 14 feet and 9 feet respectiyely.§ It is also 
heaved by two cross-courses. 

Wheal Pink. — Wheal Pink Lode (copper), underlies N. 13 deg. (Thomas.) 
Between 1821 and 1850, 1381 tons of copper ore containing 158 tons 
of copper were sold by public ticketing. || 

PoLDiOE.— Great Ore Lode (copper), underlies N. 15 deg. In Wheal 
Jewell and Quick it is the North lode. 

Poldice Tin Lode. — Underlies S. 15 deg. It is intersected and heaved 
two fathoms by the Great ore lode in the western part of the minew 

Bi$9oe Tin Lode.— Underlies 8. 23 deg. At the 80-fathom level it it 
intersected by the Great ore lode. 

Quick*s Lode (tin and copper). — It has an irregular but nearly verticsl 
underiie. 

Kitty BtUing'a Lode (copper). — Nearly vertical. 

Qarby*8 Lode (copper). — Underlie N. 10 deg. 

Hciman'a Lode (copper).— Underlie N. 10 deg. (Thomas.) The lodes 
have been traced for two miles. (Came.) 

Between 1815 and 1852, 2,992 tona of copper ore containing 208 tons of 
copper were sold by public ticketing. ^ (See p. 224.) 

PoLLADRAB DowNB MiNE.— Bor or Engine Lode. — E. 35 deg. N. under- 
lies N. 12 deg. to 34 deg. The lode varies from a few inches to 3 feet in 
width, and consists of slaty quartz, veinstone, with clay and strings of 
cassiterite, down to the 113-fathom level, where some iron pyrites also 
occurred. 

BisM or Penhale Lode.—E. 30 deg. N. Underlies N. 8 deg. to 40 deg. 
and varies in width from 2 to 5 feet. In the upper levels it consists of 
earthy brown iron ore, tin ore, quartz, and quartzose slate. At the 83- 
fathom level there were veins of quartz and strings of cassiterite in the 
slate. 

Presture North Lode.— E. 30 deg. N. Underlies N. 16 deg. to 34 deg. 
and consists of quartz, slate, and cassiterite at the 83-fathom level. 

Preuure South Lode. — E. 30 deg. N. The lode consists of quartz and 
slate and felspar clay. Cassiterite at the 83-fathom level occurs in 
irregular spots. 

Richard's Lode.—E. 30 deg. N. Underlies N. 14 deg. to N. 18 deg. 
About 4 inches wide, and consists of slaty clay with quartzose, slate, and 
cassiterite. (Kenwood.) 

PoRKELLiB United Mines. (Fig. 37.)~The lodes have a general under- 
lie north. 

Orowan Lode and Barrie Lode underlie north, but are nearly vertical. 
They are 2 to 3 feet in width, and yielded tin ore in fair quanti^. 

Horseflesh Lode.— South of Crowan lode and said to be a branefa of tlie 
Tymorgie lode which lies further south. Towards the east this lode and 

♦ F. J. Stephens, •'Mineral Resources of Falmouth." lUp. Com, Poly. Soc., 
1886. 

t J. Hawkins, **On the Intersection of Lodes." TV. B.O.S, Com.^ toI iL, 
1822, p. 240. 

::: J. Carne. § Op. cit, 

Phillips and Darlington. ** Records of Mining and Metallnrgy," 1867. 

% lind. 



TBS ABABDONSD BOVXa. ^7 

the TjBiQVgle ]io4a unllie. It imderlies north. Mid is a Mr tin lode 
abbot li faet in ividtii. 

Qrmt Tffmarffle Lode^-^Tln was fbnnd in the oatorop, bat the lode is 
only Mx. It Variea in width ap to about 8 feet and nnderliea north 
3tf deg. 

Nor^ Tymorgie Lode.— At the 24-fiftthoin leyel it is as wide as 5 feet 
in soine plaoes, and the lode yielded tin ore to the 50-fathom lerel.- 

Wheal Atk Lode.— The most southerly lode is 1 to 2 feet in width, 
and has a northerly underlie. 

Dates Lode. — A good bunch of tin ore was found near Wheal Ash 
shaft. 

North Lode.— South of North Tymorgie lode. Worked to the 80- fathom 
leveL The lode varies in width up to 7 feet and was richer in tin ore in 
the upper levels than in depth. 



Fig. 37. — PorkeUie United Mines. 




'*' sCAue. FaJtKoms § 
o so lOO \ 







South Tfmorffie Lode,— 2 to 4 feet in width. An elvan which traverses 
the sett is supposed to be a oontinoation of one in Wheal Vor.'*' 

Pbotidkkcb Mine. — The mine has bemi worked for tin and copper but 
is poor. It was abandoned in 1867.t Thomas states that it is the same 
lode as that worked in Wheal Druid. 

Whbal Pbubbia.— IFheoZ PrtcMia Lode (tin).— Underlies S. 27 deg. It 
is the same lode as the Wheal Vor lode in Treskerby. 
Wheal Boye Lode.— Yielded copper. (Thomas.) 

WHB4L Robe (near Wheal Hawke).— THieal Rote Lode (copper).— 
Underlies 8. 27 deg. 

Sixty fathoms further south is BMfiM Lode (copper), which underliee 
S. 27 deg. and Whetd Moyle Lode (copper), whieh underlies N. 13 deg. 
(Thomas.) 

* W. H. Ai^jrall, <*0n Elvan Couraes." Miners* Associatum, 1875. 
t J. Biaynard, '* Remarks on a Cross Section." Jttp. Com, Pofy, Soe.^ 1871, 
P.20U 



238 



THE ICIN^. 



RoBKBOW United. — The lode is met with 50 fathoms east of the tampike 
leading to Ponsanooth village. It is 4 to 6 feet in width, but varies down 
to about 2} feet. It underlies north 13 deg. and is explored to the 40- 
fathom level, where the granite is considered to be only 30 fathoms below. 
The lode has yielded mundio, with some silver, copper and uranium ores, 
and also some nickel. An elvan traverses the sett. 

Seton, Whsal. (Figs. 38, 39.)— This mine has yielded mainly copper 
ores but has produced *' a small proportion of tin from its lowest quality 
or halvan ores."* The workings extend to below the 300-fathom leveL 



Figs. 38 and 39.— Wheal Sdan. 







IZO F'^ 




130 ry 



The lode* near Tilly's Engine shaft yielded copper ore to the 160- fathom 
level. From this level to l^low the 20O-fathom level it is mainly a tin lode. 
Warm water issued from the lode at the 170-fathom level east of Bull's shaft. 

South Gaunter Lode. — At the 140-fathom level west of Tilly's shaft the 
lode is 4 feet in width and tin bearing. 

North Gaunter Lode.— The lode is tin bearing from the 170 to the 20O- 
f athom level, and consists of quartz, capel, and mundic. The North (or Great) 
Gauvter is the same lode as Beeves' lode eastwards, but it is heaved by a 
cross-course in Wheal Seton sett 20 to 25 fathoms. Westwards this lode 
assumes a bearing approximating to that of the ordinary lodes of the 

district.t 
Middle Lode. — At the 110-fathom level the lode yielded tin ore and 

varied in width from 2i to 4 feet. 

Phillips has described the killas at the 160-fathom level. It is a very 
hard grey clay slate in which the cleavage has been obliterated to some 
extent, in the majority of cases by metamorphism. No crystalline structure 
can be detected by the eye, and the rock in addition is traversed by quartz 
strings enclosing minute spots and crystals of iron pyrites. The microscopic 
section shows bands of transparent granular quartz alternating with layers 
of similar quartz through which minute hornblende crystals are dissemi- 
nated.]: 

At the same level Harry Tilly describes a thermal spring, and states that 
the killas in its neighbourhood is traversed by joints and is not far from the 
Great cross-course. Thirty gallons of water per minute, at a temperature of 
94 deg. F., issues from the lode. The lode is small and contains copper, 
quartz, and mundic. The water has specific gravity 1*105, and contains 

♦ C. Thomas. " Mining Districts of the West," 1867, p. 48. 
t H. C. Salmon. Min, and Smelt Mag., 1862, vol. ii., p. 277. 
t J. A. Phillips. Q.J.O.S., vol. xxxi., 1875, p. 324. 



THE ABANDOTVED MINES. 239 

1,072 grains of dLssolved material per gallon, principally salt and calcimn 
carbonate.* Phillips attributes the magnesia in the rock to the action of 
sea water which traverses the great cross-course. 

Wheal Seymour. — In the shallow parts of the lode there occurred copper 
and zlncj 

Silver Hill (Perranarworthal). — There is a copper lode near the road 
leading to Perranarworthal. Another lode further north has yielded 
mundic. 

South Wheal Basset. — Teague's Lode has been profitably worked for 
copper ores. The lode underlies north. At the 120-fathom level it varies 
in width from 2 to 4 feet and consists largely of quartz. 

The North Lode underlies north and is 2 to 3 feet in width. This lode 
has a good gossan and consists of quartz and peach, with copper and 
tin ore. 

Engine Lode.— Underlies N. 13 deg. It is a large and poor lode from the 
60 to the 90-fathom level. Between 1825 and 1856 the mine yielded 
94,649 tons of ore containing 7,200 tons of copper. J 

South Carn Brea Mine. — The work done in this mine is mainly upon 
the Great Flat lode. In this mine the Great Flat Lode was worked to a 
considerable extent about adit level, where it is in killas. The lode 
underlies from 35 deg. to 45 deg. S. At the 28-fathom level it underlies 
south 35 deg. The lode has a good gossan with vitreous and yellow copper 
ores and some tin. At the 128-fathom level the lode is 3 to 12 and even 
18 feet in width. At the 164-fathom level (95 fathoms west of the Engine 
shaft) the granite was penetrated, and at this level the veinstone consisted 
of peach, quartz, and fluorspar. Foster states that there is a copper leader 
in the lode, 2 to 4 feet in width, and that the lode makes a sudden bend in 
one place, changing its bearing from £. 33 deg. N. to E. 15 deg. N.§ Tin 
and copper ores occurred in bunches in the lode. The footwall in the 
upper levels is very near the granite, which plunges southwards at nearly 
the same angle as the lode.j 



South Condurrow Mine. — This mine is situated on the Great Flat Lode, 
which is entirely in granite in this mine. Foster states that the tin-bearing 
part of the lode is 5 or 6 feet in width, while the lode and capel together 
are 12 or even 20 feet in width. It has a general bearing of E. 34 deg. N., 
and underlies south at 60 deg. at the 80 or 90-fathom level. The lode is a 
schorl rock traversed by innumerable quartz veins, a great many of which 
dip north at a high angle. In many places it contains chlorite and iron 
pyrites with kaolin, which occasionally fills up vughs in quartz veins.^ 
Tde Middle Lode varies in width from 2 to 3 feet, producing both copper 
and tin. The lode underlies north but is nearly vertical. 

South of the middle lode is the West Basset Copper Lode, which varies 
in width from 3 to 4 feet. It splits up into branches at the 61-fathom level. 
At the 20-fathom level the lode yielded sulphides of copper in a veinstone 
of quartz, peach, and killas. At 120 fathoms west of Grenville shaft the 
copper lode heaves the Flat lode 10 fathoms, and Captain Hooper states 
that it is at this place that the Great Flat lode was first discovered. 

South Crenver. — Worked to the 94-fathom level (115 fathoms below 
surface). 

* ** Particulars of a Thermal Spring at Wheal Seton." Miners' Assoc, 1873, 
p. 53. 

t Thomas. 

X Phillips and Darlington. ** Records of Mining and Metallurgy," 1857. 

§ C. Le Neve Foster, *' On the Great Flat Lode." Q.J.G.S., vol. xxxiv.. 
1878. 

II J. Maynard, ''Report on Two Cross Sections." Bep. Corn. Poly.Soc., 1873 
p. 191. 

f ** On the Great Flat Lode." Q J. G.S. , 1878, vol. xxxiv. 



240 THE xurBS. 

SoiiTH DoLOOATH.— The mine was worked by the anoientB. The lodes 
have fine gossans below which was rich copper ore.* From 1829 to 
1831, 286 tons of ore containing 25 tons of copper were sold by pablic 
ticketiDg.f 

South Wheajl Frangb». — The sett is traversed by five lodes which have 
a bearing of about El 35 deg. N. 

North or Main Lode. — Underlies N. 12 deg. from surface to adit level 
(32 fathoms from surface). From adit level to the 50-fathom level the 
underlie is N. 10 deg., and from the 50-fathom level downwards it is about 
5 deg. N. There was a good gossan and a bunch of copper ore to the 40- 
fathom level. Tin ore and quartz was also present, mixed with ferruginous 
materials, and fluorspar, peach, chlorite, prian, &o. Below the 40-fathom 
level the lode is maiidy tin bearing, and varies in width from 2 to 12 feet. 
At the 114-fathom level it is 1 to 3 feet wide, with ore bunches. 

Grillis (or St. Auhyn) Lode.— The lode near Harvey's shaft is 6 feet wide 
and consists lai^^ly of quartz and iron with some ore. At 45 fathoms west 
of the shaft it is 2 feet wide and in an elvan. 

South Lode, — Tliis lode is 36 fathoms south of the main lode. It underlies 
south, and is about 2 feet in width. 

Little* 8 Lode. — About 2 feet in width, aftid consists largely of ferruginous 
materials. 

ITie Great Flat Lode dips into this mine from West Wheal Basset. Xtwas 
first Intersected at the 185-fathom level, and has been worked upon to a 
considerable depth. The bearing is El 41 deg. N., and the underlie is 
58 deg. south. The ore contains about 2) per cent, of black tin. The Great 
Flat lode is intersected by three north underlying lodes.! 

Between 1844 and 1856, 33,522 tons of ore containing 3,252 tons of copper 
were sold by public ticketing.§ 

South Wheal Ha.wkb.— The South Wheal Hawke Lode yielded copper. 
It underlies N. 13 deg. and is intersected by a Gaunter Lode underlying 
N. 5 d^. and containing copper. (Thomas.) 

South Roskbab Minx. — There are seven parallel lodes, but only two 
have be«i seriously worked. The South Boskear Lode and a lode to the 
north are those upon which most work has been done. Between these lodes 
is another called the Boundary Lode. The Dolcoath North ^trai Lode 
enters the sett on the south. This lode yielded copper and tin ore in Dol- 
coath, Tincroft, South Orofty, and East Pool. 

Both copper and tin ore were taken from the South Boskear lode at tiie 
170-fathom level near Gregory's En^^e shaft. The lode varied from 2 to 
3 feet in width. At Vivian's shaft tin, copper, and arsenical ores were 
extracted between the 80 and the 112-fathom levels. Near the South 
Roskear (or Pendarves) shaft, copper and tin occurred at the 132-ftithom 
level, while the Gaunter lode yielded copper ore. Qranite was not met with 
in the workings, although they extend below the 180-fathom level, nor was 
that rock encountered in the 143 cross-cut south. Argall states that the 
lode was very productive near an elvan. || 

The Copper Tankard Lode passes iuto this sett. 

Between 1821 aud 1850, 37,807 tons of ore containing 2,904 tons of copper, 
were sold by public ticketing. In 1841, copper ore at iS5 4s. a ton 
realised £9,932. 

South Wheal Seton. (Fig. 40.)~The Main Lode is 4 to 8 feet in width 
and contains copper, blende, and mundic, with peach, quartz, and killas 
veinstone. 



♦ J. Maynard, '* Remarks on Two Cross Sections." Rep. Com, Poly. Soe,, 
1871, p. 201. 
t Pliillipa and Darlington. " Records of Mining and Metallurgy," 1867. 
t FoMter. 

§ Phillips and Darlineton. '* Records of Mining on^ Metallurgy," 1857. 
;l W. H. Argall, •* On EWan Courses." Miners' Amoo., 1876. 



THE ABANDONED MINES. 



241 



The North Lode anderlles X. 35 deg. and varies in width from 3 to 4 feet- 
The lode fonna a Junction with the main (or Marriott's) lode at the 6D-fftthom 
level. Blende, copper ore, and galena occurred at the 50-f athom level, with 
quartz and killas veinstone. 



Fig. 40.— SaiUh Wheal Seton. 




ki. V r c 



60 f -* U^eJ, 



South Wheal Towan. (Fig. 41.) -Slide Lode.— Bearing N.B. and S.W. 
It underlieH N. 22 deg. to 35 deg., and varies in width from 7 or 8 inches 
to 3J feet. It consists of earthy brown ore, quartz, and slaty clay. 

At the 36-fathom level there is quartzose slate and brown iron ore and 
copper pyrites. 



Fig. 4\.— South Wheal Towan, 




South Lodc^Y^, 24 deg. N., underlies S. 16 deg. to ;>0 deg. Varies in width 
from 2 to 41 feet. It consists of earthy brown iron ore, some chlorite, and 
spots of copper pyritis to the 30-fathoni level. 

Mineral pitch occuricd in both mines. (HenNvood.) The mine is worked 
to the 114-fathom level. The shoot of ore pitched from Woolcock*s shaft to 



242 THE MINES. 

Engine shaft. 24,161 tons of copper ore oontaiaiag^ 1,610 tons of copper 
were sold by South Wheal Towaa and Wheal Lydia between 1817 and 
1847.* 

South Tresavea^n Mine. — The Engine Lode was worked for a consider- 
able distance along the outcrop, and at adit level it varies in width up to 
about 3 feet, and yielded low-grade tin ore. Pitchblende with kupfernickel, 
native silver, and rich argentiferous galena also occurred.| 

Wheal Sparnon.— W/icat Sparnon Lode. — Copper and tin. Underlies 
S. 15 deg. North of Wheal Sparnon lode is the North Lode, Copper 
and tin. Underlies N. 13 deg. 

Belfry Lode (is S. of Sparnon lode). Tin. Underlies S. 45 deg. Another 
lode further south contains copper and underlies N. 27 deg. (Thomas.) 
Gold was found in a burrow and in a cross-course.): 1,547 tons of ore 
containing 128 tons of copper were sold by public ticketing between the 
years 1815 and 1827.§ 

Wheal Spinster.— The lode has been worked for tin at surface for at 
least 10 fathoms. No copper ore was found in the upper part of the lode.!| 
4,520 tons of ore containing 400 tons of copper were sold by public ticketing 
between the years 1820 and 1829.«f 

Wheal Squire.— I7#iited Mines Great Lode. — Copper. Underlies N. 15 
deg. 

A lode north of this yielded tin. It underlies N. 15 deg. 

Further north is Oocka* Crossan Lode. Copper. Underlies 10 deg. N. 

Gates* Lode. — Copper. Underlies N. 5 deg. 

North of Gates' lode is Po8*s Lode, which contains copper and tin ore, 
and underlies N. 23 deg. 

Old North Lode.— Copper. Underlies N. 23 deg. 

Old South (or Andrew* a) Lode.— Copper. Underlies N. 15 deg. 

Wheal Lovely (or Flat) Lode. — Lode contains copper and tin, and under- 
lies N. 45 deg. 

South Flat Lode. — Copper. Underlies N. 45 deg. 

Pearce*8 Lode. — Copper. Underlies N. 15 deg. 

Another copper lode underlies N. 15 deg. (Thomas.) 

Carne stated that a lode in Wheal Squire underlies N. 54 deg. 

20,082 tons of ore containing 1,724 tons of copper were sold by public 
ticketing between the years 1816 and 1853.** 

Stray Park Mine. — The Main Lode underlies S. 14 deg., and varies in 
width from 2 to 10 feet. There is a good gossan in the upper part of the 
lode, and below this to the 124-fathom level it was very rich in copper ores. 
At the 15-fathom level the lode was 9 feet wide, and contained tin ore. At 
the 180-fa thorn level, where it traverses an el van, the tin ore was rich, while 
the lode varies in width from 3 to 4 feet. At the 204-fathom level it is 
14 feet wide, and contains good tin ore down to the 250-fathom level. The 
Engine shaft struck the granite at the 115-fathom level. Towards the east, 
at the 180-fathom level, the lode divided. The south part contained copper 
ore. 

SotUh Lode. — Underlie 13 deg. N. Varies in width from IJ feet in the 
upper levels to 5 feet at the 25(>-fathom level. At the 180-fathom level it 
is 2 fathoms south of the main lode. The lode was rich in copper ore 
from the 80 to the 160-fathom level, below which it yielded mainly tin ores. 

* Phillips and Darlington. " Records of Mining and Metallurgy," 1857. 
t R. Pearce, " Note on Pitchblende in Cornwall, Tr, Ji.G.S. Corn., vol ix., 
1864 to 1878, p. 102. 

t J. Garby, •* Notice of the Gccurrence of Gold in a Cross- Course." Tr. 
Ji.0.8. Corn., 1846, vol. vi., p. 265. 
§ Phillips and Darlin;^'ton. *' Records of Mining and Metallurgy," 1857. 
II Vi. H. Argall. Miners' Assoc. (Breage Meeting), 1872. 
H Phillips and Darlington. ** Records of Mining and Metallurgy," 1857. 
♦• Op. cit. 



THE ABANDONED MINES. 243 

There are three lodes north of the main lode, which were intersected by 
a cross-cut at the 100-fathom level. 

The first is 28 fathoms north of the main lode. It is 1^ feet in width and 
underlies N. 20 deg. This lode yielded copper and tin ore. The second is 
45 fathoms north of the main lode. It is a poor lode, with a northerly 
underlie, and about 1 foot in width. The third lode is 67 fathoms north of 
the main lode. It underlies N. 10 deg., and contains copper ore with 
quartz. 

Between the years 1829 and 1856, 38,610 tons of ore containing 2,748 tons 
of copper were sold by public ticketing. In 1841, copper ore sold at 
£6 3s. a ton realised £5,972. 

SwANPOOL Mine. — This mine was worked at about the same time as 
Wheal Clinton. In 1855 it was down to 80-fathoin level, four shafts having 
been sunken the lode. At the 20-fathom level the lode is in one place 9 
feet wide, and consisted of flucan with gossan, and rich bunches of galena 
yielding IJ to 2 tons of lead ore per fathom. At the 40-fathom level the 
lode is 2 feet wide and consists of gossan, flucan, mundic, and large stones 
of mixed blende and lead ore. At the 80-fathom level it is 2 feet wide, and 
consists of quartz, mundic, and flucan, with good branches of galena. 
The lode underlies south.* Silver and a little gold also is said to have 
occurred in the lode.f On the eastern side of Swan pool Lake are three 
levels driven on three lodes. Several shoots of lead were passed through, 
especially in the Middle Lode, which is 20 inches in width and composed of 
flucan, quartz, and galena.:|: 

Wheal Tehidy. —There are some ancient workings on the upper parts of 
the lodes, but the mine was first seriously worked in 1835. 

North or Tin Lode. — Underlie 35 deg. N. The lode varies in width from 
1 to 3 feet. It is a continuation of the East Pool or Tincroft North lode. 
It contained copper and blende as well as quartz and flucan. 

Caunter Lode, — This lode has an irregular underlie northwards. It varies 
in width from 1 to 2 feet from adit to the 70-fathom level and yielded 
copper ore and mundic in a quartzose veinstone. 

2,121 tons of ore containing 179 tons of copper were sold by public ticket- 
ing between the years 1835 and 1856.§ 

Ting Tang Mine. — Main Lode, — E. 12 deg. N. Underlies N. 8 deg. to 
30 deg. The lode contained copper pyrites, earthy brown iron ore, black and 
vitreous copper ore. At the 80-fathom level there was some chrysocoUa 
with black copper and copper pyrites. At the 90-fathom level there was 
oxide of copper. At the 140-fathom level there was blue and green 
copper carbonate with chlorite, and quartz. 

Middle Lode.—E, 21 deg. N. Underlies N. 4 deg. to 22 deg. and varies 
from 1 to 4 feet in width. It contained earthy brown iron ore, vitreous 
and black copper ore, and red crystallised oxide of copper at the 90-fathom 
level. At the 140-fathom level there was granular quartz, chlorite, and 
vitreous copper. 

Roche'8 Xodc— E. 8 deg. S. Underlies N. 10 deg. to 22 deg. Varies in 
width from IJ- to 3 feet and contains quartz, chlorite, iron and copper 
pyrites, earthy red iron, and vitreous and black copper ore from 90 to the 
120-fathom level. (Ilenwood.) 

Thomas states that there is a Flat Lode in this mine which yielded both 
copper and tin. It is the continuation of Wheal Lovely and Wheal Squire 
lode, and underlies N. 45 deg. Seven fathoms south of the Flat lode is a 
Aftttidit? Xodc (which is the South Flat lode of Wheal Squire) underlying 
N. 45 deg. Between 1816 and 1835, 38,124 tons of ore containing 3,235 



* F. J. Stephens, "Mineral Resources of Falmouth." Rep, Corn, Poly. Soc,, 

1886, p. 189. 
+ F. J. Stephens, ** Recent Discoveries of Gold in West Cornwall." Tr.ll.G.S. 

Com.y 1899. 
X F. J. Stephens, "Mineral Resources of Falmouth." licjp. Corn. Poly. Soc^ 

1886, p. 189. 
§ Phillips and Darlington. " Records of Mining and Mettillurgy," 1857. 

h2 



244 



Tan WNBS. 



Una of oopper were sold by publlo tioketiug, »ad 841 tons oontalniaS 
50tonH of oopper between 1845 ^ad 1847.* 

TOLQ&BN. — North Lode.— Copper, nadertioH N. 15 deg. (South lode 
in WbMl Jewell). 

South £ode.— Oopper. Underlies N. 15 deg. 

TBKroiA MiNB. — Trefula Lode. — Oopper. Vertioal. (Thonua.) 

Trkleioh Cohbols (Good Soooms) Ming. — Good Sueeeat or John'* 
Ooaaan Xode.— (Copper). Uaderlies N. 23 deg. 

North Qood Suceeaa Lode U situated 60 tathoinn turlher north.' ICia k 
copper lode underlying N. 23 deg. 

Between 1833 and ^855, 21,901 tons of ore oonUiniog 1,420 tons of oopp«r 
were sold by public Ucketing.| 

TRiiMBNHEGRK MiNE,^Worlied to the 204-Iatbon] level. 

Tbsllti^n Mine. (Fig. 42.)— The Main Lode bears E. 30 deg. N., and 
nnderlies S. 6 deg. to 30 deg. down to tLe 276-btiioni level. It varies In 
width from 1 to 10 feet, being widest at the SOG-fatbom level. It oon- 
sista of quartz, earthy brown ore, black copper, and oopper and iron 



Fia. 42. — Treaavean Miae. 
J, T Fl ES AV E. A N MINE 







pyrites. There was qaartz and schorl at the 264-fatbom level. At the 
228-fathoia level the lode was very rich in copper sulphide. Mr. OolUns 
has described blue peach from this mi ne, and remarks that it la a slightly 
stanniferous capel showing a " shadowy granitic structure."! 

• Phillijis and Darlington. '-Ri'cnnlsof Mining and Metallurgy ," 1857. 
J *<ii. Jfflj,, vol. iv„ 1882, p, 13. "Cornish Tinstones and Capdls." 



THE ABANDONED MINES. 



245 



-TlioiDas stftteii that there are four lodes all of which have yielded oopper. 
They underlie south. 

Between 1815 and 1856, 163,250 tons of ore containing 15,702 tons of 
copper were sold by public ticketing.* 

Wheal Tow as— Great Lode.^E. 20 deg. N. Underlies S. 8 deg. to 
28 d^g. From the 36 to the 142-fathom level the lode varies in width 
from 3 inches to 12 feet. In the upper levels the lode consists of earthy 
brown iron ore, iron pyrites, quiirtz, chlorite, tin ore, and C4>pper pyrites 
and some blende. In the 'deeper levels the lode contains cop|)er and 
iron pyritt^ and quartz coated with carbonate of iron. (Ilenwood.) 

Between 1815 and 1835,26,or>8 tons of ore containing 1,463 tons of copper 
were sold by public ticketing. [ 

Tkebk* HUT Mine. (Fig. 43.)- 0/d Som«i /^wle. CopjK^r. Underlies S* 
15 deg. (continuation of William's hxle in Choo^water Mine). 



Fig. 43. — Tresherhy Min^. 




North XocI#?.— Copper. Underlie N. 10 deg. (a branch of the old South 
lode). 

Middle /.ode.— Branch of the old South lode. It underlies north and 
falls into the North lode. 

Wheal Vnr Footle.- Tin. Undeilies S. 27 deg. It is called Prussia 
lode in Wheal Bovs and Butter's lode in Wheal Harmony. 

Chaceimter or 'WmUim'i^ /ode.— Copper. Underlies N. 40 deg. for 50 
fathoms In depth and then underlies N. 27 deg. 

William* H South Lode, — Copj>er. Underlies N. 28 deg. 

Teague's Zodc- -Copper. Undt^rlies S. 23 deg. 

Flat Lode, -Copper. Underlic*s N. 40 deg., crosses <he Chacewater 
lode at the 70-fathoni level. 

Carquean North Lode,- -Cop\)er, I'nderlies N. 15 deg. 

Carquean South Zod**.— Oopper. Underlies N. 5 deg. (Thomas.) 
Phillips and Darlington state that between the years 1815 and 1832 only 
6 tons of copper ore were sold at public ticketing. 

Tbevknen MiXE.-Carne states that the lodes were richest at a depth 
of 150 fathoms from surface. t 

Tbbwan MiSE,Trewan North Lode,- Cniipev, Underlies S. 15 deg. 
(It is the Briggan lode.) 

* Phillips and Darlington, ** Records of Mining and Metallurgy," 1857. 
t Op. cit, t p. 90. 



246 



THE MINES. 



Treivan South Zod^.— Underlies S. 23 deg. Between these lodes is a tin 
lode underlying N. 27 dog. 

Tbkwiroie Downs.— North Zodc— Contains copper. It anderlies N. 7 

deg. 
The South Lode contains copper and underlies N. 7 deg. (Thomas.) 

Wheal Tedmpbt.— TFfieai Trumpet Xode.— (Westerly continuation of 
Wheal Ann lode.) Bearing E. 22 deg. N. Varies in width from 4 inches to 
1 foot. Underlies N. 6 deg. to 24 d^. From 73 to 117-fathom level it con- 
tains earthy brown iron ore and cassiterite. 

At 157-fathom level the granite is friable and the lode contains quartK. 
(Henwood.) 

Union, Wheal, —ir/ical Union Lode.— Tin and copper. Underlies N. 32 

Crrove Lode is situated north of Wheal Union lode. It contains tin, and 
underlies N. 32 deg. (Thomas.) 

In 1838,401 tons of copper ore containing 6 tons of copper were sold by 
public ticketing.* 

United Hills. (Fig. 44.)— Lode strikes E. 26 deg. N. Underlies N. 42 
deg. to 60 deg. It varies in width from 4 inches to 7 feet to the 52-fathom 

Fig. 44.— United Hills. 







SCALE "'FaihjorTLS 

so lOp 



70 F"^ 
Level 



level, and consists of quartz, quartzose slate, copper and iron pyrites en- 
closing irregular masses of slate. (Henwood.) 

Between 182Gand 1847, 54,473 tons of ore containing 3,582 tons of copper 
were sold by public ticketing.f 

Within the Tywarnhaile sett the lode has been worked upon for a distance 
of 400 fathoms. The width of the lode is very irregular, and the ore 
occurred in hard quartz, slate, or capel. At the 50-fathom level east of 
Bennett's shaft a cross-cut was driven south to intersect a Gaunter and the 
Wheal Charles lode. The Gaunter lode at the 80-fathom level was 2 feet 
wide and contained zincblende and iron pyrites. 

United Mines.— 0/d Lode— E. 27 dog. N. 2 to 8 feet in width. Un- 
derlies N. 6 deg. to 30 deg. It consists of quartz, slate, clay, 
earthy brown iron ore, black copper ore, and copper pyrites. At the 
128-fathom level there was granular quartz, slate, zincblende, copper 
l»y rites. 



* Pliillii»3 and Darlington. " lleconls of Mining and Metallur^jj- ," 1857. 
t Oj), cit. 



THE ABANDONED MINES. 247 

At the 92-fathoni level there was a branch bearing E. 20 deg. N. about 

2 feet wide and underlying S. 10 deg. to 20 deg. It contained quartz, slate, 
and copper pyrites. 

Another at the same level is 4 inches wide, and underlies S. 50 deg. to 
60 deg., and consists of quartz, slate, and some copper and iron pyrites. 

Middle Lode,- Fj. 30deg. N. Lode vertical, and quartzose. Varies in 
width from 2 to .3 feet. 

MichelVs Lodc.-E. 25 deg. N. Underlies S. 8 dog. t<i 20 dog., is 4 or 6 
inches in width, and consists of quartz and slate, 

A branch of Michell's lode bears E. 20 deg. N., and underlies S. 6 deg. 
to 20 deg. It is 3 inches in w^idth and consists of quartz, slate, and copper 
pyrites. 

Mundic or Buzzaa Lode, — E. 25 deg. N. Varies in width from a few 
inches to 4 feet. Underlies N. 12 deg. to 30 deg. Contains copper pyrites, 
quartz, and slate to 148-fathom level. 

Bauxien'sSotith Lode— E. and W. Underlies 8. 10 deg. to 24 deg. It is 

3 inches to 3 feet in width. At the 148-fathom level it is composed of 
quartz, copper, and iron pvrites. 

Bawden's.Vorth Lode— E. 22 dog. N. Underlies S. 17 deg. to 30 deg. It 
is 1^ to 3 feet in width. It contains copper pyrites and quartz. 

NichoUs* Branch. — E. and W. Underlies S. 12 deg. to 30 deg., and varies 
from 1 to 3 feet in width. Contains copper pyrites and quartz at 98- 
fathom level. 

Polkinhorne's Lode. — E. 15 deg. S. Underlies N 14 deg. to 25 deg. It is 
2 feet in width and consists of quartz, slate, and schorl at 92-fathom level. 

A Branch of PolkinJiorve's^ Lode bears E. 20 deg. N. and underlies S. 16 
deg. to 30 deg. It consists of quartz, slate, and schorl rock. 

Gellard's North Lode.— E. 28 deg. N. Varies from 1 to 4 feet in width 
and underlies S. 16 dog. to 22 dog. from the 40 to the 54- fathom level. 
It contains quartz, felspar, black copper, and copper pyrites. 

Gellard's South Lode.—E. 20 deg. N. at the 4()-fathom level. The 
lode underlies S. 16 deg. to 28 deg. and varies in width from 1-J to 2 feet. 
It contains copper pyrites, black copper, quartz, and slate. 

MelleVs Lode.^E. 30 deg. N. Underlies N. 10 deg. to S. 20 deg., 
and varies in width from 1 to 3 feet. Consists of quartz, slate, and 
copper pyrites. 

Cfreat South Lode. — E. 30 deg. N. (in the Ale and Cakes part). From 
the 163 to the 213-fathom level the underlie is N. 10 deg. to N. 40 
deg. It varies in width from a few inches to 8 feet, and consists of 
quartz, copper pyrites, barytes, &c. The ore shoots pitch eastwards. 
(Henwood.) 

Thomas has recorded a few particulars regarding the numerous lodes 
of the United Mines, but has called the lodes by different names from 
those which Henwood gives them. 

Between 1815 and 1856, 304,528 tons of ore cont^iining 22,681 tons of 
copper were sold by public auction.* (See Consolidated Mines.) 

Wheal Unity. (Figs. 45 and i6.)— Wheal Vnhy Lode.— Copper* 
Underlie N. 25 deg. The lode was worked in Wheal Gorlaftd. 

North Lode. — Copper. Underlies N. 27 deg. Branches off from Unity 
lode and then rejoins it. 

South Lode. — Copper. Underlies N. 10 dog. 

Francis Lode. — Copper. Underlies S. 15 deg. 

Wheal Solid Lode.— Tin. Underlies S. 10 deg. Frances and Wheal 
Solid lode unite in depth. 

Barrett's Lode.— Copper. Underlies S. 10 deg. 

Cains North Lode. — Copper and tin. Underlies N. 30 deg. 

Cain^s South Lode.— Copper. Underlies N. 10 deg. 

Trefusis Lode. — Tin and copper. Underlies N. 13. This lode is the 
most southerly in the sott. North of it is Blarney s Lode, which consists 
largely of olvan in wliich tin ore occurs. It underlies N. 10 deg. 

Peter's Lode. — Copper. Underlies N. 23 dog. (Thomas.) 



* Phillips and Darlington, '' Keconls of Mining and Metallurgy," 1857. 



IHE MINES. 



Whfal Unitt Wood.— Pits on Vollar Lode.— E. 30 deg. N. From 30 
to SO-tathom levp), the lode uaderliss N. 10 deg. to N. 30 deg., and 
varies Id width trom j to 3 feet. It coiuiiata of quartz, chlorite, Soorspar, 
iron aad copper pyrites. 

Little Ore Lude. -B. 30 deg. N. Underlies ^'. 30 deg. to 38 deg., and 
is atwut 6 inohee wide. It conaiata of qoartz and slafy olay. 



Fig. 45. — KU/i/retk. Unity V'ood. 




r^ 


1 .x^'" 


OR A N 1 T t' 



Fio. iB.— Wai PoUict. Vniiy Wml. 

l^ ?.« k 

S' f^^ ^* %^ 



w" B i^ ^^ M fi^ 4^^ 




Longitudinal Section. 

TrefuiU Lode.—E 25 deg. N. Underlies N. 8 deg. to 24 deg. From 
tbe 26 tofl2ratho[n level it raries in width from l\ to 8 feet, and con- 
sists of quartz, cuptier pyrites, cblnrite, and alaty cliiy with fluorspar and 
iron pyrites. 

Greot EJiKin Lode.— K. 30 deg. N. Underlies N. 45 deg. to 50 d^. It 
is 4 (athotnn in width, and contains large quantities at tin sprinkled 
through it. 

