eth ath gh Pha hen tn an unig ghe te tte tin ta aoe fl j ili Hit ie i THE GEOLOGICAL MAGAZINE, DECADE VI. VOL. IV. JANUARY—DECEMBER, 1917. sy) THE GEOLOGICAL MAGAZINE Monthly Journal of Geology. ith Gok, © @ 1G, tS a NOS. DCXXXI TO DCXLII. EDITED BY Enis WOODWARD, Tin. FRS.; F.G.8..V-P.Z:S.. Bo ReME Ss LATE OF THE BRITISH MUSEUM OF NATURAL HISTORY; PRESIDENT OF THE PALAONTOGRAPHICAL SOCIETY 5 ETC. ASSISTED BY Prorrssor J. W. GREGORY, D.Sc., F.R.S., F.G.S. Dr. GEORGE J. HINDH, F.R.S., F.G.S. pine He HOLLANDS KCK. ARCS... DSc, F.R-S., VebGes: Prorrssor J. E. MARR, M.A., Sc.D. (Camb.), F.R.S., F.G.S. Sir JETHRO TEALL, M.A., Sc.D. (Camb.), LL.D., F.R.S., F.G.S. Prorrssorn W. W. WATTS, Sc.D., LL.D., M.Sc., F.R.S., F.G.S. Dre. ARTHUR SMITH WOODWARD, LL.D., F.R.S., F.L.S., WAESGES) DHCADEH VI“ \Rional Mus LONDON: DULAU & CO., LTD., 37 SOHO SQUARE, W.1. MONE Te NEW SHRIES- JANUARY—DECEMBER, 1917 ' 1 STEPHEN AUSTIN AND SONS, LTD. PRINTERS, HERTFORD OCT. YOUE XT: OGD XXV. SOV. XXVII. XXVIHI. OXI" LOGE XGROII: SOON Ie NOXOMLY KR: ES Om EATS: Rock-sections, Cil-y-Coed Chalk Polyzoa i : Maitai Lamellibranch and Corals Maitai Brachiopods, Gasteropods, etc. View of apa ee Iceland. Fallen Block « of Liparite, Jafnadal : : Phycomycites nee ation etc. Lateral Attachment of Rugose Corals Chalk Polyzoa ‘ Integument of Wealden Dinosaurs Picrite from Mozambique 5 Portrait of Dr. Henry Fairfield akon ; Surface Features of Discoides and Conulus Poikilosakos petaloides . Portrait of the late Charles Soe Beer Assoc. R. 8. M., F.G.S. : : F Systems of Holectypus aa ae Cen Hapsidopora and Tylopora Portrait of Alfred Harker, M.A.,LU.D., F.R.S., Pres. Geol. Soc. Gasteropoda, New Zealand Cretaceous Fossils, New Zealand Dyplodocus Carnegier 5 ae 34 (restoration) . Pycnodus platessus : : ‘ Perignathic Girdle of Discoides cylindricus Map of Charnian Movement, E. Kent Perignathice Girdle of Conulus albogalerus Rock-sections, Pahang Voleanic Series . Geological Sketch-map of part of Ulu Pahang, F. MM. States Portrait of the late Alfred N. Leeds Chalk Polyzoa Sketch-map of Ambrym Tiana. Nee Hebrides Fossil Shark showing spiral Coprolite Prof. H. Hull, M.A., LL.D., F.R.S. FACING PAGE a. Als) 20 53 63 64 97 102 115 145 150 157 193 205 219 242 255 258 289 305 305 342 307 359 389 397 399 401 441 462 503 478 496 529 542 553 LIST OF ILLUSTRATIONS IN THE TEXT. PAGE Map of Hgyptian Oilfield Region . : : ‘ Diagrammatic section across Egyptian Oilfield ‘ : : 5 : 8 Geological sketch-map of N.W. Carnarvonshire . : : i By) kB} Geological map of part of S.W. Carnarvonshire . : P : Boy LU) Sketch-map of Lodmundarfjord District 5 : » Os Animal remains in Dunliath Ferruginous Limestone, N. W. Sjootiead . 103 Two polyparia of solitary Rugosa ‘ : . 110 Diagram arrangement of outcrops of septa on Bee of polvpabiurn 5) dlatil Diagram of calice of Hadrophyllum pauciradiatum . é i . 113 Sections of Lophophyllum proliferum . : . 114 Symbols of sub-rangs and rangs (classification of loveone Oe) oy tal) Diagram of disturbed gravels : : . 159 Diagram summarizing views of Wachsmuth & Sareuen< on cninotd pane . 206 Schematic figure of ventral valve of Poikilosakos petaloides 9 . 214 Dithyrocaris tricornis and D. testudinea, Scouler 3 ; : Bn ear(al Sketch-map and section along railway, Arkleston, Paisley . ! . 274 Rock-section of Cumbraite . : . : ; : ; : . 307 Peristomial structures of Plesiechinus ornatus . 344 Schematic restoration of attachment of lantern fwslee in Diesen . 347 Rock-sections, Tholeiite ; : j 9 ; f i 4 5 BislL Rock-section, Olivine-tholeiite : : A : : . f 5 oe) Ribs of Diplodocus in position . 4 : . 360 Posterior aspect of pelvis and hind- a of Dubladecus ‘ 2 . 3861 Hind-limb of Diplodocus : 5 A ; : : 5 . 362 Two views left femur of Deniodgeus : ; ; : : 6 . 362 Fore-limb and humerus of Diplodocus A : 368 Diagram showing wrong articulation of limb Benes and Wouking af humerus of Diplodocus (ground-plan) . 5 s aa 2) OD) Mesodon macropterus (Agassiz) . : : ‘ : : : . 3886 Geological section at the Front : ; : : : : : . 432 Polymorphites, last and adult sutures . : : : : ; . 443 Development of Polymorphites jupiter . ; : : : : . 444 Sutural development of P. jupiter ‘ ; ; : : i . 445 Sutural development of Cymbites globosus . : : j Pane Te Ah Sketch-map of Folly Farm, Presteign . ‘ : ; . 482 Vertical section of upper part of borehole, Folly Harn ; 491 Restored skeleton of Ichthyosaurus, Lower Lias, pee Regis, with ‘pina coprolite (a) beneath (after Owen) . : : j : . 541 Composition of sub-Cretaceous surface of Hast Kens ‘ ‘ : . 544 Isopachyte System, Wealden, East Kent : : ; ; : . 547 Section across Hast Kent from Deal to Ellinge : : i : . 548 | GICAL MAGAZINE ihn | our nal of Geology. s | : y : WILH WHICH IS INCORPORATED ' se! n an neti ae SPE momo ren. is (= JAN 29 191) EDITED BY eS Diss Ep “HENRY “WOODWARD. ASSISTED BY PROFESSOR J. W. GREGORY, D.Sc., F.R.8., F.G.S. DR. GEORGE J. HINDE, F.R.5., F.G.S. FE, R. Si we @. s. LL.D., F.R.S., B.G.S. JOHN EDWARD nae See. ee i ee y J. H. TEALL, M.A., Sc.D. (Cams.), JANUARY. 1917. OG) Tee EINE Sr es I. Oniginan Anvicnys. Page |. ‘Ill. Reviews. fan. By A. SMirH Woop- Apractocleidus teretepes peo \RD HD ER San ets 1 | Geology of Ben Nevisand Glen Coe 30 ilfield Region of - Egypt. ~ By Late — Pleistocene Oscillations, soe es aN Ottawa Valley...........0c6ccs.eecene 32° “3 en G. a Se United States Geological Survey... 34 — and Section.) Gee aati ssw ie 5 | Petroleum and Gas Resources, i (Sea Biro peice a sntie saree Rete 36 Oiland Gas Production ............ 58a) _E. eS 5 9 | Ore Deposits, British Columbia ... 39 |} Rhode Island Coal........2..0c000 40. || IV. REPORTS AND PROCEEDINGS. The Royal Society — Zoological as : t a Society—Edinburgh Geological aleott’s Cambrian Geology Society—Geological Society of alezontology. By V. C. 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Q.J.G.S., vol. xxxv, p. 296, 1879. § Op. cit., p. 298. 7 GEOL. MaG., Vol. IX, p. 552, 1882. 8 Bala Volcanic Series of Carnarvonshire, 1888, pp. 44-5. Part of Carnarvonshire. iy drift-covered, and in consequence well cultivated. As a result only three rock-exposures occur in this area—Cil-y-Coed, Craig-y- Dinas, and Caer Engan. Cil-y-Coed and Caer Engan are two small hills, whilst Craig-y-Dinas, with Pentwr to one side of it and Bryn- mawr to the other, are on the slopes of rising ground. It will be convenient to consider each of these exposures separately, commencing with Cil-y-Coed, which is the largest and also the most south-westerly of the three. 1. Crt-y-Corp. (See Map II.) A. Surrace Fratures.—This hill, situated about three-quarters of a mile from the village of Clynnog Fawr on the north-west coast of Carnarvonshire, attains an elevation of about 480 feet O.D., and stands out prominently from the drift plain which stretches for 6 or 7 miles along Carnarvon Bay. It is the first hill of a series increasing progressively in height towards the south, and it covers . an area of nearly a quarter of a square mile, being about 1,000 yards long and 900 yards wide at its broadest part. The northern slopes of the hill are everywhere gentle, except at the extreme north- west, where crags are exposed, making the slope somewhat steeper. On the south-west and west sides, however, the ground drops very abruptly from 480 to 200 feet, below which level there is a gentle slope down into the plain. On the north side the rocks are smoothed by glaciation, and the lower flanks of the hill on every side are eovered with a thin deposit of drift. The contour of the hill was undoubtedly carved out by the Irish Sea ice-sheet, which traversed the hill from the north. There is also a small capping of drift on the, actual summit near the south-west extremity. B. Pere-Camprian, THE Rayouric Serres.—The hill in part undoubtedly owes its prominence to an igneous rock which is exposed more or less continuously in a line of crags on the west side - extending from the roadway to the top of the hill, a distance of about 650 yards. (i) Stratigraphy (see Map I1).—It will be convenient to begin our description with the most northerly rocks exposed. These are to be seen on the north-west side of the hill, 20 yards away from the small quarry that is situated here. In hand specimens the rock appears to be a dark felsite, noticeable for the presence of numerous porphyritic erystals of quartz and of pink felspar. The groundmass is fine- grained and compact, hence the rock is very hard and tough. The next exposure examined is in the quarry itself, where the rocks appear in hand specimens to be rather different from those just described. Although still felsitic-looking the rocks here are light- coloured, and only on close examination are any porphyritic crystals to be seen. In the mass the rock appears to be a rhyolite, and it is probably to the rock exposed in this quarry that Tawney and Harker refer. The rocks are much jointed and sheared, and readily break into angular chips. The main joints strike E. 10° N. and dip N. 10° W. at an angle varying from 60° to 80°. Other joints strike 1 The area here dealt with is shown on Map II in dotted lines. DECADE VI.—VOL. IV.