TrentraiVM Elam.— E. HO deg. 14. Underlies N. 10 deg. and varies 
in width fram I foot to 2 fsthoms. It is a flne-grained schorl rock with 
felspar. There were large quantities ot tin above a slide. (Henwood.) 

* Fhillipi and Darlini^toD, " Records of Mining and Metallurg}-," lUt7. 



THE ABANDONED MINEa 



249 



Between 1827 and 184% 3*2,756 tons of ore oontaining 2,405 tons of copper 
were sold by public auction.* 

WHKiU. Uny.— The Great Flat Lode strikes £. 22 deg. N., but west- 
wards tho strike is E. 37 deg. N. The general underlie is 44 deg. The 
lode is wrought for a distance of 300 fathoms in the direction of strike. 
It lies very near the junction of the granite and killas but is mainly en- 
closed in granite. [ The lode from the 190 to the 200-fathom level is 
practically vertical at Hind's shaft. The average width of the lode is 10 
feet, but it is as narrow as 4 feet in some places, as at the 180-fathom level 
on the east of the Engine shaft (t contains 50 to 70 lbs. of black tin per 
ton of ore, the percentage of black tin diminishing where the lode is wide. 
The shoots of tin pitch eastwards. Hind's sliaft is sunk to the 214-fathom 
level. King's shaft is sunk to the 100-fathom level. At the 190-fathom 
level several tons of rich copper pyrites were broken in the lode in 1884.| 

Between 1826 and 1856, 755 tons of ore containing 39 tons of copper 
were sold by auotion.§ 

Whral Virgin.— Wheal Vii-gin Lode.- Copper. Underlies N. 16 deg. 

TerrilVs Lode.— Copper. Underlies S. 13 deg. 

Cro89 Cut Lode,— Copper. Underlies S. 13 deg. 

TreQonning*8 Lode.— Copper. Underlies S. 13 deg. 

South Lode.— Copper. Underlies N. 15 deg. 

Between Tregonning's and South lode there is a tin lode underlying 
N. 50 deg. There is elvan on the south wall and killas on the north 
wall. North of the South lode is a copper lode underlying N. 10 deg. 
(Thomas.) 

Between 1841 and 1847, 22,974 tons of ore containing 1,656 tons of copper 
were sold by auction. | 



Fig. 47. 



, CBIAT WHEAL VOR 

^» terioms st»omftM0 ^moAiimi rv o^ «M4^f« TO LOOts) 






I 



toor--^ 



200 r^£»u 



^tfU F^Lt^U 



Wheal Vor. (Figs. 47 to 51.)- The Metal Lode bears E. 10 deg. to 
15 deg. N., and underlies 10 deg. to 25 deg. N. Wood-tin was found 
in the lode about the year 1867 at 180 fathoms from surface, on the 
west of the Metal shaft About 1873, similar ore was found 80 fathoms 

• Phillips and Darlington. " Recoids of Mining and Metallurgy,'* 1857. 
+ Foster, p. 640. b kj 

X R. H. Thomas, " Some Observations on the Great Flat Lode in vVheal Uny." 
Rep. Com, Poly. Sac , 1886, p. 184. 
I Phillips and Darlington, *' Records of Mining and Metallurgy," 1857. 
,1 Op. cit. 



250 



THE MINES. 



further east in the same lodOt which is aboat 2 feet in width. At 
this level the lode widened out rather suddenly, while the Teinstone 
became more chloritlc, less quartzose, and contained a large amount 
of tin, either in separate segregations or mixed with the veinstooe. 
Wood-tin occurs either in scattered grains, in small isolated masses, 
or in veins of varying and inconsiderable width, sometimes as thin 

Fig. 48. 

, GReAT WHEAL VOS 

{stcriom* smowiH^ ^moM0Mtrr of sma0T» to t.OOt».) 




as paper, but it is always in a fibrous condition. Some of the masses 
exhibit concentric structure, of clove brown and brownish yellow laminte, 
but the structure is radiately crystalline. These aggregations of divergent 
crystals sometimes enclose kernels of ordinary tin ore that radiate from 
minute cavities.'*' 

At the 162-fathom level, wood-tin occurred in large kidney-shaped masses 
associated with crystalline cassiterite and quartz in part of the Wheal 

Fig. A9,—SiUniey Wheal Metal. 




\ 



SCAL£'TalJvnma 
O 60 lOO 



Metal lode. The lode was 6 feet in width, and worth £600 per cubic 
fathom. The wood-tin occurred intermixed with ordinary crystalline tin- 



• W. H. Argall, " On the Occurrence of Wood-tin in the Wheal Metal Lode 
at Wheal Vor." Jowm. Roy, Inst, Cornwall, vol. iv., 1873, p. 256. 



THE ABANDONED HIKES. 251 

■tons, togatker with muoli chlorite, ehkloadonr, ddlomlte, felspar, and 
iqrritM.* 

Oharifls Thomaa, writing in 1867, remftrka that for aome tltao the retama 
of tin ore were SOO tons a mooth, yielding 150 tons nt line tin. In man; 




plaoes the lode was worth £1,000 a cable fathom. It was rich to the 300- 
fathom level, and then became poor.t Before 1870, it is stated to have 
yielded OT«r £3,000,000 worth of tin and oopper.j: 

Fio. 51.— PenhaU Wheal For. 




• J. H. ColtinH, "Cornish Tin Stones and Capels." Min. Mag., vol. iv„1882, 
p. 7. 

t Jfiainj FUldi of the »ttl. 1867, |>. 24. 

t U. Hancock, >' Un the Mineral Depoaiu of tlie Old Wtieot Vor." Aoy. Corn. 
POly.Soe., 1370, p. 101. 



252 IHE MINES. 

The Main Lode, in the Carleen or eastern part of the mine, bears 
K. 28 deg. Nm and underlies N. 10 deg. to 25 deg. It varies in width from 
a few inches to IJ feet, and consists of chlorite, quartz, slate, cassiterite, 
and iron pyrites at the 55-fathom level. At the 125-fathom level there was 
some arsenical pyrites with chlorite and cassiterite. The main lode in the 
Wheal Vor and Wheal Vrcja (or eastern) part varies in width from 3| feet 
to 20 feet, being widest at the 140-fathom level. At the 85-fathom level 
there was copper pyrites and black copper ore. At the 121-fathom level 
the quartzose slate was traversed by strings of cassiterite. At the 131- 
fathom level there is a bed of qnartzose slate extending 10 feet from the 
lode on the north side. At the 140-fathom level a similar bed extends to 
20 feet from the lode. The lode consists of quartzose slate^ cassiterite, 
quartz strings, and drusy quartz cavities lined with crystals. At the 240- 
fathom level there was cassiterite, iron pyrites, and felspar. It was worked 
to the 285-fathom level at Bounder*s shaft. 

Whml Sozm Lode.— Bears E. 24 deg. N., and underlies N. 20 deg. to 36 deg. 
At the 40-fathom level there was earthy brown ore and quantities of cas- 
siterite. The lode at the 100-fathom level consists of quartz, chlorite, and 
slate. At the 70-fathoni level there is a bed of quartzose slate traversed 
by quartz veins. 

Came* states that there are two el vans in the eastern part of the mine. 
The largest is on the north, and is 24 feet wide, bears N.E. and S.W., and 
underlies N. 56 deg. The lode was about 2 feet wide inkillas, but in elvan 
was 5 feet, and in some places was so broken up into branches as to make 
the whole elvan for 20 feet worth working. Hen wood) states that there 
are two elvans. The northern one is 2 feet wide, and underlies 20 deg. to 
30 deg. N. The southern is 8 fathoms in width, and underlies 40 deg. to 
50 deg. N. The lode was productive in both elvans. In the southern one 
the tin ore occurred in a somewhat sprinkled manner. In elvan the tin ore 
occurred either in unconnected masses and irregular bodies or as short 
veins. ** Floors '* containing tin ore strike off in a nearly horizontal direc- 
tion into the killas, and are similar in composition to the lode. 

The fact that the lodes only yielded tin ore while in killas and became 
poor on entering the granite is a well-known peculiarity of the district. 
Between 1821 and 1842, 4,296 tons of ore containing 330 tons of copper were 
sold by public auction.^ A company has recently been promoted to re- 
work the mine in view of the demand for tin. 

Wendron United Minks.— The Biiflfinc Lode.— At Engine shaft it is in 
granite at the 35-fathom level. It varies in width, down to that level, 
from 2| feet to 4 feet. At the GO-fathom level the lode is 4 feet to 
6 feet wide. The lode was a fair one, and good bunches of tin ore were 
found at the 35-fathom level. 

Flavders Lode- Width of lode is 1 foot to 3 feet. The granite was 
encountered below the 86-fathom level. A poor to fair tin lode. 

Liddecoafa Lode. — This crosses the Flanders lode at 10 fathoms west of 
Hiirs shaft. Varies in width from 3 feet to 4 feet. The veinstone is chloritic. 
The junction of Flanders and LiddecoaVs lode was productive of tin ore. 

LiddecodVs North Part.— At the 70-fathom level it varies in width from 
H feet to 2 feet and contains fair tin ore. 

Richard*H Lode.— At the 20-fathom level it is 2 feet to 3 feet in width. 

Wheal Fat Lode.— At the 35-fathom level the lode is 4 feet to 5 feet in 
width, with low-grade tin ore. 

West Condtjrrow. (Fig. 52.)— There are six lodes in this sett. 

Kellivose shaft is on a lode which at adit level yielded tin and copper 
ores. In width the lode is from 1 foot to 5 feet. 

At 22 fathoms south of Kellivose lode there is another, varying in width 
from 6 inches to 18 inches, which yields tin ore. 

At 60 fathoms further south there is a lode yielding tin ore. 

At 45 fathon)s south of the last there is another known as the Bounty 
North Lode. 

* " On Elvan Courses." TV. R. OS. Com., 1818, vol. i., p. 103. 

i p. 52. 

:;: Phillips and Darlington. " Records of Mining and Metallu»gy," 1867. 



THE ABANDONED MINKS. 



258 



At 14 fathoms farther south b the Bounty LodCf yarying in width from 
1 foot to 2 feet. This lode has a good gossan, and yielded tin ore. 

The Kellivose Lode, — Bearing E. 35 deg. N., and underlies N. 27 deg. 
The lode has a good gossan and consists of quartz and killas with tin and 
copper ore. At the adit level alternations of slate, clay, and granite were 
met with near the shaft (Park shaft). At Purser's shaft the lode yielded tin 



Fig. 52. — West Condurroxv. 



o So loo 






N. 



and copper and there was much flucan. At the 12-fathom level in the 
same shaft it is 3 feet to 3^ feet wide, and consist of quartz, prian, and 
killas, with bunches of copper and tin ore. A t the 24-fathom level the 
lodestuff is quartz and peach in granite. 

North Lode, — Greenstone was met with when sinking operations were 
commenced on this lode.*^ 

West Wheax Damsel. — Tremayne's Lode has been worked upon down 
to the 15(^fathom level. Thirty fathoms north of Tremayne's lode is the 
Wheal Damsel North Lode, which is about 1^ feet wide and yielded copper 
ores. 

The New North Lode is opened up as far as the 90-fathom level. 

Darlington's Lode intersects Tremayne's lode in depth, producing tin ore 
in the deep levels. 

6,392 tons of ore containing 378 tons of copper were sold by public auction 
between 1852 and 1856.t 

West Dolooath.— The Main Lode is situated below an el van. At adit 
level the width of the lode is about 2 feet. The veinstone consists of 
quartz, chlorite, flucan with mundic, and black and yellow copper ores. 
It is supposed to be a continuation of the Dolcoath main lode. 

West Fbancks. -Smith's, or the New, shaft is sunk on the Great Flat 
Lode to the 174-fathora level. The lode consists of peach, quartz, and tin 
ore. Near a cross-course the lode is large, and contains a little tin ore 
throughout. Foster states that it has similar characteristics to those of 
the same lode in West Basset Mine, except that the leader, instead of 
being a mere joint, is a quartz vein 2 or more feet in width. The stan- 
niferous part of the lode is under the loader, and the underlie of the lode in 
this mine is from 40 deg. to 53 deg. south, varying within these limits 
in the short distance of 80 fathoms4 

West Wheal Jane. -Worked to the 70-fa thorn level at Clemow's shaft. 

West Wheal Seton.— There are several lodes, but they are mainly 
branches of the main lode. The lodes contained blende and copper to 
below the 100-fathom level, and yielded tin ore below that horizon. 

Old North or Main Lode. — Underlie N. 30 deg. The lode is associated 
with an elvan, and appears to have been richest in its Immediate vicinity. 
It varies in width from li feet to 3 feet in the upper levels, where it was 
not particularly rich in copper ore. Below the 120-fathom level the lode is 
3 feet to 5 feet or even 10 feet in width, and yielded both tin and copper- 

* Information obtained from the Pendarveft Estate Office through the cour- 
teay of Mr. Vercoe. 
t Phillips and Darlin^'ton. '* Records of Mining and Metallurgy, " 1857. 
t Foster. 



254 



THE MINES. 



ore. It was rioh at the 226-fathom level, at which place It is only 5 feet 
distant from elvan. The ore ground as a whole pitches west with the 
janction of the lode and elvan, but there was another good ore bunch near 
Mitcheirs 9haft, where the veinstone was a dark chlorite with^qnartz and 
fluorspar. At the 275-fathoni level the lode was prodnctive in tin ore. In 
some levels, particularly in the higher horizons, it yielded blende and 
mundio. 

North Part, — The old North lode branched at the western Engine shaft, 
where the north part was 4 feet wide, and at the 20-fathom level con- 
sisted oC a soft killas veinstone with blende and mundic At the 110- 
fathom level the lode is 2 feet to 3 feet wide. 
* South Part,— At the 112-fathom level the lode is 6 feet wide in some 
places. 

North Lode, — This lode is a branch of the old North lode at the 
TO^fathom level, near Harvey's shaft, on the underlie side of the lode, 
2 feet wide with copper ore. 

South Lode.— This is a branch of the old North lode. From the 100- 
fathom to the 130-fathom level the lode is 4 feet to 7 feet in width, and 
contains tin and copper with flucan, quartz, and mundic. 

New South Lodp.- Nearly vertical, but has a slight northerly underlie. 
Between 1848 and 18o6, 14,766 tons of ore containing d89 tons of copper 
were sold by public auction.* 

WR8T Wheax Towan.— The lead lode as seen in the cliff at adit level is 
2 feet wide. It yielded lead and tin ore with mundic. 

Hampton's Lode, — From the 2&-fathom to the 43-fathom level the lode 
is 1 foot 3 inches wide, and contains a little tin ore. 

MiddleuH)rks* Lode,— Underlies south 20 deg., and is about 2^ feet wide. 

Goad*8 Lode, — This lode branches off downwards from the Middleworks* 
lode at an angle of about 10 deg. S. 

Wkbt Wheal Yirgi^.— Wheal yirgin Lode.— Copper. Underlies N. 
15 deg. It is intersected by Wheal Maid Lode. (Thomas.) 

Camel states that the Great Oaple Lode is called a tin lode, and is 
traversed by Tregonnitig's Copper Lode, but that in depth the lode was poor 
in tin ore and became copper bearing. The Main Lode is 9 feet wide in 
some places, but it is on an average about 3 feet. 

In Tiddy's cross-course (Consolidated Mines) vitreous copper ore and red 
oxide of copper with native copper were found in a few rich bunches.}; 

Miscellaneous Diagrammatic Sections of Mines. 
Fig. 53. — Wheal Christopher. 



S. 



N 



AOIT 



UCVCL 




♦ •* Phillips and Darlington. " Records of Mining and Metallurgj," 1867. 
.96. 
[en wood, p. 92. 



t p. 96. 



TBE ABAKKntED IIINE& 



Fio, ti.~Gli0 Doum Hine. 



Fio. 55. — CTi^ Down M'fM. Section ia Valley. 
N. '^% S. 







Fig. 56. — Clyjak and Wentucorth. 




THIS MTWES. 



Fig. 57.— Wheal WejUnorth. Via. SS.~Medlyii Moor Mine. 




KiG, 59, — Natuxkuk'e Mines {Wfieal Glarctice). 




Fill, m.— North Pool Mine. Fig. 61.— JVortA Whtal Vor. 



^ } 


!!.»■ 


..,.1 \l l\ 




\l 



\ 



THE ABANDONED MINES. 



257 



Fig. 62. — Polrose Mine. 



Fig. 63. — Souik LodM Mine- 




N 




<^0 Fa/Jvonts 



LAN OF 

;thoncuet 

lEK MINE 



Fig. 64. 

JVesterriy T^anJc of 



>|V 



• 



•V 



KaSt 



Strippxjxg 
Le-vels 




>l M «• 







1'-:;^^% 



•I 













SI 

•4 

<0 



oJ 






Deep LeA^tla 
Shallow LeveLs 



E. 



SECTION OF RESTRONCUET CREEK MINE\ 

Taylors Charles W. 

SKa ft SKaft 



DcjepXc*^^ 



DOC 



DC 



rsKt^^ 



Kjoc^ 



^aihotjub 6' thicks 



s 



258 



CHAPTER XVICI. 



MINING ECONOMICS. 

Intkoductory Kemarks. 

This area embraces the most important miniog district in Corn- 
wall, and although in late years mining has declined in the 
region owing to foreign competition and the consequent deprecia- 
tion in value of the ores for which the area is so celebrated, it is 
still justly famous for its ancient historical connections, its mineral 
wealth, and the geological problems which it present:?. The 
abundance of the metalliferous minerals encountered in mining 
operations early attracted the attention of man, and in more 
recent times the variety of its mineral products has afforded a 
fascinating field for study to observers in the various branches of 
the science. As a field for economic enterprise it once held a 
premier position, and could the history of the financial side of 
this mining area be adequately written, it would form a voluminous 
record of facts and figures connected with the dealings of specu- 
lators of slight scientific interest. Some of the rich repositories 
of tin and copper ore have yielded immense fortunes to their 
lessees and to the lords of the soil. This is now changed, and 
there remains awildernessof mine burrows, engine bouses, and smoke 
stacks, spoiling the appearance of the country, but bearing mute 
witness to the prosperous mining days of the past. Since 1865 
the decline was fluctuating but gradual, as first copper and then 
til) suffered from outside competition. It should, however, be 
remembered that with mining at greater and greater depths the 
expenses of working (pumping, hauling, &c.) increased to an 
extent sufficiently great to seriou&ly affect the industry, and with 
many of the richest ore bodies already worked out, the condition 
of the mines contributed in no small degree to the final collapse. 
The disastrous drop in the price of tin about the middle of 
the seventies saw the closing down of many mines which had 
the price been maintained might yet be working. The value 
of tin ore at the present time is so high that as time goes 
on it may be confidently expected to once more raise the status 
of Cornish mining. The only barrier to immediate progress 
in this direction appears to be the difficulties which will have to be 
encountered in opening up the old sites already so extensively 
explored, since the ramifications of levels and working places are 
such as to present a difficult problem in the unwatering of the 
submerged mines, many of which are connected underground by 
a vast system of drivages. There is brightness, however, in the 
reflection that a few of the mines have survived the period of 
dej)rc*ji6ion, and one at least has worked without cessation for over 
150 years, and still holds a high place in the tin-mining world, 
^Hjing the largest, deepest,aud most productive tin mine in existence. 



HISTORY OF THE MINING INDUSTRY, 259 

In the preceding pa^es it has been found necessary to make 
constant use of published works on the district, since so few of the 
mines are now accessible. Among the more important publica* 
tions those of De la Beche and Kenwood have been of great . 
service. In later times the names of Collins and Le Neve Foster 
are intimately connected with Cornish mining. The ancient 
History of Cornwall has been written ^ain and again, but the 
leading works are those of Carew, Camoen, Borlase, Hawkins, De 
la Beche, and Hunt. In this memoir an attempt has been made 
to deal with the various points of interest to miners in the region. 
In the methodical treatment which is adopted there is no claim to 
originality, but some of the old problems have been revived and 
viewed in a new aspect. The alluvial, or stream tin-deposits, which 
have been so well described by Henwood, and others, are now 
exhausted, but their origin and mode of occurrence have been 
discussed by Mr. HiU in Part I. of this memoir. 

The tables, which give the detailed output for individual mines 
from 1815 onwards, should be regarded as a general measure of the 
relative importance of the mines, and not as being strictly accu- 
rate, since in former days the records were not preserved so 
carefully as they have been latterly. 

In conclusion, it should be mentioned that assistance has been 
freely given by Mine Captains and others, who have afiforded every 
facility for observations underground. 

In Cornwall the survey is indebted for much information to the 
Duchy Office, the Estate Offices of Tehidy and Pendarves, and to 
Messrs. Henderson & Son, of Truro, and others, where mine plans 
and records have been placed at our disposal. In London similar 
facilities have been afforded at the Home Office and the Office of 
Woods and Forests. The scales to which the mine plans are 
drawn vary from 4, 6, 8, 10, 12 to 20 fathoms to the inch, of which 
8 fathoms to the inch is the commonest. 



History of tue Mining Industry. 

There are good reasons for the belief that the Phoenicians 
exported tin from Cornwall several centuries before the 
Christian era. Borlase states that the Romans and Greeks 
also ** studiously insinuated themselves into the same traffic." 
Until the middle of the 13th century Cornwall was the most 
important source of tin, but the ore was obtained from alluvial 
deposits and the backs of the lodes, the latter of which were 
worked away, leaviug open cuts called '' coffins " or '^ goffins." The 
works of Pryce and Borlase give excellent accounts of the early 
history of mining, and are of particular interest as dealing with 
the time about which the steam engine was introduced, and it 
may be said that it is from this period that the working of tin 
and copper ores became an important national industry. The 
main obstacle in early times to the progress of deep mining in 
Cornwall was the inability of the miners to cope with the subter- 
ranean water which Hooded the excavations. Before the intro- 

s 2 



260 MINING ECONOMICS. 

ductioQ of the steam engine the water was raised in kibbles by 
means of a whim worked by horses. The Bag and Chain pump* 
was another device for lifting water. The old ^* Fire Engine ** is 
.the first steam pump, and, as modified by Trevithick, was a great 
advance on earlier appliances. The most important invention was 
made by Newcomen, whose Cornish pumping engine, with Watt's 
modification, was destined to assist mining operations enormously. 
Prior to this the mines Vbuld not be worked to great depth, and 
the old Pool Mine, for instance, was only 55 fathoms in depth at 
the time Borlase wrote, while the deep workings of BuUen 
Garden Mine were in 1778 only about 90 fathoms from surface. 
As Borlase quaintly remarks, it was necessary '' that to obviate 
the inconvenience (of water) the captain should be a kind of 
engineer." 

The introduction of gunpowder in the Cornish mines about the 
beginning of the 18tb century was another important advance in 
mining work. 

Pryce gives an interesting account of the state of copper 
mining at the period of its inception, and says that the people 
were ignorant alike of its value and the modes of dressing it. 
Thus, he states in ] 778 that " though the richness of our copper 
works is not a late discovery, yet it is not a hundred years that 
the knowledge of working them to good effect hath been under- 
stood." About the year 1 700, some Bristol merchants, by their 
interest in the copper mines, stimulated the industry, while about 
1730 large quantities of copper ore were raised from Boskear, 
Pool, and other mines, in spite of the prevailing local ignorance 
of the value of the ores. 

From 1726 onwards the yearly output is tabulated in the 
statistical table, and a perusal of those tables will sibw that the 
output increased fairly steadily year by year until past the middle 
of the 19th century, when the decline commenced. The richest 
and most accessible ores were rapidly being exhausted, and the 
prices for copper ore had fallen off owing to outside competition. 
With increasing depth, many of the mines yielded tin ore in such 
quantity as to warrant their exploitation for tin instead of copper, 
so that many mines once yielding copper ore exclusively now 
yielded tin ore in abundance, and transferred the attention of 
investors to tin mining. (Fig. 64.) 

From 1750 to 1800 the tin mines were yielding a tolerably 
uniform annual amount of black tin, but early in the last century 
they commenced to increase their output, and there was a steady 
rise in the annual returns of black tin up to the sixties. From 
the seventies to the present time, although the output has been 
fairly well maintained, it gradually decreased, while in the last ten 
years it has fallen off considerably. Foreign competition so 
lowered the price of tin ore that many mines failed in the seventies. 
For several years past the price of black tin has been increasing, 
and there is every reason, should the record high figure now 

* Invented by Captain Savory, of Exeter. Borlase, Nat, BUt., Com., 1758, 
p. 170. 



HISTORY OF THE MINING INDUSTRY. 



261 



reached be maintained, for looking forward to the opening up of 
many of the old mines. 

The statistics published by the Home Office since 1881, and 
those contained in the Memoirs of the Geological Survey, show 
that the number of working mines has suffered a great dpcrea^e 
in the last fifty years. The following tabular statement gjives the 
number of mines in this district which at the various dates were 
yielding tin or copper ores. Many of the mines were, of course, 
yielding both ores: — 

1858 

1863 

1868 

1873 

1878 

1883 

1888 

1893 

1898 

1903 

The amount of copper ore produced from the mines in the 
Camborne area in late years is only a few tons per annum, and is 
scarcely worth consideration, some of the ore being obtained while 
prospecting old sites. 

The following tabular statement of the outputs of three promi- 
nent mines which are still working is of peculiar interest, as it 
traces the evolution of mining from the upper levels to the deeper- 
seated zones, accompanied by the substitution of tin for copper : — 



Mines 


yielding 


Till ore 


Copper. 


50 


70 


56 


90 


48 


52 


74 


40 


:^ 


30 


42 


20 


32 


10 


25 


6 


16 


3 


15 


5 



DOLCX>ATH. 



I 



oO 

o 



^ a. 
o o 

SO 






1846 

1847 

1848 

1849 

1850 

1851 

1852 

1853 

1854 

1855 

1856 

1857 

1858 

1859 

1860 

1861 

1862 

1863 

1864 

1865 



T. Cwt«.IT. Cwtii. 

18453,504 0,233 14 
2,156 01138 12 



2,057 

1,254 

1,028 

1,115 

801 

832 

1,040 

992 

711 

617 

566 

593 

757 

712 

417 

508 

636 

621 

607 



01135 
95 
77 
72 
55 



i 











01 





ol 



8 

2 

10 

11 

8 

42 14 
51 17 
45 10 
28 6 

24 8 

25 18 
34 8 
38 15 
28 14 



Cwts 



Wheal Basset. 



East Pool. 



SI 



6^ 



a> o 

SO 




CO ••^ 

3^ 



r. (Jwta. T. Cwts. r, Cwt« 



18 
29 
39 
39 
44 



18 
16 
16 
3 
13 



360 
363 
352 
416 
544 
635 
723 
805 
864 
985 
1,026 
1,029 
944 



13 



5,442 

5,966 

7,207 

1018,378 

7,713 

7,600 

6,183 

10 4,754 

18 *,258 

3,894 

2,931 

2,599 

1,998 

1,726 

2,036 



19 
9 

18 
9 



0487 
0503 
0608 
0646 
0680 
0594 
.. 
0414 
0365 
0300 

o;2:u 

211 
0154 
0138 
0183 



17 .. 
13 21 

2 31 

9| 46 

12 25 

18 20 
32 







112 
01 
32 
41 



45 

13 42 9 

14 60 1 
19 51 15 



17 

5 

11 



48 181 

77 
117 
158 



1613 

7 
1012 








IT. Cwts. 

929 

633 

608 
1,088 
1,136 
1,422 
2,050 
1,740 
2,157 
2,034 

,287 
2,821 

,535 

,300 
1,280 
1,896 
2,435 
2,944 



T. Cwta 

73 5 

43 15 

34 

64 

66 

70 



0106 



2 
16 
17 
2 
16 
10 
11 
4 

13 

14 

19 

15 

15 

9 

0120 6 

0149 8 

,264 0155 16 

2,805 oil 26 3 

2,083 Ol 93 9l 



86 

98 

99 

134 

0,178 

0138 

66 



0, 



54 
93 



Gwti. 



20 16 

22 

49 11 

38 8 

49 13 

51 9 

36 7 

44 2 

58 5 

49 15 

97 8 

134 17 

136 18 

257 1 



2G2 



MINING ECONOMICS. 





DOLCOATB. 


Wheal Baaset. 


East Pool. 


• 

s 


Copper 
Ore. 


^ Metallic 
1 Copper. 


T. CwU. 


r. Cwte.i 


Metallic 
Copper. 


Black 
Tin. 


Copper 
Ore. 


Metallic 
Copper. 


Blaok 
Tin. 




T. Owtt. 


T. Cwts. 


T. CwU. 


T. Cwt8.| 


T. Owt».| 


T. Cwti, 


1866 


688 


52 1 


919 7 


2,108 


0174 9167 3 


1,808 


0^ 97 9 


379 13 


1867 


267 


15 18 


847 18 


1,700 


0132 7292 13 


1,582 


76 14 


321 8 


1868 


153 


12 11 


984 4 


1,539 


0115 12264 17 


1,753 





79 15 


364 14 


,1869 


153 


10 11 


813 i 


1,572 


0130 8313 4 


1,641 





85 


325 8 


1870 


57 


3 17 


1,034 15 


1,341 


0106 12|353 9 


1,854 





90 14 


251 17 


1871 


80 


5 11 


1,169 18 


442 


35 2'335 22,430 


0125 12 


109 19 


1872 


46 


3 3 


1,284 16 


528 


38 8255 ^ 


2,520 





138 8 


90 14 


1873| 


16 


1 1 


1,045 6 


488 


67 1 


286 6 


1,933 





95 17 


384 1 


1874 


75 


5 16 


1,120 19 


396 





41 8|310 18| 


1,920 





95 9 


419 18 


1875 


• t • 


• • • 


1,241 10 


714 





62 17 


248 qi,823 





85 12 


571 5 


1876 


41 


2 8 


1,263 5 


759 





67 13 


147 6^1,806 





90 18 


364 1 


1877 


30 6 


2 1 


1,404 13 


448 


9 


40 10,164 811,527 





90 12 


392 


1878 


13 11 


12 


1,539 2 


227 


18 


23 8*208 d2,564 11 


151 4 


489 15 


1879 


4 4 


3 


1,780 8 


99 


2 


8 23 


2,362 


7 


112 10 


864 9 


1880 


• • • 


... 


1,737 14 


29 


12 


2 7 15 


1,350 


3 


75 13 


1,268 4 


1881 


• • • 


... 


1,816 5 


• t • 




... ; 8 4 


903 18 


45 15 


1,317 14 


1882 


• t • 


1 •'* 


1,976 3 


• • • 




.... 60 9 


380 16 


19 1 


1,536 2 


1883 


• • • 


1 •• • 


1,875 12 


• • • 


... 173 10 


48 





2 10 


1,402 


1884 


• • • 


... 


2,423 3 


• • • 


... 267 3 


376 





• ■ • 


1,573 


1885 


• • • 


1 ... 


Z,555 3 


• • • 


... i395 


229 





• • « 




1,512 


1886 


• t • 


1 


2,383 a 


• • • 


... 379 4 


* . • 




• . • 




1,440 


1887 


• • • 


' 


2,366 


• • • 




... 370 


... 




• • ■ 




1,233 


1888 


• 9 • 


1 

1 ••• 


2,239 


• • • 




... 416 91 15 





• • a 




1,179 


1889 


3 


• t • 


2,125 


• • • 




... 386 10 26 





• • i 




1,105 


1890 


• • ■ 


« t • 


2,023 10 


3 





... i396 01 312 





• 9 1 




995 


1891 


• • • 


• • • 


2.131 12 


• • • 


1 ... 402 


451 





• • 1 




1,070 17 


1892 


• • • 


• • • 


2,535 


• • • 


... 458 


15 


c^ .. 




1,004 


1893 


• • • 


i ... 


2,421 9 


• • • 


i ... 432 10 


729 





1 




938 7 


1894 


• • • 


• • ■ 


2,126 


• •• 


1 ... 1470 4 


730 





1 ••< 




940 


1895 


• ■ • 


• • • 


1,766 


... 


! ... ,536 4 


373 


.. 




877 


1896 


• • • 


• • • 


2,039 7 


... 


1 ... 554 


• • • 


• • 




529 6 


1897 


• • • 


• • • 


2,095 


... 


; ... 539 C 


64 


(^ .. 




309 


1898 


• • • 


• • • 


2,302 7 


... 




... 356 C 


16 





1 




770 


1899 


4 


► ... 


2,078 18 


... 




... 1268 C 


22 





., 




816 


1900 


• • • 


• • • 


2,004 8 


• • • 




... ;523 C 


• • • 








739 


1901 


• • « 


• • ■ 


2,035 11 


• •• 




... ,575 C 


10 









699 


1902 


• • • 


t • • 


1,828 9 


... 




... 794 C 


31 









663 


1903 


... 


• • t 


1,739 17 


11 





... 728 C 


27 









706 


1904 


• • • 


1 
1 ••• 


1,705 4 


• • • 




... 613 C 


863 









661 


1905 


... 


1 
... 

1 


1,696 16 


... 




... 768 C 

1 

1 


70 









585 10 



Notes on Tin-Ore Dressing in the Camborne Area. 

Oldek Methods. — Writing over a century and a half before Borlase, 
Carew,'*' in his quaintly-worded description of Cornwall, gives a very good 
insight into the state of mining at that time. 

Among other subjects the dressing of ore is dealt with, and from Carew's 
account the methods in use in his time were very simple. The ore was 
first broken with hammors ** and Uien carried to a stamping mill, where 
three, and in some places six, great logs of timber bound at the ends with 



Surn-i/ of Cornrvall, 1602. 



TIX-ORE DRESSING. 263 

iron, and lifted up and down bj a wheel driven with water, do break it 
smaller. If the stones be over moist they are dried by the fire in an iron 
cradle or grate. From the stamping mill it passeth to the crazing mill, 
which between two grinding stones, turned also by a water wheel, bmiseth 
the same to a fine sand ; howbeit of late times they mostly use wet stampers 
and so have no need of crazing mills for their best stuff but only for 
the crust of their tails."* After the stuff was stamped it was spread on 
a sloping green turf aud " softly tossed*' while a current of water flowed 
through it aud washed awa^' the waste. 

The processes of tin ore dressing about the middle of the 18th century 
have been well described by Borlase,[ and later by Pryce,J who utilised 
the same diagram as Borlase to illustrate his description. Borlase re- 
marks that the ore was passed under stamps weighing 140 lbs. apiece. 
The grating was a plate of metal 1 foot square and ^ in. in thickness, 
and was "full of small holes punched in it about the bigness of a moderate 
pin.'* The pulp from the stamps passed through three pits in succession, 
making a settlement in each according to dcusity. The material from the 
first or fore-pit was the richest. The stuff from the other two pits was 
known as the " slimes." The overflow from the pits went to waste. The 
contents of the fore-pit were dug out and treated in a buddle 7 feet 
long, 3 feet wide, and 2 feet deep. The tin-dresser stood in this pit and 
spread the material on a plane sloping surface at the head of the buddle ; 
the stuff being spread in the form of a series of small ridges parallel 
with the direction of a current of water which passed over the plane from 
a launder, or trough. In this way the slime was washed out of the stuff, 
and the whole of the material fell over into the pit in which the tin-dresser 
stood, and there settled in three grades, according to quality ; that nearest 
the head being the purest. The head was put into a kieve (or tub) and 
washed by stirring (tozing or tossing) for a quarter of an hour, so that 
the light waste rose to the top, which after settling was skimmed off. The 
rich part at the bottom of the kieve had to be rebiiddled, and again put in 
kieves. Finally, it was ** packed " by smartly tapping the kieve with a 
hammer, so as to shake the heaviest minerals to the bottom. The skim- 
mings were saved and treated with other products. The two other classes 
of stuff from the first huddling operation underwent a similar treatment. 
The slimes which were deposited in the second and third pits just below 
the stamps were treated in a different way from that in which the coarse 
material from the first or fore-jjit was treated. The slimes were con- 
ducted to a pednan (or circular pit) where they were stirred, and made 
gradually to overfiow into a long pit divided into two parts. The part 
near the pednan was smaller than that further away, which was 10 feet 
long, 3 feet wide, and 8 inches deep, and separated from the smaller by a 
wooden partition. The material from the pednan passed successively over 
into the two parts of the long pit. In the larger part of the pit the stuff 
settled in two grades. That at the head of the pit was dug out and passed 
over frames, while that at the tail was carried back to the small part of 
the pit just below the pednan, where it was again washed (or '* trunked") 
over before it could be treated in frames. The frame consisted of two 
plane surfaces of timber called respectively the head and the body. The 
ore was spread over the head in the form of a series of ridges parallel with 
the direction in which a stream of fresh water was fiowing from a launder 
over a distributing arrangement similar to that employed in the buddling 
operation. The stuff was carried gently forward by the current on to the 
body of the frame, which was slightly inclined, and then the heaviest 
material, however fine, settled, while the lightest flowed to waste. When 
a thin layer of concentrate was deposited, the plane was tilted up by one 
of the lateral edges and the material washed off by a spray into a wooden 
chest. When the chest was full the stuff was treated in kieves and tozed, 
sifted and packed. The sieving took place under water in the kieve, and 

• Op.vit. edition published with notes b}- Tonkin in ISll, p. 39. See also 
Heath, ** Account of Scilly," 1750. 
+ Nat. Hist. Corn., 1758, p. 178. 
X Min. Coinvb., 1778. 



264 MINING ECONOMICa 

by agitating a sieve in which some of the stuff to be dressed was placed, 
the material was cleansed of very fine particles of waste, and the coarse 
waste remained in the sieve. The concentrate from the kieves might be 
taken to the frames and again washed, only once more to be tosed in 
kieves. Borlase states that a hundred sacks, each containing 12 gallons 
of dressed tin ore, could, in the space of a few days, be dressed for 50 
shillings by this process. 