—NO. I. 2 18 LE. Wynne Hughes—Geology of N. 40° E. and dip N. 50° W. at an angle of 60°, being thus roughly at right angles to the major joints. In traver sing the hill in a south-easterly direction from the quarry several rock exposures are met with. A few yards away from the quarry a dark rock, containing porphyritic crystals of quartz and pink felspar, is seen once more. It is in every respect macro- scopically similar to the dark felsitic rock mentioned above. We thus have a band of pale felsitic rock (which we may term the pale variety) lying between two dark felsitic bands (which we may term the dark variety). The more southerly band is about 40 feet wide. Following is a narrow band of the pale variety. Succeeding this a dark felsitic rock again occurs as a band about 20 feet wide. Macroscopically it only differs from the dark bands in that the pink felspars are distinctly smaller. This band is succeeded by another of the pale variety—15 feet thick—and in turn by a massive dark band, macroscopically very similar. Proceeding eastwards from this point, there is no exposure for fully 100 yards until another small quarry is reached. From here on to the most easterly part of the hill, igneous rock is exposed at several places, but in all cases it consists of the pale variety, macroscopically similar to bands already noticed in the first quarry. Along the south-west flanks of the hill a similar alternation of the pale and dark rocks is evident. These bands, however, are not persistent. For instance, the thin band does not occur on this side, so that two bands have here coalesced, giving a massive band of the dark variety having a width of fully 100 feet, Further south occurs also a tongue of the dark variety wedging into the pale variety. The line of strike given by this rough banding of the two varieties of rock is N. 60° H. (ii) Microscopie Description.—On examining thin sections of the rock from the various exposures there is found to be a surprising resemblance between the pale and the dark varieties. (a) Phenocrysts.—In both cases porphyritic quartz and felspar crystals are prominent, the quartz being the more abundant. The quartz sometimes show good crystal forms, but more often are corroded and rounded (Pl. I, Figs. 1, 2), and frequently the matrix may be seen in cracks in the crystals (Pl. I, Figs. 1 and 5). Most of the porphyritic crystals of felspar are plagioclases with multiple twinning (Pl. I, Fig. 5), but in nearly all cases simply twinned or untwinned crystals of orthoclase are also present (Pl. I Fig. 1). The plagioclases appear to approximate to albite, and erystals of chequer albite’ are occasionally present. This chequer albite is sometimes intergrown in perthitic fashion with untwinned felspar. Phenocrysts of biotite are also sparingly distributed throughout the rock. Muscovite, evidently of secondary origin, is always present. (6) Groundmass.—These various phenocrysts are embedded in a felsitic groundmass. This again shows a general similarity in both the pale and the dark varieties, although a certain amount of 1 J.S. Flett, Mem. Geol. Surv. (Newton Abbot), 1913, p. 60. eS ‘mon. MaG., 1917. Prarr I ROCK-SECTIONS, CIL-Y-COED. ». ' Part of Carnarvonshire. 19 variation is usually to be seen even in a single rock section. The matrix is typically cryptocrystalline, but occasionally becomes microcrystalline in character. Microspherulitic textures are of frequent. occurrence, and on the whole this is more commonly the case in the dark variety. In many cases the manner in which the various types of matrix are intermingled one with another and drawn out in streaky fashion shows that we are dealing with rhyolites having a well-defined flow- structure. This structure is sometimes developed on a very small seale (Pl. I, Figs. 1, 3). In other cases, however, the original character of the rock is by no means so clear, since in these the matrix with its different types of recrystallization presents a patchy rather than a streaky texture, suggesting at first sight a tuff. The streaky appearance, however, still persists to a certain extent, and in such cases the patches frequently end off rather abruptly along the direction of the flow-structure. It is extremely difficult to determine whether such rocks are lavas with flow brecciation or rhyolitic tufts containing rhyolitic lapilh. The presence of the very numerous and large felspar i oeneees and still more so of the quartz phenocrysts immediately suggests that the rocks belong to a series of Pre-Cambrian age, since these characters appear to be of universal occurrence in the “Page Cambrian rhyolites of Wales, whereas they are not found in the Ordovician rhyolites. In this connexion it is also noteworthy that the micro- spherulitic texture described above appears to be of frequent occurrence in the Pre-Cambrian rhyolites of North Wales, whereas it is not found to any extent in rhyolites of Ordovician age in North Wales. C. CamBrian Snonuient ce Serius. (1) Conglomerate. (a) Strati- graphy.— Beyond the rhyolite we come to the crags which form the highest ridge on the hill at its south-west end. These crags are due to the presence of a hard conglomerate, the nature of which is well shown on the weathered surfaces. The well-rounded pebbles in this conglomerate vary considerably in size; whilst the majority are from 1 to 2 inches in diameter, others may attain a diameter of 12 inches. These pebbles are embedded in a fine gritty matrix. All the pebbles consist of felsites with porphyritic crystals of quartz and felspar, and _ they closely resemble the rocks of the rhyolitic series already described. In fact, near the line of junction of the conglomerate and the rhyolitic auc. where the pebbles of the conglomerate have been pressed into the rhyolitic rock, the resemblance between the two is so close that it is only on careful examination that the outline of the pebbles can be seen. This conglomerate strikes N. 80° E. When followed across the strike in a south-westerly direction the conglomerate passes into a grit which is, however, still occasionally pebbly. This conglomerate band continues until it is buried in the drift on the south-west slopes of the hill. Proceeding along the strike in the opposite direction—north-east— the pebbles decrease rapidly in size in the course of a few yards, but the matrix retains its original character. In a newly opened quarry 20 EL. Wynne Hughes—Geology of at the north-east end of the hill, quite a number of pebbles of rhyolite, some 3 to 4inches long, are seen, but the majority of the pebbles are small and well rounded. It is only in this exposure that we get any indication of stratification in the conglomerate. Generally the dip of the rock is quite obscure, as is often the case in massive conglomerates; but in the freshly cut rock in this quarry alternate layers of pebbles and fine grit are distinctly visible. The lie of the pebbles suggests a dip of about 50° to S.K. In the quarry the rock is seen to be jointed, some joints sloping in the direction of the dip of the pebbles, crossed by others at right angles. (2) Microscopic Examination.—Several thin sections were prepared from specimens collected from different places along the outcrop, both from the highly pebbly conglomeratic portion and from the less pebbly and more gritty portion. Every slide confirms the con- glomeratic nature of the rock. They show the presence of felspar, quartz, and numerous chips of rhyolite and fragments of tuff (Pl. I, Fig.6; PLII, Fig. 1). The felspars usually exhibit multiple twinning, but are mostly decomposed. The quartz almost invariably show subangular edges. The matrix is felspathic and fine-grained, often containing small crystals of muscovite. Sections of some of the larger pebbles were also examined, and these compare in every respect with the rhyolitic rocks described above (p. 19). They contain crystals of felspar and quartz embedded in a felsitic groundmass, which in some cases shows a characteristic flow-structure. At right angles to the strike—in a south-east direction—the conglomerate rapidly changes to a grit, the width of a distinctive conglomerate being about 18 feet. (ii) The Grit Band. —(a) This band of grit is about 12 feet thick, and extends from the south-west to the north-east end of the hill. Under the microscope the grit is seen to contain angular and sub- angular crystals of quartz. in large number, along with numerous felspar crystals (partly kaolinized) ; and occasional chips of rhyolite also oceur (PI. II, Fig. 1). (6) This fine erit, “when followed southwards across the strike, gives place to a distinctly coarser rock which is very much weathered. When followed along the strike to the south-west this rock becomes still coarser and still more weathered. A microscopic examination shows the rock to be largely composed of angular quartz erystals— often sheared—set in a felspathic cement (Pl. II, Fig. 5). Both these bands of grit, fine and coarse, persist in a north- easterly direction for a distance of 900 yards, with but a slight break where the hill is capped with drift. At the north-east end of the hill there is the same succession of conglomerate, fine grit and coarse ~ grit, precisely as one would expect to find them on the supposition that the dip 1 is, as stated above, S. 30° E. There is a decided dip in the ground beyond the outcrop of the quartz grit, and no further exposure is visible, all the land on the south-east side of the grit being under cultivation. This is most unfortunate, as it is impossible without further exposures on that side to determine the exact relation of the grits to the other formations of the district. 12 wes, IDL. ROCK-SECTIONS, CIL-Y-COED; anp 4 anp 6 BWLCH-Y-LLYN. . Part of Carnarvonshire. | 21 D. Sommary oF tHe Succession.— We have then at Cil-y-Coed the following descending sequence :— : (i) A quartz grit 6 or more feet thick. (ii) A fine felspathic grit 8 feet thick. (iii) A conglomerate 18 feet thick. All with a strike N. 60° E. and a dip of 50° to S. 30° E. These rocks rest on (iv) A volcanic series consisting of rhyolitic lavas and tuffs which appear to dip 60-80° N. 10° W. The pebbles in the conglomerate are undoubtedly derived from the underlying rhyolitic series. This apparent discordance of dip suggests the presence of an unconformity between the sedimentary rocks and the volcanic series of rocks. ‘The exposures, however, are not sufficient to actually prove the existence of this unconformity, and it would require considerable trenching to make it apparent. EK. Retarron to tae Surrounpine ABeEas.—On attempting to trace the beds into surrounding areas we find that Cil-y-Coed is somewhat isolated. (i) North and West Side.—On the north and west side the mass is flanked by glacial drift, which stretches as ‘a continuous sheet right to the seashore, 500 yards distant. Gi) South-Hast and East Side.—On the south-east and east side the ground is under cultivation, and no semblance of solid rock is to be seen except in a field near Garregboeth, distant 30 yards from the nearest exposure of the grits. Here an arenaceous slate is seen, but it is doubtful whether this rock is really in situ. Assuming that it really is in place, then it undoubtedly forms a continuation of a considerable mass of arenaceous slate which is exposed at Pen-y- garree some yards further on. Between these two exposures there is an intrusive mass of picrite. This band of arenaceous slate gives rise to a prominent feature at Pen-y-garreg, and it can be traced for at least two miles to the south-west, the outcrop generally running in a north-east to south- west direction. In the Survey memoir this arenaceous slate is considered to be of Silurian (Ordovician) age, but no fossils have as yet been found in the neighbourhood. The slate is very different from the blue and purple slates of the Cambrian Series, which are so persistent in the Nantlle Valley and were traced by the Survey as far as Llwyd-Coed, three miles north-east of Cil-y-Coed. The Survey assume the existence of a fault im this neighbourhood throwing down the Silurian beds against Cambrian rocks. The memoir states :— “* South of Llanilyfni the strike of the Cambrian rocks changes to east and west, and the purple slate does not occur south or south-west of Mynydd Llanllyfni and Ty Coch near Clynnog Fawr. The drift-covered district further south is composed of black and ferruginous Silurian shales and grey sand- stones. The point farthest south where purple slate has been found is at Llwyd-Coed about a mile south of Llanllyfni, and to the west of the last-named place the ground is so obscure that the reason for the disappearance of the slate is unknown. The fault which throws the (Cambrian) slate against the quartz porphyry ridge (St. Annes—Llanllyfni ridge) is probably continued along 22 E. Wynne Hughes—Geology of the boundary of the trap as far as Llanllyfni, and west of that village perhaps throws the slate down against the low Cambrian grits and conglomerates that form the western boundary of the porphyry.’’* If we accept these slates on the south-east side of Cil-y-Coed as Ordovician, as the Survey imply, the only inference that can be drawn is that the Cil-y-Coed Series is of earlier date than Lower Ordovician. (iii) South-West Side.—On the south-west side the rock surface slopes steeply until cultivated land is reached. ‘This is the case all along this side exvept at the extreme end of the mass. Here the rock disappears in a wooded glen, and although the glen is narrow and deep, with a brook running down its entire length, no exposure is seen anywhere in the glen; but the debris in the bed of the brook suggests the proximity of the rhyolitic series. On the south side of this brook and 30 yards from it is an old ‘‘trial”’ level. This adit cuts into slate. The slate is black and is irregularly cleaved, the cleavage striking E. 10° N. and dipping 80° S. 10° E. In this adit there are about five hard black bands varying from 1% inches to 2 feet in thickness and dipping in the same direction as the cleavage, but at a slightly smaller angle. The black bands are not cleaved, but are somewhat stratified parallel to their edges. They undoubtedly mark the true dip of the beds, which is therefere about 60° to the south. The slate in the adit is undoubtedly identical with the black . ferruginous slate of the Ordovician system. It is in the direct line of strike of the grits on Cil-y-Coed. The difference in the dip, but the much greater difference in the nature of the exposures on each side of the brook, coupled with the narrow glen separating the two, suggests the presence of a fault at this point. The map accompanying the Survey memoir shows a fault between the Cambrian and the Silurian Series curving round to the west at a point about 100 yards to the north-east of Cil-y-Coed. This fault has already been referred to (p. 21) in the extract from the Geological Survey memoir. A continuation of this fault in its south-westerly direction for another 1,200 yards, before turning to the west, would bring it down the glen separating the Cambrian and Pre-Cambrian rocks from these Ordovician slates in the quarry. Such a prolongation of the fault is shown in Maps I and II. (iv) Worth-Hast Side.—Following the strike of the Cil-y-Coed rocks in a north-easterly direction we come again to cultivated land, where no rock exposure is visible. A careful search in all the fields on this side of the hill discloses no rock exposures. The River Desach cuts its way through a gap on this side, but even here no rock exposures are found. A little way on, however, at Pentwr, half a mile from the most easterly exposure on Cil-y-Coed, a small quarry was opened in 1912 for building-stone. The rock here exposed is a bluish fine-grained grit, approximating almost to a hard shale. At the south-west end of the quarry is green slate, but no indication of the dip is disclosed in this exposure. Further to the east, 60 to 70 yards away, there is again an exposure of green slate; the weathered surface shows the cleavage to strike E.N.K.—W.S.W., 1 Mem. Geol. Surv., 1866, p. 143. Part of Carnarvonshire. 23 but the dip of the beds is not clear in such a small exposure. Continuing from here in a N.N.E. direction we come to a much larger exposure of rocks at Craig-y-Dinas, separated from Pentwr by three small exposures of purple slate. The several exposures in this neighbourhood will now be described in greater detail. 2. Penrwr, Cratc-y-Dinas, anp Bryn-Mawe. These three places are on the slopes of a ridge which stretches practically from Glynllifon to Cil-y-Coed. The crest of this ridge along almost its whole length attains an altitude of 200 feet. At Craig-y-Dinas the River Llyfnwy cuts through the ridge in a roughly semicircular sweep exposing precipitous rocks at several localities on both banks of the river. A. Camprran, Sepimentary Rocks. (1) Conglomerate.—This rock is best exposed on the right bank of the river at the end of the gap farthest from the sea. The pebbles in this conglomerate are com- parable in size with those at the north-east end of the exposures at Cil-y-Coed, being seldom more than an inch in length. They consist essentially of rhyolitic and felsitic chips. In addition occasional chips of a slaty nature occur, and in this respect the rock differs from the Cil-y-Coed conglomerate. The matrix of the conglomerate is felspathic, and approximates both in hand specimens and under the microscope to that already described at Cil-y-Coed. The rock is considerably sheared, and the pebbles have arranged themselves in the direction of shear, which dips generally at an angle of 70° S8.S.E. The true dip of the conglomerate is obscured by cleavage. (ii) G@rit.—Overlooking the conglomerate, to the south-east of it, is a coarse grit in which there are several bands of a much finer grit. Some of these bands, though only 1 inch thick, are very persistent. In one locality the river runs for 100 yards in a N.K.-S. W. direction. Here the bands are perfectly horizontal, suggesting that the strike of the rock is approximately in the same line. Further down the river runs east and west, and here the dip of the beds can be observed owing to the alternation of fine and coarse bands. A lateral gap, at another locality further east, shows that the banding is persistent on both sides of the gap. The dip given by this banding is 50° S.E. At the extreme southerly bend ofthe river the grit becomes much less felspathic, approximating more nearly to a quartzite. ‘I'he rock weathers almost white, and on breaking shows crystals of opalescent quartz. This type of rock is predominant on the south-east bank of the river. Near the farm of Pen-y-bont (also on the left-hand side of the river) there is another exposure of quartz grit. It forms a small island bounded on one side by the river and on the other side by a ‘“‘cut out” or old overflow channel. The line of outcrop here trends 20 N. of E., and the beds are very nearly vertical. This does not agree with the observations in the main mass. (iii) Purple Slate—For some distance beyond this grit the land is completely under cultivation and no exposures are visible. However, in a well that was dug in 1913 in the school playground at Bryn- eurau (500 yards south-west of Craig-y-Dinas) purple slate was 24 HEH. W.Hughes—Geology of Part of Carnarvonshire. reached. Exposures of purple slate also occur in the meadow below Coch-y-big, and also near the outhouses at Llech-y-dwr. The dip of the slate cannot be ascertained, but the position of the three exposures gives some indication that the strike here is similar to that of the Cambrian slates in the Nantlle Valley—namely N.N.E.