Pryce has described the process known as dilleughing, which is simply 
a method of cleansing the concentrate from the kieves by means of a fine 
hair sieve* which was pressed down on the water and turned round with a 
swaying motion so as to ari*ange the materials it contained according to 
their specific gravity, the operation being assisted by the sorting action 
of the water coming in through the bottom of the sieve. When this was 
accomplished the poorer material covering the waste was skimmed off into 
a kieve to be treated again. 

In 1828 Henwood gave an account of the dressing of tin ore in Cornwall,! 
but beyond the fact that the stamps were heavier, and that there was a 
general improvement in details, as was only natural with the increasing 
importance of tin mining, the general principles of treatment seem to have 
been much the same as in the time of Borlase. At the present time there 
are several of these old-style dressing plants to be seen — particularly in 
the St. Austell district. A still later work, which includes notes on the 
treatment of ores in CornwaU, is Hunt's " British Mining " (1884), while Le 
Neve Foster's recent book, *• Ore and Stone Mining '' (1900), refers fre- 
quently to Cornwall in the sections on ore dressing.]: 

Dressing Machinebt at Present in Use. — In the last few years con- 
siderable improvements have been effected in processes for the prepara- 
tion of black tin for the market, and although at the present time no two 
mines employ exactly the same process there is a general similarity in the 
arrangement of the plants of the larger mines. 

The following descriptions refer to the more important appliances 
actually in use in the mines of the Camborne district. A short description 
of their action may also be of intei*est, although most of them have received 
attention in other works : — 

Three well-known types of stamps are used in the mines of the Camborne 
district-(l) The old Cornish stamp (Plate XIII.), (2) the Califomian 
stamps, and (3) Husband's pneumatic stamps. The old Cornish stamp is 
still used for crushing in many mines, but in recent installations the more 
efficient Californian stamp is en* ployed. The Cornish stamp requires but 
little attention and was the type employed throughout the most prosperous 
mining days of the last century. Each head weighs about 700 lbs., but is 
frequently less. The Californiam stamps, which possess the advantage of 
improved cams and rotating shanks, weigh from 800 to 1,200 lbs. apiece, 
and are designed to deal about 80 blows a minute. Those used at Dolcoath 
have been described by Josiah Thomas, who remarks that each iron coffer 
or mortar box takes five stamps, and that each set of ten stamps is worked 
from a separate belting. The cam shafting is 5 inches in diameter. Each 
head weighs 800 lbs. and with a 9-inch drop deals 80 blows a minute.§ 
The head deals two blows during one revolution of the cam shaft, so that 
with a 5-stamp battery 10 blows are delivered for each revolution of the 
shaft. Each head of Californian stamps crushes from 1^ to 3 tons of the 
hard blue veinstone daily, and on e-asier stuff can crush much more than 
this. 

The screens usually employed are perforated plates, as they are more 

* Min. Cornub., 1778, p. 223 ; or De la Beche, Geological Report, p. 578. 

t On the manipulations to which the ores of tin and copper are subjected in 
the Central Mininpj District. 2r. It.O.S, Com,^ vol. iv., p. 145, 

X A useful modern book of reference on ore dressing is one by K. H. Richards 
(U.SA.), 1903. 

§ The new Californian stamps at Dolcoath Mine. Journ, R, Intt, Com.^vol. 
xii, 1193, p. 39. 



TIN-ORE DRESSING. 265 

durable than wire gratings, althongfai the ose of the latter, by affording a 
better chance for the passage of the pulp through holes of a given size than 
in the case of perforated plates, prevents the prodaction of an undue 
quantity of slime, which would otherwise be formed if the pulp were kept 
too long in the mortar box, by being unable to pass freelj'^ through the 
screen. This is one of the points which should be borne in mind in view of 
the enormous amount of tin which is annually lost to the mines of this dis- 
trict in the form of slime. Common sizes for perforated plates are Nos. 36 
or 37, and for wire gratings 20 or 25-mesh (400 to 625 holes to the square 
inch). In the veinstone in the deep parts of such mines as Dolcoath, Wheal 
Basset, &c., a fine degree of stamping is necessary owing to the fineness of 
the particles of black tin, so that the production ol a certain amount of 
slime is unavoidable. 

An important innovation in ore-dressing appliances has been made dur- 
ing the last twenty years in the introduction of the Frue vanner (Plate XIV.). 
These machines are now used in most of the mines for the first 
treatment of the pulp as it comes from the stamps. The principal 
part of the machine is a broad endless belt which travels con- 
tinuously in a nearly horizontal direction supported on rollers. The 
upper surface of the belt, which is slightly inclined, travels upwards to- 
wards the end at which the pulp is fed on. An excentric at the side of the 
machine communicates a lateral oscillating movement to the belt. 
The action is as follows : — The pulp passes on to the belt from a distribut- 
ing arrangement situated at the end towards which the upper part of the 
belt is travelling. The heavy mineral grains sink on to the belt, and, owing 
to their weight, a*'e enabled to pass under a series of jets of water, and to 
be carried over the end of the machine with the belt, where they are 
washed off in a trough of water situated below the belt. The lighter 
particles of veinstone are, on the contrary, carried back with a current of 
water down the incline in a direction opposite to that in which the belt is 
travelling. The concentrate from the Frue vanner contains, in addition 
to black tin, a little coarse quartz, tourmaline, sulphides, &c. The tailings 
consist of grains of quartz, tourmaline, and other minerals, in addition to fine 
slime, which usually contains black tin in a fine state of division. The 
oscillating movement prevents the material from clogging. The inventors 
state that no initial classification of the pulp according to size is required, 
and that too much water interferes with the efficient action of the machine. 
By using only sufficient water to render the pulp free- working, it is claimed 
that a considerable amount of slime tin is retained in the concentrate, 
owing to the interference of the layer of material on the table with the flow 
of water, which otherwise would carry away the slime tin. This explana- 
tion however, if true, leads to the supposition that coarser veinstone waste 
is also retained by the same cause, which implies an imperfect separation, 
which is not the case, since the machines with a fair quantity of clear water 
act efficiently. The amount of pulp which can be treated on a Frue vanner 
daily is from 5 to 10 tons. 

Wilfley (Plate XV.) or Buss tables are bumping tables employed for 
separating sands containing black tin. In some mines they are used to 
make the initial separation of the piilp in place of Frue vanners, but at 
Dolcoath Mine a Wilfley table is used at a later stage in the process of 
the preparation of black tin. Broadly speaking, the table is a rectangular 
frame slightly inclined in a direction at right angles to its length. At one 
end an oscillating or bumping movement is imparted to the table by an 
excentric. A number of wooden strips, or riffles, of varying length, and an 
inch or so apart, are fixed to the table from the short edge at the feet end, 
parallel with the longer edges of the table. The longest strips are near the 
lower edge of the table, and the shorter near the feed or upper edge. The 
object of these strips is to interfere with the pulp as it flows down the 
table, in such a way that the current is prevented from having a dominating 
influence over the effect of the shock produced by the excentric. The 
heavy particles of the pulp which is fed on at one end of the long upper 
edge of the table commence to traverse the table in a diagonal direction 
near the ends of the riffles, being carried forwards by the influence of the 



266 MINING ECONOMICS. 

shock imparted to them by the table, and downwards by the flow of a current 
of clean water issaing from sprays in a pipe extending along the upper edge 
of the table. In this way black tin, some tourmaline, large grains of quafbs, 
&c., trarel diagonally down the table but gradually separate into two or 
more streams, according to the density of the minerals. These products 
are caught in separate launders. The lightest mineral waste or flakej 
minerals are generally carried over the rifiSes by the water and are con- 
ducted awa3'^ in a special launder. 

In using these tables it is obvious that the best results are obtained when 
the material consists of grains of uniform size ; that is, the material should 
be classified before treatment. 

In the later stages of tin dressing revolving frames are used, and there 
are many modifications of them. They all consist of a circular revolving 
d6»ck of the shape of a shallow convex or concave cone. Some of them are 
doable decked. They are generally employed in the concentration of slune 
tin. In the concave tables, such as those made by Bartle, the slime is fed 
on to the table from a fixed distributing arrangement. The stream at once 
commences to flow inwards- the heavier particles lagging behind the 
lighter. As the table revolves the deposit is brought under the influence 
of a gentle stream of clean water which washes away the waste. When the 
table has nearly completed a revolution all that is left on it at this particu^ 
lar segment of the table is a rich concentrate, which is readily washed o£F 
by a powerful spray into a separate launder. The arrangement is auto- 
matic and continuous. 

The double-deck revolving tables are merely modiflcations of the above. 
Instead of one large deck there are two decks placed concentrically, 
revolving on the same axis. At certain points the concentrate from the 
outer deck is washed off, but the tailings flow on to the second deck and 
undergo a further separation. The Acme table (Plate XVI.) is a new modi- 
fication of the double-deck table. The tables are concentric, but the outer 
one is concave while the inner is convex. The tails from the outer deck 
are led into a launder and lifted by a raft wheel and delivered on to the 
inner deck where the material is again separated. 

Buddies are circular pits employed in the last stages of tin-ore dressing. 
The floor of the huddle slopes downwards from the circumference to the 
centre (concave huddle) (Plate XVIII.), or from the centre to the circum- 
ference (convex huddle) (Plate XVII.) In the case of convex buddies the ore 
is distributed at the *' head " or centre of the huddle over a cone-like 
distributor. In concave buddies, the ore is distributed at the circum- 
ference by means of radial trough-shaped arms, which revolve round a 
vertical axis at the centre of the bed. In either case light brushes sus- 
pended from radial arms sweepoverthesurfaceof the deposit to keep it even. 
Where the stuff under treatment has to be *' huddled" several times the 
convex huddle is used first, as a rule^ the final operations being carried 
out in the concave buddle. In the convex huddle the velocity and volume 
of the stream of ore flowing over any unit area is greater at the head of the 
buddle than at the circumference or**tai1," so that the action is more 
vigorous than that which takes place in concave buddies, where the reverse 
is the case. The minerals are not washed off as in the case of revolving 
tables, but are allowed to accumulate until the deposit is about a foot or less 
in thickness. The machine is then stopped and the various qualities of 
stuff, arranged in concentric annular deposits, are dug out and each treated 
separately. 

A Dumb pit (Plate XIX.) is a small convex buddle in which a rough classi- 
fication is effected at a certain stage in dressing. It is a very simple 
arrangement. The material is poured into the middle of the bed in a thick 
stream from a pipe. Tlie heavier minerals remain in the middle of the pit 
while the lighter are washed to the circumference where they settle. When 
the pit is full the stuff is dug out in annular sections, and, according to its 
quality, treated in different ways. 

The last operation in the preparation of black tin for the market takes 
place in kieves (Plate XX.), or large tubs. The dressed tin ore already 



TIN-ORE DRESSING. 267 

highly concentrated is stirred up in the kieve with plenty of water 
(*' toz&A ''). It is then allowed to settle while the tub is smartly struck on 
the outside with a hammer or crowbar (*' packed"). The effect of this is to 
make the lighter stuff rise to the top, where it can be skimmed off. The 
rich concentrate below is then ready for market. 

Plane tables or ragging frames are used for the treatment of tin-bearing 
slimes which have already been treated in the dressing j'ards, and would 
otherwise be thrown to waste. It is this appliance which is so extensively 
used on the tin Streamworks for treating the material which is regarded at 
the mines as waste. Each consists of a fixed rectangular frame over which 
the slime is distributed from a trough or launder which feeds a series of 
these frames. The heavier particles from the slime remain on the table 
while the lighter stuffs flow to waste. After a minute or so a fair amount 
of concentrate has settled on the table, and this is washed off by a cascade 
of water which is dashed over the surface from a trough, which topples 
over automatically when it is full of water. At the same time an arrange- 
ment at the foot of the table, actuated by a lever connected to the toppling 
trough, directs the concentrate into a special launder. 

The most recent innovation is the VVetherell electro-magnetic separator, 
which is being used for the extraction of wolfram from the ore at East PtK)l 
Mine. The separation of cassiterite and wolfram is almost impossible by 
ordinary dressing methods,owing to the similarity in density of the minerals. 
A series of costly experiments was carried out at East Pool Mine in 
attempting to solve this problem, and at one time it was hoped that the 
fusion of wolfram with soda, so as to produce sodium tungstate which is 
soluble, would be a feasible method. Tungstate of soda was produced at 
East Pool Mine for a few yeara in this way, but eventually the process was 
dropped as being too unprofitable. The separator seems to be doing good 
work, and as wolfram is now at a high price the use of these machines may 
become more common. 

The partially dressed ore containing tin and wolfram, after having been 
calcined, contains a certain amount of ** iron " which is also extracted by the 
magnetic separator. 

The "iron" impurities are derived from two sources: (1) iron oxides 
resulting from the decomposition of iron pyrites during roasting, and those 
originally present in the ore, and (2) metallic iron, from the wear and tear 
of the stamps and other machinery used in handling the ore. The following 
is an account of the action of the separator : — 

The ore from the calciner, after being allowed to cool, is distributed on 
to a travelling belt. Above the belt are arranged four electro-magnets, 
under which the ore passes successively as it travels along with the belt. 
Under the poles of each magnet there is a narrow india-rubl3er band, which 
travels at right angles to the belt, upon which the ore is spread. By this 
means magnetic particles passing under the bands are picked up in a con- 
tinuous stream, and carried laterally on the lower surface of the bands to- 
wards and over the edge of the belt,where passing out of the magnetic field 
they fall into a box. The first two magnets pick up iron and iron oxides. 
The next two are more strongly magnetised and pick up wolfram. The 
black tin with veinstone particles travels along with the belt and falls 
over into a box. The wolfram, from the last magnet at least, may have to be 
passed through the machine for a second time to free it from a little oxide 
of iron and also cassiterite dust, which is carried along in the current of 
wolfram particles as they leap up to the n)agnets. Before it is ready for the 
market the wolfram requires treatment on a hand huddle. 

The machine is d<^igned to treat about 10 tons of concentrates daily. 
If the ore which is being treated contains copper this is picked up with 
the oxide of iron resulting from the decomposition of copper pyrites and 
so does not pass over the belt with the tin. 

Present Methods of Obe Concentration.- The ordinary processes 
in the preparation of black tin for the market in the Camborne area have 
a general uniformity. In other parts of Cornwall recent Installations of 
dressing plant are quite different from that used i»i Camborne. In the 



268 MINING ECONOMICS. 

oastern part of Cornwall the aim has been to reduce manual labour by 
arranging: the appliances so that the products from the different machines 
can be led from one place to another automatically. In addition to this 
the general principle is one in which the materials are classified according 
to the speed with which they fall through water, by means of spitzlaten 
and spitzkasten. ^ 

Th<^ following is a brief general account of the actual processes in use in 
the Canil)orne Mines: — 

The ore which is broken in the stopcs is roughly selected underground 
by the miners, and that which is worth treating is hauled up to the surface 
and there dumped on to the spalling floors, where women and elderly men 
are employed under cover to still further separate, by means of sledge 
hammers, the ore-bearing parts of the rock from that which is waste. The 
ore is then carried to the stamps, or, if any of the lumps are too large, 
they are passed through Blake Marsden or other rock-breakers and then 
led to the stamps. 

The pulp from the stamps is splashed through perforated plates 
(gauge No. 36), and then passed on to Frue vanners. Perforated plates 
are used in preference to the wire gratings, owing to their greater 
durability. On the vanners the pulp is separated into concentrates and 
tailings. The concentrates are taken to a calciner and roasted, and then 
mixed with wsjier and roughly classified in Dumb pits. Two products are 
obtained in this way—" Head " near the centre of the pit, and " Tailings " 
near the circumference. The liead is treated in buddies or on Wilfley 
tables, after which it proceeds to the kieves. If sufficiently rich, the use 
of the Wilfley tables and buddies is dispensed with, and the material is 
transferred to the kieves direct. In the kieves it receives final treatment, 
the marketable product being known as " crop tin." If a Wilfley table has 
been used the tailings from it are sent back to the stamps. The ** tailings " 
from the Dumb pit are pulverised in a rotary pulveriser, and treated on 
revolving tables and buddies, and flnally in kieves. The black tin from 
this operation is known as " fine tin." 

The tailings from the Frue vanners are led into an upward current 
separator, which is a box in which there is an upward flow of watelr regu- 
lated by a tap. Two products are obtained. The finer material, known as 
slimes, is buoyed up by the current and overflows into a launder, while the 
coarse material, called sands, passes out through another opening into 
launders known as " strips." The heavier portions of the sands collect in 
the strips and are dug out periodically, when they are again pulverised 
and treated on vanners. The light part of the sands passes out of the 
strips and flows to waste. When the vanners are treating the heavy 
part from the strips the tailings from them are treated on ragging 
frames. 

The slimes from the separator flow over into settling pits, after which 
they are treated on ragging frames. The concentrates from the frames 
pass into settling pits and then over revolving tables, after which the 
" head " is calcined. After calcining the slime is again treated on revolving 
tables, and the concentrate known as " slime tin " is ready fcr sale. The 
tailings from the ragging frames go to waste. 

At King Edward Mine (situated on part of the South Condurrow sett), 
a tin-dressing plant has been erected for the instruction of students of 
the Camborne Mining School. The general arrangement is as follows : — 
The pulp from the Californian stamps flows successively through three 
compartments of a set of spitzluten. The coarse material from the first 
compartment is treated on a Buss table ; the material from the second is 
treated on a Frue vanner, and the finer stuff from the third compartment is 
led to a settling pit, from which it passes on to an Acme table. The tailings 
fn)m the Buss table are pulverised and again passed through the spitz- 
luten. The head from the Acme table is then roasted. The concentrates 
from the Frue vanner and Buss table are also roasted before being treated 
further, but these products are kept separate. The overflow from the last 
compartment of the spitzluten goes to pyramidal settlers, and the various 
grades of material so produced are treated on ragging frames. The head 
is roasted, and is known as ** slime" tin. 



TIN-ORE DRESSING. 269 

The methods of dressing the tin ore have so far improved in recent years 
that ore containing as little as 1 per cent, of cassiterlte can be mined 
with profit, proY idcHi the veinstone is not too hard and has not to be hauled 
a great distance. It should also be remembered that the working expenses 
in treating a certain quantity o' stuff at a mine is not necessarily doubled 
by doubling the amount under treatment. Advantage is talcen of this fact 
in several mines where a large quantity of fairly good stuff is treated 
with as little handling as possible, where formerly less but richer stuflE was 
considered the proper course. 

At Dolcoath the output of the mine in the last ten years has been 
nearly doubled, reducing the average produce of the mine from 79 down 
to 36 lbs. of black tin per ton of ore. The dressed product, known as 
black tin, when ready for the market, generally contains under 65 per 
cent, of metallic tin. The Home Office Report for 1904 states that for that 
year the average amount of metallic tin obtainable from ordinary black 
tin was a little over 63 per cent., while the amount obtainable from stream 
works (" slime tin ") was a little over 46 per cent. 

There can be no doubt that many of the old burrows contain sufficient 
tin ore to pay for the cost of treating them. In fact, many of the old heaps, 
and particularly the waste sands or tailings from former dressing opera- 
tions, could, where there is a large quantity of them, be pr^ fitably worked at 
the present time. Where the mine was originally only worked for copper 
or arsenic, the burrows may bo exceptionally ri^h In tin ore. It is stated 
for instance, that the huge pile of tailings situated on Cam Brea Mine 
sett contains 8 lbs. of black tin to the ton, and Is valued at £200,000, of 
which a great deal would have to be spent In obtaining the tin. Pryce,* 
who resided at Redruth, makes the following statement with regard to the 
copper contained in some old heaps : — "Even burnt leavings of tin are 
often considerably valuable, especially if they are cupreous ; and even the 
poorest of these leavings bring 10s. or 20s. a ton ; which Is better than to 
throw them away as was the case no further back than 40 years. All 
burnt leavings taken from tin stuff till 1735 were esteemed good for 
nothing. But In that year there were several parcels lying on sundry 
stamp plots In this parish which Induced Mr. Morgan Bevan, an old ex- 
perienced assayer, to try whether he could reduce them to metal. For 
the first time he essayed a sample of three tons, and to his own great sur- 
prise as well as that of others, he found he could give £7 4s. 6d. a ton for 
them, which he actually did, and presently after bought several parcels 
more of Messrs. Carter, Reynolds, Penrose, Cornish, &c., the principal tin 
dressers of those days. From that time all burnt leavings were taken care 
of, provided they were sufficiently Impregnated with copper." Pryco 
instances Chacewater Mine burrow as a case in point. 

At the present time an enormous quantity of black tin is annually lost 
to such mines as Wheal GrenvlUe, Dolcoath, Carn Brea, East Pool, South 
Crofty, and Wheal Basset, In the form of slime tin, the complete saving of 
which is a problem as yet unsolved. In the event of such solution the 
many stream works situated below the mines on the Red River and the 
river which runs down from Wheal Basset would become idle. In 1904 
over £37,000 was realised by the sale of black tin extracted from the 
refuse of these mines by stream work companies situated on the rivers 
below them. 

In the dressing of tin ore It Is Important to ascertain the true nature of 
the stuff which Is being treated. If a highly concentrated black tin is 
obtained at the expense of a loss in the form of slime tin In Its production 
it may prove un remunerative solely from the escape of valuable mineral 
products into the river. 

Examination of the Products from the Various Operations in 
THE Dressing of the Tin Ore, — Samples of the various products 
obtained In the different processes of tin ore dressing have been mounted 
for microscopic examination, and the slides photographed. The sands 
shown In the plates are photographed In ordinary truus^pitted light and 
magnified 20 times. (Plates XXII., XXIII.) 

• JJin. rornub., 1778, p. 230, 



270 HINTNG ECONOinCS. 

The amouDt of cassiterite present in the sands has been estimated bj 
the method of redaction io hydrogen, in the laboratory at Jermyn Streeti 
with the assistance of Dr. Pollr.rd. 

The series of tin washings described below was obtained from the Soath 
Crofty dressing floors on the 21st June, 1904. The descriptions of the 
products refer to tho dried sample, the moisture present varying from "OS 
per cent, to '4 per cent. 

The ore from the mine contains cassiterite, copper pyrites, misplckel, 
and associated veinstone minerals, and possibly some wolfram. 

The pulp from the stAmps is shown in Fig. 1, Plate XXII. It is a speckled 
grey sand containing Ih per cent, of cassiterite. Under the microscope 
the grains are seen to vary in size from fine dust to fine sand with large 
grains. On sizing the material by means of sieves less than 2 per cent, 
remains on 30-mesh, 22 per cent, remains on 60-mesh, 20 per cent, on 90: 
mesh, 10 per cent, on 120, and 46 per cent, passes through 120-mesh sieve. 
The minerals present are felspar, quartz (with fluid cavities), tourmaline 
(brown and blue), fluorspar, chlorite, a little mica, and zircon. Cassiterite 
occurs generally in small grains, and there is also present copper pyrites, 
mispickel, hnematite, ilmcnite, and some hydrated oxide of iron, and a 
little chalyblte. Some of the larger fragments seen in the plate consist of 
felspar and quartz with dusty inclusions. The clear grains are quartz, 
fluorspar, felspar, &c. The minerals in half-tone are tourmaline, chlorite, 
&c. Cassiterite is also represented in half-tone, and is often seen strongly 
bordered. Some of the minerals are opac^ue, owing to dusty inclusions in 
felspar, quartz, &c., but there is also present copper pyrites, mispickel, and 
minerals with dark tints, deep green, blue and red. 

The pulp from the stamps passes to the Frue vanners, and Fig. 2, Plate 
XXII., shows the concentrate obtained from them. It is a fine, slightly 
gritty sand, with a brownish hue, and contains 21 per cent, of oxide of tin. 
Under the microscope the grains are seen to be small, but some are as laige 
as js of an inch across. In sizing by sieves 3 per cent, remains on BO-mesh, 
11 per cent, on GO-mesh, 11 per cent, on 90-mesh, 4 per cent, on 120-mesh, 
and 71 per cent, passes through a sieve of 120-mesh. The grains consist 
of cassiterite, pyrites, ilmenite, zircon, &c., with a considerable amount of 
fluorspar, tourmaline, quartz, and chlorite. The larger grains are quartz 
(with included tourmaline needles), cassiterite, pyrites, chlorite, and iron 
oxide. There is a little felspar. The cassiterite grains are generally 
subangular. 

The concentrate from the Frue vanner is then calcined. After calcining 
the material is of a dark, slightly brownish red colour. The only difference 
between this material and the one just described is that the sulphides are 
destroyed while there is an increase in the amount of oxide of iron. There 
has also becm a tendency for some of the grains to clot together, but they 
are broken up in the pulveriser. This material is treated in a huddle. 
The *' head" from the buddle is not shown in the plate, but it is a very 
flne dark purplish or reddish brown sand, consisting of large and small 
grains of cassiterit'C, about 48J per cent., small particles ot tourmaline, and 
a little quartz and fluorspar. All the material passes through a 30-me8h 
sieve, 2 per cent, remains on CO-mesh, 4 per cent, on a 90 -mesh, 3 per cent, 
on 120-mesh, while 91 per cent, passes through a sieve of 120-mesh. As a 
whole the material is clean and the grains of fairly uniform size, although 
there are a good many fine grains. The photograph is very similar to that 
shown in Fig. 2, Plate XXII., but the grains are of more uniform size. The 
** tailings *' from the buddle are not shown in the plate. The material is a 
gritty dark purplish or reddish brown sand, the grains of which vary con- 
siderably in size, from the fineness of dust to large particles. Some grains 
are ^ of an inch across. In sizing by sieves, 8 per cent, remains on SO-mesh 
sieve, 30 per cent, on 60-mesh, 20 per cent, on 90-mesh, 5 per cent, on 120- 
mcsh, while 37 per cent, passes through a sieve of 120-mesh. Oxide of 
iron from burnt pyrites is abundant. Fine grains of cassiterite are 
[)Pt\sent, and a f<3w larger grains of tho same mineral. Quartz, fiuorspar, 
and t-onrmaline are also present iu abundance. About 11 jKjr cent, of 
cassiterite is present. 

Tho ** heiwl" from the buddle is treated in "kieves." The concentrate 
from the kicves is show4 in Fi^. 3, Plate XXII. In sizing by sieves 1 per 



TIN-ORE DRESSING. 271 

'^nt. vemaiiu on SO-mesh. 6 per cent, on 60-mesh, 9 per cent, on 9D-mesh, 
5 per cent, on 120-niesh, while 79 per cent, passes 120-mesh. Some of the 
grains are as large as ^ of an inch across. In appearance it is a very fine 
dark pnrplish or reddish brown sand containing abundant cassiterite (62 
per cent.). There is also tourmaline, and a little fluorspar and quartz. 
Oxide of iron, in opaque grains of various sizes, is likewise present. The 
pioduct is a fairly clean one, and is known as ** crop tin." Fig. 4, Plate XXII., 
is a sample of the skimmings from the kieves. In appearance it is a very 
fine dark pnrplish or reddish brown sand containing 8 per cent, of cassi- 
terite. There is oxide of iron, tourmaline, fluorspar, and quartz. It 
practically all passes tlirough a sieve of 120-mash, a few grains only being 
arrested by the 90 and 120 sieves. 

The tailings from the Frue vanners, containing slirao tin, are sliown in 
Fig. 5, Plate XXII. It is a fine light grey gritty sand. In sizing by sieves 
9 per cent, remains on SO-mosh, 50 per cent, on 60-mesh, 15 per cent, on 
90-mesh, 6 per cent, on 120-meah. while 20 per cent, passes 120. Under the 
microscope it is seen to consist of very fine, almost dusty, particles of 
quartz, with a little tourmaline and chlorite. Large grains are also 
present, and consist mainly of quartz. The quartz contains dusty inclusions 
which under high powers of the microscope are seen to be fluid cavities. 
Aboit i per cent, of cassiterite is present. 

The tailings from the Frue vanners are led into an upward current 
separator which yields two products-slimes and rough waste. The sample 
shown in Fig. 7, Plate XXII., is from the slimes. Seen in bulk it is a dirty 
grey clayey-looking powder. It all passes through a sieve uf 120-mesh except 
some raica which is arrested. Under the microscope the material consists 
of small grains of quartz, a little fluorspar and chlorite, and some tourmaline 
and extremely fine dusty fragments of these and other minerals. About 
•8 per cent, of cassiterite is present. As a whole, although very fine 
grained, the material is not of uniform size. Fig. 6, Plate XXII., shows a 
sample of the rough waste from the upward current separator. It is a 
clean grey speckled sand, containing grains of quartz, mica, tourmaline, 
"fluorspar, chlorite, and some small grains of cassiterite ('2 per cent.) 
Although on the whole it is rather coarse-grained, the grains vary con- 
siderably in size. In sizing by sieves 2*5 per cent, remains on 30-mesh, 
30 per cent, remains on 60-mesh, 26*5 per cent, remains on 90-mesh, 12 
per cent, on 120-mesh, while 29 per cent, passes through a sieve of 120-mesh. 
It is this material which is passed through launders or strips, so that the 
heavier portions may settle and be once more treated on the vanners 
after being pulverised. The slime is calcined, treated on ragging frames 
and revolving tables. The concentrates from the revolving tables are 
shown in Fig. 8, Plate XXII. It is a fine dark grey powder consisting of 
small grains of fairly uniform size, all of which pass through 120-mesh 
sieve. Tourmaline is abundant, and in addition to cassiterite, of which 
there is 9 per cent., there is also a little fluorspar, chlorite, quartz, and 
hsematite. The material is known as •' slime tin." The waste from the 
ragging frames and revolving tables is a loose clayey-looking dirty grey 
powder, all of which, except the mica, passes through a sieve of 120-mesh. 
Under the microscope the particles are seen to be of irregular size. The 
larger particles consist of quartz, a little tourmaline, chlorite, and fluor- 
spar. The smaller particles are fine dust of the same minerals. About 
•5 per cent, of cassiterite is present. 

In the examination of this series of products, the most striking point is 
the general great variety in the sizes of the grains in each sample of the 
material, and it is probable that if the materials were sized before treat- 
ment losses would be considerably reduced. 

A significant result of the examination of the products by the micro- 
scope is that from each of the operations in the production of *' crop " or 
"slime" tin, the " wastes " exhibit a greater variety as regards the size 
of their constituent grains than do the grains in tho concentrates. From 
this it may be inferred that grains ol cassit^^rit-o, which are less tlian tho 
average size of the grains in tho conceutrales from any ot the operations, 
tend to be lost in the tailings of the subsequent oiK'ration. 

If the samples obtained are to l)e relied on as being i^ood average products, 
then the concentrates from the Frue vanners contained a little over J (81 per 



272 HINING ECONOMICS. 

cent.) of the total amount of cassiterite in the pulp oomingfrom the stamps. 
That is to say that every 100 tons of pulp coming from the stamps contains 
1^ tons of cassiterite, of which 1*26 tons pass into 6 tons of concentrates 
coming from the vanners containing 21 per cent, cassiterite ; and *24 tons 
pass Into 94 tons of tailings, containing, therefore, about ^ per cent, cas- 
siterite. In the subsequent operations resulting in the production of 
''crop" tin, the amount of cassiterite present In the tailings becomes 
greater and greater as the concentrates get richer and richer. Unless 
these tailings are very carefully treated great losses are liable to occur. 
In the operations leading to the production of *♦ fine " or ** slime" tin, the 
materials worked with are poor, so that as large a proportion of loss is 
not to be expected, but with the rapid handling of a great deal of stuff a 
considerable portion of the cassiterite originally In the tailings Is onavold- 
ably lost. 

A less extensive series of microscope slides showing the products from 
different operations was prepared for materials obtained from Dolcoath, 
which is a mine yielding almost exclusively tin ore. Fig. 1, Plate XXIIL, Is 
a sample of the pulp as it comes from the stamps. It is a fine brownish 
sand containing grains of various sizes. In testing the sizes of the grains 
by sieves 1^ per cent, remains on 30-mesh, 14 per cent, on dO-mesh, 22 per 
cent, on 90-mesh, 7*5 per cent, on 120-mesh, while 55 per cent, passes 
through a sieve of 120-mesh. The particles consist of quartz, much of 
which contains many Inclusions of acicular blue tourmaline ; blue tour- 
maline, a little chlorite, some fluorspar, and colourless and brown cas- 
siterite. It is an exceptionally rich sample containing 11 per cent, of 
cassiterite. Some of the large opaque grains consist of quartz crowded 
with tourmaline needles associate with the remains of some decomposed 
ferruginous mineral. There are many very minute grains. 

The next sample, Fig. 2, Plate XXIIL, is that of the concentrates from the 
Frue vanners. In general appearance It Is a very fine greyish brown tand, 
consisting of variously sized grains of quartz, some of which contain 
much Included ferruginous material and tourmaline; a little fluorspar, 
tourmaline, chlorite, and an abundance of cassiterite (27^ per cent.), 
some of which is in a very fine state of division. Tests by siev- 
uur show that 8 per cent, of the material remains on a 30-mesh 
sieve, 19 per cent, on a 60-mesh, 9 per cent, on a 90-mesh, 4 per cent, 
on a 120-mesh, while 60 per cent, passes through a sieve of 120-me6lu 

The concentrates from the Frue vanners are calcined and treated in an 
upward current separator. The coarse material so obtained goes to a pit 
buddle. The sample shown In Fig. 3, Plate XXIIL, Is from the head of the 
buddle. In general appearance it is a coarse dark brown sand, consisting 
of grains of quartz with inclusions of tourmaline and fluid cavities. There is 
also fluorspar and cassiterite in abundance (50 per cent.). Some of the 
materials are coarse and others fine, and as a whole the sizes of the grains are 
very varied. They are greatly stained with iron oxide. Trials by sieving 
show that 4 per cent, remains on 30-mesh,51 per cent, on 00-mesh,29 per cent, 
on 90-mesh, 5 per cent, on 120-mesh, while 11 per cent, passes through a 
sieve of 120-mosh. This material Is passed on to a Wilfley table, and the 
resulting concentrate is sold as " crop tin," which contains 78 per cent, 
cassiterite (61*5 per cent, metallic tin). It b a mixed coarse and fine sand 
of a brown colour. The grains are mainly cassiterite, but there is some 
ferruginous material. In sieving 1 per cent, remains on 30-mesh sieve, 
39 per cent, on 60-mesh, 24 per cent, on 90-mesh, 9 per cent, on 120-mesh, 
while 27 per cent, passes through a sieve of 120-mesh. 

The overflow from the upward current separator is treated in a buddle. 
Fig. 4, Plate XXIIL, represents the material from the head of the buddle. 
It is a fine brown powder containing 3^ per cent, cassiterite. There is 
much oxide of iron, and acme fluorspar, quartz, and a little tourmaline. 
The product is a good one, consisting of uniformly sized grains nearly all 
of which pass through a sieve of 12()-mesh. 

The next, Fig. 5, Plate XXIIL, is a sample of the concentrate from the 
Acme table upon which the stuff last described was treated. It is an 
impalpable light brown powder containing 78 per cent, cassiterite, with a 
little oxide of iron and tonrmallne. This material is sold a? ''fine tin." 



TIN-ORB DRESSING. 273 

It all posseA through a sieve of 120-me8h. The tailings from the Frae 
▼aimers are a reddish brown powder, consisting of grains of qnartz with 
many dusty ferruginoos inolosions ; and very fine particles of tourmaline, 
quarts, chlorite, and ferruginous minerals. Oassiterite is present only in 
small quantity (*85 per cent.), but after a series of operations it is 
separated and ultimately sold as ''slime*' tin. The material is very fine, 
nearly all passing sieve of 12(y-mesh. The use of the upward current 
separator for treating the calcined concentrates from the vanners appears 
to be most important and could not be dispensed with. 

From a general standpoint, the most striking feature in the micro- 
scopical diagrams of the various products is the want of uniformity in 
the sizes of the grains, which, except In a few cases, points to a defect in 
the usual methods employed. If the tin grains were themselves of uniform 
size this objection would not be of much importance, but a large pro- 
portion of the tin occurs in very minute particles, and it is a rule in all 
dressing appliances to separate this "slime" from the coarser-grained 
*' crop " tin as soon as possible, and subject each to a separate series of 
operations. No convenient method has yet been discovered for accu- 
rately sizing the grains, so that a certain amount of loss is inevitable, but 
a saving on the present system might be made by the judicious employ- 
ment of upward current separators in which the minerals could be classi- 
fied according to the relative speeds with which they fall through water. 
Each product might then be treated by itself ; the '* crop *' on Frue vanners 
or Buss tables, and the slimes on Luhrlg vanners or on revolving tables. 
A fine degree of stamping is essential, but the production of an excessive 
amount of sline might be obviated b}' the use of wire screens, so that the 
pulp could pass away from the stamps as soon as possible after crushing. 

A few samples were obtained from the large tin stream works near 
Reskudinnick, called Kieve Mill. The waste material from the dressing 
floors of the mines is discharged into the Red River, and successively 
treated by a number of stream work companies situated at various 
points along the stream. The material under examination has therefore 
already been treated by stream works before it arrived at Kieve Mill. 
The river as it approaches the works is divided into two parts by a 
wooden partition, and arranged in such a way that the water can be made 
to flow through one part or the other by means of sluices. This is done 
so that the amount of water passing at dififerent times of the year may 
be regulated to a steady flow. By means of stops, or transverse partitions 
in the river, the coarse particles of sand being carried along in the current 
are arrested and sink in the bottom of the river just above the works. 
The water carrying slime flows on into long pits, any one or more of 
which can be used or not as desired (Plate XXI.). Here the slime is allowed 
to settle. Fig. 6, Plate XXIII., is a sample of the sands which have settle d 
in the river just above the works. In appearance it is a clean speckled 
sand containing from | to I7 per cent, cassiterite. Under the microscope 
the grains are seen to be both large and small. In testing the sizes of 
the grains by sieves 3 per cent, remains on 30-mesh sieve, 53 per cent, 
on 60-mesh, 22 per cent, on 90-mesh, 7 per cent, on 120-mesh, while 15 per 
cent, passes a sieve of 120-mesh. The larger grains are subangular or 
rounded. Quartz occurs in large grains with many fluid cavities, and con- 
tains other inclusions, such as tourmaline ; fluorspar, chlorite, and a little 
tourmaline and oxide of iron are also present. The large opaque minerals 
seen in the plate are principally quartz crowded with tourmaline needles 
(peach). Some of it is bright green chlorite and mica. There is also some 
brown staining which appears as half-tones in the largest fragment. The 
dusty-looking inclusions are mainly fluid cavities in quai;tz. 

Fig. 7, Plate XXIII., is a sample of the slime from the settli ng pits. Seen in 
bulk, the slime is a brown or reddish brown impalpable powder, and contains 
•5 per cent, cassiterite. Under the microscope most of the particles arc 
extremely small. Tt)urmarmo is plentiful, chlorite and fluorspar are also 
present. Limonite and hjcniatitiMV<-ui' in particles and us stiiininj;. Most 
of the grains are too line U> be readily identilied in tlie slide, and all pass 
.through a sieve of 120-niesh. The slime is stirred up in a current of wnter 
and passed on to ragging frames, of which there are a great numbt^r. 



274 MIKING ECONOMICS. 

(Plate XXIV.). The oonoentrate is settled in pits, and passed over another 
series of frames into settling pits, after which it is treated on revolTing 
tables of the Bartle type. Then it proceeds to baddies. The slime tin so 
collected is similar in appearance to Fig. 5, Plate XXIII., but is even finer, 
and consists of an impalpable dark pnrplijsh brown powder. The grains 
are clean and sharply angled, of uniform si2se, and all pass through a sieye 
of 120-mesh. Cassiterite (40 per cent.) with tourmaline, much hsematite, 
and a little fluorspar appear to be the most abundant minerals. 

The coarse sands which settled in the stream above the works (Fig. 6, 
Plate XXIII.) are washed down periodically by a strong current of water into 
'* strips '* or troughs, in which transverse wooden partitions or ** stops " are 
fixed at i u tervals. The lighter sands fiow out of the strips, but the heavier 
sink and are dug out periodically. Fig. 8, Plate XXIU., is a sample of the 
material which was deposited in the " strips." It is a clean dark speckled 
sand, consisting of quartz, chlorite, oxides of iron (limonite and hfiematlte), 
tourmaline, fluorspar, and some chalybite. There are a few grains of 
cassiterite (about 1 per cent.). This material is pulverised in a rotary mill 
and worked over on revolving frames and buddies. In this way particles 
of cassiterite which were locked up in grains of quartss., &c., are liberated 
and extracted. Tested by means of sieves it is found that 3 per cent. 
remains on a 30-mesh, 60 per cent, on a 60-mesh, 20 per cent, on a 90-mesh, 
7 per cent, on a 120-mesh, while 10 per cent, pass through 120-mesh. A 
sample of the sands from the river, about } of a mile below the works at 
Kieve Mill, is a clean dark speckled sand, consisting of quartz with fluid 
cavities, and tourmaline inclusions, fluorspar, tourmaline, chlorite, a little 
chalybite, and some iron oxide. Cassiterite is se^i in^. several oases 
actually adhering to larger fragments of oUier minerals. Tne sample con- 
tains about li per cent, of tin. Tested by sieves 3 per cent, remains on 
30-mesh, 70 per cent, on 60-mesh, 19 per cent, on 90-mesh, 4 per cent, on 
120-mesh, while 4^ per cent, pass through a sieve of 120-mesh. 

Mineral Statistics.* 

* Compiled from statistics contained in: — Tr. R,0,8, (hm,, vol. i., 1818, 
&c., for years 1815 to 1832 (copper only). OryWt AnnutU Mining SheeU 
(Redruth) for years 1833 to 1836 (copper only). Tr, R,G,8. Com,, vol. v. 
(Hen wood), p. 466, for year 1838 (copper only). Geol, Hep, Com., Devon, and 
West Somerset (De la Beche), 1839, for year 1837 (tin only). Mining Review, 
1839 and 1840. for tin ore in 1838 and 1839. Mem, Qeol, Survey, vol. ii., 1848, 
for years 1845 to 1847 (copper only). Records Royal School of Mines, vol. i., 
part iv., 1853, for years 1848 to 1852 (copper and lead from 1848 to 1852; 
tin in 1852). Mem. Qeol. Survey (Mineral Statistics), 1853 to 1881 (for all 
minerals, the output of zinc, mundic, arsenic, nickel and cobalt, umber and 
ochre, iron, &c., commencing in 1854 ; public ticketings, stannary returns, and 
inspectors' reports). General Report and Statistics, part Hi,, Output, \asaidihy 
the Home Uffice, all minerals for years from 1882 to 1904. Under the heading 
of Remarks the output of copper ore and copper for a stated interval prior to 
1857 is obtained from the Records of Mining and MetaUurgy^ by John Arthur 
Phillips and John Darlington. These figures fill in to a certain extent the 
lucuna in the official statistics, i.e., the years 1837 to 1844, and represent the 
sales at public ticketings in Cornwall. The returns prior to 1882 are 
approximate only, so that figures representing the total outputs of minerals 
for the years mentioned must oe regarded as general relative measures of the 
actual output and not as being strictly accurate. Not only do tiie annual 
returns in the early statistical tables dififer according as the returns were 
made bv the stannaries, public ticketings, or inspectors' reports, &c., but 
much of the ore was sold by private contract and the scJes never recorded. In 
early years it was customary for the smelters to demand 21 cwts. to the ton, 
while in a number of other ways the tables are rendered inaccurate. Statistics 
are not obtainable for the years 1837 to 1844 (with the exception of copper in 
1838 and black tin in 1837). Another point to which attention should be called 
18 error ari.sing from the ambiguity caused by diflferent mines bearing 
the same name, and in such cases it is frequently almost impossible to 
determine from which mines certain annual outputs refer. Such names for 
instance as ** Prosper," *' Providence," "Virgin," ** Fortune." are common 
names for mines. Under the heading of Remarks the figures for the period up 
to 1856 are those given by Phillips and Darlin^n. The output since 1867 
is also given so as to complete the statistics furnished by them. 



BilNERAL STATISTICS. 



276 



Ovipvi of Copper Ore cmd Copper from 1815 to 1836, c 
1845 to 1905 ; arid of Black Tin from 1852 to 1905. 



Name of Mine. 



Balmynheer 

Mine 
Baldhu - 
Bamcoose 

Basset, Wheal - 



Basset, Consols 
Bassett and 

Gpylls 
Bell Tin Mine 
Bellvean Mine 
Bissoe Bridge - 
Bissoe Pool 
Bolenowe 

Boscawen and 
Wheal Andrew 



Boys, Wheal - 
Brewer, Wheal 



Buckets, Wheal 
Buller, Wheal - 

Buller and 
Beanohamp 

Bnrra Burra 
Mine 

Calvadnack 

Camborne 

Ck)nsoIs 
Camborne Vean 



Cam Brea 



Total yield and largest 
amount raised in one year. 



Black 
tin. 



Tons. 

350 

84 



14,178 
794 



2,900 

314 

10 

4 

44 



1,410 
167 



1,150 
138 
170 

• • • 

350 

77 



29,600 
1,195 



Copper 
ore. 



Tons. 



206 

94,200 
7,713 

330 



138 
69 



22 
1,420 
1,142 



2,700 

1,281 

98,700 

13,560 

41,700 

6,539 

260 



1,180 

189 

37,500 

3,297 



158,200 
10,430 



Copper. 



Tons. 



26 

8,100 
680 

18 



• • . 
... 

• • . 

• • ■ 



130 

78 



170 

85 

14,340 

850 

2,600 

443 

12 



80 

15 

2,770 

229 



11,300 
1,050 



Remarks. 



Yielded between 1868 and 

1880. 
In 1880. 
In 1819, 1820, and 1821 

(Phillips and Darlington). 
From 1815 to 1827 ; 1832 to 

1836, and from 1851 to 

1905. 
From 1859 to 1861.^ 
From 1861 to 1875. 

In 1874. 

In 1879 and 1880. 

In 1833 and 1839. 

In 1896. 

In 1842 (according to 
Phillips and Darlington). 

In 1832, 1833, and 1834, and 
in 1894. 

5,091 tons of copper ore 
containing 273 tons of 
copper were sold be- 
tween 1831 and 1845. 

Between 1873 and 1878. 

Between 1845 and 1852. 

5,373 tons of copper ore 
containing 328 tons of 
copper were sold be- 
tween 1842 and 1853. 

Between 1846 and 1849.. 

Between 1845 and 1875. 

Between 1823 and 1828. 
1832 to 1836 and in 1838. 
In 1862 and 1863, and in 

1875 and 1876. 
Between 1854 and 1875. 

Between 1853 and 1891. 

Between 1816 and 1832, and 
1845 and 1855. 

Between 1815 and 1856, 
29,932 tons of ore con- 
taining 2,259 tons of 
copper were sold. 

From 1833 to 1836, in 1838, 
and between 1845 and 
1895 ; tin in 1837, 
1838, and 1839, and since 
1852. 



T 2 



276 



MINING ECONOMICS. 



Total yield and largest 
amount raised In one year. 



Name of Mine. 




Cam Brea— 
conU 



Cnrn Brea and 

Tincroft 

United 
Cam Camborne 

Cardrew 

Consols 



Carharrack 
Carvannel 



Cathedral Mine 

(Consols) 
Chance, Wheal 

(Gwennap) 
Chance Consols 

Clarence, Wheal 
Clifford Amal- 
gamated 



Tons. I Tons. 



Clifford United 

Clowane«, 

Wheal 

Clyjah and 
Wentworth 

Combclluck and 
Meugeurn 

Com ford, Wheal 
(and North 
Tresavoan) 

Condurrow 



6,587 
096 

115 
42 



li 



H 



365 



3i 

• • • 

i;^ 

125 
26 

2,03() 



. • • 

• •a 



8,454 
1,533 

6,310 

1,247 

15,900 

1,594 



2,500 
474 



585 

312 

14,800 

1,323 

3,998 

67 

144,300 

15,180 



7,580 

1,461 

2,500 

874 



1,570 
128 

30,200 



Tons. 



... 



363 
75 

305 

62 

850 

107 



180 
37 



40 

21 

1,530 

156 

337 

2 

9,140 

965 



612 

118 

155 

50 



Remarks. 



161,503 tons of ore contain- 
ing l2fiQ9 tons of copper 
were produced between 
1833 and 1856. From 
1857 to 1895, 75,900 tons 
of ore containing 5,858 
tons of copper. 

Between 1896 and 1905. 



Between 1862 and 1879. 

Between 1827 and 1836. 

17,143 tons of ore contain- 
ing 1,141 tons of copper 
were sold between 1826 
and 1838. 

In 1885. 

Between 1851 and 1856, 
1,782 tons of ore contain- 
ing 139 tons of copper 
were sold. From 1857 to 
1859, 700 tons of ore con- 
taining 40 tons of copper. 

From 1874 to 1881. 

Between 1815 and 1828, 

Between 1826 and 1827 
(Phillips and Darlington). 

In 1835, 1865, and 1866. 
Between 1833 to 1836 and 
between 1845 and 1876. 

Between 1835 and 1850 
'« Wheal Clifford" sold 
9,495 tons of ore contain- 
ing 725 tons of copper. 
Between 1857 and 1872, 
135,400 tons of ore con- 
taining 8,480 tons of 
copper. 

Between 1893 and 1895. 

Between 1815 and 1824. 

Between 1854 and 1862. 
Between 1878 and 1883. 



85 j Between 1845 and 1885. 

19 ! 

2,020 From 1845 to 1876. 



AUNERAL STATISTICS. 



277 



Name of Mine. 



CoQdurrow — 
cont. 



Consolidated 
Mines 



Cook's Kitchen 



Copper Bottom 



Crane Mine 
(and Bejawsa) 

Creegbraws and 
Penkevil 



Crenver, Abra- 
ham and Oat- 
field 
Cupid, Wheal - 
Conrtis, Wheal 



Damsel, Wheal 



Total yield and largest 
amount raised in one year. 




Tons. 
40i 



8,510 
349 



1,320 
134 



6 



It 
20 



Tons. 
1,941 



32 331,300 



38,800 
2,120 



265 



1,770 

326 

14,530 

2,062 



960 112,050 
804 11,073 



44 

2,290 

354 



37,600 
2,919 



Remarkik 



Tons. 
128 



27.000 
1,530 



2,100 
161 



25 



160 

28 

875 

119 



7,740 
797 

2 

120 
20 



3,300 
304 



20,095 tons of ore contain- 
ing ] ,500 tons of copper 
were sold between 1818 
and 1856. From 1857 to 
1865, 10,400 tons of ore 
containing 543 tons of 
copper. 
From 1815 to 1836, in 1838, 
and from 1845 to 1857 ; 
some black tin in 1837 
and since 1852. 

441,286 tons of ore contain- 
ing 37,402 tons of copper 
sold between 1815 and 
1856. In 1857, 1,105 
tons of ore containing 
59 tons of copper. 

From 1815 to 1836, in 1838, 
and from 1845 to 1897; 
some tin in 1837,1838, 
and 1839, and since 1852. 

43,606 tons of ore contain- 
ing 2,484 tons of copper 
sold between 1815 and 
1856. 

In 18:^5, 1836, and in 1860. 
1,43<) tons of ore contain- 
ing 121 tons of copper 
were produced between 
1836 and 1851. 

In 1851, 1852. and 1853 and 
since 1862. 

Between 1815 and 1832, and 
1845 and 1902. 

15,496 tons of copper ore 
containing 1,022 tons of 
copper sold between 1815 
and 185(1 

Between 1815 and 1832, and 
1845 to 1870. 

From 1855 to 1862. 

In 1838 and from 1864 to 

1869. 
2,341 tons of ore containing 

142 tons of copper were 

sold between 1838 and 

1844. 
From 1815 to 1836, in 1838, 

and 1845 to 1872. 



278 



lONINO EOONOIOOB. 



Name of Mine. 



Total yield and largest 
amount raised in one year. 



Black 
Tin. 




Coppetr. 



Bemarki. 



Dolcoath (Wh. 
E[arriet» &c.) 



Dmid, Wlieal - 

East Wheal 

Basset 
East Basset and 

Grylls 
East Carn Brea 

East Wlieal 
Crofty 



East Wheal 

Damsel 
East Downs (and 

Silverwell) 
East Wheal 

EUen 
East Grenville 
East Wheal 

Lovell 
East Pool and 
Wheal Agar 



Tons. 

7730 

2,555 



87 

. • • 

H 

6 

41 
37 



23 

2,405 

232 

38,490 



East Wheal 

Seton 
East Wheal 

Tolgus 
East Treskerby 
East Trumpet - 
East Wheal \'or 
East Wheal Unyj 

Ellen United, 
Wheal 



57 



20 
32 
32 



Tons. 
230,300 
9,807 



214 

176 

15,050 

2,039 



22,080 
4,021 

54,000 
6,173 



85 

231 
198 
327 



88,300 



1,720 

17,140 

713 

36 



352 

156 

12,600 

1,541 



Tons. 
16,100 
794 



28 

22 

1,520 

308 



1,365 
230 

3,500 
483 



11 

10 
16 



5,010 



122 

1,260 

36 

3 



32 

14 

750 

77 



From 1815 to 1836, in 1838, 
and from 1845 to 1905. 

From 1815 to 1856, 
241,522 tons of ore con- 
taining 17,478 tons of 
copper. From 1857 to 
1874,6,300 tons contain- 
ing 375 tons of copper. 

In 1815 and 1816. 

From 1826 to 1832, 1845 to 

1878. 
In 1864 and 1865. 

Since 1859. 

From 1832 to 1836, in 1838, 
and between 1845 and 
1855. ' 

100,962 tons of ore contain- 
ing 7,280 tons of copper 
sold between 1832 and 
1854. 

In 1891. 

From 1863 to 1899. 

Between 1859 and 1861. 

In 1875. 

Between 1859 and 1891. 

In 1836, 1837, and 1838, and 
from 1845 to 1905. 

38,780 tons of ore contain- 
ing 2,918 tons of copper 
were sold from East Pool 
between 1835 and 1856. 
From 1857 to 1903, 54,310 
tons containing 2,769 
tons of copper. 

Between 1847 and 1875. 

Between 1847 and 1863. 

Between 1863 and 1865. 
Between 1868 and 1871. 
In 1856 and 1857. 
Between 1881 and 1884. 

From 1834 to 1836, in 1838, 
and between 1845 and 
1865. 



MINERAL STATISTICS. 





Total yield and largest | 




amount 


raised in 


ono yefir. 




Nuns of Mine. 








Bemarks. 




Black 

Tin. 


Copper 


Copper. 




Tona. 


Tons. 


Tons. 




EHen United, 








20,0^ tons of ore contain- 


Wheal-cont. 








ing 1,365 tons ot copper 
vtero sold between 1826 
and 1854. From 1855 to 
1865, 3,290 tons of ore 
containing 159 tons of 
copper. 


Emily Henri- 




1,820 


136 


Between 1862 and 1871. 


etta, Wheal 




027 


43 




Emma, Wheal - 




630 
323 


27 
14 


In 1875 and 1876. 


Ed;s, Wheal 


25» 






Between 1853 and 1859. 


(EnyaMinea) 


78 








Falmonth and 


... 


1,150 


40 


Id 1832, 1833, 1834, and 


^"i'"', . 




207 


10 


bi'lAveeii ISIifj and 1872. 


Wheal (and 








Botivt-eii IMl'-l and 1833. 


Falmouth 








1,808 tons of ore were sold 


Consols) 










FaDiiy, Wheal 




8,450 
1,740 


780 
166 


copper. 
From 1815 to 1822. 


Pnraden. Wheal 


"2 




In 1800. 


GaHidna United 


174 


3 




Between 1801 and 1880. 


(iind Polen- 
Geriy, Wheal - 












187 


8 


In 1824 and 1825 (Phillips 










and Darlington). 


GorlsDd, Wheal 


15 


38,.'i00 


2.850 


Between 1815 and 1836 : in 






2,959 


243 


1838 and 1845, and 1878. 


G rambler. 


50 


11 


1 


In 1835 and in 1872. 


Wheal 










Gramhler and 


4 


8,440 


740 


From 1845 to 1808. 


St Aubja 




1,490 


112 


7,280 tons of ore contain- 
ing 569 tons of copper 
were sold between 1843 
and 1856. From 1857 to 
1868, 2.600 tons contain- 








1 inu 297 tons ot copper. 


Great Wheat 


30 






Between 1848 and 1858. 


Baddem 


13 








Great Briggan 




1,390 

506 


ft3 
31 


Between 1861 and 1866. 


Great Wheal 


1,860 


92,100 


4,600 


Between 1815 and 1830, 


Boay (Chace- 


284 


4,108 


314 


1845 and 1897,and in 1904. 


water Mine) 








33,486 tons of ore contain- 
ing 1,669 tons ot copper 
were sold between 1823 








. and 185(5. From 1857 to 








18(iC, 35,060 tona contain- 










ing 1,432 tonsot copper. 



280 



laNING ECONOMICS. 



Name of Mine. 



Gustavus Mine 
Great Wheal 

Loyell 
Great North 

Downs 
Great North 

Tolgus (Wheal 

Elizabeth) 
Great South 

Tolgus 
Great Wheal 

Vor 



Grenyille, 

Wheal 

Hallenbeagle 
(Boscawen) 
and Croft 
Gothal 



Harmony and 
Montague - 



Henry, Wheal 
Hope, Wheal - 



Jane, Wheal - 
Jewell, Wheal - 



Killifreth 

King Edward 
(part of South 
Condurrow) 



Total yield and largest 
amount raiHed in one year. 



Black 
Tin. 


Copper 
ore. 


Tons. 

• . ■ 
64 


Tons. 
89 

•• ■ 


14 

• • • 

• • • 


9,110 
2,513 
4,120 


101 

66 

9,620 

847 


16,500 

3,297 

2,270 

743 


4,635 
1,006 

• . • 


2,330 

738 

10,020 

2,879 



• • • 



3,830 
344 

9 



I 



4,060 

259 

3 




22,450 
2,309 



1,860 

503 

4,910 

1,011 



740 

286 

38,100 

4,061 



I 



681 
128 



Tons. 



6 



640 
182 
215 



1,100 

256 

205 

75 



190 

67 

510 

152 



2,400 
350 



150 

39 

491 

118 



30 

14 

3,015 

526 



56 
11 



Remarks. 



Between 1852 and 1864. 
Between 1871 and 1876. 

Between 1862 and 1897. 

From 1832 to 1834 and be- 
tween 1845 and 1862. 

Between 1854 and 1869. 

Between 1853 and 1877. 
Copper from 1822 to 1826, 
1832 and 1836,and in 1838. 

4,300 tons of ore contain- 
ing 330 tons of copper 
were sold between 1821 
and 1842. 

Between 1860 and 1905. 

From 1834 to 1836, in 1838, 
and between 1845 and 
1859. 

30,580 tons of ore contain- 
ing 1^03 tons of copper 
were produced between 
1835 and 1846. 

Between 1820 and 1834, and 
from 1845 to 1880. 

Between 1819 and 1844, 
29,407 tons of ore con- 
taining 2,950 tons of cop- 
per were sold. 

In 1835, and between 1815 
and 1847. 

Between 1826 and 1832, and 
1845 and 1866. 

5,584 tons of ore containing 
534 tons of copper were 
sold between 1824 and 
1837. 

Between 1847 to 1895. 

From 1815 to 1836, and in 
1838. 

58,160 tons of ore contain- 
ing 5,222 tons of copper 
were sold between 1815 
and 1853. 

Between 1859 and 1904. 

In 1904 



HlNiCHAL 8TATISTI0B. 



LoTeU, Wbeftl- 

Lor«ll, The, 

Mine 
Ijovell Consols 
Lf diA, Wheftl - 

Uaid, Wheal 
(and Carhar- 
rack) 



Uar^, Wheal • 

Mmiy Consols, 

Wheat 
Hedljit Moor 

Mine 
Metal and 

Flow, Wheal 
Mount Carbis- 
Mofle, Wheal - 
Music, Wheal ' 

Naiiuegollan • 
NaDceknhe 
Nanglles aad 
Wheal An- 

NenCook'i Kit- 
New Dolcoath 

New Wheal , 

Frances 
New Wheal ' 



New Wheal 

Lovell 
New Wheal 

SetoD 
N«w8oatliB]len 
New Treleigh 
ConoolB (and 
New Tre- 
leigh) 
NewTrevennen 
New Trumpet 
CoQBola (Lov- I 
ell United) ! 



3,900 
2,267 I 
27300 I 






Between 1852 and 1863. 
Betweeu 1874 and 1876. 



' Between 1821 and 1S36, 
1838, and Irooi 1845 ta 
1852. 

I 23,552 toas of ore ciintain- 
ing 1,542 tons of copper 
were sold between 1820 
and 1852. 

' Between 1845 and 1847. 

Betweeu 1827 and 1836, 

1845 and 1872. 
Betneen 1830 and 1832, 
I 1845 and 1849. 
Between 1874 and 1880. 



! Betwe« 



L 1885 and 1901. 



Between 1882 and 1885. 
I Between 1861 and 1863. 
i Bctweeci 1815 to 1825, and 
I iD 1832, 1833. 
: In 1854. 
, Since 1851. 

, Between 1845 and 1876, 
' and in IWo. 

I Between 1877 and 1891. 

i Between 1872 and 1875. 

' In 1861 and 1862. 

. Between 1861 and 1863. 

Between 1865 and 1874. 

t' In 1863. 



HINDIG ECOMOHICS. 





Total yield and largeat 






amount rained in 


one year. 




Name of Mine. 








BMBarka. 


Black 
Tin. 


Copper 
ore. 


Coppei. 




Tons. 


Tona. 


Tona. 




NewWhMlVot 


125 






Between 1850 and 1861. 


ftnd Eut 


09 








Wheal UeUI 










NelaoD, Wheal 




6 


i 


In 1863. 


North BasMt - 


ire 


27,800 


2,200* 






38 


5,104 


552 




North Wheal 




280 


22 




Buller 








(PhiUipa and Darlington). 


North Wheal 


5 


1,020 


60 


Between 1854 and 1861. 


Busy 




264 


18 




North Busy 


22(1 


750 


45 


Between 1875 and 1887. 


United 




253 


14 




North Wheal 


i^io 


9,170 


535 


Between 1854 and 1899. 


Cpotty 




1,582 


100 




North Wheal 


"h 


580 


45 


Between 1862 and 1854. 


Damsel 




322 


24 




North Dolcoath 




43 


3 


Since 1862. 


North Downs - 


12 


22,800 


1,890 


Prom 1815 to 1836, and 






1,492 


132 


from 1845 to 1871. 

Tin in 1837 and ainoe 1852. 

19,348 tons of ore coutaia. 
ing 1,600 tona o( copper 
were sold between 1815 
and 1855. From 1856 to 
1871. 10,500 tona of ore 
containing 855 tona <^ 


North Wheal 




440 


30 


Between'l857 and 1862 . 


Frances 










North Wheal 




2,670 


210 


Between 1859 and 1867. 


Qramhler 




511 


45 




North HaUen- 




61 


4} 


In 1862 and 1803. 


beagle 










North Wheal 


70 






Between 1861 and 1875. 


JaDO 


19 








North Lovell - 


9 








North Metal - 


8 






In 1883 and 1884. 


North Penatm- 


60 






Between 1880 and 1836. 


thal 










North Pool - 


IS 


47,670 
6,447 


2,860 
433 


Between 1845 and 1867. 




1,440 


132,070 


9,710 


Between 1819 and 1836, 


(and Wberi 


190 


7,419 


265 


1845 and 1874. 


Crotty) 








1 51,800 tons of ore contain. 
ingll,S50tons of copper 
were sold from Nort* 
Roskear between 1816 
and 1856. From 1857 to 
1874, 15.600 tons oontain- 
Ing 1,155 tons of copper. 


North Tres- 


150 


19.270 


1,290 


Between 1859 and 1882. 


kerby 


12 


2,323 


146 





HUOEBAL STATISTICS. 



Name of Miae. 




Old Wheal Baa- 

aet 
Old Wheal Xol- 

gna 
Old Tolgus 

Unitod 
Pedn an Drea 

(and Sparnon 

CoiisoIh) 



United 
Peodarves and 

St. Aubyn 
Penhale Wheal 



Penstruthal 
(aodPeostm- 
tbal Consola) 



PeraeveraDce 
Mine (and 
Went worth 
and Copper 
Hill) 

Peevor, Wheal 

Piult, Wheal - 



Plenty, Wheal- 
Polerebo- 
Poldice - 



Poldice and 
East Wheal | 
Maid I 



Between 1854 and 1800. 

In 1859. 

In 1859. 

Between 1654 and 1891. 

Between 1866 and 1881. 
In 1854. 

Between 1866 and 1868. 
Between 1866 and 1871 

Between 1825 and 183S, 
1845 and 1879. 

Between 18L9 and 1846, 
51,830 tons of ore con- 
taining 3,073 tons ot 
copper were sold. 

Between 1856 and 1877. 



■ Between 1872 and 1889. 

Between 1815 and 1833, 
1845 and 1855. 

1,881 tons ol ore contain- 
ing 158 tons of copper 
were sold between 1821 
and 1850. 

Ill 18:S8 {t'liillips and Dar- 



in 1838 and between 1845 
and 1873. 

Tin in 1837, 1838 and 1839, 
and since 1852. 

2,902 tons of ore contain- 
ing 208 tons of copper 
vn-re sold between 1815 
and 1853. From 1868 to 
1873, 3,635 tons of ore 
containing 231 tons of 
copper. 

In 1891. 



MIXIXG EOOXOIUCI. 



Total yield and Urg««t I 
WDanut nined in on» }-«ar. I 



^^ I '-'ZE" "••»«•'• 





Tona. 


Tons. 


Pol^ue, A\'hMl 




4% 


Polhigey Muor 


28 


... 


and Polhlgey 






New Mine 






Prtwper.Wheal 


8« 


311 




39 


191 


Prosper United 


830 


22,490 




191 


4J23 


PfDMia. Wheal 


206 


13 


(uidCardKW 






United) 






Kaven, Wheal - 




1,147 
505 


BedtDth ; 




740 


Console 1 






Hose, Wlieal • j 


18 


12,820 
3,717 


Roaltear - - i 




23 


St. Andrew - i 




370 


St. Aubyn 


'& 


1.380 


United 1 






St. Day United ; 


3,280 


22.9Q0 


(St. Day 


480 


3.175 


Manor-Pol- 






dice. Unity . 






Wood, Wheal 






JJaid, and \ 






Wheal Gor- 






land) ; 






Soorrler Conaola 


15 


... 


Seton, Wheal - 1 

1 


990 


113,050 
5.402 


Seymour.Wheal 




075 


Sonth Basset - ' 




37.100 



41 I Id 1830 and IS37 (Phillips 
and DarlUvton). 

a 1804 and 1S74. 



7 I Between 1862 and 18701 
3 I 
1.020 ; Between 1803 and 1872. 



i Betweien 1874 and 1883. 



117 Between II 



50 Between 1836 and 1843 
(Phillips and Darlington). 
I Between 1862 and 1872. 

I In 1864 and 1865. 



834 



1.300 ; Between 1852 and 1893L 
230 ' 9,728 tons of ore conUin- 
j ing %8 tons i)[ eupper 
' were sold bt-tween 1852 
. and 1856. From 1857 to 
1867. 11,170 tona con- 
I taining 602 tons of oop- 
I pe'. 
... { In 1874 and 1875. 
7,080 I In 1838 and from 1845 to 
! 1877. 
451 Lan[e8t ontput in 1847. 
43 In 1815 and ISlC (Wheil 
Ann), and In 1877 and 
1878 (Will-ill Seymour). 
3,020 From 1833 to 183tt, in 1838. 
and between 1845 and 
1861. 
267 94,049 tons of ore contain- 
ing 7,200 tons of copper 
were sold between 1825 
and 1656. 
211 In 1822 and from 1863 to 
1805. 
8,554 Between 1821 and 185C, 
aooordlng to Phillip* 
i and Darlington. 



MINERAL STATISTICS. 



2B5 



Name of Mine. 



Total yield and largest 
amount raised in one year. 



Black 
Tin. 



South Garn 

Brea 
Soath Condur- 

row 
South Wheal 

Crofty 
South Dolcoatb 

South Wheal 

Ellen 
South Wheal 

Frances 



South Wheal 

Lovell 
South Penstru- 

thal 
South Roskear 



South Tolearne 
and West 
Condnrrow 

South Tolgus 
(South Wheal 
Tolgus) 

South Towan - 

South Wendron 

Mine 
Sparnon, Wheal 

SparroWyWheal 



I 



Sperries, Wheal 



Spinstcr,Whcal 



Tons^ 
845 
129 

11,430 

861 

5,080 



9,710 
728 



81 



i 
175 



230 



14 



Ui 



Copper 
ore. 



Tons. 

3,550 

628 

1,060 

247 

33,700 

3,208 

1.800 

273 

2,600 

747 

66,590 

6,463 



21,600 
1,464 



1,300 
543 

36,770 
2,839 

12,900 

2,088 

7 

1,710 

460 

1,510 



2,275 



702 



Copper, 



Remarks. 



I 



Tons. 

312 

87 

106 

30 

9,000 

164 

145 

19 

115 

38 

5,660 

505 



1,400 
113 



114 

50 

2,850 
224 

720 
137 



141 
33 
65 



84 



4(M) 
65 



Between 1856 and 1877. 

Between 1864 and 1902. 

Between 1854 and 1905. 

In 1832 and 1834 and be- 
tween 1859 and 1876. 
Between 1856 and 1861. 

Between 1845 and 1895. 

33,522 tons of ore contain- 
ing 3,252 tons of copper 
were sold between 1844 
and 1856. From 1857 to 
1878, 34,500 tons of or© 
containing 2,503 tons of 
copper. 

Between 1860 and 1868. 

In 1880. 

Between 1825 and 1836, in 
1838, and from 1845 to 
1881. 

37,807 tons of ore contain- 
ing 2,904 tons of copper 
were sold between 1821 
and 1850. 

Between 1859 and 1883. 



Between 1848 and 1865. 



Between 1819 and 1827, 
1832 to 1836, and in 1838. 
Between 1875 and 1878. 

Between 1815 and 1821. 

From 1832 to 1836, in 1838, 
and in 1865. 

2,227 tons of ore contain- 
ing 147 tons of copper 
were sold between 1829 
and 1841. 

Between 1^30 and 1832, 
1845 and 1855. 

3,116 ions of ore contiiin- 
ing 117 ions of cop|)er 
were sold between 1829 
and 18;>1. 

Between 1815 and 1829. 



286 



xnnNG EOONOiacB. 





Total yield and 


largest 






amount raised in one year. 




Name of Mine. 








T^AfiiflvIrR 


BUok 
Tin. 


Copper 
ore. 


Copper. 


Xt^lUil£iiO. 




Tons. 


Tons. 


Tons. 




Squire, Wheal 


••* 


20,000 


1,506 


Between 1817 and 1825, 




••• 


4,705 


412 


and in 1852 and 1853. 
20,082 tons of ore contain- 
ing 1,724 tons of copper 
were sold between 1816 
and 1853. 


Stray Park - 


590 


19,100 


1,190 


Between 1828 and 1836, 
1838, and 1845 to 1867. 




88 


2,344 


164 


Between 1829 and 1856, 
38,610 tons of ore con- 
taining 2,748 tons of 
copper were sold. 


Stray Park and 


••• 


1,330 


100 


In 1827. 


Camborne 










Vean 










Susan, Wheal - 


••. 


566 


30 


In 1822 and 1825. 




••* 


360 


20 




Tehldj, Wheal 


••• 


1,725 


120 


From 1834 to 1836, and 


% 


••* 


339 


31 


between 1855 and 1861. 
2,021 tons of ore contain- 
ing 180 tons of copper 
were sold between 1835 
and 1856. Between 1857 
and 1861, 560 tons of ore 
containing 41 tons of 
copper. 


Tincroft - 


22,700 


104,500 


5,940 


Black tin in 1837, 1838, and 




829 


9,559 


515 


1839, and since 1852; 
between 1815 and 1836, 
1845 and 1895. 
94,210 tons of ore contain- 
ing 5,346 tons of copper 
were sold between 1815 
and 1856. From 1857 to 
1895, 18.560 tons contain- 
ing 1,106 tons of copper. 


Ting Tang 


• •• 


40,240 


3,270 


Between 1816 and 1835 and 




• •• 


4,310 


307 


from 1845 to 1847. 


Tolcame- 


99 


5,630 


303 


Between 1860 and 187a 




97 


1,065 


56 




TolguUow 


570 


20 


3 


Between 1882 and 1903. 


United (and 


171 


*• • 


•• • 




WestPoldice) 










Tolgus, Wheal 


••• 


30,750 


2,855 


Between 18^ and 1836 and 




••• 


5,286 


620 


in 1838. 
33,531 tons of ore contain- 
ing 3,450 tons of copper 
were sold between 1820 
and 1839. 


Trannack, 


•• • 


8,200 


540 


In 1822, from 1832 to 1835, 


Wheal 


• • • 


1,448 


122 


and in 1864. 


Trannack and 


•• • 


255 


23 


In 1851 and 1852. 


Bosence 











inNERJU, STATISTICS. 





Total field and 


latest 






amonut 


raiseil in 


one year. 




Nune ol Mloe. 








Remarks. 


Black 
Tin. 


Copper 

ore. 


Copper. 






Tons. 


Tons. 


Tons. 




TrefDsia.WheBl 


205 


350 


23 


Between 1853 and 1863. 




51 


196 


13 




Trepijorran - 




1,660 


202 Between 1815 and 1822. 






398 


48 


TwgothDan 

Consols 
Treleigh 




1,417 


63 ' Betsvecn 1840 and 1844. 




13,420 


1,030 In 1835 and 1836. and be- 


Consols 




2,308 


217 1 tween 1845 and 1856. 

21,000 tons of orecontalu- 
1 inc 1.420 tons of copper 
1 were sold between 1838 
1 and 1855. 


Trftleighwood 


533 


37 


3 . Between 1874 and 1878. 


Mine 


131 






Trpsavean 


106 


151,700 


9,940 B^itween 1815 and 1836, in 






8.178 


894 


18.^8, and from 1845 to 
1879. 
163.260 tons of ore contain- 
ing 15,702 UIU.H o£ eoppor 
were sold between 1815 

and 1871. 4,460 tons of or* 

copper. 


TreuTean 




2,130 


176 


Between 1845 and 1848. 


Barrier 




874 


83 


2.830 tons of ore contain- 
ing 244 tons of copper 
were sold between 1844 
and 1848. 


Treslterby - 


S 


32.510 


2,945 


Betnt>en 1815 and 1822 and 






4,696 


467 


in 1832. 


Treskerbj and 




18,500 


1,675 


Between 1823 and 1827. 


Chance Con- 




3,915 


356 




solidated 










Trethellan - 




12,690 


580 


In 1638, and between 1845 






2,612 


143 


and 1860. 
35,545 tons of ore contain- 
ing 1,922 tons of copper 
were sold between 1837 








and 1856. 


Trerennen and 


730 


37 


4 ' Between 1854 and 1876. 