-S.S.W. If this were the case, purple slates would be present at a point within 300 yards of the grits at Craig-y-Dinas, in the exact position in which they should stratigraphically occur. Unfortunately the exposures are not sufficient to verify this. The Survey memoir mentions Llwyd-coed (2 miles to the north-east) as the most southerly exposure of the Cambrian purple slates.’ (iv) Green Slate.—One hundred yards due east of the exposure of — purple slate at Llech-y-dwr the one already referred to at Pentwr is found. This exposure shows a band of fine grit in green slate, both macroscopically very similar to the grits and green slate that overlie the purple slate both in the Nantlle and Llanberis quarries. Still further east, 60 to 70 yards away, near Ysgubor- Wen, there is also an exposure of green slate. As already mentioned, the weathered surface shows the cleavage to strike E.N.E.-W.S.W., but the dip of the beds cannot be determined in such a small exposure. No further exposures of any description are to be seen in this neighbourhood until we come to the hill of Y Foel. The whole of this hill consists of black slate showing poor cleavage and containing iron pyrites in large quantity. These slates are put down as of Ordovician age in the Geological Survey map, but no fossils have been obtained here. They closely resemble the black slates in the quarry to the south-west of Cil-y-Coed. EXPLANATION OF PLATES. , PLATE I. Fie. 1.—Quartz-rhyolite, Cil-y-Coed. Showing two large crystals of corroded quartz (a) and (b); fluxion structure (c) winding round a crystal of muscovite on the left and of orthoclase (d) on the right. Natural light. x 18. ,, 2.—(Fig. 1 above, under crossed nicols.) Showing microspherulitic structure. The quartz crystal (a) and the orthoclase crystal (d) are the same as in Fig. 1. The flow-structure (c) is still evident. x 18. », 3.—Rhyolite, Cil-y-Coed. Showing very small spherulites (d) and fluxion structures (b); also porphyritic crystals of biotite (a) and orthoclase (c). Natural light. x 18. ,, 4.—(Fig. 3 under crossed nicols.) Showing microspherulitie structure (a) and (b). x 80. ,, 5.—Rhyolite, Cil-y-Coed. Showing slight flow-structure (b) ; phenocrysts of plagioclase (a) and quartz (c), corroded and invaded by the groundmass. Crossed nicols. x 18. ,, 6.—Conglomerate, Cil-y-Coed. Showing a chip of felsite (a) ; quartz (d) ; and an angular chip of tuff (b) containing a quartz crystal (c) and a decomposed felspar (e). Natural light. x 18. PAPE Tale - ,, 1.—Matrix of conglomerate, Cil-y-Coed. Containing subangular quartz crystals (a) and grains of felsite (b) and (d) in an abundant sericitiec matrix (c). Natural light. x 18. 1 See extract on p. 21. Dr. Walcott’s Cambrian Geology & Paleontology. 25 Fic. 2.—Matrix of conglomerate, Cilgwyn. Containing subangular quartz erystals (c) and grains of felsite (a) in an abundant sericitic matrix (6). Natural light. x 18. . ‘ », 8.—Quartz grit, Cil-y-Coed. Containing angular quartz crystals (c) embedded in a felspathic groundmass; small grains of felsite (rather decomposed) (a); occasional felspars (6); and abundant iron-ore (d). f Natural light. x 18. », 4.—Quartz grit, Bwlch-y-llyn. Containing angular quartz crystals (a) embedded in an abundant matrix (c) now largely decomposed into sericite.. Abundant iron-ore (6). Crossed nicols. x 18. », ).—Sheared quartzite, Cil-y-Coed. Crossed nicols. x 18. », 6.—Sheared quartzite, Bwleh-y-llyn. Crossed nicols. x 18. (To be concluded in owr next Number.) V.—Dr. Cuartes D. Watcorr’s CamBrian GEOLOGY AND PaLmontToLoey.! By V. C. ILLING, F.G.S. O the student of Cambrian geology, the writings of C. D. Walcott are always matters of enlightening study, not only for the matter they contain but also because they combine that admixture of stratigraphy and paleontology in which the latter, though accorded a prominent position, is always used to the full to subserve the wider claims of the former. | In a consideration of the series of papers on Cambrian Geology and Paleontology in the Smithsonian Miscellaneous Collections, the subjects covered are so varied and extensive that only a few of the more salient points can be considered. Perhaps it will be most convenient to discuss the material under the two general considera- tions of the more purely paleontological and the stratigraphical. Among a series of new forms, some of the most remarkable are a number of Merostomata, Malacostraca, Holothuroidea, and Annelids, found in the Burgess shale of the Stephen Formation in British Columbia. In many cases the impressions of the organic structures are beautifully preserved in the fine-grained material, a fact to which full justice is done in the figures. The Merostomata are particularly interesting in this connexion as indicating to what a degree of development these Middle Cambrian faunas had attained. But to the stratigrapher it is the trilobites to which the main interest generally attaches, and among the various groups the Mesonacide or Olenellidz stand out in their interest andimportance. This family, characterized by its large head, large crescentic eyes, rudimentary facial sutures, genal spines, and long and variable thorax, has now been divided into a number of genera based mainly on variations in the thorax. Walcott recognizes six main stages in the development in an order of decreasing number of thoracic segments. 1. Nevadia Stage. The seventeen anterior thoracic segments are of the usual type, but are followed by eleven primitive posterior segments with spinous extensions. 2. Mesonacis Stage. The first fifteen segments are normal, except the third, which is enlarged, and the fifteenth, which has a median spine. The ten posterior segments are normal in shape but small. 1 Smithsonian Miscellaneous Collections, 1910-15. 26 Dr. C. D. Walcott’s Canibrian 3. Hlliptocephala Stage. The first fourteen segments are of the uniform type, while the posterior five segments are short and have long median spines. 4. Holmia Stage. The sixteen segments of the thorax are all of the uniform type. 5. Pedeumias Stage. The third segment is enlarged and the fifteenth segment is developed into a long spine. Beneath and behind this spine there are from two to six similar but smaller spines. 6. Olenellus Stage. There are only fourteen segments, of which the third is enlarged; the fifteenth segment has developed into a strong telson. These changes in the thorax are sufficiently marked to form good generic delimitations in most families of trilobites, but it seems possible that the Mesonacide were undergoing rapid evolution; thus Olenellus thompsoni goes through a Holmia and Psdeumias stage before reaching the true Olenellus stage, and it may be that the discovery of new material will produce adults of transition stages, which will make generic identification difficult where genera have been made somewhat lavishly. It cannot be assumed that the collections of these Lower Cambrian forms are within measurable distance of completion. A tentative sub-zoning of the Lower Cambrian is suggested by Walcott, based partly on the known stratigraphical occurrences ot the Mesonacids in the few rare instances where successive forms exist in the same region, but mainly on the order of development. D. Olenelius Zone (Upper). C. Callavia Zone. B. Llliptocephala Zone. A. WNevadia Zone (Lower). It will be interesting to find how far this tentative scheme will stand the test of future work. In Europe there are at present no positive facts by which the merits of the classification can be tested, but the series of beds of the Solva type of lithology, which occur in Wales and at Nuneaton in the English Midlands, are suggested as a hunting- eround—we cannot call it a “happy” one—which ought to be exhausted: Another subject of general interest is the sudden appearance of life in the Cambrian period, which has for long engaged the attention of geologists, and acted as a harmless safety-valve when the impetus to theorize would not be denied. But in the case of the papers under discussion, behind the explanation there is a unique knowledge of the stratigraphical relationships of the Cambrian and pre- -Cambrian rocks in North America, coupled with the new light shed on Cambrian stratigraphy by the recent researches of Mr. Bailey Willis and Mr. Blackwelder in China and of H.M. J. Deprat and H. Mansay in Yun-nan. The suggestion that there is an extensive break in the succession between the Cambrian and pre-Cambrian in all known localities, and that the Algonkian deposits are all epicontinental, appears to be the most probable explanation of the sudden appearance of prolific organic life in the Lower Cambrian. However, there Geology and Paleontology. 