Tremeoheere 










TreTiskey - 


1 


17,790 


1,550 


Between 1845 and 1855. 






2,884 


285 


17,940 t«na of ore eontain- 
ine 1,508 tons of copper 
were sold between 1844 
and 1855. 


Treroole - 




3.400 


141 


In 1827 and from 1859 to 






640 


25 


1862. 


TreworlLs 


412 




30 


Between 18G0 and 1873 and 




52 


407 


22 


in 1882. 


Trumpet 


4,510 


4 


i 


BotwL.,-n 1854 and 1880. 


Consols 


298 








Trumpet 


12 




::: 


Between 18G3 and 1865 


United 











2S8 



KXIONO ECONOMICS. 



Name of Mine. 



Total yield and largest 
amount raised in one year. 




Remarks. 



Tryphena 
United Hills - 



United Mines 
(Gwennap 
United) 



Unity and Unity 
Consols 

Unity and Pol- 
dice 

Unity Wood, 
Wheal, and 
Wheal Union 



Uny, Wheal 



Virgin, Wheal 
(part of Clif- 
ford Amalga- 
mated) 



Vyvian, Wheal 



Tons. 
31 
26 



250 

77 



40 

22 



570 
128 



7,660 
423 



02 
26 



Tons. 
74 
26,110 
3,300 



284,400 
14,374 



•••' 



83,100 

6,897 

21,620 

858 



2,860 
353 



7,420 
046 



4,140 j 

378 i 



Tons. 
16 
1,490 
209 



19300 
1,012 



6,890 

554 

1,290 

56 



155 
27 



415 
72 



235 
22 



In lB47and 1848 and in 1862. 
From 1822 to 1836, 1845 to 

1847. 
54,473 tons of ore contain- 
ing 3,582 tons of copper 
were sold between 1826 
and 1847. 
Some tin in 1837 and since 
1852; between 1815 and 
1836, 1845 and 1861 ; in 
1880 and 1881, and from 
1893 to 1901. 
304,530 tons of ore contain- 
ing 22,680 tons of copper 
were sold between 1815 
and 1856. Between 1857 
aAd 1861,43.110 tons of 
ore containing 2,063 tons 
of copper. 
Between 1852 and 1855. 

Between 1815 and 1832. 

Between 1815 and 1836, in 
1838, and since 1853 ; tin 
in 1837 and since 1852. 

32,760 tons of ore contain- 
ing 2,465 tons of copper 
were sold between 1823 
and 1842. 

Between 1853 and 1893. 

Between 1826 and 1856, 
755 tons of ore yielding 
39 tons of copper were 
sold. Between 1857 and 
1866, 2,070 tons of ore 
containing 112 tons of 
copper. 

In 1815 and from 1834 to 
1836, and from 1845 to 
1847. 

22,974 tons of ore contain- 
ing 1,656 tons of copper 
were sold between 1821 
and 1847. 

From 1832 to 1836, in 1838, 
and between 1845 and 
1864. 

8,277 tons of ore contain- 
ing 500 tons of copj>or 
were sold between 1827 
and 185(S. Between 1857 
and 1864, 200 tons of ore 
containlDg 10 tons of 
ooppor. 



MINERAL STATISTICS. 



289 



Name of Mine. 



Total yield and largest 
amouut raised in one year. 



Black 
Tin. 



Copper 
ore. 



Copper. 



Remarks. 



Wellington, 

Wheal 

Wendron Con- 
sols 

Wendron United 
Mines 

West Basset - 

West Buller - 
WestCarvannel 
West CliflFord - 
West Wheal 

Damsel 
West Wheal 

Frances 
West Wheal 

Gorland 
West Wheal 

Grenville 
West Wheal 

Jane 
West Wheal 

Jewell 



West Wheal 
Peevor 

West Pink 

West Poldice 
(and West Pol- 
dice United) 

West Wheal 
Seton 

West Wheal 
Squire 

West Stray 
Park 

WestTolgus - 

West Tresavean 
West Wheal 

Towan 
West Trethellan 

West Wheal 

Virgin 
West Wheal 

Vor 



Tons. 



2,390 

269 

27 

10,150 
1,000 



18 

8,940 

68 



410 
58 

8 



1,200 

130 
650 
158 

3,720 

299 



4 



5 
520 
114 



Tons. 
.2,830 

48 



101,500 
7,673 
1,170 
110 
73' 
29.150; 
2,166 
28' 

■r 

7o; 
11 

50 

6.620 
1^83 



280 

1,152 

336 

114,4.50 
7,155 
3,390 
1,148 
3,635 
485 
47,700 



1,390 

435 

90 



Tons. 
213 

8 



7,155 
532 
125 

• • • 

3 

1,560 

117 



410 
113 



15 
90 

28 

9,300 
520 

:^3 

139 

275 

37 

4,020 



63 
20 



Between 1822 and 1827 
(Phillips and Darlington). 
Between 1854 and 1869. 

In 1853>nd in 1875, 1876. 

Between 1852 and 1890. 

In 1849. 
In 1859. 
In 1865. 
Between 1852 and 1874. 

Between 1854 and 1896. 

Between 1871 and 1876. 

In 1859. 

Between 1854 and 1889. 

In 1832 and 1833 and be- 
tween 1845 and 1852; 
tin 1837 and in 1852. 

Between 1831 and 1852, 
12,578 tons of ore con- 
taining 858 tons of copper 
were sold. 

Between 1879 and 1887. 

In 1832, 1833, 1834. and 1835. 

From 1832 to 1836; be- 
tween 1874 and 1884 ; tin 
in 1837 and since 1852. 

Between 1848 and 1890. 

Between 1818 and 1822. 

Between 1854 and 1868. 

From 1832 to 1836 and be- 
tween 1861 and 1883. 
In 1837. 
Between 1853 and 1882. 

Between 1845 and 1850. 

In 1818. 

In 1878. 



290 



HINIXG EOONOlflCS 



OtUpvi of MinerrUs, other th/m Tin and Copper^ from 1848 

to 1905. 



Total yield and largest amount raised in 

one year. 







J 






1 TS 


1 . 




1 1^ 




Name of 
Mine. 


o 

►2S 


Lead. 


1 


t 

c 


Iron pyrites an< 
sulphur ores. 


Crude and 
refined arsenic 




Ochre and mnbe 


Other 
products. 




Tons. 


Tons. 


0Z8. 


Tons. 


Tons. 


1 - 1 

1 
Tons. Tons. 


Tons. 




Basset 


14 


9 


144 


... 


... 


••• ... 


•*. 




Consols 




















Basset 


... 


... 


... 


120 


... 


... 


... 


•. • 


In 1879. 


VaUey 












1 






Bissoe Pool - 


•. . 


... 


... 


... 


.. • 


4 

A • . . . 


... 




Boscawen 


... 


•.« 


... 


33 


••* 


... ... 


• . . 


139 tons 


















. 


arsenical 




















pyrites 




















since 




















1864. 


Buller, Wheal 


... 


... 


... 


... 


43 


... 


... 


•. . 


In 1857. 


Burra Burra 


3 


2i 


55 


320 


... 


• .. 


•. * 


•. . 




Mine 




















Camborne 


... 


... 


... 




4 


200 


• . . 


••• 




Consols 




















Camborne 


... 


• «. 


... 




... 


30 


••. 


• .. 




Vean 




















Cam Brea - 


... 


• . . 


•.. 




• . . 


4,140 


••• 


•• • 


16 tons 




• . . 


... 


. • • 




•*. 


302 


. .. 


... 


arsenical 
P3rrites. 


Carn Brea 


... 


... 


... 




... 


3,142 


... 


• a. 


390 tons of 


and Tin- 


... 


... 


• *. 




••• 


421 


• . . 


... 


wolfram 


croft 


















(239 high- 


United 


















est yield 
in one 
year). 


Carn Cam- 


• . . 


. • . 


... 


... 


... 


72 


•• . 


... 


40 tons of 


borne 


















arsenical 
pyrites. 


Carvannel - 


. . . 


• . . 


•.. 


... 


4i 


• • • 


. . . 


... 




Clifford Amal- 


. . . 


... 


... 


1,011 


5,550 


7 


•• . 


... 




gamated - 


•.. 


. *. 


... 


974 


550 


••• 


•. . 


• *• 




Comford, 


•. • 


*. . 


••• 


. .. 


... 


13 


. . . 


... 




Wheal (and 




















North Tre- 




















savean) 


















Concord, 


60 


36 


... 


•.. 


. • • .. * 


.. . 


... 


Between 


Wheal 


















1845 and 
1847. 


Condurrow - 


. • • 


• • • 


. • • 


. • • 


6J| 34 


• • • 


... 




Consolidated 


•• . 


• • . 


...j 60 


1,050 1\ 


... 


. • * 




Mines 






1 












Cook's 


* . « 


... 


• • • • • • 


. • . 


120 


. • . 


... 


222 tons 


Kitchen 






1 










arsenical 




















pyrites. 



MINERAL STATISTICS. 





Total yield and larKust amonnt 


raised In 








one year. 
















•a 




ft 




Nairn of 










Jill 


d 
1 = 


1 


Other 


Uioe. 


t 

1 


^ 


i 

s 


i 
g 


a 


products. 




^ 






1 " 


i. 


o 


1 






Tods, Tons., Ozs. 


Tons. 


Tons. 


Tons. 


Tons. ToiiH. 




Crane Mine- 


2 lil 13 












Creecbrawa 




'A 


160 


GO 


!!! l(ni 




and Pen- 


; 










nrsenlcHl 


kOTil 










pyrites. 


Crenver. 


4i 3! 15 


...'. 744 









Abr.ihnm, 


... 


... 296 






and ftitneld 




1 






Cnpid. Wheal 


















22 tons 



CoartJs. Wheat 
Damsel, 

Wheal 
Daniell. 

^\'hcal 
Dolcoath 



3: 



...j 
i 



3201 n.ioo! 487 



. 114 tons ot 
flunrapur. 
'' In 1872. 

' C34 tons 
.' arsenical 
pyrites 
(270 high- 
year). 
2cwt8.bis- 

1 107 tons of 
arsenical 
pyrites. 

. Between 

I 1856 and 

I 1801. 
1,860 tons 

fmm, 100 

sodium 

tongstste. 



bait ore 
4toDsbis' 



taining 
nickel.co- 
balt, and 
bismuth. 



' IflXINO ECONOMICS. 



Total yield and largest amount raised 



|! 



East Wheal 
Tolgua 

Emily Henri- 
etta, Wheal I 

Kalmoutlianil 
Sperriea, 
WheAl 

Fortune, 

Wheal 

Gorland, 



In 1880. 

. 20itotiBof 

wolfram. 

60 14toaBftr- 



Great South 

Tolgua 
Great Wheal 



' of aneiii- 

. ca,l py- 
rites 
(5,778 
la^feot 

, outpat la 

one year). 

,..! 373 tons 

I kTsenical 

I (218 tons 

I ou^at in 
I oney«ar). 



Nancekiihf^ 
Nangiles an 
Wheal An- 

New TreleigU 
Consols <and[ 
New Tre- 
leigh) I 



6 12 tons 

arsenic*! 

. pyrites. 



MINERAL STATISTICS. 





Tot^ yield «Dd l>rgwt smoDBt rsiaed in 








one yew. 
























Name of 










il 


ll J 


1 


Other 


Mine. 


i 
1 


i 


1 


1 
% 


1 

■a 

i 


products. 












s, s 


t *^ 




















-5 






TonH.|ToaB. 


Om 


Tons. 


Tons. 


Tons. Tons. 


Tons,] 


North Wheal 






415 


92 






Busy 




382 








North Busy 


\ 


584 172 




... 24 tons of 


United 




31ft ...| 


... arsenical 
pyrites. 


North Wheal 




5! 1,470 ... 


... 992 tons 


Crofty 




380 ... 

i 


pyrites 

: (545 tons 

higlie»t 


















output in 



North Wheal 

North Pool 
North Kos- 

North Tres- 



Old 



Old 



Wheal 

Tolgu^ 



P«dnanDres 
(and Spar- 
non Consols) 

Pendarves 

United 

Perseverance 
Mine (and 
Wentwotth 
and Copper 
Hill) 

Wheal 

Poidice 



Wheat 



...1 13 tons 

arsenical 

pyritos. 

321 1^22 tons 

... arsenical 

I pyrites. 



lUNlNG EOOROHICS. 





Ti. 


»1 yield and largest aniuuat. raised ia 










oue 


year. 
















•0 






S 




NnniB of 
Mi no. 


!i 






1 


u 


i! 
^1 


. 


i 


Other 
products. 




1 


1 




1 


£1 

|5 


1 = 

k 


1 
1 




















o 






Tons. 


Tons. 


Ozs. 


Tods. 


Tona. 


Tons. 


Tods. 


Tons. 




8t. Aubyn 








... 




... 




... 


172 tons 


UniWd 


















flnonpu-. 


StDayUnited 






... 






... 


38 




124 tona 


(St. Day 




















Munoi-— 


















pyrite.; 


Poldice. 


















49 tona 


UnityWood, 


















fluonpMr. 


Wheal Maid. 




















Wheal Uor- 




















land) 




















Seton, Wheal 








10 


25 


t,900 
155 






10 tons of 
flnorspu. 


Sej-iDour, 








is 












Wheal 




















South Cam 












4 








Brea 




















SoLitb COB- 












4 








dnrrow 




















South Wheal 








... 


1,110 


3,251 






19 tons of 


Crofty 


















woUrmm. 


South Wheal 


4 


3 




137 


42 










Ellen 




















South Gairas 


1,930 


1,025 


71,930 




11 












50« 


243 


23,455 











185S «nd 
1860. 


South Roa- 




... 




35 




(B5 








kear 












257 








South Wheal 




" 








93 






In 1872. 


Reton 




















South Tolgua 


i 


i 




8 


77 


... 








<South 


















Wheal Tol- 


















gus) 


















Stray Park - 










4a .. 








Swan pool - 


706 


178 
141 


3,579 




:: :: 






Id 1859 
and 1860. 


Tincroft 


22 


15 






.,.18,286 
... 553 




... 




ToJbuIIow 










... 222 




184 


152 tona 


tJ 111 ted (and 
















ftraenlc»l 


Wfsf, Pol- 
















pyritM. 




















Trannaek. 








^ 


..., 








Wlieal 


















Tresavcan - 


il 


3 






312 








United 








271 


1.290 158 








Mines 










9«6' 








Unity and 


"i 


"i 






... 243 






Unity Con- 
















boIh 





















MINERAL STATISTICS. 





Total yield and largest amooDt ndaed In 








one je*T. 














-D . 1 


ft 




Xame ol 
Mine 


I 


i 


1 


i 

1 




.s 

1 
t 


Other 
products. 












E " 


£ '=■ 
















"■ 


\ 


a 






Tons,ToDS 


Ozs. 


;;: 


Tons. 


TonB.|Ton8. 


T„„..j 


Unity Wood 


I! lA 




.. 


21 


12!J .. 




and Wheal 












Union 










1 


Uny, Wheal - 






6 




50l 


West Wheal 










...iKiS tons 


Damsel 










' Huorspar 




i 










(332 tons 
















hiRhest 
















yield in 
















one year.) 


West Wheal 










... .. 




256 tons 


Damsel 












fluorspar. 


and Cupid 










382 207 




West Wheal 


2«| 19 


158; 390 


27,170 




Jane 


.. 1 


...j 76 


4^)0 






West Wheal 










» :: 




Peevor 














1 


West Poldice 










6 




...I 


(and West 
















Poldice 
















United) 
















West WhesI 










24 


4,026| .. 




Seton 














1 


West Tolgu* 








97 




... .. 




West Wheal 








11 


200 


... .. 




Towan 

















Stream Works, <fcc. — Tin Ore obtained from Mine Refuse, 
Forethxires, <£'c. 

Red River and River from Corn Brea and Tineroft. 







Metallic tin 




Year. 


Dressed tin ore. 




Value. 








£ 


1882 - - 


1.2.52 


728 


5336 


1883 - - 


1,103 16 






1884 • 


1,154 2 


635 


35.018 


18B5 - - 


1,142 18 


628 10 


37.218 


1886 - - 


1,104 3 




48.177 


1887 - - 


1.010 10 






1888 - - 


1,446 6 


867 


63.182 


1889 - 


911 




43.392 


1890 - 


1.302 




52.080 


1891 - 


880 




33,704 


1892 - - 


905 4 




34,780 



296 



MINING fiCONOHICS. 



Bioer from Wheal Bastet, West Basset, Wheal Vny, Ac., to Portreath. 







Metallic tin 






Year. 


Dressed tin ore. 


obtainable by 


Valae. 






- 


smelting. 


- 




• 


Tons cwts. 


Tons cwts. 


£ 




1882 - 


265 


148 8 


1139 




1883 - 


255 10 


125 


9,200 




1884 - 


171 . 17 


93 


6,039 




1885 - 


184 9 


103 


6,887 




1886 - 


170 10 


••• 


7,679 




1887 - 


207 1 


••• 


9,690 




1888 - 


206 3 


123 


9,852 




1889 - 


278 


• • • 


7,619 




1890 - 


428 


• • • 


17,126 




1891 - 


330 


• • • 


10,469 




1892 . 


261 2 


• • • 


10,016 





Total Annual Production of Tin Ore of Oormoall from Abandoned Mine- 
heapSf Waste from Mine Dressing Floors, Stream Works, Ac* 



Year. 




Black tin. 


Metallic tin. 


Value. 




Tons cwts. 


Tons. 


£ 


1882 - 


1,654 


950 


... 


1883 - 


1,439 


709 


... 


1884 - 


1,415 


778 


. •• 


1885 - 


1,395 


770 


• • • 


1886 - 


1,337 


802 


• • . 


1887 - 


1,278 


767 


* • . 


1888 - 


1,742 


1,045 


... 


1889 - 


1,272 


763 


. • • 


1890 - 


1,796 


1,078 


• • • 


1891 - 


i,:^i 


780 


... 


1892 - 


1,282 


769 


. • . 


1893 - 


1,228 


737 


45,601 


1894 - 


i,:^oo 


780 


29,075 


1895 - 


1,000 


400 


25,000 


1896 - 


716 


322 


15,603 


1897 - 


877 14 


.395 


22.057 


1898 - 


746 


335 


20.020 


1899 - 


709 


319 


32,088 


1900 - 


761 


342 


39,030 


1901 - 


687 


^m 


30,805 


1902 - 


825 


350 


40,049 


1903 - 


839 


356 


42,136 


1904 - 


721 


334 


37,387 


1905 . 


818 18 


377 


46,824 


Refuse Heaps of Abandoned Mines, 


"Old Men's'' 1 


burrows, &c. 


Year. j Dressed tin. 


Metallic tin. 


Value. 


1 

1 Tons cwts. 


Tons cwts. 


£ 


1882- - - 17 17 


10 6 


870 


1883- - - 8 14 


4 18 


483 


1892 - 


86 19 


56 10 


4,364 


1893 « 


64 16 


42 2 


2,952 


1894- 


- 


72 5 


46 19 


2,544 



* Mainly from the mine tailings flowing down the rivers above mentioned. 



INDEX TABLES OF THE MINES. 



297 



Index Tablbs of thb Minss. 

The following table coutains an alphabetical list of the mines included 
in this sheet, together with the parishes in which they occur. The mines 
now working are the Basset Mines, Carn Brea and Tincrof t United, Cook's 
Kitchen, South Crofty, Dolcoath, East Pool and Wheal Agar : — 



Mink. 
Abraham Consols - 
Agar, Wheal 
Ale and Cakes 
Andrew, Wheal 

Ann, Wheal - 
Annie, Wheal 

Baddern (Baddon), 

Wheal 
Baldhu - 
Bal Ding 

Baimynheer Mine - 
Banns, Wheal 
Barberry, Wheal - 
Barncoose Mine - 
Basset, Wheal 
Basset and Grylls - 
Beauchamp, Wheal 
Bell and Lannarth 
Bellvean Mine 
Bissoe Pool - 
Bodilly Consols - 
Bolenowe 
Boscawen Mine 
Boys, Wheal - 
Bramble, Wheal - 
Brewer, Wheal 
Briggan, Wheal 
Britannia, Wheal - 
Brook, Wheal 
Buckets, Wheal 
Buller and Basset 

United 
Buller, Wheal 
Burra Burra Mine- 
Busy, Wheal 

Calvadnack Mine - 
Camborne Consols - 
Camborne Veaii 
Captain, Wheal 
Carbon a Mine* 
Cardrew Consols - 
Carharrack - 
Carleen Mine 
Carnarthen - 
Carn Brea 
Carn Camborne 
Camemow 
Carnmeal Mine 
Carnkie 
Carqueen 
Carvennal 
Cathedral Mine - 
Chacewater Mine- 



Parish. 
Crowan 
Illogan 
Gwennap 
Gwennap 

Kea 

f Ken^\yn 

\ Wendron 

Gwinear 



Kea 

Kea 

Wendron 

Wendron 

St, Agnes 

Redruth 

Illogan 

Illogan 

Wendron 

Gwennap 

Gwennap 

Gwennap 

Gwennap 

Wendron 

Camborne 

Kenwyn 

Kedruth 

Sithney 

Gwennap 

Redruth 

Gwennap 

Gwinear 

Redruth 

Wendron 
Redruth 
Kenwyn 
Kenwyn 

Wendron 

Camborne 

Camborne 

Redruth 

Crowan 

Redruth 

Gwennap 

Breage 

Illogan 

Illogan 

Camborne 

Camborne 

Breage 

Illogan 

Gwennap 

Gwennap 

Gwennap 

Kenwvn 



and 






Mine. 

Chance, Wheal 

Charles, Wheal 
Christopher, Wheal 
Clarence, Wheal - 
Clifford, Wheal - 
Clifford Amalga- 
mated 
Clinton, Wheal - 
Clinton, Wheal 
Clowance, Wheal - 
C Iowa nee Wood 
Mine - - - 
Clyjah and Went- 
worth - - - 
Combellack Mine - 
Comford, Wheal - 
Concord, Wheal - 
C'ook's Kitchen 

Copper Hill - 

Copper Bottom 
Copper Tankard - 
Cornwall Mine 
Courtis, Wheal 
Crack (^^rowder 
Mine - - - 
Crane and Bejawsa 
Creegbraws - 
Crenver and Wheal 

Abraham - 
Crofty, Wheal 
Crowan and Wen- 
dron Mines 
Cudy, Wheal - 
Cupboard Hill 

Mines 
Cupid, Wheal 
Cusvey - - - 

Damsel, Wheal 
Daniell, Wheal 
Derrick, Wheal 
Dolcoatii Mine 
Dopps Mine - 
Dream, Wheal 
Druid, Wheal 
Drym Mine - 

Duchy, Wheal 

Dudnance 

East Wheal Abra- 
ham - . - 

East Ale and 
Cakes 



Parish. 
r Gwennap 
{ Redruth 
St. Agnes 
St. Agnes 
1 llogan 
Gwennap 

Gwennap 
Gwennap 
My lor 
Crowan 

Crowan 

Redruth 
Wendron 
Gwennap 
St. Agnefl 
Illogan 
I Redruth 
\ Camborne 
Crowan 
Camborne 
St. Agnes 
Crowan 

Gwinear 

Camborne 

Kenwvn 

Crowan 
Camborne 

Wendron 
Wendron 

Gwennap 
Gwennap 
Gwennap 

Gwennap 

Kenwyn 

Redruth 

Camborne 

Redruth 

Wendron 

Illogan 

Crowan 
/ Illogan 
\ Wendron 

Illogan 



Crowan 



Gwennap 



'^\f6 


MINING 


ECONOMICS. 




Mine. 


Pabish. 


Mine. 


Pabish. 




C Gwennap 


Grambler, Wheal - 


Gwennap 


East Wheal Basset 


< Illogan 


Great CondoErow - 


Camborne 




CRedruth 


Great Conflolidated 


Gwennap 


East Wheal Buller 


Gwennap 


Great Wheal Bad- 




East Carn Brea - 


Redruth 


dem (Baddon) - 


Kea 


East Wheal Chance 


Kenwyn 


Great Wheal Busy 


Kenwyn 


East Wheal Crofty 


Illogan 


Great East LoveU 


Wendron 


East Wheal Damsel 


Gwennap 


Great Wheal For- 




East Downs Mine - 


St Agues 


tune - - - 


Breage 


East Wheal Ellen - 


St. Agnes 


Great Drym Con- 




East Wheal Fal- 


TKea 
\ Kenwyn 


sols - - - 


Crowan 


mouth 


Great Wheal 




East Wheal For- 




LoTell 


Wendron 


tune - - - 


Sithney 


Great Wheal Metal 


Breage 


East Grenville 


Camborne 


Great North 




East Wheal Lovell 


Wendron 


Downs 


Redruth 


East Wheal Music - 


St. Agnes 


Great North 




East Pool Mine - 


Illogan 


Tolgus 


Illogan 


East Rosewarne - 


Gwinear 


Great St. Vincent - 


Illogan 


East Wheal Seton- 


' Camborne 
Illogan 


Great South 
Tolgus 


Redruth 


East Wheal Spar- 




Great Wheal Vor - 


Bieage 


non - - - 


Gwennap 


Grenville, Wheal - 


Camborne 


East Wheal Tolgus 


Redruth 


GrillU, Wheal 


Ulogan 


EastTowan - 


St. Agnes 


Gustavns Mine 


Camborne 


East Tresavean - 


Camborne 


Gwinear Consols - 


Gwinear 


East Treskerby - 


St. Agnes 






East Trumpet Mine 


Wendron 


Hallenbeagle Mine 


Kenwyn 


East Wheal Virgin 


Gwennap 


Hangman's Barrow 


Crowan 


East Wheal Vor - 


Sithney 


Harmony, Wheal - 


Redruth 


Edgecumbe, Wheal 


Gwennap 


Harriet, Wheal - 


r Sithney 
\ Camborne 


Elizabeth, Wheal - 


Illogan 


Ellon WhAfl.1 - 


/ Illogan 
\ St. Agnes 


Hatchet, Wheal - 


Camborne 


J'JIIOlly VT UOax — 


Hawk, Wheal 


Redruth 


Emily Henrietta, 




Hender, Wheal - 


Crowan 


Wheal 
Emma, Wheal 


Illogan 
Breage 


Henry, Wheal 


/ Kenwyn 
1 Gwennap 


Enys, Wheal - 


Wendron 


Hope, Wheal 


TKea 

\ Gwennap 


Falmouth and 








Sperries - 


Kea 


Illogan Mine 


Illogan 


Fancy, Wheal 


St. Agnes 






Fanny, Wheal 


Illogan 


Jane, Wh€»l - 


Kea 


Fire, Wheal - 


Illogan 


Jewell, Wheal 


Gwennap 


Forest, Wheal 


Illogan 








C Gwennap 


Kellivose Mine 


Camborne 


Fortune, Wheal - 


< Breage 


KilUfreth Mine - 


Kenwyn 




(^Illogan 


King Edward Mine 


Camborne 


Foster, Wheal 
Fox Hole Sett 


Wendron 
Illogan 


Knight, Wheal - 


r Illogan 
1 Camborne 


Frances, Wheal - 


Camborne 




^ 


Friendship, Wheal 


Gwennap 


Lily, Wheal - 


Redruth 


Fursden, Wheal - 


Sithney 


Little North 








Downs 


Redruth 


Garlidna 


Wendron 


Longclose Mine - 


Illogan 


Gernick 


Crowan 


Louisa, Wheal 


Redruth 


Gerry, Wheal 


Camborne 


Lovell, Wheal 


Wendron 


Gilbert, Wheal - 


Redruth 


Lower Bolenowe 




Gilly Mine - 


Camborne 


Mine - - - 


Camborne 


Gine, Wheal - 


Camborne 


Lushington, Wheal 


Illogan 


Girl, Wheal - 


Gwennap 


Lydia, Wheal 


Illogan 


Gons, Wheal - 


Camborne 






Good Success Mine 


Redruth 


Maid, Wheal 


Gwennap 


Gorland, Wheal - 


Gwennap 


Margaret, Wheal - 


Gwinear 



INDEX TABLES OF THE MINES. 



299 



Mine. 
Maria, Wheal 
Mary, Wheal 
Medlyn Moor Mine 
Mengeam 
Messar, Wheal 
Metal, Wheal 
Millet, Wheal 
Montague, Wheal - 
Meant, Wheal 
Mount Carbis 
Music, Wheal 



Nancegollan - 
Nancekuke, see 

South Wheal 

Ellen - 
Nangiles 

Nelson, Wheal 

New Burra Burra - 
New Clifford - 
New Cook's Kit- 
chen - - - 
New Dolcoath 
New Wheal 

Frances 
New Hallenbeagle 
New Hendra Mine 
New Wheal Lovell 
New North Pool - 
New Rosewarne 
Mine - - - 
New Wheal Seton - 
New Treleigh 
New Trevenen 
New Trumpet Con- 
sols - - - 
New Vor and Metal 

United 
New W^ndron 

Mine - . . 
North Wheal 

Basset 
North Briggan 
North Buller 
North Wheal Busy 
North Crofty 
North Wheal Dam- 
sel - - - 
North Dolcoath - 
North Downs 
North^Wheal Fran- 
ces - - - 
North Grambler - 
North Hallen- 

beagle 
North Wheal Jane 
North Lovell Mine 
North Metal Mine 
North Wheal Metal 
North Penstruthal 
North Pool Mine - 
North Prospidnick 



Pabibh. 
Redruth 
Redruth 
Wendron 
Wendron 
Redruth 
Breage 
C rowan 
Redruth 
Sithney 
Redruth 
St. Agnes 



Crowan 



Illogan 

Kea 

j Camborne 
\ Crowan 

Kenwyn 

Gwennap 

Illogan 
Camborne 

Crowan 

Kenwyn 

Breage 

Wendron 

Illogan 

Gwlnear 
Camborne 
Redruth 
Wendron 

Wendron 

Sithney 

Wendron 
( St. Agnes 
\ Illogan 
Redruth 
Redruth 
Kenwyn 
Illogan 

Gwennap 

Camborne 

Redruth 

Illogan 
Redruth 

St. Agnes 

Kenwyn 

Wendron 

Sithnev 

Breage 

Gwennap 

Illogan 

Sithnev 



MiNB. 

North Roskear 

North Treskerby - 

North Trewan 

Mine - - - 

North Wheal Vor - 

Old Wheal Basset - 
Old Wheal Jewell - 
Old Wheal Lovell - 
Old Pool Mine 
Old Trevenen Mine 

Park an chy Mine - 
Pedn an Drea 
Peevor, Wheal 
Pellor. Wheal 

Metal 
Pendarves Consols 
Penhaldarva - 
Penhale Mine 
Penhale Wheal Vor 
Penkevii 
Pen nance Mine 
Penrose, Wheal 
Penstruthal Mine- 
Perseverance M ine 

Pink, Wheal - 

Plenty, Wheal 
Polcrebo 
Poldice Mine 
Poldory 
l^oldow^n 
Polhigey Mine 
Polgine Mine 
Polladras Mine 
Prosper, Wheal 
Providence, Wheal 
Prussia, Wheal 

Quick, Wheal 

Raven, Wheal 
Releath Mine 
Retanna Hill 
Rose, Wheal - 
Rose Ann Mine 
Roselidden Mine - 
Roskrow United - 

St. Aubyn United - 

St. Day United 
Sarah, Wheal 
Scorrier Consols - 
Scorrier Old Mine 
Seton, Wheal 
Seymour, Wheal - 
Silver Hill - 

Sithney, Wheal 
Sithney Carnnieal 
Mine - 



Pabish. 

{Camborne 
Illogan 
St. Agnes 

Redruth 
Breage 

Illogan 

Gwennap 

Wendron 

Illogan 

Wendron 

Gwennap 

Redruth 

Redruth 

Breage 
Camborne 
Kenwyn 
Breage 
Breage 
Kenwyn 
Gwennap 
Budock 
Gwennap 
Redruth 
( Gwennap 
t Redruth 
Redruth 
Crowan 
Gwennap 
Gwennap 
Breage 
Wendron 
Camborne 
Breage 
Kenwyn 
Illogan 
Redruth 

Gwennap 

Redruth 
Wendron 
Wendron 
St. Agnes 
St. Agnes 
Wendron 
St. Gluvias 

/ Gwennap 
\ Redruth 
Gwennap 
Crowan 
St. Agnes 
Kenwvn 

• 

Camborne 

Kenwyn 

Perranar- 

worthal 
Sithney 

Sithnev 



300 



MINING ECONOMICS. 



Mine. 
Sithney Wheal 

Metal 
Sithney Wheal Vop 
South Wheal 

Basset 
South Cam Brea - 
South Wheal 

CliDton 
South Condurrow - 
South Crenvep 
South Cpofty 
South Dolcoath - 
South Wheal Ellen 
South Wheal Fran- 
ces - - - 
South Garras 
South Gorland 
South Great Tol- 

gus - 
South Wheal Gren- 

ville - - - 
South Wheal Hawk 
South Lovell 
South Penstruthal 
South Roskear 
South Wheal Seton 
South Tincpoft - 
South Tolcarne 
South Wheal Tol- 

gus - 
South Wheal 

Towan 
South Tresavean - 

South Wendron 
Mine - - - 
Sparnon, Wheal; - 
Sparrow, Wheal 
Sperries, Wheal - 
Spinster, W^heal - 
Squire, Wheal 
Susan, W^heal 
Swanpool 

Tallack, Wheal - 

Tehidy, Wheal - 

Tincpoft 

Ting Tang Mine - 

Tqdpool Mine 

Tolans Mine - 
Tolcarn Mine 
Tolgullow 
Tolgus, Wheal 
Tolgus United 

Mine - - - 

Towan, Wheal 

Towan Consols 
Trannack, Wheal - 
Trefula Mine 
Trefusis, Wheal - 
Tregajorran - 
Tregonebris - 



Parish. 

Sithney 
Sithney 

lUogan 
lUogan 

G wen nap 

Camborne 

Crowan 

lUogan 

lUogan 

St. Agnes 

niogan 
Kenwyn 
G wen nap 

Redruth 

Camborne 

Redruth 

Wendron 

Gwennap 

Camborne 

Camborne 

lUogan 

Camborne 

Redruth 

St. Agnes 
Perranar- 

worthal 

{Constantino 
Wendron 
Jtedruth 
Illogan 
Kea 

G>vennap 
Gwennap 
Camborne 
Falmouth 

St. Agnes 
Illogan 
Illogan 
Gwennap 
( Gwennap 
\ Kenwyn 
Redruth 
Gwennap 
Kenwyn 
Redruth 

Redruth 
/ Illogan 
( St. Agnes 
St. Agnes 
Sithney 
Redruth 
Gwennap 
Illogan 
Wendron 



MiNB. 

Trelawney, Wheal - 
Treleigh Consols - 
Treleighwood Mine 
Trelusback Mine - 
Tremenheere 
Trenear Mine 
Trenithick Mine - 
Trenithick Wood 
Mine - - - 

Tresavean Mine - 

Treskerby Mine - 
Tretharrup - 
Trethellan - 
Trevamo Mine 
Trevensou 
Trevenen Bal 
Treviskey 
Trevoole 
Treworlis Mine 
Trewirgie Downs - 
Trumpet Consols - 
Tryphena, Wheal - 
Tywarnhayle 

Mines 



Union, Wheal 

Union Mines 
United Hills - 
United Mines 
Unity, Wheal 
Unity Wood, Wheal 
Uny, Wheal - 

Virgin, Wheal 
Vor, Wheal - 
Vraws, Wheal 
Vrea, Wheal - 
Vyvian, Wheal 

Wallis, Wheal 
Wellclose Mine 
Wellington, Wheal 
Wendron Consols - 
Wendron United 

Mines 
Wentworth, W^heal 
W^est Basset - 
West Bosprowal - 

West Wheal Buller 

West Carvannel - 
West CliflFord 
W^est Condurrow - 
West Wheal Dam- 
sel- 
West Dolcoath 
West Frances 
West Wheal Gren- 
ville - - - 
West Wheal Jane - 
West Wheal Jewell 



Parish. 
Redruth 
Redruth 
Redruth 
Stithians 
Wendron 
Wendron 
St. Agnes 

Wendron 

{Gwennap 
Redruth 
Gwennap 
Gwennap 
Gwennap 
Sithney 
Illogan 
Wendron 
Gwennap 
Crowan 
Wendron 
Redruth 
Wendron 
Camborne 

St. Agnes 

fRedmith 
\ Wendron 
Gwennap 
St. Agnes 
Gwennap 
Gwennap 
Kenwyn 
Redruth 

Gwennap 
Breage 
Sithney 
Breage 
Constant! ne 

Breage 
Wendron 
Camborne 
Wendron 

Wendron 
Redruth 
Illogan 
Gwinear 

/ Camborne 

\ Illogan 
Gwennap 
Gwennap 
Camborne 

Gwennap 

Camborne 

Illogan 

Crowan 

Kea 

Gwennap 



INDEX TABLES OF THE MINES. 



301 



MiNB. 

Weat Lovell - 
West Wheal Lush- 

ington 
West Wheal Seton 
West Wheal Towan 
West Stray Park - 
West Peevor - 

West l>oldice 



Pabibh. 

Wendron 

lUogan 

Camborne 

Illogan 

Camborne 

Redruth 

{Kenwjii 
G wen nap 



Mink. 
West Wheal Tol- 
gus - - - 
West Trefula 
West Tresavean - 
West Trethellan - 
West Wheal Virgin 
West Wheal Vor - 

Widden, Wheal - 



Parish. 
/ Illogan 
\ Redruth 
Redruth 
Gwennap 
Gwennap 
Gwennap 
Breage 
( Kca 
\ Wendron 



The following index gives the positions of the mines on this sheet. 
The Roman numerals indicate the numbers of the G-inch and 2o-inch maps 
issued by the Ordnance Survey. The letters indicate the quarter sheets 
of the Cf-inch maps, while the figures represent the numbers by which 
the 25-in.3h maps are designated. Thus Doleoath Mine LXIII., S.W. 9 
means that Dolcoath is situated on the 6-inch Ordnance map LXIII. in the 
S.W, quarter sheet ; while on the 25-inch map it is situated on sheet 
LXIII. in map No. 9. 



BREAGE, Parhhof. 

Carleen Mine, LXXV., N.E. 4. 

(or Carleen Wheal Vor.) 
Cammeal Mine, LXXV., N.E. 8. 

(and Wheal Fortune.) 
Emma, Wheal, LXXV., N.E. 8. 
Fortune, Wheal, LXXV., N.E. 8. 
Great Wheal Fortune, see Wheal 

Fortune. 
Great Wheal Vor and PoUadras, 

LXXV., N.E. 4. 
Great Wheal Metal, see Wheal 

Metal. 
Metal, Wheal, LXXV., N.E. 4. 
North Wheal Vor, see Penhale 

Wheal Vor. 
New Hendra M ine. 
North Wheal Metal, part of Wheal 

Wallis. 
Penhale Wheal Vor, LXXV., N.E. 4. 
Penhale Mine, see Penhale Wheal 

Vor. 
Pellor Wheal Metal. 
Poldown, see Great Wheal \'or. 
Polladras Mine, see Great Wheil 

Vor. 
Vrea, Wheal, part of Great Wheal 

Vor. 
Vor, Wheal, LXXV., N.E. 4. 
West Wheal Vor, see Wheal Emma. 
Wallis, Wheal, see Penhale Wheal 

Vor. 



BUDOCK, Parish or. 
Wheal Penrose, L XXVII., N.E. 3. 



CAMBORNE, Parish of , 

Bolenowe, LXIII., S.W. 14. 
Camborne Consols, LXIII., S.W. 9. 
Camborne Vean, LXIII., S.W. 9. 
Carn Camborne, LXIII., S.W. 9. 
Carnemow, see Pendarves United. 
Copper Tankard, LXIIL, N.W- . 5. 
Copper Hill, LXX., N.W. 2. 

(see also in Redruth Parish.) 
Crane and Bejawsa, LXIII., S.W\ 9. 
Crofty, Wheal, part of North Kos- 

kear. 
Dolcoath Mine, LXIII., S.W. 9. 
East Grenville, LXIII., S.W. 14. 
East Wheal Seton, LXIII., N.W. 5. 

(part of East Crofty, see in 

Illogan I'arish.) 
East Tresavean, LXIIL, S.W. 14. 
Frances, W'heal, see Camborne 

Vean. 
Gerry, Wheal, LXIIL, S.W. 9. 
Gilly Mine, LXIII., S.W. 9. 
(line. Wheal, see Polgine. 
Gons, Wheal, part of J)olcoath. 
(Jreat C^ondurrow, LXIIL, S.W. 10. 

(part of Pendarves United.) 
Grenville, Wheal, LXIIL, S.W. 14. 
Gustavus Mine, LXIIL, S.W. 9. 
Harriet, Wheal, LXIIL, S.W. 9. 
Hatchet, Wheal, LXIIL, N.W. 5. 
Kellivose Mine, LXIIL, S.W. 13. 
King Edward Mine, part of South 

Condurrow. 
Knight, Wheal, LXJIL, N.W. r>. 
Lower Bolenowe Mine, LXIIL, S.W, 

14. 
Nelson, Wheal, LXIIL, S.W. 13. 
New Dolcoath, see Polgine. 



302 



HINTNG ECONOMICS. 



New Seton, LXIIL, N.W. 5. i 

North Dolcoath, see Dolcoath. ' 

North Roskear, LXIIL, N.W. 5. 
Pendarves United (Oooaols), LXIIL, 

N.W. 5. 
Polgine Mine, LXIII., S.W. 14. 
Boskearnoweth, part of North Ros- 

kear 
Seton, Wheal, LXHL, N.W. 5. 
South CJondurrow, LXIII, S.W. 14. 
South Wheal Grenvllle, LXIII., 

S.W. 14. 
South Roskear, LXHL, N.W. 14. 
South Wheal Seton, see Gilly Mine. 
South Tolcarne. LXIII., S.W. 13. 
Susan, Wheal, LXIIL, N.W. 5. 
Tpyphena, Wheal, LXIIL, S.W. 13. 
Wellington, Wheal, see Roskear- 

noweth. 
West Wheal Buller, LXIIL, S.W. 

14. 
West Ck)ndurrow, see Kellivose and 

South Tolcarne. 
West Dolcoath, LXIIL, S.W. 13. 
West Wheal Seton, LXm., N.W. 5. 
West Stray Park, LXIIL, S.W. 9. 



CONSTANTINE, Parish of. 

South Wendron Mine, LXXVI., 

N.E. 4. 
Vy vian, Whtml, LXXVIL, N.W. 1. 



CROW AN, Parish of. 

Abraham Ckinsols, see Crenver and 

Wheal Abraham. 
Garbona Mine, LXX., S.W. 9. 
Clowance, Wheal, LXIX., N.E. 8. 
Glowance Wood Mine, LXIX., 

S.E. 12. 
Copper Bottom, LXIX., N.E. 8. 
Courtis, Wheal, LXIX., S.E. 12. 
Crenver and Wheal Abraham, 

LXIX., S.E. 12. 
Crowan and Wendron Mine, see 

Parish of Wendron. 
Drym Mine, see Crenver and Wheal 

Abraham. 
East Wheal Abraham. 
Gernick, LXX., N.W. 
Great Drym Consols, LXIX., 

S.E. 12. 
Hangman's Barrow, LXX., N.W. 
Hender, see Copper Bottom. 
Millet. Wheal, LXIX., S.E. 16. 
NancegoUan. LXX., S.W. 13. 
New Wheal Frances. 
Nelson, Wheal, LXIIL, S.W. 13. 
Polcrebo Downs, LXX., S.W. 9. 
Rosewame United, LXIX., N.E. 4. 
Sarah, Wheal, LXIX., S E. 12. 



South Crenver. 
Trevoole, LXX., N.W. 1. 
West Wheal Grenville, LXX^ 
N.W. 1. 



FALMOUTH, Pariah of. 

Swanpool Mine, LXXL, S.E. 15. 

GWENNAP, Parish of. 

Ale and Cakes Mine, see United 

Mines. 
Andrew, Wheal, LXIV., N.W. 2. 
Beauchamp, Wheal, LXm., S.E. 12. 
Bell and Lannarth, LXHL, S.E. 11. 
BeUvean Mine, LXIIL, S.E. 12. 
Bissoe Pool, LXIV., N.W. a 
Brewer, Wheal, LXHL, S.E. 12. 
Britannia, Wheal, LXIV., N.W. 5. 
Carharrack, LXIIL, N.E. 8. 
Carqueen Mine, LXIII., N.E. 4. 
Cathedral Mine, LXIU., N.E. 8. 
Carvaniiel Mine, LXIII., S.E. 12. 
Chance, Wheal, LVI., S.E. 16. 
Clifford, Wheal, LXIV., N;W. 5. 
Clifford Amalgamated, see United 

Mines and Great Consolidated 

Mines. 
Clinton, Wheal, LXHL, N.E. 4. 
Comford, Wheal, LXIH., S.E. 12. 
Cupboard Hill Mines, see United 

Mines. 
Cusvey, part of Great Consolidated 

Tilines 
Damsel, Wheal, LXIIL, N.E. 8. 
East Ale and Cakes, see United 

East Wheal Basset, LXIU., S.E. 11. 

East Wheal Buller, see Wheal 
Beauchamn. 

East Wheal Damsel, LXm., N.E. 8. 

East Wheal Spamon, see Wheal 
Grambler. 

East Wheal Virgin, part of Great 
Consolidated Mines. 

Edgcumbe, Wheal, LXUI., S.B. 12. 

Fortune, Wheal, see Great Con- 
solidated Mines. 

Friendship, see Wheal Andrew. 

Girl, Wheal, part of Great Con- 
solidated Mine. 

Gorland, Wheal, LXHL, N.E. 4. 
(part of St. Day United.) 

Grambler, Wheal, LXIII, N.E. 8. 
(and St. Aubyn.) 

Great Consolidated Mines, LXFV., 
N.W. 1. 

Henry, Wheal, LXIV., N.W. 1. 

Hope, Wheal, see West Wheal 
Damsel. 

Jewell, Wheal, LXn\, N.W. I. 



INDEX TABLES OF THE MINEa 



303 



Maid, Wheal, LXIV., N.W. 1. 

(part of St. Day United.) 
Moyle, Wheal, see Ting Tang. 
New Clifford. 
North Damsel, see West Wheal 

Jewell 
North Penstruthal, LXIIL, N.K. 4. 
Old Wheal Jewell, part of St. Day 

United. 
Park nn Chy Mine, LXllI., N.E. 4. 
Pennance Mine, LXIII., N.E. 8. 
Penstruthal Mine, LXIII., S.E. 12. 
Pink, Wheal, LXIII., N.E. 4. 
Poldice Mine, LXIV., N.W. 1. 

(part of St. Day United.) 
Poldory Mine, part of United 

Mines. 
Quick, Wheal, seo Old Wheal 

Jewell 
River Colnv Mine, LVI., S.K. 12. 
St Aubvn United, LXIIL, N.E. 4. 
St. Dav United, LXW., N.W. 1. 
South Wheal Clinton, LXIIL, 

S.E. 12. 
South Gorland, see West Wheal 

Jewell 
South Penstruthal, LXIIL, S.E. 12. 
Spinster, Wheal, see Wheal 

Damsel. 
Squire, Wheal, LXIIL, N.E. 8. 
Ting Tang Mine, LXIIL, N.E. 8. 
Todpool Mine, LXIV., N.W. 1. 
Toleam Mine, LXIIL, N.E. 4. 
Trefusis, Wheal, LXIIL, N E. 7. 
Tresavean Mine, LXIII., N.E. 12. 

(and Tretharnip.) 
Treskerby Mine, L\a., S.E. 16. 
Tret harm p, see Tresavean. 
Trethellan Mine, LXIIL, S.E. 12. 
Treviskey Mine, LXIIL, S.E. 12. 
Union Mine, see Wheal Andrew. 
United Mines, LXIV., N.W. T). 
Unity, Wheal, LXIV., N.E., 1. 

(part of St. Day United.) 
Virgin, Wheal, part of Great Con- 
solidated Mines. 
West Carvannel. 
West Clifford, see Ting Tang 

Mines. 
West Wheal Damsel, LXIII., N.E. 8. 
West Wheal Jewell, LXIIL, N.E. 4. 
West Poldice, LXIIL, N.E. 4. 
West Tresavean, LXIIL, S.E. 12. 
West Trethellan. 
West Wheal Virgin, part of Great 

Consolidated Mines (in Tolcarne.) 
West Poldice, LXIIL, N.E. 4. 



GWINEAli, Parish of. 

Annie, Wheal, LXIL, S.E. 16. 
Brook, Wheal, LXIL, S.E. 16. 
Crack Crowder Mine, LXIL, S.E. 16. 



£ast Rosewame, LXII., S.E. 16. 
Gwinear Consols, see Rosewame 

United. 
Margaret, Wheal, LXIL, S.E. 16. 
New Rosewame Mine, LXIX., 

N.E. 4. (part of Rosewame 

United.) 
Rosewame Consols, LXIX., N.E. 4. 
Rosewame United, LXIX., N.E. 4. 
West Bosprowal, LXIL, S.E. 16. 



ILLOGAN, Parish of. 

Agar, Wheal, LXIIL. N.W. 6. 
Barncoose Mine, LXIIL, N.W. 6. 
Basset, Wheal, LXIIL, S.E. 11. 
Carnarthen, see South Dolcoath. 
Carn Brea, LXIIL, N.W. 6. 
Camkie Mine, see Wheal Basset. 
Clarence, Wheal, LVL, N.E. 7. 
Cook's Kitchen, LXIIL, S.W. 10. 
Druid, Wheal, part of Cam Brea. 
Duchy, Wheal, LVL, S.W. 10. 
Dudnance, part of South Crofty. 
East Wheal Basset, LXIIL, S.E. 11. 
East Wheal Crofty, LXIIL, N.W. 6. 
East l»ool Mine, LXIIL, N.W. 6. 
East Wheal Seton, see Emily 

Henrietta. 
Elizabeth, Wheal, see Great North 

TolfTUS. 

Ellen Wheal, LVL, S.E. 11. 
Emily Henrietta, LXIIL, N.W. 6. 
Fannv, Wheal, LXIIL, N.W. 6. 
Fire, Wheal, LVL, S.W. 10. 
Forest Mine, LXIIL, S.W. 14. 
Fortune, Wheal, see Wheal Agar. 
Fox Hole, LXIIL, S.W. 10. 
(".reat North Tolgus, LVL, S.W. 14. 
(ireat St. Vincent, LVL, S.W. 10. 
GrilHs, LXIIL, S.W. 14. 
Illogan (part of Tincroft), see 

Wheal Providence. 
Knight, Wheal, LXIIL, N.W. 5. 
Lushington, Wheal, LVL, N.W. 6. 
Lydia, Wheal, LVL, N.E. 7. 
Longclose, part of South Crofty. 
Nancekuke, see Wheal Clarence. 
New Cook's Kitchen, LXIIL, N.W. 6. 
New North Pool, LXIIL, N.W. 6. 
North Wheal Basset, LXIIL, 

S F 11 

North Wheal Crofty, LXIIL, N.W. 

6. (part of East Crofty.) 
North Wheal Frances, LXIIL, 

S.W. 10. 
North Pool Mine, LXIIL, N.W. 6. 
North Roskear, LXIIL, N.W. 5. 
Old Wheal Basset, see South Wheal 

Ellen. 
Old Pool Mine, part of North 

Crofty. 



304 



MINING ECONOMICS. 



Providence, Wheal, LXIIL, S.W. 10. 
Robarts, Wheal, LVI., S.W. 14. 
South Wheal Basset, LXIIL, S.E.11. 
South Cam Brea, LXIIL, N.E, 7. 
South Orofty, LXIH., N.W. 6. 

(part of East Crofty.) 
South Dolcoath, LXIIL, S.W. 10. 
South Wheal Ellen, see St. Agnes 

x^apish 
South Wheal Frances, LXUL, 

S.W. 10. 
South Tincpoft, LXIU., S.W. 10. 
Sparrow, Wheal, LVI., S.E. 11. 
Tehidy, Wheal, LXHI., N.W. 6. 
Tincpoft, LXIIL, N.W. 6. 
Towan, Wheal, LVI., N.E. 7. 
Tregajorran, LXIIL, N.W. 6. 
Trevenson, part of South Croftv. 
West Basset Mine, LXIIL, S.W. 10. 
West BuUer, LXIIL, S.W. 14. 
West Wheal Frances, LXIIL, 

S.W. 10. 
West Wheal Lushington, LVI., 

S.W. 10. 
West Wheal Tolgus, LXIIL N.W. 2. 
West Wheal Towan, see Wheal 

Lushington. 



KEA, Pariah of. 

Andrew, Wheal, LXIV., N.W. 2. 
Baddern, (Baddon), Wheal, LXIV., 

N.W. 2. 
Baldhu, LXIV., N.W. 2. 
Falmouth, Wheal, LVIL, S.W. 14. 
Falmouth and Sperries, Wheal. 

LVn., S.W. 14. 
East Wheal Falmouth, LVII, 

S.W. 14. 
Great Wheal Baddern, see Wheal 

Baddern (Baddon). 
Hope, Wheal, LXIV., N.W. 2. 
Jane, Wheal, LXIV., N.W. 2. 
Nangiles Mine, LXIV., N.W. 2. 
Sperries, Wheal, LXIV., N.W. 2. 
West Wheal Jane, LXIV., N.W. 2. 
Widden, Wheal, LXIV., N.W. 2. 



KENWYN, Parish of. 

Ann, see Wheal Seymour. 
Boscawon Mine, LVL, S.R. 16. 

(part of Great Wheal Busy.) 
Burra Burra Mine, LVIL, S.W. 9. 
Busy, Wheal, see Great Wheal 

Busy. 

Chacewacer Mines, see Great Wheal 
Busy. 

Creegbraws Mine, LXIV., N.W. 1. 
(and Ponkovil.) 



Daniell, Wheal, L\1L, S.W. 13. 
East Wheal Chance, LVI., S.E. 16. 
East Wheal Falmouth, LVU., 

S.W. 14. 
Great Wheal Busy, LVII., S.W. 13. 
Hallenbeagle Mine, see Boscawen, 

part of Great Wheal Busy. 
Henry, Wheal, LXIV., N.W. 1. 
Killifreth Mine, LVI., S.E. 16. 
New Burra Burra. 
New Hallenbeagle, see Boscawen. 
North Wheal Busy, LVI., 8.E. 12. 
North Wheal Jane, LVH., S.E. 15. 
Penhaldarva. 
Penkevil, see Creegbraws. 
Prosper, Wheal, LXIV., N.W. 1. 
Scorrier Old Mine, LVI., S.E. 16. 
Seymour, Wheal, LVH., S.W. 13. 
South Garras. 

Todpool Mine, LXIV., N.W. 1. 
Tolgullow, see Unity Wood and 

West Poldice. 
Union, see Wheal Unity Wood. 
Unity Wood, Wheal, LVIL, S.W. 13. 
West Poldice, LXIH., N.E. 4. 



MYLOR, Parish of, 

Clinton, Wheal, LXXL, S.E. 

PERRANAR WORTH A L, 
Parish of 

Silver Hill 

South Tresavean, LXIV. 

REDRUTH, Pariah of 

Barberry, Wheal, see W^heal 
Plenty. 

Boys, Wheal, LVL, S.E. 16. 

Briggan, Wheal, LVL, S.E. 16. 

Buckets, Wheal, LXUL, N.E. 7. 

Buller, Wheal, LXIIL, S.Pl 11. 

Burncoose, Wheal, LXIIL, N.K. 7. 

Captain, Wheal, LXIIL, N.E. 7. 

Cardrew Consols, see Wheal 
Prussia 

Chance, Wheal, LVL, S.E. 16. 

Clyjah and Wentworth, see Perse- 
verance Mine. 

Copper Hill, part of Wheal Buller. 

Cupid, Wheal, LXIIL, N.E. 4. 

Derrick, Wheal, LXIIL, N.E. 3. 

Dopps Mine, see Pedn an Drea. 

East Wheal Basset, LXIIL, S.W. 11. 

East Cam Brea, LXIIL, N.E. 7. 

East Wheal Tolgus, LXIIL, N.E. 3. 

Gilbert, Wheal, LXIIL, N.E. 3. 

Good Success Mine, see Treleigh 
Consols. 



MINING ECONOMICS. 



305 



Great North Downs, LVII. S.B. 16 
Great South Tolgus, LXIIL, N.E. 7. 

(North Buller.) 
Harmony, Wheal, LXIII., N.E. 3. 
Hawk, VVhe.al, LVI., S.E. If). 
Lily, Wheal. I.XIII., N.E. 4. 
Little North Downs. 
Louisa, Wheal. 
Mary, Wheal, LVI., S.E. 1."). 
Maria, Wheal, see Treleif:h Consols. 
Messar, Wheal, see Great North 

Downs. 
Montagne, Wheal, LXIIL, N.E. 3. 
Mount Carbis, LXIIL, N.E. 7. 
New Treleigh, see Treleigh Consols. 
North Briggan, LVL, S.E. 1(>. 
North Buller, see (ireat South 

Tolgus. 
North Wheal Buller, LXIIL, N.K. 7. 
North Downs, LVL, S.E. 15. 
North Grambler. 

North Trewan Mine, LVL, S.K. 16. 
Pedn an Drea, LXIIL, N.E. 7. 
Peevor, Wheal, LVL, S.E. 15. 
Perseverance Mine, LXIIL, N.E. 7. 
Pink, Wheal, LXIIL, N.E. L 
Plenty, Wheal, LVL, S.E. 15. 
Prussia, Wheal, LVL, S.E. 15. 
Raven, Wheal, LXIIL, N.W. 2. 
St. Aubvn United, LXIIL, N.E. 4. 
South Great Tolgus, LXIIL, N.E. 7. 
South Wheal Hawk, LVI., S.E. 10. 
South Wheal Tolgus, LXIIL, N.E. 3. 
Sparnon, Wheal, LXIIL, N.E. 7. 
Tehidy, Wheal, LXIIL, N.W. 0. 
Tolans Mine, see East Wheal 

Tolgus. 
Tolgus, Wheal, LXIIL, N.E. 3. 
Tolgus United Mine, LXIIL, N.E 3. 
Trefula Mine, see Wheal Lilv. 
Trelawney, Wheal, LXIIL, N.E. 8. 
Treleigh Consols, LVL, S.E. 15. 
Treleighwood Mine, LXIIL, N.E. 3. 
Tresavean Mine, LXIIL, S.E. 11. 
Trewirgie Downs, see Wheal Buller. 
Union. Wheal, LXIIL, N.E. 3. 
Uny, Wheal, LXIIL, N.E. 7. 
Wentworth, see Perseverance. 
West Peevor, LVL, S.E. 15. 
West Wheal Tolgus, LXIIL, N.W. G 
West Trefula, LXIIL, N.E. 3. 



East Treskerby. (?) 
East Wheal Towan, L\l.. N.E. 7. 
Ellen, Wheal, LVL, S.E. 11. 
Fancy, Wheal, LVL, N.E. 7. 
Music, Wheal, now Wheal Ellen. 
North Wheal Basset, LVL, S.E. 11. 
North Ilallenbeagle, LVL, N.E. 8. 
North Treskerby, LVL, S.E. 10. 
Uose, Wheal, LVL, S.E. 10. 
Kose Ann Mine, LVL, N.E. 7. 
Scorrier Coiisi)ls, LVL, S.E. 12. 
South Wheal Ellen, LVL, S.E. 11. 
South Wheal Towan, LVL, N.E. 7. 
Tallack, Wheal, LVL, N.E. 7. 
Towan Consols, LVL, N.E. 7, 
Towan, Wheal, LVL, N.E. 7. 
Trenithick Mine, LVL, N.E. 8. 
Tywainhayle Mine, LVL, N.E. 7. 
United Hills, LVL, N.E. 7. 



ST. A ONES, Pai^h of. 

Banns, Wheal, L\l., N.E. 7. 
Charles, Wheal, LVL, N.E. 7. 
Cornwall, LVIL, N.W. 5. 
Concord, see North Treskerby. 
East Wheal Ellen. (?) 
East Downs Mine, L\'L, S.E. 10. 
East Wheal Music, LVL, N.E. 8. 



ST. GLUVIAS, Pariah of. 

Koskrow United, LXIV., S.W. E. 



SITHJSEY, Parish of. 

Bramble, Wheal, LXX., S.W\ 13. 

Christopher, LXX., S.W. 13. 

East Wheal Vor. (?) 

East Wheal Fortune, see Sithney 
\Vheal Vor. 

Fursden, Whe^l, LXX., S.W. 14. 

Harriet, Wheal, LXXVL, N.W. 2. 

Mount, Wheal, LXXVL, N.W. 2. 

New Vor and Metal United. 

North Metal Mine, LXXV., N.E. 4. 

North Prospidnick, LXX., S.W. 13. 

Peverill, Wheal, see Wheal Furs- 
den. 

Polcrebo Downs, LXX., S.W. 9. 

Prospidnick Mine, LXX., S.W. 13. 

Sithney, Wheal, LXXVL, N.W. 5. 

Sithney Carnmeal Mine, LXXM., 
N.W. 1. 

Sithney, Wheal Metal, LXXV., 

N.E. 4. 
Sithney Wheal Vor. (?) 
Trannack, Wheal, LXXM., N.W. 2. 
Trevarno Mine, LXXVL, N.W. 1. 
Vraws, Wheal, see North Prospid- 
nick Mine. 



STITHIAXS, Parish of 

Trelusback Mine, LXIIL, S.E. 10. 



306 



HtNING ISCONOMICS. 



WENDRON, Parish of, 

Ann, Wheal, LXXM., N.W. 2. 

(or Trumpet United.) 
Bal Ding, LXX,, S.K. 12. 
Basset and Grylls, Wheal LXX^ 

S.E. 11. 
Buller and Basset United Mine, 

LXIIL, S.E. 15. 
Balmynheer Mine, LXX., N.E. 7. 
Bodillv Consols, LXX., S.W. 14. 
Calvadnack Mine, LXX., N.E. 7. 
Cudy, Wheal, LXX., S.E. 15. 
Crowan and Wendron Mine, for- 
merly Releath Mine. 
Combellaek Mine, LXXVL, N.E. 3. 
Dream, Wheal, LXXVL, N.W. 2. 
Duchy, Wheal, see Old Wheal 

Lovell. 
East Trumpet Mine, LXXVL, 

N.W. 2. 
East Wheal Lovell, LXX., S.E. 15. 
Enys, Wheal, LXX., S.K. 11. 
Foster, Wheal, LXX., S.E. 11. 
Garlidna, LXX., S.K. 11. 
Great Wheal Lovell,LXXVI.,N.E.3. 
Great East Lovell. 
Lovell, Wheal, LXXVL, N.E. 3. 
Medlyn Moor Mine, LXX., S.E. 11. 
Mengeivrn, LXXVL, N.E. 3. 
New Wheal Lovell, LXXVL, N.E. 3. 
New Trcvenen. 
New Trumpet Consols, LXXVI., 

N.E. 3. 



New Wendron. 

North Lovell Mine, LXX., S.E. IL 

Old Wheal Lovell. 

Old Trevenen Mine, LXXVL 

N.W. 2. 
Polengrean, we Garlidna. 
Volhigey Mine, LXX., N.E. 7. 
Vorkellis United, see Basset and 

Grylls. 
Vorkellis Moor, LXX., S.E. 15. 
lieleath Mine or Crowan and Wen- 
dron Mine, LXX., S.W. 10. 
lietanna HiU Mine, LXX., S.E. 12. 
Roselidden Mine, LXXM., N.W. 2. 
South Lovell. 
South Wendron Mine, LXX\T. 

N.E. 4. 
Tregonebris see East Wheal Lovell. 
Tremenheere Mine, LXXVL, 

N.W. 6. 
Trenithick Wood Mine, LXXVI., 

N.W. 6. 
Trevenen Bal, LXXVL, N.W. 2. 
Trevenen Mine, LXXVL, N.K 3. 
Trenear Mine, LXX., S.E. 15. 
Treworlis Mine, LXXVL, N.W. 6. 
Trumpet Consols Mine, LXXVI., 

N.W. 2. 
W^Uclose Mine, LXXVI., N.W. 2. 
Wendron Consols, LXX., S.E. 15. 
Wendron United Mines, LXX., 

N E. 7 
Wid'den, Wheal, LXXVL, N.W. 2. 
West LoveU. 



Total Yield of Tin and Copper in Cornwall (Fig. 65.) 

The following statistical table has been compiled from numer- 
ous publications containing details of the annual output of ore, 
yield of metal, amount realised by sales, produce, standard price, 
and price of metal on market, but it should be remarked that the 
figures given by some of the authorities who have made indepen- 
dent estimates for certain years do not agree. This is probably 
owing to the same general difficulties as were experienced in 
estimating the total yield of the individual mines, namely, that 
the private sales were not formerly divulged in the way that the 
amounts sold by public ticketing were. The table, which up to 
1882 is largely from Hunt's " British Mining," may be regarded 
as fairly reliable, and since 1882 as quite trustworthy. In its 
preparation the following are the principal works that have been 
consulted : — 

Pryce. — ^^ Mineralogia OormihiensisJ* 1778. Annual output of copper 
ore from 1720 to 1775, Prior to 1700 the amounts are only 
glveu in round figures (p. 14). 



Total yield of tis ani> copper. 







q- 


1 










*, 






'. ; 








-4 

1- 




^ 


^T— ' 


-J 






1 '■ 








3? 












-' 


/- 


-^L = 









< 




" 


> 










--'J' 


;l 


<" 
















•=M 


2^ 








^ 


V 














4 


-■' 1 


^ 


>- 


'■ 














'Lv-^ 




c 


7 








> 


- 


— 








'■"22 


■ 


Y 




i 




—- — 






-— 




4 










>. 








'.. 


\ 














\ 


',^ 










\ 


"S 














3 


J 


^ 


3 

k 










?? 














L 








I 


z 












c 


> 






> 





307 

■3 



1? 






308 MINTNG ECONOMICS. 

Gilbert, C. S. -" History of Cornwall," vol. ii., 1817, p. 707. Annual 
output of tin (in blocks'" and tons) from 1750 to 1816. 

Trans. Roy, Geol. Soc. Com., vol. ii., 1822, vol. iii., 1828, vol. iv., 1832. 
Yield of copper ore and copper, &c., from 1771 to 1832. 

Grylls, H.— " A Synopsis of Mining from 1729 to 1833." Copper ore, 
copper, &c., from 1729 to 1832. Blocks of tin from 1750 to 
1832. 

Lemon, Sir Charles. — Journ, Stat. Soc, vol. i., 1838, p. 70. 

Courtney, J. S.— *'A Treatise on the Statistics of Cornwall," Rep, Roy. 
Com. Poly. Soc, 1838, p. 81. Tonnage of tin from 1750. 

Came, J .— " Statistics of the Tin Mines of Cornwall and of the Con- 
sumption of Tin," Jotirn. Stat, fifoc., voL ii., 1839. Tonnage 
from 1750 to 1837. 

De la Beche, H. T.— " Geological Keport of Cornwall, Devon, and West 
Somerset," 1839, p. S)6. Copper ore and copper, &c., from 1771 
to 1838. 

** Mineral Statistics," Afem. Geol. Surv.^ 1848 to 1881. Copper ore, 
copper, black tin, metallic tin, standard and market prices, &c 

Grylls, H.— ''Annual Mining Sheet," No. 21, 1852. Copper ore, &c, 
from 1833 to 1852. 

Hont, R. — ''British Mining," 1884. Copper ore, copper, black tin, 
metallic tin, standard and market prices, &c., from 1726 to 1882. 
*' Mines and Quarries, General Keport and Statistics " (Home Office), 
part iii., Output. All products and prices from 1882 to 1905. 

In the statistical table the price of copper has been given in two ways : 
(1) the price which the miner received for each ton of copper in the ore 
sold, and (2) the price of copper on the London market. In a third 
column the standard for copper is also given, and this is the sum which 
governed the money transactions between the smelter and the miner, and 
was not a sum actually paid. The term has been explained by Percy, 
Lemon, Kickard, Phillips and Darlington, Salmon, Hunt, and others. 

In the early days of copper mining the smelters generally made 
contracts with the miners for definite periods and undertook to buy the 
ore at a certain rato, which was determined by a standard price pre- 
viously agreed on by the miner and smelter, and this was usually the 
selling price of tough cake copper. The standard having been settled, 
the sum which the miner received for the copper in the ore was at this 
rate; but he paid back to the smelter a certain sum known as the 
*' returning charges," generally £2 15s. per ton of ore. These '' return- 
ing charges " were generally in excess of the actual cost of smelting, so 
that this was one source of profit to the smelter. The miner farther 
gave him an extra cwt. in the ton to cover losses in carriage, and he 
also made allowance for moisture. Another source of profit to the 
smelter arose from the fact that the percentage of copper shown by the 
assayer*s results was generally lower than the percentage procurable in 
smelting.! As there was a certain *' returning charge " due to the 
smelter on every ton of ore, it paid him better to buy low-grade ores 
than rich ones, as the proportional cost of extraction per ton of metalllo 
copper to the total amount of the returning charges was less. It was to 
the smelter's advantage to keep the standard as low as possible and to 
the miner's interest to raise it. 

♦ A block weighs from 360 to 380 lbs. There are, roughly, about 61 blocks 
in a ton. The weight of a block lias, however, varied from time to time. In 
130o it was I2i\ lbs. ; in 1577, 308 lbs. ; in 1587, 324 lbs. ; in 1597, 335 lbs. ; 
ill 1607 it was 346 lbs. Sir John MacLean, Ji?wr». Roy. Imt. Corn,, 1874, p. 187. 

t *' The amount of copper obtainable by smelting British ores is about ^ or 
4 i)er cent, more than the amount calculated from the dry assay. Thus, in the 
case of an ore containing 5 per cent, of metal by dry assay, the actual yield 
has been taken as 5i i>er cent."— ♦'General Statistics," part iii.. Output, p. 200. 



TOTAL YIELD OP TIN AND COPPER. 



309 



As competition increased and the market price of copper became fixed 
by auction at public tlcketings, the importance of the ^ standard ** was dimin- 
ished, but for the sake of comparison it was calculated, after the sales, 
from the market price of copper and the produce of the ore. 

In early days, therefore, the standard ^as an amount agreed upon by the 
miner and smelter, and determined the amount the miner was to receive for 
the ore. In later times it ceased to have any value beyond affording a 
means of making comparison, and instead of being a sum agreed on, it was 
an amount calculated from the selling price of the copper. 



Method of calculating the price of 
CJopper in early days. 



Tough cake copper sold at £120 

per ton. (Has nothing to do with 

the estimation.) 
The standard agreed on = 118. 
Suppose 140 tons of ore containing 

8 per cent, of copper on sale. 
Returning charge ^ 140 x i*2 15 ^ 

£385. 
Amount of copper in ore, viz., 

8 per cent. ^ 11*2 tons. 
Value of copper in ore, according to 

standard = 11*2 x £118 
= £1,3210 
.'. Amount received by miner = 

£l,321-6-£385 = £936*6 

= £67 per ton. 



Method of calculating the standard 
in later times.* 



140 tons of ore containing8 per cent. 
copi)er, sold at public ticketing, 
for £936-6 
The standard is calculated as 

follows : — 
The returning charge = 140 x £2 15s. 
= £385. 
.-. £936-6 -f- £385 = £1,321*6 
.-. £1^21'6. _ 

11-2 
-^ £118 per ton (standard). 



The smelter, in estimating the value of the ore before making his offer to 
the miner, generally consults a table prepared from actual practice, showing 
the cost of working the ore, which guides him in his calculation. The 
following is an abbreviated example of a page in the smelter's note 
book : — 



Cost of working 5 per cent, copper ore is 

10 



ft 
»♦ 
♦» 

»» 
>» 
»» 



»» 
»» 
»» 



15 

20 
20 
30 
30 
50 
50 
70 



»» 
«» 

>» 

•» 



If 






if calcined, is 

if not calcined, is 6 19 2 

if calcined, is 6 9 2 

if not calcined, is 5 9 2 

if calcined, is 4 15 8 

if not calcined, is 4 3 8 

(precipitate) 3 15 5 



£ s. d. 

16 19 10 per ton of copper. 

11 3 6 

9 4 10 

8 9 2 



M 



y* 



n 

»» 
yy 
yy 

)♦ 



1» 

»» 



yy 



With regard to tin, the ** standard is the amount paid by the smelter per 
cwt. of metal contained in the ore, as calculated from the results of an assay 
by the dry method, after deduction of Ij from the produce per 20 (OJ per 
cent.) for returning charges. By an old trade custom there is also a de- 
duction on the weight of the parcel of tin ore of 3 lbs. per cwt. It is 
customary to reckon the price to the nearest eighth of a pound sterling 
above or below the calculated price."t 



idard price should nol be confused with the tonn standard copper, 
ding to Brown and Turnbull, ♦' A Century of Copper." 1900, con- 
cent, of copper. Toujrh copper containing 99.\ per cent, bee also 



* The Stan 
which, accord 
tains 96 per cent, ot copper 
Part III., "General Statistics." 

t "General Statistics,'' part iii., Output, 



3:o 



MINING ECONOMICS. 









f* J 
















Value of 


I)aU». 


Black Metal- 
Tin, lie Tin. 

1 


rrice per 
Ton Metal- 
lic Tin. 


Copper 
Ore. 


Metallic 
Copper. 


Standard. 


Copper at 

Mine, 
per Ton. 


1 

i 


Tons. 


Tuns. 


! £ 


s. 


a. 


Tons. 
Cornwall. 


Tons. 


£ 


s. 


d. 


£ 8. d. 


1726 


• tt • 


. • • 


1 


• • • 




5,000 


• • • 




t • • 




• • • 


1727 


• • • 


• • • 




• • • 




6,700 


• • • 




1 • • 








1728 


• • • 


... 


1 

1 


• • • 




6,800 


• • • 




• • 








1720 


• • • 


• • • 




• • • 




6,870 


• • • 




» • • 








17:30 


• • • 


• • • 


1 


• • • 




j 6,900 


• • • 




k • • 








1731 


• • • 


1 

• • • 




• • • 




7,000 


• • ft 




1 • • 








1732 


■ • • 


• • • 


1 


• • • 




7,290 


• • 




» • • 








173:i 


• • • 


• • • 




• • • 




7,000 


• • • 




>• • 








17:i4 


• • • 


• • • 


1 


• t • 




6,000 


• • • 




• • 








1735 


• • • 


• • • 


1 


• • • 




5,240 


• • • 




• • 








1736 


• 1 1 


• • • 




« • ■ 




8,000 


• • • 




• • 








1737 


• • • 


• • • 




• • • 




9,000 


• t • 




» • • 








1738 


• • • 


• • • 




• • • 




10,000 


• • • 




• • 






1.. _ 


1739 


... 


• • • 




• • • 




11,000 


• • • 




• • 








1740 


• • • 


• • • 




• • • 




5,000 


• • • 




• • 








1741 


• • ■ 


• • • 




• • • 




5,500 , 


• • • 




• • 








1742 


• • • 


... 