21 must still remain the reservation that there is room for many important discoveries in the pre-Cambrian sediments; and although the contention may be true in the main, we may still find the progenitors of the Cambrian types in pre-Cambrian sediments situated in favourable localities, i.e. as distant as possible from the centre of the pre-Cambrian shield and beyond the limits of the Algonkian continents. . The present best-known pre-Cambrian fossils are the Peltina of the Belt series, but as an interesting supplement to the recent researches of Professor Garwood on the importance of the work of alge in the formation of the geological record, Walcott describes a series of forms which he compares to the Cyanophyicee in the limestones of the Belt series and other Algonkian deposits of the Cordilleran region. Apart from these and a few rather doubtful eases, fossils are conspicuously absent in the pre-Cambrian. At the same time a break appears to exist between the pre-Cambrian and Cambrian in Asia, North America, and Europe. In Eastern Asia, as far as the evidence at our disposal will allow us to speculate, north- ward transgressive movements seem to occur in Lower and Middle Cambrian times, the transgression being continued into Upper Cambrian times. A similar set of movements are found in North America with minor oscillations and local regressions in Middle Cambrian times. In Europe there is a suggestion of similar conditions, a basal unconformity, a set of shallow water and laterally varying Lower and Middle Cambrian deposits with abundant non- sequences (some parts of the Middle Cambrian are more extensive and suggest open waters, but not deep waters), and an important transgression in the Upper Cambrian. Thus the Cambrian period in all three regions represents a time of great oscillatory transgressive movements culminating in the Upper Cambrian, during which the great Algonkian continents were invaded by shallow seas in which marine faunas thrived and multiplied. The record of this oscillatory but generally progressive submergence is shown not only by the stratigraphical relationships of the strata, the proved disconformities and overlaps, but appears also in a general survey of the geological provinces of this period. Taking NorthAmerica and Hastern Asia for example, the Lower Cambrian faunas can be broadly grouped into two main provinces, the North American with Olenellus, etc., and the Eastern Asiatic with its peculiar form Redlichia. In Middle Cambrian times there are again two broad subdivisions, the Pacific and Atlantic, but the dividing line has shifted eastward into the American continent, and the faunas are more varied as a result of the wider extent of shallow seas. During Upper Cambrian times there is a general merging of the various faunas, and the differentiation into provinces becomes indistinct. — The history of the faunas is an indication of the history of their habitat, and this Cambrian record indicates the migration and then the breaking down of barriers, the gradual evolution of a narrow strip of shallow seas on the border of large continents, to an epoch of shallow seas and islands, and finally wide marine areas merging and growing around much diminished continental areas. 28 Notices of Memoirs—Carboniferous Flora at Gullane. NOTICES OF MEMOTRS. —~>—_—_ J.—Rerporr or tun ComMITrEE FoR INVESTIGATING THE Lower CarponiFERous Frora av GULLANE.' Consisting of Dr. R. Kidston (Chairman), Dr. W. T. Gordon (Secretary), Dr. J. 8. Flett, Professor E. J. Garwood, Dr. J. Horne, and Dr. B. N. Peach. NEW discovery of petrified plant-remains was made, in 1914, ata point below high-water mark near Gullane, Haddingtonshire. The place could only be reached at certain states of the tide. In order to accelerate collecting, blasting operations were proposed, and a grant voted at last meeting of the Association to meet the expenses. The locality, however, lies within the area of the Forth Estuary, and, although the military and police authorities readily gave per- mission to blast on the foreshore, it was considered inadvisable to act on that permission meanwhile. No part of the grant was used therefore, but sufficient material has been collected to amplify considerably the data already obtained. Some 150 thin sections. of the material have been prepared and examined. The flora represented in these sections is as follows :— Lepidodendron veltheimianwn, Bensonites fusiformis, R. Scott. Sternb. Pitys prumeva, Witham. Stigmaria ficoides, Sternb. Pitys day, sp. noy. Botryopteris (?) antiqua, Kidston. Pitys, sp. nov. Chief importance is attached to the specimens of Pitys, as so many well-preserved specimens have never been obtained elsewhere. Many of these examples had the bark preserved, while one of them consisted of a branch tip still clothed with needle-like leaves. Much light has been thrown on the stem structure of the genus, while the details of the connexion of leaf and stem have also been determined. As regards the other plant types represented, it is interesting to note the similarity between the whole assemblage and the flora of the Pettycur Limestone at Pettycur, Fife. Indeed, the form Bensonites fusiformis, R. Scott, has not, so far, been recorded except from Pettycur. Both Gullane and Pettycur lie on the Forth, and the geological horizon of the rocks at both localities is not very different, so that the similarity of the floras is not surprising. The specimens from Gullane occur in a greyish-white clastic rock, which on examination proved to be a highly decomposed volcanic ash. It is suggested that the decomposition of the ash, by vapours emitted from the voleano during its activity, produced solutions of mineral matter which caused the petrifaction of plant fragments included in the ash. These plant fragments occur quite sporadically through the rock, and they have evidently not been drifted in water. The petrifying solutions have been both calcareous and siliceous, so that some specimens are preserved in carbonate of lime, others in silica, while a few are partly in the one and partly in the other. The perfection of the preservation is very striking, and it is proposed to continue collecting specimens when possible. 1 Read before the British Association, Section C (Geology), Newcastle, 1916. Notices of Memovrs—The Paleoliths of Farnham. 29 I].—Tae Patmorirus or Farnuam.! By Henry Bory, F.G.S. HE information contained in a previous paper on the same subject (Proc. Geol. Assoe., vol. xxiv, pp. 178-201) is here revised and enlarged. The implements of the Alice Holt Plateau (ineluding Terrace A) are usually large (5 to 8 inches long), and very few are later than the Chellean period. On Terrace B, on the contrary, the majority of unabraded implements are small (3 to 4 inches long), and quite 40 per cent are Acheulean. ‘here are also many flakes, used as scrapers, which may be Mousterian. ‘Terrace C, beyond a few Le Moustier flakes, yields no clear evidence of its age; but it is not impossible that the valley may have been excavated to this depth in early Chellean times. On ‘Terrace D unabraded implements are extremely rare, but among them are a few which may be of Le Moustier age. Another terrace (EK) about 20 feet above the river is covered with a thick layer of drift, but has so far only yielded one implement. REV LewSs- I.—A prAcTocLzEIDUS TERETEPES: A NEW OxrorDIAN PLEsIosauR In tHE Hounrertan Museum, Guascow University. By W. R. Smetiiz, M.A., B.Sc. Trans. Roy. Soc. Edin., vol. li, pt. iii, LOMG: N this paper the author gives a very detailed account of the remains of a Plesiosaur collected by Mr. A. N. Leeds in the Oxford Clay of Peterborough. The skull and caudal region are missing, but otherwise the “skeleton is nearly complete. In many respects this form is intermediate between Cryptocleddus and Tricleidus. Thus, in the fore-paddle the humerus articulates distally with the madius, ulna, pisiform, and a small accessory ossicle, as is the case in Triclecdus. On the other hand, in the shoulder-girdle the inter- clavicle is very small or absent, and the triangular clavicles meet extensively in the middle line as in Cryptocleidus. For these and other reasons the author has established a new genus for the reception of this form. Many of the characters, however, which are regarded as indicating the higher organization of this type, are certainly merely the result of the great extension of the ossification of the bones consequent upon the advanced age of theindividual. Such characters are the extension forward of the scapule in advance of the clavicles, and the elongation of the dorsal rami of the scapule and of the postero-lateral processes of the coracoids. This interesting paper is illustrated by nine text-figures and one plate. 1 Read before the Geologists’ Association, December 3, 1916. 30 Reviews—Geology of Ben Nevis. II.—Tae Grotoey or Ben Nevis anp Guun Coz (Explanation of Sheet 53). Memoirs of the Geological Survey, Scotland. By E. B. Bartny, M.A., and H. B. Mavre, M.A.; with contributions by, Cre 0. CroveH, J.8. Grawr Wison, G. W. Grabyam, M.A., H. Kywaston, B.A., and W. B. WrieHt, B.A. pp. 247, with 12 plates. 