• • • 




6,050 


• • • 




» • • 








1743 


• • • 


... 




• • • 




7,040 


• • • 




1 • • 








1744 


• • • 


... 




• • • 




7,230 


• • • 




» • • 








1745 


••• 


... 




• • • 




6,700 


• • • 




»■ • 








1740 


» • • 


... 




• • • 




7,000 


• • • 




1 • • 








1747 , 


• • • 


... 




• • • 




4,900 


... 




» • • 








1748 


• • • 


• • • 




• • • 




(),000 


• • • 




» • • 








1749 


• • • 


• • • 




• • • 




1 7,200 


• • • 




1 • • 








1750 


• • • 


2,870 


04 


17 





9,400 


• • • 




■ • • 








1751 


• • • 


2,273 


05 


2 


() 


11,000 


• « • 




• • • 








1752 


• • • 


2,550 


07 


2 





12,050 


... 




b • • 








1753 1 


• • • 


2,510 


08 


d 





13,000 


• • • 




1 • • 








1754 


• • • 


2,724 


07 


17 


(5 


14,000 


• • • 




k • • 








1755 


••• 


2,757 


07 








14,240 


f 


< 


1 tt • 








1750 


••• 


2,774 


62 


12 





1(),000 


• • • 




t • 




1 




1757 ' 


• • • 


2,752 


59 


5 





17,000 


• • • 




k • • 








1758 1 


• • • 


2,720 


5() 


5 





15,000 


• • • 




» « • 








1759 , 


• • • 


2,()37 


50 








10,700 


• • • 




k • • 








1700 


• • • 


2,717 


50 








15,780 


• • • 




k ■ ■ 








1701 


• • • 


2,395 


59 


17 


() 


17,004 


• • • 




k • • 








1702 


• • • 


2,58-1 


04 


15 





16,05-1 


... 


, 


* • • 








1703 


• t • 


2,730 


08 


17 


6 


17,898 


• • • 




1 • • 








1704 


• • • 


2,018 


(59 








21,489 


• • • 




• • 








1705 


• • • 


2,757 


09 








10,774 


• • • 




• • 








1700 


• • • 


3,055 


09 








21,251 


• • • 




• • 








1707 


• • • 


2,850 


■ 09 








18.502 


« • • 




• • 








17(>8 


• • • 


2,0(>7 


09 








23,071 


• • ■ 




• • 








1709 


• • • 


2,898 


09 








2f),055 


• •• 




• • 








1770 


• • • 


2,977 


06 


10 





30,770 


• • • 




• ■ 








1771 


• • • 


2,823 


05 








27,89(') 


3,347 


81 








{EftimateJ) 


1772 


• • • 


3,1.59 


()3 


5 





27,9(>5 


3,556 


81 








53 


1773 


• • • 


2,852 


5^^! 








27,r>03 


3,320 


70 








45 


1774 


• • • 


2,458 


52 


10 





30,254 


3,630 


08 








44 


1775 


• • • 


2,019 


00 








2iV.MM) 


3,59() ) 


78 








53 


1770 


• • • 


2,()52 


59 


l.'» 





29,4:i3 


3,5:^2 


79 








54 


1777 


• • • 


2,770 


59 


10 





28,210 


3,380 


77 








52 


1778 


• • • 


2,515 


()0 


10 





2l,7(M> , 


2.9()5 


72 





o| 


49 


1779 


• • • 


2,()78 


()() 








31,115 


3,734 


73 








48 


1780 


• • • 


2/.l2(' 


01 


.5 





24,433 ; 


2,932 


83 








58 


1781 


• • • 


2,010 ' 


01 


.5 





28,749 > 


3,450 


77 








52 


1782 


1 
• • • 1 


2,510 


70 








28,122 ' 


3,375 


70 








45 










TOTAL YIELD OF TIN 


AI«D CX)PPER, 






3 


J1 


1 

Date. 


Black 
Tin. 


Metal- 
lic Tin. 


Price per 
Ton Metal- 
lic Tip 


Copper 
Ore. 


Metallic 
Copper. 


Standard. 


Value of 

Copper at 

Mine, 


1 






• A V Jk A T 


»«■ 


1 


1 






per 


Ton. 




Tods. 


Tons. 


£ s. 


d. 


Tons. Tons. 


£, s. 


d. 


£ 


s. 


d. 




1 
1 








Cornwall. 


' 








1783 


• •• i 


2,570 


70 





35,799 4,296 i 76 





51 








1784 


• • • 


2,685 


70 10 





36,601 4,392 72 





47 








1785 


• • • 


2,885 


72 





36,959 4,434 71 





46 








1786 


• • • 


3,399 


72 





39,895 4,787^ 75 





50 








1787 


• • • 


3 204 


72 





38,047 4,500 


f>7 





43 








1788 


• • • 


3,352 


m 10 





31,541 3,800 


57 





40 








1789 


• • • 


3,405 


62 10 





:^3,281 >| 


3,900 


iui 





47 








1790 


• ft • 


3,193 


72 10 





34,700 


4,100 












1791 


• • • 


3,470 


79 





36,500 


4,250 


' h'stimai 


led. 








1792 


• • • 


3,809 


92 10 





;«,3oo 


4,450 








1793 


• • • 


3,202 


98 





40,(KK) > 4,650 












1794 


... 


3,351 


95 10 





42,816 4,920 


88 





67 








1795 


• • • 


3.440 


93 





43,589 5,070 


87 





64 








1796 


• • • 


3,061 


m 10 





43,313 5,120 J 93 





70 








1797 


• • • 


3,240 


97 





47,iK)9 5,201 9(5 





72 








1798 


• • • 


2,820 


94 





51,358 5,600 






• • • 




1799 


• « • 


2,862 


97 





51,273 4,923 121 





95 








1800 


• • • 


2,522 


101 





55 981 5,187 133 3 





10C> 








1801 


« • • 


2,328 


105 





50,611 5,2()7 117 5 





90 








1802 


• • • 


2,627 


108 10 





53,937 5,228 110 18 





84 








1803 


• • • 


2,914 


109 





()0,506 5,()15 122 





95 








1804 


• • • 


2,993 


JW) 





()4,()37 5,375 l.i6 5 





10() 








1805 


• • • 


2,742 


112 10 





78,452 6,2.11 1(>9 16 





138 








1806 


• • • 


2,855 


120 10 





79,269 6,8f')3 138 5 





106 








1807 


• • • 


2,4 2() 


117 10 





71694 6,7 1() 120 





91 








1808 


• • • 


2,330 


114 





67,867 6,7t>5 100 17 





74 








1809 


• • • 


2,508 


122 





76,215 


6,821 113 12 





113 








1810 


• • • 


2,006 


157 





66,048 5,(>82 132 5 





100 








1811 


• • • 


2,384 


141 10 





66,786 6,141 120 10 





90 








1812 


• • • 


2,373 


128 





71,547 ': 6,720 111 1 





82 








1813 


• •• 


2,324 


131 





74,017 6,918 115 7 





86 








1814 


• • • 


2,611 


l.')<» 1() 





74,322 6,3()9 130 12 





99 








1815 


• • • 


2,1M1 


140 10 





78,48:5 6,525 117 16 





85 








1816 


• • • 


3,348 


114 10 





77,334 6,()97 98 13 





68 








1817 


• • • 


4,120 


93 10 





76,701 , 6,498 108 10 





76 












Corn wall and 


















1) 


ovoii. 






1 










1818 


• • • 


4,06<*) 


84 15 





86,174 


6,849 134 15 





104 








1819 


• • • 


3,315 


75 5 





88,736 


6,804 127 10 





92 








1820 


• • • 


2,990 


73 5 





91,473 7,508 113 15 





80 








1821 


• • • 


3,373 


75 13 


4 


98,426 8,515 103 





71 








1822 


• • • 


3,278 


95 10 





104,523 9,U0 KM 





74 








182:^ 


• • • 


4 213 


94 15 





95,750 7,928 109 18 





78 








1824 


• • • 


5,005 


88 





<)9,700 7,S21 110 





99 








1825 


• • • 


4,358 


91 6 


8 


107,454 8,22(> 114 





97 








1826 


• • • 


4,()03 


77 





117,308 9,02() 123 3 





72 








1827 


» • • 


5,555 


76 





126,710 10,311 |106 1 





75 








1828 


• • • 


4,931 


73 5 





130,366 9,921 


112 7 





72 








1829 


• • • 


4,434 


74 





1 124,502 9,656 


109 14 





73 








1830 


• • • 


4,444 


73 15 





133,904 j 10,748 106 5 





1 69 








1831 


• • • 


4,300 


73 10 





144,402 12,044 100 I) 





68 








1832 


• ■ • 


4.:i23 


72 15 





137,357 11947 100 





72 








1833 


• • • 


4,()()r) 


72 15 





138,.'H)0 11,191 111 





74 








la-vt 


• • • 


3,9S<) 


78 





n.3 2'.)6 11,225 111 





79 








1835 


• t • 


4 21^8 


, 91 





l.-)0,617 12,270 10(; 11 





73 








1836 


• • • 


4 054 


109 10 





1 10,981 


11647 




115 12 





82 









312 



MINING ECONOMICS. 



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315 



APPENDIX. 



Bibliographical. 

List of Whitincjs Kkfkkkin(j to thk Gfx>lu(jy of thk DrsTRicr.* 

1758. BORL.VSE. Kev. W.— The Natural History of C\>rn\vall. 

1778. Pkyce, W. — Miueraloqia Coruubiensis, 

1787. Ki^i»KOTii, M. II.- Ohservatious relatives to the Mineral and 

Chemical History of the Fossils of Cornwall. 
1797, 1802. R-\^HLKi<;n, I*.— Si>ecimens of British Minerals, selected fpom 

the Cabinet of I*. K., with general descriptions of each 

article. 
1800. Tayu)R. J.— Sketch of thellistory of Mining in Devon and Cornwall. 

Phil, Mdfj,, vol. v., p. 1^57. 
1811. Bekgkk, Dr. il. F.- Observations on the Physical Structure of 

Devonshire and Cornwall. Tr, (ieul. Soc, vol. i., p. 93. 
Cahew» K. C.— Survey of Cornwall. (KVprinted from 1st work in 

1602.) 
1814. LvrtoNs, Kev. D. and S. — Mdfjmi Jiritami'mt vol. iii. 

MacCill()ch» Dr. J. On the (Granite Tors of Cornwall. Tr. Geol, 

Soc.y vol. il., p. ()0. 
PuiLui*s» W. -On the Veins of Cornwall. Tr, iieoL Soc, vol. ii., 

p. 110. 
A Description of the Oxvd of Tin, the production of Corn- 
wall. Tr. Grul. Soc, vol. ii.* p. 3:iG. 
1816. On the Oxyd of Uranium, the production of Cornwall &c. 

Tr, iieo], .Soc, vol. iii., p. 112. 

1817. GiLBKHT. C. S. -An Historical Survey of the County of Cornwall, 

p. 208. 
Williams, .1. (.Junr.). Accouni of some Remarkable Disturbances 
in the Veins of the Mine called Wheal IVevor, in Cornwall. 
Tr, Geol. Sor.y vol. iv. 

1818. Cahne, J.— On Klvan Courses. Tr. Roij. Gcul. Sue. Cor/i., vol. i., 

pp. 97, 211. 
On the Discovery of Silver in the Mineji of Cornwall. Ibid.f 

p. 1J8. 
Hawkins, Sir C. Observations on Ciold found in Tin-Stream Works 

in Cornwall. i/>i(f.,- p. 23;"). 
HirLi-:, J.— Cavern in Doleoath Mine. Ibid., p. 225. 

1819. Thomas, K. -Report on a Survey of the Mining District of Corn- 

wall from CJiact^water to (\imborne. 
1822. Cakne, J.— On the Relativ<^ Age of the Veins of Cornwall. Tr, Roy. 
(icol, Soc. Cuj'M., p. 19. 

Hawkins, .7. On the Stratified Deposits of Tin SUme called Floors, 
and on the DilTusion of Tin Stone* through the Mass of some 
Primitive Rocks. Tr, l\<nj, (icol. Soc, Corn., vol. ii., p. 2^). 

On thv Nomenclature of the Cornish Rocks and the Legiti- 
mate InfereiKM's to be Drawn from them. Tr. Roy, (icol. Soc 
Corn.y vol. ii.. p. 22."). 

-On the lnt<*i*section of Lodes in the Direction of their Dip 



or Underlie. Ibid.y p. 232. 
1824. Dhkw, S.— The History of Cornwall. 

DcFJiENOY, 1*. A., and K. Dh Bkaimont. -Sur le gisement, 
I'exploitation et le traitmeiit des minerais d'etain et de cuivre 
du Cornouailles. Ann. dea Mincsy T. i.\., p. 827. 

* De la Boclie puMisluMl a l»il»lioi;ra})liy in liis Ri'iiort on Devon, Cornwall, 
and West Somersot, in \s:\\). Mr. W. W'hitakcr brou«,'!it ihc list tlowii to 1874, 
while Mr. J. B. Scrivonor has hri(lLr«'tl llic ic:M» extentlin.L,' to HHKi. It is mainly 
from these sources that the acj-ompanyin'^ KiMioi^rAphy has been comjaled by 
Mr. D. A. MacAlisier. Many other works published l)otli at home and al)roa<l 
refer to this ar<?a, but their incnrin'ralioM would uuuei'o.-sirily increase a li^r 
?vlready suflieiently e«Miipendiou--. 



316 APPENDIX, 

1826. DuFRBNOY, P. A., aod E. Db Beaumont,— Sar la constitntion 

geognostiqtie et les gites metallif^res da Ck>moDaille8 et du 
Devonshire. Ann, Sci, Nat.^ vol. vii., p. 195. 

1827. Caknb, J.— On the Period of the Commencement of Copper Minin^f 

in Cornwall ; and on the Improvements which have been made 
in Mining. Tr, Roy, Geol. Soc, Com., p. 35. 

On the Singular State of some Ancient Coins lately 

found in the Sands of Hayle ; and on the Evidence De- 
ducible from them Relative to the Period of the Earliest 
Deposition of Sand on the Northern Coast of Cornwall, ibid., 
p. 136. 

On the Granite of the Western Part of Cornwall. Ibid., 



p. 208. 
DuFRENOY, p. A., and K De Beaumont. — ^Voyage Metallurgique en 

Angleterre. 
Hen WOOD, W. J.— On a Singular Exudation of Gas in the Union 

Mines. Tr, Roy, Geol, Soc, Corn., p. 203. 
— Notice of some Circumstances Connected with the Heave of 

a Copper Lode by a Flucan Vein, in the Consolidated Mines, 

Gwennap. Ibid., p. 329. 
MicHELL, J.— Notice of the Analysis of Copper Ore found at Wheal 

Falmouth, which appears very much like the Buntkupfererz of 

Werner. Ibid,, p. 338. 
PENDARVFis, K. W. W.-Noticc of the Native Copper of Condurrow 

Mine. Ibid., p. 333. 
Thomas, U.— History of Falmouth. 

1828. Carne, J. — Copper Mining in Cornwall. Tr. Roy. Geol. Soc. Com^ 

vol. iii. 
Pendarveh, E. W. W.— Tr. Roy. Geol, Soc. Corn., vol. iii. (Native 
Copper in Condurrow Mine). 

1829. Fox, R. W.— Some liemarks on Mineral Veins. Phil. Mag.^ ser. ii., 

vol. vi., p. 17. 
Henwood, W. J.— a Summary of Experiments recently made 

on the Temperature of Mines. Edin. Journ. of Set., vol. x., 

p. 234. 
Oeynhauhen, C. vox, and H. von Decoen.— On the Junction of 

the Granite and the Killas Kocks of Cornwall. Phil. Mag.^ 

ser. ii., vol. v., pp. 161, 241. 
Taylor, J.— Records of Mining. 

1830. Brayley, E. W.— On the Probable Connection of Rock Basins, in 

Form and Situation, with an Internal Concretionary Stracture 
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318 



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320 APPENDIX. 

1869. Barnett, a. K.— A Ramble through Wheal Buller, West Basset, and 

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1892. CoujNs, J. H. — Origin and Development of Ore Deposits in the 

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pRKSTwini, ,1. — The Raised Beaches and *• Head " or Rubble-Drift 
of tlie South of Knprland : Their Relation to the Valley Drifts 
and to the (ilacial Period ; and on a Late })ost-Glacial Sub- 
mergence. Quart. Journ. (ieoL Soc, vol. xlvlii., p. 163. 



BIBLIOORAPHT. S23 

1892. UsgHBB, W. A. E. — Devon and Ck>rni8h Oranites. Geol. Mag., p. 167. 

1893. Ck>LLiNS, J. H.- Origin and Development of Ore Deposits in the 

West of England. Jotim. Roy. hist, CortUt p. 327. 

VoGT, J. H. L.— Bildung von Erz lagerstatten durch differentiations- 
processe in basisclien eruptivmagniata. Zeit. /. Prdkt, Geol,^ 
pp. 4, 125, 257. 

Worth, R. N. — On the Age and History of the Granites of Devon 
and Cornwall. Tr. Roy. Geol. Soc. C'o))i., vol. xi., p. 480. 
1804. Dalmkr, K.— Der Altcnberg-Graiipener Zinnerzlagerstiitten Dis- 
trict. Zeit. f. Prakt. (icol.y p. 313. 

VoGT, J. H. L.— Beitrage Ziir gcnetischcn classification der durch 
raagmatische clilTerentiationproccsse and durch pneumatolyse 
enstandenen erzvorkonimen, p. 381. Zeit /. Prakt. Geol. 

1895. Collins, .1. H. -On the Origin and Development of Ore Deposits in 

the West of England. Journ. Roy. Inst. Corn.y p. 49. 
VoGT, J. H. L. — Pueuinatolytische bczw. pneumatohydetogene 

Producte. Znin.s/cm gang^ruppe^ p. 145.; Apatite gang- 

gnippe, pp. 3(57, 444, 405. Zeit. /. J^rakt. Geol. 
WuNscH, F. A. — On Raised Beaches. Tv. Roy. Geol. Soc. Corn., 

vol. xi., p. ()05. 

1896. Fox, H. -The Radiolarian Cherts of Cornwall. Tv. Roy. Geol. Soc, 

vol. xii., p. 39. 
Phillips, J. A. and II. Louis.— A Treatise on Ore Deposits (2nd 

Edition). 
StuI'Hbns, F. J.— Some Mining and Geological Notes on the Crowan 

and Gwinear District. ()4f/t Ann. Rep. of the Roy. Corn. Poly. 

Soc,, p. 44. 
On Certain Rocks in the Falmouth District. Roy. Corn. 

Poly. Soc. Rep., 1890. 
Thomas, R. A. — Notes on Cornish Minos. Ibid., p. 89. 

1897. Collins, J. H.— Cornish Minos and Tin Miners, ijoth Afin. Rep. 

Roy. Corn. Poly, Soc, p. 04. 

MiEKS,'lI. A.- On some British Psoudomorphs. Jonru. Alin, Soc, 
vol. xi., p. 2(>^. 

RoBEKTS, S.- The Submarine Forest Bod of Maon Perth, near Fal- 
mouth. Tr. Roy. Geol. Soc. Corn., vol. xii. 

Stephens, F. J. — On the Occurrence of Radiolarian Cherts and 
other Rocks botwoon Trefusis Point and Poriryn. (j^th Anii. 
Rep. Roy. Corn. Poly. Soc, p. KM. 

On ail Altered Ash Bod at Ponryn. Tr. Roy. Geol. Soc 

Corn., vol. xii. 

1898. Collins, J. II.— On the Origin and Dovolopmont of Ore Deposits in 

the West of England. Journ. Roy. Inat. Corn., p. 283. 
Fox, H. — The Wryan Liinestonos and other Liniostonos associated 

with Radiolarian Cherts in South Cornwall. Tr. Roy. Geol. 

Soc. Corn., vol. xii. 
IIambley, W. — Notes on Cornish Mining. OG//t Ann. Rep. Roy. 

Corn. Poly. Soc, p. 85. 
Hill, J. B.- The Killas between Gerrans Bay and Carrick Roads. 

Summary of Progress of Geological Survey for 1897. pp. 78-79. 
1899, The Lower Pabeozoic Rocks of the South of Scotland 

viewed in connection with the Lower I^aboozoic Rocks of Corn- 
wall. Tr. Roy. Geol. Soc Corn., vol. xii. 
The Killas botw(»on Falmouth andllolford River. Summary 

of Progress of Geological Survey for 1898, pp. 97-103. 
Stkpuens, F. J.— Recent Discoveries of Gold in West Cornwall, 

Tr. Roy. Geol. Soc Corn., vol. xii. 
1900. Hill, J. B.- The Killas of the Falmouth district, and of Nare Point 

(Meneago). Summarv of Progress of Geological Survey for 

1899, pp. 8S-95, ir>7-i(>8. 
PoLLAKi), Dr. \V. Analysis of clay from the I-'al est u;iry. Sunnuaiy 

of Progress of (Geological Survey lor 1899. p. 17.'). 
Stephkns, F. J.— Alluvial Deposits in the Lower Portion of the Red 

River Valley, near Camborne. Tr. Roy. Geol. Soc. Corii., 

vol. xii. 

\ '2 



324 APPENDIX. 

1901. Hill, J. B. — On some G^logioal Straotores in West Cornwall. Tr. 
Roy. Geol, Soc Oom,, vol. xii. 

The Greenstones and Mica Traps of the Falmouth district. — 

The Carnmenellis granite. Summary of Progress of Geological 
Survey for 1900, pp. 61-64, 106-1 10. 

1902. -The Plutonic and other Intrusive Rocks of West Cornwall 

in their Relation to the Mineral Ores. Tr. Boy. Geol, »Soc. 
Corn.j vol. xii. 

The Pillow Lavas of Gorran Haven. — The Carnmenellis 

Granite and Metamorphic Aureole.— The Elvans of the Fal- 
mouth and Gwennap district. Summary of Progress of Geological 
Survey for 1901, pp. 18, 22-26. 

1903. Flbtt, J. S. — Note on some Brecoiated Stanniferous Veinstones from 

Cornwall. Summary of Progress of the Geological Survey fop 

1902, pp. 154-159. 
Dixon, E. E. L. — The Killas of Illogan, &o. Summary of Progress of 

the Geological Survey for 1902, p. 25. 
Hill, J. B. -The Killas of Truro and Chacewater. — The Carn- 
menellis Granite. Summary of Progress of the Geological 

Survey for 1902, pp. 25, 30, 31, 38. 
MacAlistbu, D. a. — The Mineral Lodes of the Camborne district. 

Summar}*^ of Progress of the Geological Survey for 1902, pp. 39, 

40. 
Colli N8, J. H. — Lead-Bearing Lodes of the West. Tr. Roy. Geol. 

Soc. Corn., vol. xii., part viii., p. 683. 

1904. MacAliutbr, D. A. — A Cross Section and some Notes on the Tin and 

Copper Deposits of Camborne. Tr, Roy. Geol. Soc. Corn. 

vol. xiL, part ix. 
Grbbn, Upfibld. — Notes on the Correlation of some Cornish Beds 

with the Gedinnien of Continental Europe. Cteol. Mag.^ 1904, 

p. 403. 
Flbtt, Dr. J. S.— First notes on the Petrography of Western 

Cornwall. Summary df Progress of Geological Survey for 1903, 

pp. 150-102. 
Hill, J. B. — The Greenstones of Camborne. — ^The granites of Carn- 
menellis, Carn Brea, and Cam Marth. Summary of Progress 

of Geological Survey for 1903, pp. 23-26. 
MacAlistbe, D. a. — Vertical Distribution of the Mineral Ores in 

the Camborne district. Summary of Progress of Geological 

Survey for 1903, pp. 26-28. 

1905. Fawns, S.— The Tin Deposits of the World. 

MacAlibtbb, D. a.— Notes on Ore-dressing in Cornwall. Summary 
of Progress of Geological Survey for 1904, pp. 28, 153-163. 

1906. Hill, J. B. — The unconformity between the Devonian and Lower 

Palffiozoics of Cornwall. Summary of Progress of Geological 

Survey for 1905. 
Geology of Cornwall, Victoria County History (in the 

press). 
—The older and newer Palseozoics of West Cornwall, 

Geo(. Afog., May 1906, pp. 206-216. 



INDEX. 



Abandoned mines, 220—254. 
Abraham, Crenver and Sarah mine, 

description of, 225, 226. 
Acme pevolvinf? table, 266. 
Active mines, 207—220. 
Apir, Wheal, depth of granite, 117. 

and ?]ast Pool, Wheal, 219, 220. 

Allport and Phillips, Messrs., 41. 
Alluvia, freshwater, 101--10:J; 

marine, 15, 100, 101 ; rate of 

fxrowth, 103. 
Alluvium, 1.5. 
Amphibolite, 42, 43. 
Analysis of siliceous schist, 3(5 ; 

clay, 111 ; el van, 74 ; pranite, 60 ; 

jDrreenatone, 45, 51 ; killas, 85, 86 ; 

limestone, 38 ; mica trap, 77. 
Andalusite hornfels, 84 ; slate, 82, 

83. 
Andes] te, 42, 45, 47. 
Andn^w, Wheal, lodes of, 228. 
Ann, Wheal, descr'ption, 220. 
Antimony, occurrence of, 179. 
Antron, 12. 

Aplite, 5:^, 55, 62, 63, 72, 73. 
Area and physical features, 1—12. 
Ardevora, 6, 30, 100, 104. 
Argentiferous galena, 181, 182 ; out- 
put from mines individually, 290 — 

295. 
Arsenic, output from mines, 290 - 

295. 

• works, 112. 

Arwenack, 25. 
Ashfield, 80. 

Baddern, WMieal. See Baddon. 
Baddon. Wheal, 111. 
Backs of lodes, tin in, 190. 
Baldhu, 7, 10, 14, 28, 29, 65, 97, 105. 
Balmynheer Mine, ore bunch in, 

1(54 ; produce, 221. 
Banded veinstone, V,^, 
Baripper, 70. 

Barncoose, 95 ; mine, 221. 
Barnett, A. K., 74, 76. 
Barrow, G., 90, 93. 
Bartle revolving table, 2iM), 
Ba^>ins, Upland, 12. 
Basset, Wheal, notes on, 207 ; car- 

bonas, 164 ; ore bunches, 163 ; 

dip of granite, 115 ; output since 

1851, 261, 262. 
and Grylls, Wheal, lodes of, 

221. 
Beacon Hill, 70. 
Bearing of lodes, 148; relation to 

productiveness, 186. 



Beauchamp, Wheal, notes on, 222 ; 
dip of granite, 115. 

and Buller, Wheal, notes on, 

Bejawsa and Crane Mine, lodes of, 

225. 
BellMine, note on, 222. 
Bellevu(», 42. 
Bibliograf)hy relating to geology 

of the district, 315 324 ; mines, 

207 ; mineral statistics of Corn- 
wall, 274, 30(), 308. 
Bismuth, distribution of, 179 ; out- 

j)ut from East Pool and Dolcoath, 

291. 
Bissoe, 91. 97. 112. 
Bissom, 110. 
Black tin, output from individual 

mines, 275—289 : output from 

Cornwall, 310- 314. 
Black water, 35. 
Block of tin, weight of, 308. 
Blown sand, 15, 103. 
Blue Pool, 88. 
Boase, Dr. H. S., 54. 
Bolenowe Crofts, 71, 110. 

Moor, 110. 

Bolitho, 53. 57. 

Boscolletb, 76, 79, 80. 

Bosloake, 62, 106. 

Boswvn, 53, 57. 

Boys,*^ Wheal, lodes in, 222. 

Boyers Cellars, 47. 

Breadth of lodes, 153. 

Breage, 29 ; mining district, 175 ; 

mines in parish of, 301. 
Breccia in Consols Mine, 166. 
Brecciated veinstones, 131^ 133; 

microscopic structures, 155, 156. 
Brecciation, of killas, 25 ; lodes, 

132 ; origin of. 132. 
Bricks, manufacture of, HI. 
Brill, 107. 
Buddie, concentrates from, 270, 

272 ; convex and concave, 266. 
liudock, 13, 52, 53, 60, 107 ; mines 

in parish of, 301. 
Buller, Wheal, note on, 222 ; dip of 

granite, 115. 
and Beauchamp, Wheal, notes 

on, 222. 

Downs, 13, 71. 

Building stone, 106—110, 
Bunch, detlnition of, 161. 
Burncoose, 44. 
Burnthouse, 42, 43, 106. 
Buss table, 2()5. 
Busy, Wheal, lodes of, 223. 



326 



INDEX. 



Calciuer, concentrates from, 270, 
272. 

Calcite, 40. 

Calvadnack, 11, 106. 

Camborne, 11, 12, 13, 14, 28, 29, 47, 
48, 49, 50. 51, 64, 70, 73, 105, 110, 
111 ; bearing and width of cross 
courses, 158 ; strike of lodes, 149 ; 
oxidation of lodes, 194 ; underlie 
of lodes, 150 ; mines in parish of, 
301. 302. 
— Beacon, 62, 63. 

Mines, relation of copper ore 

to granite, 173 ; of tin ore, 171. 

V^ean, dip of granite, 114; 

granite ridge in, 117. 

Capel, 136 ; Pryce, Carne, Phillips, 
Thomas, Foster, Collins, on, 136, 
137. 

Oarbonas, 164 ; in Wheal Basset, 
164. 

Carbonate zone in lodes, 188. 

Carclew, 13, 28, 47, 179. 

Card re w Downs Mine, lodes of, 222. 

Carharrack, 111 ; mine, lodes of, 
222. 

Carleen Mine, note on, 222. 

Carn Arthen, 106, 108. 

Carn Brea, 1, 13, 53, 62, 81, 95, 100, 
108, 109. 

Castle, 109. 

granite, 62, 63 ; analysis 

of, 63 ; jointing, 62, 63 ; subter- 
ranean features, 113, 114. 

Mine, veinstone of, 155. 

mining region, relation of 

ores to granite, 174. 

and Tincroft United 

Mines, notes on, 208, 210; ver- 
tical distribution of ores in, 175. 

Carn Camborne, 51. 

Carne, J., 95, 113 ; on cross courses, 
158, 159. 

Carnemough Mine, note on, 235. 

Cam Marth, 1, 13, 53, 63, 64, 81, 
106, 108. 

granite, 63, 64 ; struc- 
tures of, 64 ; subterranean fea- 
tures, 113, 115. 

mining district, relation 

of ores to granite, 174. 

Carnmenellis, 1, 13, 52, 71, 81, 106. 

granite, 53 — 60 ; subterranean 

features, 114, 115. 

mining region, relation of ores 

to granite, 174, 175; strike of 
lodes, I'tO. 

Carnon, 97, 98, 103. See Lower 
Carnou. 

Downs, 32, 111. 

Stream, 112. 

Valley, 87, 101. 

Carnsew, 108. 

Car queen Mine, cross course in, 
222. 



Carrlne Common, 14, 28. 

Carvannel Downs, 12. 

Carwynnen, 107. 

Oarilek Roads, 5, 9, 14, 15, 21, 33, 
34, 76, 78, 92, 94, 101. 

Cassiterite, 194, 195. See Tin. 

Caverns, 90 ; formation of, 33, 34. 

Cavities in lodes. See Vugs. 

Caunter lodes, 140—143, 205—207 ; 
In Dolcoath ; Cook*s Eitchon, 140 ; 
Carn Brea, Camborne Vean, West 
Roskear, Great North Seton, 
South Wheal Seton, Wheal Setou, 
North Wheal Crofty, South Orofty , 
141 ; Wheal Crofty, Gustavus, 
Tehidy, East Pool, Park an 
Bowan, Wheal Harriet, Great 
Condurrow, West Basset, Wheal 
Basset, Wheal Gorland, South 
Wheal Hawk, East Wheal Chance, 
Wheal Basset and Grylls, Crenver 
and Wheal Abraham, 142 ; Her- 
land, North Downs, United Mines, 
Killifreth, 143. Origin of, 143 ; 
strike of, 149 ; Pryce, W., Thomas 
R., Carne, J., De la Beche, [Sir] 
H. T., on, 140 ; Henwood, W. J., on, 
143. 

Chacewater, 14, 17, 32, 35, 64, 69, 
97, 109. 

Mine, lodes of, 223 ; copper 

ore in el van, 166. 

Channals Creek, 76, 78. 

Charles, Wheal, notes on, 223. 

Chemistry of secondary deposition 
In lodes, 191—194; BischoflP, G., 
on, 194 ; Evans, J. W., 193 ; Pen- 
rose, R. A. F., 193 ; Van Hlse, C. H., 
192, 193 ; Vogt, J. H. L., 193 ; 
Weed, W. H., 192. 

Chert, 17, 18,29, 37. 

China clay. 111. 

stone, 110. 

Chute of ore, 161 ; in Cam Brea, 
Cook*s Kitchen, Dolcoath, Great 
Flat lode. Wheal Uny, 163. 

Chynhale, 62. 

Chywoon, 56. 

Circulating waters, 187 — 189 ; deep- 
seated, 187 ; Emmons, S. F., on, 
188 ; Van Hise. C. R., on, 187. 

Classification of lodes, 143; Prvce, 
W., on, 143 ; Carne, J., 143, 140. 

Clays, 110, 111 ; analysis of. 111. 

Cleavage, 20, 22,33-35. 

Climate, 12. 

Clinton, Wheal, 26, 45, 92 ; notes on, 
223. 

Clowance, 73, 85, 105. 

Coast line, 1. 

Cobalt, distribution of, 179; output 
from East Pool, 290. 

Cober River, 2. 

Valley, 7, 11, 13, 107. 

Coldwind, 67. 



INDEX. 



327 



Collins, J. H., 19, 36, 38, 45, 47, 65, 
74, 75, 76, 78, 79, 80, 86, 109, 143 ; 
on brecciated veinstones, 133 ; on 
veinstone in Dolcoath, 217, East 
Wheal Lovell, 227 ; Wheal For- 
tune, 228 ; Cam Brea Mine, 210 ; 
Dolcoath main lode, 214 ; gold in 
lodes, 180; minerals, 109, 200, 
203. 

Comby veinstone, 131. 

Comford, 67. 

Concentrates from Frue Vanners, 
tin in, 272. 

Concentration of ores, in prepara- 
tion for market, 267, 269 ; second- 
ary in lodes by natural processes, 
189, 190. 

Conglomerate, 39; in lodes, 131. 
See Crush conglomerate. 

Consolidated Mines, lodes of, 223 — 
225 ; copper ore in breccia, 1(56. 

Constantino, mines in parish of, 
302. 

Contact metaraorphisni, 81 — 86. 

Contortion of slate, 33. 

Cook's Kitchen Mine, description of, 
211, 212; cross-course in, ir)8 ; 
dip of granite, 114, 115; ore 
chute, 163; vertical distril)n- 
tiou of ores, 175 ; width of lodes, 
163. 

Coombe, 14. 

Copper standard. 308, 309. 

and tin lodes. Sec Lodes. 

ore, vertical distribution in 

lodes, 175 — 178 ; output from mines 
individually, 275—289. 

Cornwall, output of tin and copper 
ore since 1726, 310—314 ; curve 
of output of tin and copper for, 

:w. 

Cosawes, 84. 

Cosawes Pascoe, 42. 

Coswinsawsan, 13, 74. 

Country rock, alteration bv lodes, 

134, 139. 
County cross-course, 159. 
Course of ore, 161. 
Cowlands Creek, 7(5, 79. 
Crane and Bejawsa Mi no, notes on, 

225. 
Crawfurth Smith, 223. 
Crazing mill, 26:^. 
Creegbrose. 32, 110. 
Creek Stephen, 33. 
Crelly, 73, 109. 
Crenver, Wheal Abraham and Sarah, 

notes on, 225, 226. 
Croft Michell, 57, 71, 107. 
Crofty Mines, notes on, 212, 213; 

vortical distribution of ores in, 

176, 177. 
Crop tin, 271, 272. 
Crosbv, \V. O., on origin of jointing, 

148.' 



Cross-courses, 36, 87, 157—160 ; age 
of, 9 ; direction, 158 ; width, 158 ; 
nature and composition, 157 — 160 ; 
underlie, 157 ; metalliferous min- 
erals in, 160 ; in mines, 158, 159, 
1(50; as boundaries, 158, 159; re- 
lation to jointing, 158. 

Crowan, 7, 12, 13, 28, 52, 60, 85, 88, 
106 ; mines in parish of, 302. 

Beacon, 11, 53, 57. 

Crush conglomerates, 21, 22, 27 ; in 
lodes, i:^. 

Curve showing output of tin and 
copper from Cornwall since 1726, 
307. 

Cupid, Wheal, note on. 226. 



Damsel, Wheal, lodes of. 226. 

Daniell, Wheal, lodes of, 226. 

Daniell's Point, 98. 

Decomposition of lodes, 187. 

Degradation of clilTs, (5. 

De la Beclie, [Sir] H. T., 3, 29, 32, 
43, 44, 51, 54, 74, 90, 95, 96, 98 ; 
n'ferences to, 113. 

DiMHidation, (). 

Deposition of ores, order of, 182 — 
lvS4 ; local conditions affecting, 
181 ; secondary, 187. 

Derrick, Wheal, lodes of, 226. 

Devis, 44, 110. 

Devonian, base of, 17. 

rocks, 39, 40. 

Devoran, 10 1. 

Diabase, 50. 

Dilleugher, 201. 

Dip, 34; of killas, 23; granite 
114-117; angle of, 114. 

Direction of lodes, 148. 

Distribution of the ores, 171 ; tin 
and copper in lodes, 175—178; 
linear, of mines, 205 — 207. 

Dixon, E. K. L., 32, 33, 50, 73, 74, 
85. 