1916. Price 7s. 6d. f{\HIS memoir describes the geology of the region that contains the — highest mountain and perhaps the wildest and most rugged country in Great Britain. All phases of its geology are replete with interest. The area is a greatly dissected part of the main Highland plateau, with a summit level of about 3,000 feet. Ben Nevis and other high peaks rising above this level are regarded as features dating from an earlier geographical cycle. Loch Linnhe, lying in a north-easterly direction along the shatter-belt of the Great Glen, divides the area into two unequal parts. Another system of valleys runs W.N.W.-E.S.E.; and these remarkable ‘through’ valleys, cut athwart the grain of the country, are consequent upon the pre-glacial uplift of the Highland plateau. Glacial erosion is believed to have cut off spurs and thus widened the valleys. In some cases it is responsible for hanging valleys, although general deepening of valleys by ice action is considered improbable. A large part in breaking up the ‘through’ valleys into segments is attributed to the formation of pre-glacial delta-watersheds or corroms. While accepting many of Professor J. W. Gregory’s views as to the origin of fiords, the authors are not inclined to attribute so much potency as he does to earth- movements (gaping faults and joints) in the development of the typical West Highland fiords. The subject of prime interest in this memoir, however, is the structure and succession of the Highland Schists. These rocks form the basement of the whole district, but are partly covered by extensive outpourings of Old Red Sandstone lavas (Glen Coe and Ben Nevis), and are intruded by great masses of plutonic rocks, principally granite (Ben Cruachan, Ballachulish, Ben Nevis). The Highland rocks consist of alternations of phyllite, mica-schist, and “quartzite, with thin horizons of limestone which form good datum-lines for the inter- pretation of the structure. The folding of the rocks is very complex. Mr. E. B. Bailey has developed the view that the rocks are arranged in a number of great recumbent folds, which are frequently ruptured along fold-faults or slides. In certain cases the major folds have been bent into later secondary folds, and have been dislocated by ordinary faults. In consequence of the extraordinary inversion and repetition the beds have suffered, the original stratigraphical sequence is doubtful, and it is not known which is the top or bottom of the list of formations. As usual, in the interpretation of regions of extreme complexity such as this, differences of opinion arise; and in regard to the Kinlochleven district Mr. Carruthers holds views at variance with those of Mr. Bailey. The chief difficulty appears to be the number of formations recognized by the respective observers. Mr. Carruthers increases the number of stratigraphical horizons and Reviews—Geology of Ben Nevis. 31 consequently diminishes the complexity of structure. Without special knowledge of the area it is impossible to decide between the rival views. Mr. Bailey, however, accepts Mr. Carruthers’ interpre- tation as on an equal footing with his own for the district in question, his own view being based on a restricted sequence and greater structural complexity. The interest of the region is well maintained in the next series of rocks, the Old Red Sandstone lavas which centre about Glen Coe and Ben Nevis. They consist of hornblende-, pyroxene-, and biotite- andesites, with rhyolites, and have been poured out on to a very uneven surface of the Highland schists. The two great areas of lava in this region, although forming the highest ground, owe their preservation to subsidence within great circular faults. One of these encircles the Glen Coe lavas, except on the south, where the fault- line is broken through by the Cruachan granite. Igneous material rose along the peripheral fault during subsidence, but never penetrated to the inner side of the fault plane. The fault intrusion is chilled against the fault plane, and is usually separated from it by a band of flinty crush-rock produced by the friction of the subsiding mass. Both the larger granite masses of the region show distinct inner and outer portions, of which the former are the younger. They are interpreted as magmas which filled the voids caused by successive cauldron-subsidences. The concentric arrangement of the Ben Nevis granites and lavas is explained in this way. The magmas are believed to have been emplaced largely by the stoping method described by Daly. The detailed petrography of the Old Red Sandstone igneous rocks is dealt with in a separate chapter. Their composition is illustrated _ by a fine series of new chemical analyses. There is a useful | historical account of the terms granite, granitite, tonalite, adamellite, banatite, granodiorite, etc., but the conclusions adopted as to their scope are open to criticism. Two new rock names, aplogranite and appinite, have been invented, but their definitions are at once too vague and broad to be of much use. The uselessness of measuring the quantitative relations of the minerals of igneous rocks by the recognized micrometric methods is illustrated by a highly fallacious diagram. The various granites of the region have produced remarkable metamorphic effects on a great variety of rocks, including schists, sediments, and igneous rocks. These are dealt with in a chapter which is a distinct contribution to the literature of contact metamorphism. A group of W.N.W. dykes of dolerite, basalt, and monchiquite are regarded as of Tertiary age. A small explosion vent in the Allt Coire na Ba may also be Tertiary. The breccia is invaded by a basic rock which proves to be a fresh nepheline-basalt. The final chapters deal with the glacial phenomena and with the economic products of the area. Roofing slates and granite are quarried on a comparatively large scale at Ballachulish. The memoir, which has been edited and mainly written by Lieut. E. B. Bailey, is excellently illustrated by twelve fine plates 32 Reviews—Late Pleistocene Oscillations and numerous maps and diagrams. The Scottish Survey geologists are to be congratulated on the memorable results of a long, patient, and intricate piece of work. Gi Wes Il[.—Lare Pretsrocene Oscmnarions oF Sua-LEVEL IN THE Orrawa Vatiny. By W. A. Jounsron. Geological Survey of Canada, Museum Bulletin No. 24; 1916: ies the attention of British geologists is at the present time mainly directed to economic problems, it is nevertheless very desirable that a paper of such scientific importance as that about to be discussed should be brought to their notice. ‘The author has made a notable contribution to the study of late-glacial changes of sea-level, and the facts he has put on record might almost be said to constitute a complete demonstration of the applicability of the theory of isostasy to these changes. It will be recalled that this theory ascribes the raised or tilted shorelines which are found around the centres of glacial dispersal to the sinking in of the earth’s crust beneath the pressure of the ice- sheets, and its subsequent recovery when the ice has melted away. The depression and recovery were greatest at the centres of dispersal where the ice was thickest, with the consequence that the shorelines are highest near these centres and descend gradually towards the margins of the glaciated districts. Before they reach these margins, however, they invariably pass beneath the present sea-level. ‘There are no late-glacial raised beaches in the peripheral parts of the glaciated districts, the shorelines which were formed during the retreat of the ice from these areas being all beneath the present sea- level. This relation indicates very clearly that the general sea-level must have been considerably lower during the earlier stages of retreat than at the present day, and the same conclusion can be arrived at on @ prior’ grounds by considering the effect on the ocean-level of the binding up of enormous quantities of water in the ice-sheets. We have, therefore, in seeking for an explanation of the late-glacial changes in the relative level of land and sea, two factors to deal with. The first is the isostatic recovery of the earth’s crust, the second is the general raising of level of the ocean due to the melting of the ice-sheets. According as the first or second of these factors predominated there occurred either emergence or submergence in the isostatically affected areas. This appears to be the explanation of the curious fact established by Brogger in the Christiania region, that the first change of level after the retreat of the ice was one of submergence, ice at a somewhat later stage of retreat, gave place to emergence. That this is the course of events to be expected from the interplay of the two factors mentioned is apparent from the following considerations. 1. At the period of deposition of the earlier late-glacial marine deposits from which Brogger drew his conclusions, about one-third to one-half of the total retreat of the ice-margin had been accomplished; and it is roughly at this stage of retreat, when the climate had already considerably ameliorated, and there was at the same time & of Sea-level in the Ottawa Valley. 33 a large body of ice still in existence, that the most rapid return of water to the ocean is to be expected. 