Dolcoath, description of, 214 —219 ; 
caunter lode, 140 ; cross-course, 
158; dip of granite in, 114; dis- 
tril)ution of tin in, 171, and of 
cop[)er, 173; dressing of ore .at, 
272 273; 'Miorses " in, 139; 
structure of lodes, 134, 135 ; ore 
chutes in, 1(53 ; outi)nt of tin and 
copper since 1845, 2(51, 262 ; ridge 
of granite in, 117; veinstone of, 
155 ; vertical arrangement of the 
ores, 175; width of lodes, 153. 
l^\ ; length of main lode, 153. 

Double deck tabl(\ 2(56. 

Dressing of (in ore, 2():2 273; ](^s^ 
\\\ 2(V.) ; note on, 273. 

• niacliiniM'v, 2()l 2(»9. 

Duchv olVice, 259. 

i:)urnl*>-pit, 26(5. 

Duncan, Dr, P. M., 30. 



328 



INDEX. 



Earthenware, manufacture of, 111. 
East Ale and Cakes Mine, note on, 

226. 
Wheal Basset, depth of granite 

in, 114. 

Cam Brea. dip of granite, 114. 

Wheal Chance, note on, 226. 

\^ heal Damsel, notes on, 226, 



227. 

— Downs Mine, note on, 226. 
Wheal Lovell, granite of, 59 ; 



pipe of ore in, 165; veinstone, 
227 ; character of lodes in, 132. 
Pool, 47 ; output since 1845, 



261, 262 ; depth of granite, 117 ; 
granite ridge, 117 ; vertical dis- 
tribution of ores, 176, 177; irre- 
gular ore mass in, 166. 
— Pool and Wheal Agar United, 
description of, 219, 220. 

Wheal Soton and Emily Hen- 



rietta, notes on, 277. 
— Wheal Sparnon, hxles of, 227. 
Tresavean, note on, 227. 



Eathorne, 107. 

Economics, general, 104 — 112 ; 
mining, 258 — 314. 

Elvans, 7, 14, 43, 44, 48, 64—74 ; 
analysis of, 74 ; intersections of, 
74 ; jointing, 66, 72 ; microscopic 
characters of, 66 — 73 ; relation 
to granite, 65 ; siliciilcation of, 
07, 69, 70 ; pinitiferous, 69, 70 ; 
schorlaceous, 68 ; texture of, 65 ; 
trend, 65; weathering, 65; in 
mines, 119—123; subterranean 
occurrence, 118—123; remarks on 
occurrence, 120 — 123; underlie, 
119—123; width, 65, 118—123; 
faulted by lodes, 147; connection 
with genesis of ores, 182 ; relation 
to ore bunches, 184. 

Emilv Henrietta and East Wheal 
Seton, notes on, 227. 

Enys, 27, 66, 109. 

— Wheal, veinstone of, 155. 

Extraction, magmatic, 107. 

Eiosion, 5. 

Estuaries, 1, 5 ; silting of, 6, 100, 
101. 

Fal basin, 2. 

river, 33, 34, 100, 103. 

valley of, 10. 

Falmouth, 10, 12, 13, 14, 15, 30, 92, 

94, 99, 100, 102, 111; mines in 

parish of, 302. 

Bav, 90,91. 

Harl)our. 92, KM). 

Series. M, 17, 2SJ—'Xi. 

Wlieal, notes on, 228. 

Kancv, Wheal, note on, 228. 
Faults, 31, 32, 33, 34, 30, 40, 87. 
Faulting in lodes, 140 ; Moissenet, 

M. L., on, 187, 



Feock, 14, 31. 

Fine-tin, 272. 

Flat lodes, 150. 

Flett, Dr. J. S., 28, 38, 40, 46, 57, 73, 

83,155; on brecoiated veinstones, 

133; order of arrival of tin and 

copper, 183. 
" Floors," ore in, 166. 
Flucans, 157. See Oross-ooorsesi. 
Fluorspar, output from mines, 291, 

293,294,295. 
Flushing, 13, 26, 45, 46, 83, 94, 110. 
Folding, 21, 23, 31, 32, 33, 36; pitch 

of, 35. 
Footnotes, abbreviation of, 113. 
Forepit, 263. 

Forest, Wheal, lode in, 228. 
Formations and their distribation, 

13—15. 
Fortune, Wheal, note on, 228. 
Foster [Sir], C. Le Neve, 113 ; on 

East Wheal Lovell, 132 ; leaders, 

136. 
Fox, Howard, 18, 29, 37, 80, 91, 93. 

R. W.. 91. 

Fractures, 22 ; direction of, 87. 
Frames, revolving, 266; ragging, 

267. 
Frecheville, R. J., on Dolcoath, 214, 

215; Carn Brea, 210; Cook*s 

Kitchen, 211. 
Freeman & Co., Messrs. John, 54, 

60, 108, 110. 
Freestone, 109, 110. 
Friendship, Wheal, lodes of, 228. 
Fr()gpool, 66, 67. 
Frue vanner, 205 ; concentratcjs 

from, 270, 272 ; tailings from, 271. 
Fumerole action, 168. 

(;aloua, 181, 182; output from 
mines individually, 290-— 295. 

Garby, .1., 113. 

Garlidna Mine, note on, 228. 

Garnetiferous p:reenstGne, 48—51. 

Garras Mine, descripton of, 230. 

Genesis of the ores, 167 ; of silver- 
lead ores, 170 ; connection with 
granite, 167 ; Beaumont, Elie de, 
on, 107; Collins, J. H., 167; 
Daubree,A., 107; Foster, Clement 
Lc Neve, 107 ; Vogt, J. H. L., 
107. 

Gerrans Bay, 4, 14, 15, 33, 37, 38,90, 
91, 93, 100. 

Glacial jwriod. 5. 

Glaciation, 93 ; absence cf, 90. 

Gloweth, 70, 79. 

Gold in lodes, 180. 

CJood Success Mine, lode of, 241. 

Gorland, Wheal, notes on, 229. 

Gossan, 188, 190, 194 ; output from 
mines, 290—295. 

Governs, 34. 

G rambler. Wheal, note on, 229. 



INDEX. 



329 



Grampoundy 39. 

Grampoand and Probus Series, 14, 
17, 39, 40. 

Granite, 4, 7, 9, 11, 13, 52 ; region, 
11 ; analysis of, 60 ; cleavage, 54, 
55 ; crashing strength, 108 ; folia- 
tion, 59 — 61; jointing, 54—56, 
62—64, 107 ; microscopic charac- 
ter, 56—63 ; stratiform, 11 ; struc- 
tures of, 54—56; texture, 107; 
schorlaceous, 55, 56 ; topaz-bear- 
ing, 57 ; subterranean features, 
113—115,117,118; connection of 
ores with, 167, 175 -178 ; relation 
to ore bodies, 171—173; faulted 
by lodes, 147 ; vein-* in, 107. 

industry, 106— 110; depression 

in, 108 ; recent supply of, for dock 
and harbour works, 109. 

of Constantino, 55. 

East Wheal Lovell, 58. 

Hendra, 58. 

Mabe, 55. 

Wendron, 55. 



Great Cross Course, Dolcoath and 
Cook's Kitchen, 158, 159. 

Flat lode, chutes in, 163 ; dis- 
tribution of tin and copp_»r ores 
in, 177, 178 ; length of, 152 ; posi- 
tion, 130; underlie, 150, 151; 
walls, 139 ; width, 153. 

•South Tolgus, note on, 229. 



Green, Upfield, 19. 

Greenbank, 25. 

Green Bottom, 32. 

Greensplat, 66, 67. 

Greenstone, 13, 41 — 52; analyses of, 
45, 51 ; influence on deposition 
of ores, 186 ; microscopic charac- 
ters of, 42 — 52 ; subterranean 
occurrence in mines, 123. 

Greenwith, 67, 109. 

Gregwartha, 110. 

Greisen, 57, 58. 

Grenville, Wheal, dip of granite, 
115. 

Grylls and Basset, Wheal, notes on, 
221, 222. 

Gustavus Mine, lode in, 230. 

Gwarneck Mine, description, 2^50. 

Gwennap, 7, 11, 13, 14, 04, 66, 97; 
distribution of tin and copper 
ores, 178 ; strike of lodes, 149 ; 
list of mines in parish of, 302. 

Gwinear, mines in parish of, 303. 

Gyllyngvase, 100. 

Halabezack, 107 ; striku f lodes, 
149. 

Farm Mine, ore bunches in, 

164 ; produce of, 230. 
Ilallenbeaglo Mine, notes on, 2^]0. 
Halwyn, 79. 

Handsouibody, H. G., 100. 
Hirmony, Wheal, notes on, 230. 



Harriet, Wheal, notes on, 230. 

Hatchet^ Wheal, notes on, 230. 

Hawke, Wheal, notes on, 230, 231. 

Head, 6, 15, 93-95. 

Helston, 13. 

Henderson & Son, Messrs., 259. 

Henwood, W. J., 97, 103, 113; on 

cross-courses, flucans and slides, 

158. 
Higher Card re w, 69, WJ, 

Carnon, 67. 

Rosewarne, 70. 

Trelease, 76, 79. 

Hill, J. B., 9, 19, 39, 45, 74, 80, 179 ; 

on Cam Marth granite, 114 ; 

lodes in joints, 148 ; cross- 
coursers, 158. 
Hinde, Dr. G. J., 18, 29, 37. 
History of mining economics, 259 — 

261. 
Home Oflice, 259. 
Horn f els, 84, 85. 
"Horses," 139 ; in Dolcoath, Binner 

Downs, Cook's Kitchen, 139. 
Huel. See under name of the mine. 

Illogan, 14, 28, 73, 85 ; mines in 
parish of, 303, 304. 

Index tables of mines, 297—306. 

Intersections of lodes, 186 ; in Cook's 
Kitclien, Wheal Basset, North 
Roskear, and Wheal Crofty, 144 ; 
South CoPidurrow, South Frances, 
South Crofty, Treskerby, United 
Minos, Wheal Gorland, Wheal 
Unity, Carzise Mine, Poldice, 
Scorrier Mine, Wheal Hawke, 
Nangiles, and East Wheal Crofty, 
145 ; Ting Tang, Consolidated 
Mines, and South Wheal Towan, 
146; Dolcoath, 214, 215; East 
Wheal Chance, 226. 

Iron, :^). 

oxide, output from mines, 290 — 

295. 

pvrites, output from mines, 

290—295. 

Ironstone. See Greenstone. 

Irregular masses of ore, 164—167. 

Isoclinal folding, 19. 

James, W., on bunches in Wheal 

Basset, 103. 
Jewell, Wheal, notes on, 2^1. 
Joints in granite, 54 — ^56; 62, 63, 

64 ; in elvan, 66, 72 ; in mica trap, 

76 78 

1 lodes in, 56, 132, 148. 

Judd, Professor J. W., 86. 
Junctions of lodes, 186. 

Keii, 101); mines in parish of, 301. 
Kehellan, 14. 
Kennal Vale 59, 107. 
Kenwyn Parish, mines in, 301. 



330 



INDEX. 



Kenwjn Valley, 14. 

Kergilliack. See Lower Kergilliack. 

Kerling Downs, 68, 109. 

Kieve, 266, 267 ; concentrates from, 
270; crop tin, 271. 

mill stream works, 273. 

Killas, 4, 14; general description, 
16—24 ; geological age of, 18, 19 ; 
analysis of, 85, 86 ; luematized, 
35 ; microscopic characters, 26, 36, 
39, 40, 82-85 ; weathering of, 32, 
34, 35 ; silicification of, 34, 35 ; 
connection of ores with, 185, 186. 

Killiganoon, 32. 

Killiow, 10, 14, 67. 

Kirkcaldy, David, 108. 

Ejiotenschiefer, 82. 

Knotted schist, 82-86. 

Lakes, 12. 

Lambe Creek, 76, 79. 

Lamorran, 6, 111, 103. 

Lamouth Creek, 76, 79. 

Lanner, 13, 111. 

Lanner Moor, 66, 67. 

Lead, 9, I^; output from mines, 290 — 
295 ; and silver ores, 181. 

Leaders of lodes, 135. 

Length of lodes, 152. 

Lenticular quartz veins, 133. 

Limestone, 17, 33, 37 ; analysis of, 
38. 

Linear distribution of mines, 205- - 
207. 

Little Falmouth, 18. 

Localities for minerals, table of, 
195-204. 

Lodes, of tin and copper, age of, 9, 
130 ; banded, 132 ; belts of, 205— 
207 ; cauiiter, 140 ; classification, 
142; distribution, 9, 125; in 
faults, 154 ; faulting by, 146 ; flat 
lodes, 150; intersections, 143, 
186 ; in joints, 148 ; leaders of, 
135, 136; length, 152; table of 
minerals in, 195—204 ; mineral 
pitch in, 185 ; order of arrival of 
minerals, 182 — 184 ; oxide, car- 
bonate and sulphide zones, 188 ; 
productiveness at intersections 
and irregularities, 186; secondary 
ores in, 190, 191 ; structure, 131, 
133 ; termination of, 153 ; trend 
of, 148 ; underlie, 149, 150 ; walls 
of, 139 ; width, 153, 187 ; Mois- 
senet, M. L., on width of, J 87. 

Longdowns, 56, 106. 

Loss in dressing, 209. 

Lovell Mine, ore body in, 165 ; 
notes on, 231. 

Lower Carnon, 109. 

Kergilliack, 110. 

Newham, 36. 

Palteozoic divisions, sequence 

of, 17. 



Lower Tretharrup, 60, 107, 108. 
Lushington, Wheal, notes on, 232. 

Mabe, 107. 

MacAlister, D. A., 9, 10, 51, 155. 

Machinery, dressing, 264, 269. 

Maen Forth, 14, 15, 29, 34, 92, 99, 
100. 

Magmatic extraction of ores, 169. 

Magnetic separator, 267. 

Maid, Wheal, lodes in, 232. 

Malpas, 14, 30. 

Manganese, 17, 37, 38 ; distribution 
of, 179. 

Maria, Wheal, note on, 232. 

Mary, Wheal, lodes of, 232. 

Mawla, 14, 28, 73. aif ^ 

Mawnan Smith, 29. 

Medlyn Moor, granite of« 58. 

Mine, note on, 232. 

Menagissey, 73. 

Menerdue, 11. 

Messack, 76, 78. 

Pointy 30, 94. 

Metamorphic aureole, 4, 7. 

zone, microscopic characters, 

82-86. 

Metamorphism on granite margin, 
81—86. 

Meteoric waters, action on lodes, 
187—194. 

Mica traps, 14, 74—80; age of, 75, 
80 ; analysis, 77 ; distribution, 
76; joints, 76, 78; lithological 
character, 74—76 ; microscopic 
characters, 77, 78; weathering, 
75. 

Micro-granite, 65. 

Microscopic characters, of chert, 28, 
37 ; elvan, 66-73 ; granite, 56— 
63 ; greenstone, 42—52; killas, 
26, 36, 39, 40, 82—85 ; mica trap, 
77, 78. 

— — examination of products from 
ore dressing, 269 — 274 ; struc- 
tures of veinstones, 155. 

Middle Point, 18. 

Mine plans, 9, 259. 

Mineral area, 6 — 9 ; geology of, 113 ; 
scenery of, 10, 11. 

localities, 195—204. 

— — pitch in killas, 185. 

statistics, 275-289 ; 306— 

314. 

veins, 7. See Lodes. 

Minerals, table of, 195—204; 
secondary deposition of, 187 — 
194 ; order of arrival in lodes, 
182, 183, 184 ; conditions afifecting 
deposition, 184 ; characterising 
tin lodes, 168, 169 ; in cross- 
courses, 160 ; order of arrival, 
131, 182, 183, 184 ; Collins, J. H., 
and Flett, J. S., on order of 
arrival, 183. 



INDEX, 



331 



Minos, alphabetical list of, 297 — 
301 ; in each parish, 301—306 ; 
abaudoned, 221 — 256 ; active, 207 
— 220; number working in last 
50 years, 261 ; output of tin and 
copper, 275—289; output of 
minerals other than tin and 
coppi>r, 290 — 295; linear distri- 
bution of, 205—207 ; bibliography 
relating to individual mines, 207 ; 
elvans in, 119 — 123; granite, 114 
^118; greenstone, 124; cross- 
courses, i58, 159, KK); killas, 185, 
186; minerals, 195—204; lead 
and silver in, 181, 182; pitch of 
ore bunches, 161 ; chutes and 
courses of ore, 161, 163 ; vortical 
distribution of the ores in, 175-- 
178 ; subordinate ores, 178 — 180. 

Minettt»s, 46. 

Mining industry, 10 ; decadence of, 
9, 11 ; history, 259 -261 ; econo- 
mics, 258 — 314. 

maps, 10, 259. 

Mongleath, 46. 

Mount Hawke, 112. 

Murchison, Sir K. I., 3, 19, 03. 

Music, Wheal, stock-work in, 105. 

Mylor, 92 ; mines in parish of, 304. 

Creek, 94. 

series, 14, 16, 25-29. 



Nancegollan, 107. 
Nancekuke Common, 12. 
Nangiles Mine, notes on, 232, 2.'^3. 
Nansavallan, 109. 

W^od, 66. 

Nare Point, 18. 

Native metals and oxides in upper 

parts of lodes, 188. 
Newbridge, strike of lodes at, 149. 
New Cook's Kitchen, granite riclgo 

in, 117. 

Wheal Virgin, lodes of, 2:«. 

Level 1, note on, 2.33. 

Seton, lode of, 233. 

Newham, 74, 109. See Lower 

Newham. 
Newton, K. T., 28. 
Nickel, occurrence of, 179 ; output 

from East I'ool, 291. 
Nine Maidens, 10<5, 109. 
North Wheal Frances, granite in, 

114. 

Jane, note on, 234. 

Koskear, description of, 234, 

235. 

Downs, lodes of, 233, 234. 

Vool, note on, 234. 



Ochre, output from mines, 290—295. 

works, 112. 

Ordovician. See Lower Paheozoic. 



Ore bunches, 161 ; form of, 161 » 
origio, 161; width, 163; Mois- 
senet, M. L., on origin of, 187 ; 
relation to granite and killas 
junction, 161 ; relation to joint- 
ing, 161 ; to breccia ted masses, 
1^)1 ; connection with granite, 
171-173; chute, 101; pipe, 161, 
164, 165. 

dressing, 2(>2— 274 ; products 

from, 209-274. 

Ores, natural history of, 161 ; 
genesis, 1()7 — 171 ; concentration 
of, 9 ; local conditions affecting 
deposition, 184 ; association with 
elvans, 182, 181, 185 ; relation to 
greenstone, 186 ; connection with 
granite, 167, 175—178; distribu- 
tion, 171; occurrence at granite 
margin, 171 — 173 ; distribution 
of subordinate, 178 ; table of 
minerals, 195—204; solution and 
rcdistrihution, 187 ; secondary 
dej)osition, 187 ; ord(^r of arrival 
in lodes, 131, 182-184; vertical 
distribution of tin and copper, 
175-178; lead and silver, 
wolfram, zinc, bismuth, antinumy, 
nickel, cobalt, manganese, 
uranium and gold, 178—180. 

Organic remains, 4, 30, 37. 

Outcrops of lodes, tin in, 190. 

Output, tin and copper from 
individual mines, 274—289 ; 
minerals other than tin and 
copper from individual mines, 
290 — 295 ; of tin and copper from 
mines of Cornwall collectively, 
310 — 314; tin-ore from mine 
heaps, 29() ; tin-ore from stream- 
works, 2*J5, 29<); Dolcoath since 
1845, 2()1 262; Wheal Basset 
since 18.51, 261 202 ; East Pool 
since 1845, 201-202; lluctuating, 
2f>0. 

Oxidation of ores, 187 ; depth of, 
194. 

Oxide of iron, output from mines, 
290 2U5. 

- - zone, ISS. 

Paheozoic divisions. See Lower 

Paheozoic. 
Parish, mines in each, 301- 306. 
I'each, C. W., 37. 
, 137; Pryce, W., Carne, J., 

Phillips, ,7. A., Foster, C. Le 

Neve, Flett, J. S., on, i:^. 
Pednan, 263. 
Pedn an Drea, granite in, ll.~) ; car- 

boiia, 1()5 ; lodes, 2'.\7). 
Peevor, Wheal, descrii)tion of lodes, 

23(). 
Pegmatite, 53. 
Pencoose, ()7, 107, 109. 



332 



INDEX. 



Peudapves United, notes on, 235. 

Estate Office, 259. 

Pendennis, 29. 

Point, 14,33, 76, 78, 79. 

Pendowep, 14, 1% 87, 90, 91, 93, 100, 

103. 
Pengegon Coombe, 71. 
Pengpoep, 13, 42, 44. 
Pen hale, 50. 

Moor, 69, 85. 

Pennance, 14, G4, 94. 
— — Mine, note on, 236. 

Point, 34, 92. 

Penpoll, 76, 101. 

Creek, 31. 

Penryn. 10, 11, 12, 52, 76, 78, 80, 82, 
86, 106, 107, 108, HI. 

Creek, 13, 18, 44, 46, 83. 

Pentuau, 98. 

Penwarne, 83, 107. 

Penwerris, 45. 

Perranapwopthal, mines in parish 

of, 304. 
Perranwell, 10, 67. 
Petroleum in killas, 185. 
Pink, Wheal, note on, 236. 
Pipe, definition of, 161. 
Pitch of ore bunches, 161 ; relation 

to granite and killas junction, 

161. 

mineral, 185. 

Philleigh, 14, 30, 34. 

Phillips, J. A., 50, 51, 63, 65, 74, 76, 

77,85, 86. 
Pill, 94. 

Plain of marine denudation, 2, 3, 5. 
Pleistocene deposits, 88—89,90—98. 

sea, 5. 

Pliocene sea, 5. 

Pneumatolysis, 168 ; in acid 

plutonic rocks, 169 ; in basic 

plutonic rocks, 169 ; Teall, J. J. 

H., on, 169. 
Point, 112. 
Polcrebo, 14, 73, IOC. 

gravels, 3, 88, 89. 

Poldice, lodes of, 236. 

Polladras Downs Mine, notes on, 

236. 
Pollard, Dr. W., 111. 
l^olmarth, 72. 
Polwheveral, 83. 
Ponsanooth, 13, 42, 53, 60, 84, 107, 

110. 
Porkellis, 102, 109. 

Moor, 11,59, 111. 

United Mines, lodes of, 236, 

237. 
Porthcurnick, 15, 93, 100, 103. 
Vorthon stock, 110. 
Porth Tow in, 14, 32, 33, 35, 40, 85, 

103; mining district, 175; strike 

of lodes of, 149. 
l»ortreath, 36, 92, 100. 
Portscatlio, 01, 93. 



Portscatho series, 14, 17, 33—37. 

Praze, 13, 53, 61, 73, 107, 110. 

Prian, 138 ; Hunt, R., od, 138. 

Probus, 14. 39. 

Products from ore dressing, 269. 

Produce of mines, fluctuating, 260 ; 
tin and copper, 275—289; minerals 
other than tin and copper, 290 — 
295 ; of Cornwall, 310-314. 

Productiveness of lodes at intersec- 
tions. 186 ; near elvans, 184, 185 ; 
in greenstone, 186. 

Prospldnick, 107. 

Providence Mine, note on, 237. 

Prussia, Wheal, lodes of. 237. 

Pseudo-conglomerates, 21 — 22. See 
Crush conglomerate. 

Pseudomorphs, 191, 204 ; Miers, 11. 
A., on, 191, 204. 

PuUa Cross, 66. 

Pulp, 270, 272. 

Pumping engine, 260. 

Purple and green slate, 29 — 32. 

Pvrites, output from mines, 290 — 
295. 

Pyroxene hornfels, 84. 

Quarries, elvan, 109, 110. 

, granite. 107. 

, greenstone, 110. 

Qiiartzite, 19, 26—28. 
Quartz pjrphyrv, 57. 
veins, 27, 29, 33, 45. 

Radiolaria, 4, 32, 37. 

Hadiolarian chert, 18, 29. 

Ragging frames, 267. 

Kaised beaches, 5, 15, 91, 92 ; gold 

in, 180. 
Rame Common, 59. 
Recent deposits, 99—103. 
Red River, 2 ; output of tin ore 

from stream works, 295. 
Redruth, 11, 12, 13, 14, 28, 63, 64, 

84, 111 ; mines in parish of, 304 ; 

mining region, 174 ; strike of lodes 

near, 149 ; bearing and width of 

cross-courses, 158. 
References, abbreviation of, 113. 
Reid, Clement, 89, 100. 
Reskajeage Downs, 12, 14, 32, 33. 
Reskudinnick Mill stream works, 

273. 
Restronguet, 100, 101. 
Creek, 13, 14, 27, 28, 31, 47,87, 

94,95,97,98, 112. 
Returning charges, 308. 
Revolving frames, 266. 
River terraces, 102. 
Road mo till, 110. 
Roberts, S., 91). 
Rogers. Rev. J., 37, 99. 
Rose, Wheal, lodes of^ 237. 
Rosewarne, 70. 



I>'DEX. 



333 



Roskear Mines, distribution of ore 

in, 176, 177. 
Roskrow United, note on, 238. 
Raan Lanihome, 6, 14, 30, 34, 103, 

111. 

Saint Agnes, mines in parish of, 305. 

Anthony, 33, 103. 

Day, 7/11, 13, 28, 32, (\S, 67, 

97, 111. 



United Mines, conrse of 
Olre in, 172. 

Gluvias, mines in parish of, 



305. 



.Just, 14, 92. 
Creek, 30. 



Mawos, 14, :^, 92, O-K 

Sand dunes, 103. 

Sands from tin-ore dressing, 269 — 

274. 
Sarah, Abraham and Crenvcr Mines, 

notes on, 225, 226. 
Saveock Water, 68, 109. 
Scenery, 2, 10-12. 
Schistose structures, 23. 
Scorrier, 11, 28, 97, 105 ; underlie of 

lodes, 150. 
Scovan, Pryce, W., Phillips, W., 

Thomas, R., Hunt, K., on, 138. 
Screens, 264, 265. 
Secondary deposition of ores, 187 ; 

chemistry of, 191 — 194 ; En^nions, 

S. F., on, 188 ; Van Hise, C. R., 

189 ; De Launey, L., and E. Fuchs, 

189 ; Vogt, J. H. L., 189 ; Penrose, 

R. A. F.. 189; Finch, J. W., 189; 

Hill, J. B., on, 190. 
Sedgwick, Rev. Prof. A., 3. 
Semmous, W., on veinstone in Carn 

Brea, 210. 
Separators, upward current, 271 ; 

maijnetic, 267 ; products from, 271, 

272. 
Seton, Wheal, 86 ; notes on, 238, 239, 
Seymour, Wheal, note on, 239. 
Shear structures, 21. 
Shortlane End, 14, 76, 79. 
Silver, 9 ; output from mines, 290- 

295. 
— — Hill, lode of, 239. 
and lead, distribution of, 181 ; 

genesis of lodes, 170. 
Sills of greenstone, 124. 
Silting of estuaries, 6, 100, 101. 
Silurian. See Lower Puljfozoic. 
Sithney, 29 ; mines in parish of, 305. 
Sketch map showing geology, 8. 
Skinner's Bottom, 35. 
Slate, 20. See Killas. 
Slickensides in lodes, 147. 
Slides, 36, 157. See Cross-courses. 
Slime tin, 271,273; noto on, 272; 

examination of, 273. 
Smelting, cost of, 3U9. 
works, 112. 



Smith, Edward, 98. 

Spils and vegetation, 104—106 ; on 

granite margin, 106 ; of granite 

area, 105, 106; depth of solid 

granite, 106 ; Fal basin, 104 ; 

greenstone area, 106 ; killas area, 

104; mica-trap areas, 106 ; mineral 

area, 105. 
Solutions, circulation of, 187 — 194 ; 

effect of plutonic intrusion, 187. 
Somervail, A., 19, 86. 
South Wheal Basset, notes on, 239. 
Carn Brea Mine, description, 

239. 
Condurrow, notes on, 239 ; dip 

of granite, 114; depth of granite, 

117. 

Crenver, note on, 239. 

Croft}', veinstone of, 155 ; 

f;ranite in, 117, 118; dressing of 

ores at, 270-272. 
Dolcoath, note on, 240 ; dip of 

granite, 114. 

Francos, notes on, 240. 

Wheal Hawke, note on, 240. 

Roskear, 47 ; notes on, 240. 

Wheal Seton, lodes of, 240. 

Tolcarne, dip of granite, 114, 

117. 



Wheal Towan, lodes of, 241. 

Tresavean Mine, note on, 242. 

Wendron Mine, ore pipe in, 

164. 

Sparnon, lodes of, 242. 

Sparry Bottom, 67, 111. 

Spinster, Wheal, note on, 242. 

Springs, 111. 

Spurr, J. E., on lodes in joints, 
132. 

Squire, Whenl, lodes of, 212. 

Stamps, Cornish, 264 ; Californian, 
264. 

Standard, 308, 309, 310—314. 

Statistics, mineral, 274—314 ; of tin 
and copper from mines indivi- 
dually, 275—289 ; minerals other 
than tin and copper, 290—295 ; 
lluctuating output of mines, 260, 
306 ; bibliography of, 274, 306, 308. 
»SVe under Output. 

Steam engine, 260. 

Stephens, F. J., 18, 29, 45, 47 ; on 
gold in raised beaches, 180 ; Pen- 
nance Mine, 2.36; Swanpool Mine, 
243 ; Wheal Clinton, 223. 

Stithians, 106 ; mines in parish of, 
305. 

Stockwork in Wheal Music, 165. 

Stone industry, 106, 110. 

Stratiform (granite, 54, 62. 

Strav Park Mi no, lodes of, 242, 
243. 

Si ream-till, 6, 90—07. 

— deposits, 1."). 
- valleys, 11. 



334 



INDEX. 



Stream-tin works, output of tin from, 
295,296. 

Stress, direction of, 23. 

Strike of killas, 23 ; lodes, 148. 

Structure of killas, 19—24. 

Submergence, 5. 

Submarine forests, 5, 15, 99, 100. 

Submerged valley deposits, 97 — 98. 

Sulphide zone in lodes, 188 ; second- 
ary enrichment, 188, 189, 190 ; 
oxidation of, 188—190. 

Sulphur ores, output from mines, 
290, 295. 

Sunny Cove, 90, 92, 94. 

Superficial deposits, 14. 

Surface waters, effect on lodes, 
187—194. 

Swanpool, 12, 29, 92, 100. 

,Miue, notes on, 243. 

Table, Wilfley and Buss, 265 ; revolv- 
ing, double-deck, and Acme, 266. 

Tailings, tin in, 272. 

Teall, Dr. J. J. H., 37, 75, 77 ; on 
pneumatolysis, 169. 

Tehidy, Wheal, notes on, 243; 
probable depth of granite in, 
118. 

Thickness of lodes, 153. 

Thomas, Richard, 101, 113. 

Tidal estuaries, 1. 

Timber, 105. 

Tin, 9 ; smelting, 112 ; standard, 
309. 

and copper lodes, connection 

with granite, 167 ; genesis, 170 
See Lodes. 

Tin-ore dressing, 262 — 274 ; pro- 
ducts from, 267—274. 

, magmatic extraction of, 168, 

169; secondary concentration in 
outcrops of lodes, 190 ; depth of, 
183 ; vertical distribution in lodes, 
175 — 178 ; output from mines, 
275—289; output from Cornwall, 
310-314. 

Tincroft and Carn Brea United 
Mines, notes on, 208 — 210 ; granite 
in, 117. 

Ting Tang, granite in, 115 ; lodes of, 
243. 

Titaniferous iron ore, magmatic ex- 
traction, 169. 

Tobban Horse, 36. 

Tolcarne, 107 ; lodes of, 244. 

Tolvern, 101. 

To ugh way joints, 148. 

Towan, 100, 103. 

Beach, 91,94. 

, Wheal, lodes of, 245. 

Town(anna, &.\, 109. 

Trachyte, 42, 4(). 

Trannack, 61, 85. 

, Wheal, 52, 110; granite of 

01. 



Trebowland, 71. 

Vean, 43. 

Tredeague, 71. 
Trefula Mine, lodes of, 244. 
Trefusis Point, 26, 92. 
Tregannock Mill, 13. 
Tregarne Mill, 82. 
Tregathennan, 61. 
Tregenver, 26. 
Tregolls, 72. 
Tregoney, 6, 100. 
Treleigh, 47. 

Consols, lodes of, 244. 

Treleighwoud Mine, notes on, 230. 
Trelissick, 74, 76, 77. 
Trelonck, 111. 
Treluswell, 13, 42, 53, 60, 61, 

110. 

Tremenbeere, not« on, 244. 
Trend of lodes, 148. 
Trenoweth, 73. 
Tresahoe, 108. 
Tresavean Mine, note on, 244 

granite, 115; ore chute, 173. 
Tresevern Croft, 72, 109. 
Treskerby Mine, granite of, 115 

lodes of, 245. 
Treslothan, 51. 
Trtswithian Downs, 73. 
Trethannas, 57. 

Tretharrup. jSfce Lower Tretharrup. 
Tretkeague, 107. 
Trevales, 56, 66, 109. 
Trevenen Mine, note on, 245. 
Treviades, 83. 
Trevince, 66. 
Treviskey, 13, 42. 
Trevissome, 47, 83. 
Tre^oole, 73, 110. 
Trewan Mine, lodes of, 245, 246. 
Trewirgie Downs, lodes, 246. 
Trist, S. J., 37. 
Troon, 71. 

Trumpet, W^heal, lodes of, 246. 
Truro, 9, 14, 31, 32, 102, 111. 

River, 74. 

Truthall, 6L 

Tuckingmill, 48, 51, 70, 110. 

Tuugstate of soda, output from 

mines, 291. 
Turnaware Point, 14. 
Tyack, W., 88, 89. 

Umber, output from mines, 290— 

295. 
Unconformity, 39. 
Underlie, angle of, 118 ; of lodes, 

119, 150; Great Flat lode, 150; 

relative of lodes and elvans, 151. 
Union, Wheal, lodes of, 246. 
United Hills, notes on, 240. 
Mines, lodes of, 246, 247, 150; 

main lode, 153. 
Unity, Wheal, lodes of, 247. 
Wood, Wheal, lodes of, 248. 



INDEX. 



335 



Uny, Wheal, notes on 249 ; granite 
in, 114, 117. 

Upheaval, 5. 

Upland basins, 102. 

Upper parts of lodes, 188. 

Uranium, distribution of, 179 ; out- 
put from East Pool, 291. 

Ussher, W. A. E., 19, 75, 90 ; on 
quartz veins, 133. 

Vadose circulation, 187. 

Valleys, 2 ; age of, 101 ; along fault 
lines, 36 ; systems, 102. 

Van Hise, C. li., on circulating 
waters, 187. 

Vanner, Frue, 205. 

Vegetation, 12; influenced by aspect, 
105; and soils, 104—106.* 

Veinstone, breccia tod, 131, 132, 133 ; 
comby, 131 ; banded, 132 ; origin 
of, 131 ; miners' terminology, 154 ; 
microscopic structure, 155 ; of 
Cam Brea, 155 ; South Crofty 
155; Wheal Envs, 155; Dolcoath, 
156. 

Velanhaus< ,88. 

Vercoe, H., . '»3. 

Vertical distribution of tin and 
copper ores, 175 — 178. 

Veryan series, 14, 17, 'M—^\8. 

Victoria Point, 79. 

Virgin, Wheal, lodes of, 249. 

Vor, Wheal, 112; lodes of, 249, 250, 
251, 252; tin stone in, 166; 
"floors," 167; minerals in cross- 
course, 160 ; relation of ore to 
granite, 172. 

Vugs, 138; in Dolcoatli, 138; in 
Wheal Rose, Consols Mine, Great 
Condurrow, 139. 

Vyvian, Wheal, ore body in, 105. 

Walls of lodes, 139. 

Water, circulating, 187 — 189; 
vadose, 187—189; oxidation by 
oxygen in, 188 — 194 ; flowage in 
rocks, 188, 189, 190. 



Water level, 112. 

supply, 111, 112. 

Weathering in lodes, 188—190 ; 

chemistry of, 190-194. 
Weeth, 70. 

Farm, 48. 

Wendron, 7, 57, 107, 109 ; mining 

district, 175 ; strike of lodes, 149 ; 

United Mines,252; mines in parish 

of, 300. 
West Basset, lodes of, 220. 
Condurrow, lodes of, 252, 253. 

— — Damsel, lodes of, 253. 

Dolcoath, lode of, 253. 

Frances, note on, 253. 

— — Wheal Jane, note on, 253. 
— — Poldice, granite in, 115. 

— Wheal Seton, lodes, 253, 254. 
— — Towan, lodes of, 251. 

— Wheal Virgin, lodes of, 254. 
Wetherell magnetic separator, 267. 
Wheal. See under name of mine. 
White Alice, 72, 59. 

Whitley, H. M., 99, 100, 103. 

— N., 93. 

Width of lodes, 153 ; origin of, 154 ; 
Moissenet, M. L., on, 187 ; Dol- 
coath, 16^3. 

— of el van, 118—123. 
Wilfley table, 2()5. 

Wolfram, distribution of, 178 ; out- 
put from mines, 290, 291, 292, 294 ; 
magnetic separator, 267. 

Woods and Forests, Office of, 259. 

Woolfs Cross-course in Wheal Vor, 
160; Godolphin Bridge Mine, 
160 ; Wheal Rose, 160. 



Yield of mines, fluctuating, 260. See 
Output. 



Zinc, 9 ; distribution of, 178 ; output 

from mines, 290 — 295. 
Zones of ore deposition, 170 ; 

secondary enrichment, 188 — 194. 




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