2. Brogger has clearly established that the isostatic recovery progressed with a wave-like motion from south to north along the Cattegat, following up the retreating ice-margin. This seems to indicate that the recovery takes some time to get under way, and does not attain its maximum rate until the neighbourhood is altogether clear of ice. At this particular period of the retreat, therefore, it would be natural to expect that the rise of the ocean level might be, for a time, faster than the isostatic recovery, and submergence would result. .. ater, when the isostatic recovery had gathered pace and the amount - of water returning to the ocean from the waning ice-sheets had become gradually less, we might expect the isostatic recovery to attain the upper hand and give us progressive emergence. Now the best test of the validity of this theory is its applicability to the isostatically affected areas of the British Isles and North America. Unfortunately, inthe British Isles the highest late-glacial shoreline is only 100 feet above the present sea-level, and within this small vertical range evidence of the kind utilized by Brogger is not to be expected. In North America, until the appearance of the paper under review, no investigation, such as would bring to light a relation of this nature, appears to have been placed on record. Johnston now brings forward evidence, of a nature similar to that adduced by Broégger, to show that the late-glacial changes of sea-level in the Ottawa Valley were precisely the same as those established for the Christiania region, namely, that the sea first rose on the land as the glaciers retreated, and that it was not until a later date that emergence supervened. Moreover, he makes a further point of great importance in establishing the isostatic theory on a firm basis. This point, for which there was no direct evidence in the Norwegian ease, is to the effect that the tilting of the Great Lakes region was in progress before and during the rise of the sea in the Ottawa Valley, for, presumably from a consideration of contemporaneous ice-margins, it is concluded that ‘‘ the Ottawa Valley must have been, in part at least, occupied by the ice-sheet during the existence of Lakes Iroquois and Algonquin, and at least a small amount of uplift affected the region at the foot of Lake Ontario during the life of Lake Iroquois. Uplitt also affected the northern portion of the Great Lakes region, and probably included the upper portion of the Ottawa Valley near Mattawa during the existence of Lake Algonquin, and while the ice-sheet still occupied the upper portion of the Ottawa Valley” ' Further, it is not a case of alternating elevation and depression, ‘‘for the results of investigations by numerous geologists, of the raised beaches of the Great Lakes region, has shown that differential uplift took place almost continuously as the ice withdrew.” We thus have direct proof that a district which was rising relatively to those around it was nevertheless undergoing submergence beneath the level of the sea, that in fact the two Paginse eared to explain the late-glacial changes of level were in action simultaneously in the same region. DECADE VI.—VOL. IV.—NO. I. 3 34 Reviews—United States Geological Survey. There is now but one thing wanting to make the analogy between the isostatic phenomena of America and Europe perfect in every detail, and that is the discovery of a shoreline corresponding to the ‘early Neolithic’ or ‘ Littorina-Tapes’ raised beaches of Great Britain and Scandinavia. This should represent in the south a distinct resubmergence, and in the north a pronounced check or slowing down in the general emergence. We must congratulate the author of the paper under review on having made a striking advance in Quaternary geology. Is it too much to hope that-he will carry his researches further, and complete the history of the changes of level in his district down to the present day ? W. B. Wriear. TV.—Turrety-stxta AwnvaL Report or THE DIRECTOR OF THE Unirep Srates GrorocicaL SuRVEY TO THE SECRETARY OF THE INTERIOR FOR THE YEAR ENDED JUNE 30, 1915. pp. 186, with 2 coloured plates. Washington, Government Printing Office, 1915. Y its very reticence and conciseness this slender volume is eloquent testimony to the extensive and multifarious character of the work carried on by the United States Geological Survey. How large and useful are the services it renders may be gathered from the following extract from the opening page of the report itself: ‘‘ The recognition by citizens generally that the Geological Survey is a bureau of information as well as a field service has gradually placed upon it a large burden of work as well as of responsibility. The amount of correspondence involved in performing this public duty may be indicated by the fact that approximately 50,000 letters of inquiry were handled in the different scientific branches of the Survey last year. The scope of these inquiries is not less noteworthy, for they range from requests for information concerning the geology of every part of the United States or the water supply, both under- ground and surface, of as widely separated regions as Alaska and Florida, or for engineering data on areas in every state in the Union, to enquiries regarding the natural resources of foreign countries, especially those of Central and South America.” So large has the Survey grown that for convenience of administration it is divided into six main branches, each of which is subdivided into various divisions, certain of which are further subdivided into sections. First and possibly foremost of them comes the Geologic Branch, which is responsible for the geological work of the Survey. Though it was primarily formed for the comparatively restricted task of the classi- fication and examination of the public lands reserved to the state, its scope has been extended to the preparation of a geological map of the whole of the United States. The nature of its duties is best set forth in the words of the Report: ‘‘ At present the geologic branch is not only the effective agency of the Survey in the geologic investigations carried on by the Government in all parts of the United States and Alaska but also the great geologic information bureau to which the American public, from Key West to Point Barrow and from San Reviews—United States Geological Survey. 35 Diego to Eastport, applies for knowledge of every sort concerning the earth’s crust and its mineral constituents. To the people of this country and, in a surprising degree, to the citizens of other countries, the Survey is the principal source of geologic information regarding not only the geology of the United States and its possessions but also that of Mexico, Central America, and even South America. Through its correspondence it is asked for data regarding the geology and mineral deposits of all parts of the world. The geologic branch has therefore the double task of geologic surveying, including the investigation, description, and mapping of the geology and mineral deposits of all parts of the country, the classification of the public lands, and the publication of the results of its work on the one hand, and of furnishing to the public miscellaneous geologic information derived from all sources on the other.” The Geologic Branch is divided into four divisions, viz. geology, Alaskan mineral resources, mineral resources, chemical and physical researches, which though working on independent lines yet co-operate effectively with one another. We read that the scientific staff of the division of geology at the beginning of the year consisted of 66 geologists, 33 associate geologists, 26 assistant geologists, 15 junior geologists, and 22 geologic aids, a total of 162. It must further be remembered that besides the Federal Survey many, if not all, the States have their own Bureaus of Mines and Geological Surveys, and much of the field-investigation and paleontological research has been conducted in connexion with the local staffs. In order to secure uniformity in the geological names the question is considered by a standing committee of the branch, the secretary of which scrutinizes the nomenclature and classification in all manuscripts submitted for publication. The work of the division of chemical and physical research is not wholly confined to the customary routine analyses, but includes many investigations of considerable scientific interest. The ‘division of mineral resources is responsible for that valuable annual return entitled ‘‘ Mineral Resources of the United States’’; upon its preparation no fewer than sixty persons are wholly or partly engaged. The Topographic Branch is engaged on geodetic work, and up to date has mapped 40-2 per cent of the entire country; its skilled staff numbers 159. One of the most important objects of the work carried on by the Water Resources Branch is the investigation of underground water with the view of the irrigation of arid areas; the skilled staff numbers 76. The fourth Branch, viz. the Land Classification Board, which was _ the origin of the Survey, collates the results of the investigation of public lands made by the branches already mentioned. Since the classifications required by the public lands laws fall into two broad groups, depending upon the presence or absence of mineral deposits or of water respectively, the Board is divided into two divisions, the - one for mineral and the other for hydrographic classification. Last of all we have the Publication and Administration Branches. The total expenditure on the whole Survey amounts to nearly one and a half million dollars. This is not the place to discuss at length the points suggested by 36 Reviews—Petroleum and Gas Resources of Canada. this Report or the lessons for ourselves that may be drawn from it, and we shall confine ourselves to a brief paragraph. There is much to be said for establishing an institution to serve a similar purpose for the British Empire—an institution which should ever be ready to explore outlying and little-known quarters of the Empire, and to investigate and report upon their resources,'! and which should cordially co-operate with and encourage the local geological surveys. Something has already been done, and perhaps as the result of these tragic days something more may eventuate ; we have at least been | thoroughly taught the danger of depending solely upon the result of haphazard individual effort. At the Imperial Institute there is a small staff under the Colonial Office to undertake investigations of the kind in point, with particular reference to the Crown Colonies. Very useful work has been turned out, but all on too small a scale: the staff is not large enough, and the financial equipment far from generous or sufficient. Geological surveys exist at home and in the great dependencies: all work independently and without mutual co-operation. In Great Britain the Geological Survey, which— perhaps humorously—is placed under the Board of Education, has devoted itself to investigations of some scientific interest, but appears to have carefully avoided the risk of being reproached with doing anything which might prove of economic value. Only under the stress of war has it so far broken through its traditional aloofness from mundane affairs as to issue a series of monographs on the mineral resources of the United Kingdom. A small and distinct Survey is maintained in Dublin. To complete the picture of heterogeneity it only remains to add that the actual working of mines comes within the purview of the Home Office. V.—Perroreum and Nartoran Gas Resources or Canapa. By Freperick G. Crapp and others. Vols. I and II. Canada, Dept. of Mines, Mines Branch No. 291. fJ\HAT the various members of the British Empire are alive to the extreme importance of the question of liquid and gaseous fuel is shown by the recent activities of the government departments of the chief self-governing Colonies in investigating their natural resources of oil and gas. Canada, whose oil industry dates back as far as 1857 and whose gas industry has now far outstripped the former in value, and is growing enormously, has rendered a service to the oil investigator in the publication of two volumes on Petroleum and Natural Gas Resources of Canada, which, in addition to a series of general chapters on Petroleum problems, combine in a very accessible form the available knowledge on the various fields, and include a series of useful maps. The first of the volumes deals with general oil and gas problems, geological, chemical, engineering, and economic, and the composite authorship gives it this advantage, that the various subjects have each been considered by investigators and workers in the particular branch; thus we are spared the anomaly of the geologist writing on engineering or the engineer writing on geology, with the usual ‘ Reviews—Petrolewm and Gas Resources of Canada. 387 unfortunate results. It would have been preferable to include more of the Canadian element in the authorship, for certainly in the first volume the writers appear only at their ease when citing examples from the United States, but as a general treatise on petroleum vol. i will probably find a much wider circle of readers than those interested in Canadian oil-fields. In it are collected what is really a series of essays on petroleum problems, some of them but mediocre, a dull restatement of well-trodden ground, but others distinctly fresh and well-balanced, with clear concise wording - where descriptive, and full of suggestive ideas where theoretical. _ It would probably have been of advantage to omit most of the first chapter, for to summarize the world’s oil occurrences in thirty pages, country by country, is to attempt the impossible and to involve the bewildered student in a labyrinth of dead place-names. Chapter ii contains much useful physical and chemical data, while under the heading ‘‘ Geological Occurrence of Petroleum and Natural Gas”, chapter iv, there is a clear and short account of the various theories of the production of natural hydrocarbons, in which the ' author safely joins both sides of the warring camps of the upholders of organic origin. But the remarks on oil migration do not break any fresh ground, and here unfortunately the need is most lamentable. ‘There comes a time in the history of all theories when a few adverse storms are necessary to unsettle the fallacies which take root so easily and to orient ideas to fresh facts. It is a pity that the current ideas of oil migration have lived so long in the belt of calms, for, strange as it may seem when considering the importance of the subject, we do not yet know how, when, why, or how far an oil will migrate. Gravitation, capillarity, different specific gravity of water and oil (and some authors concede gas pressure) are the sum-total of the admitted agents on migration, yet it is doubtful whether any one of these has any primary effect on the initial movements of the oil, and it is just these which are so important. Gravitation in ‘the accepted sense of the migration theorist requires free pore-space for downward motion, but water-borne sediments will certainly be water-clogged in their finer deposits. Capillarity will cause oil to migrate in fine dry deposits, but it is a movement from the larger pore-space to the smaller, not from the fine deposit to the coarse, and in addition there is the same difficulty that the sediments will almost certainly not be dry. The differential specific gravity of water and oil will have its expected result in the proper conditions, i.e. where the pore-space is large enough to allow a certain limited circulation of liquids, but the hydrocarbons originate in the fine- grained deposits, and it is just this initial migration from the fine deposits to the contiguous coarse deposits wherein lies the difficulties with the present theoretical ideas. When, however, the secondary processes which take place in argillaceous sediments immediately after deposition are examined, and the gradual diminution of pore- _ space during compacting, with its necessary out-pressing of water and other liquids, is taken into account, it is evident that here is a very potent factor in the expulsion of liquids from fine material which is easily compacted to coarse material which is more resistant to 38 Reviews—Johnson & Huntley—Oil & Gas Production. pressure. There is no doubt that the effect of earth stresses, as apart from the pressure of the overburden, will have similar results. Turning now to the chapter on drilling, the 105 pages devoted to this subject are an extremely useful summary of the methods of drilling, dealing with the matter in a way which adds interest to a subject which is usually not very entertaining. The conservation of oil and gas resources 1s another subject of striking importance. Vol. ii contains a description of the oil-fields of Eastern and Western Canada. In Eastern Canada the more important points of interest are the recently developed gas-field of New Brunswick, and the possible resources in oil shales in the same province. Ontario is still the chief oil and gas producer, but of recent years Alberta has been coming to the fore with a rapid increase in gas production. In this province the hydrocarbons are obtained from the Cretaceous Sandstone, at an horizon approximating to the Dakota sandstone. In Athabaska and contiguous regions there are the extensive outcrops of asphaltic sands, the so-called ‘‘ Tar Sands”’, while farther north in the Mackenzie River region wide untapped areas are awaiting further development. Vos VI.—Privertes of Or anp Gas Propucrion. By Roswent H. Jonnson and L. G. Hunrrey. pp. 371. John Wiley & Sons. Price 16s. net. (Y\HE geological aspect of the occurrence of petroleum and natural gasis by no means overburdened with explanatory textbooks, and although the volume under discussion deals in addition with other branches of the oil industry, a large proportion of its pages is devoted to geological considerations. To the European student it is also welcome inasmuch as it emphasizes the essentially American’ aspect of the subject, but the widespread occurrence of natural hydrocarbons in the American Paleozoic leads the authors into dangerous generalizations. Thus it produces the assertion that ‘it is probable that a considerable production will some day be developed in the older formations when they have been thoroughly prospected in Europe and Asia”; butit must be remembered that the conditions of occurrence of the Paleozoic rocks in the Central United States have not their counterpart on this side of the Atlantic, although Asia may produce many similarities. On the other hand, the long chapter on the Oil and Gas Fields of North America is distinctly good, and the chapters dealing with Oil and Gas Reservoirs and the Migration and Accumulation of Oil and Gas, although necessarily short, contain the germs of very suggestive ideas. It is a distinct relief to get away from that obsession for anticlines which has of recent years somewhat obscured the vision of many oil-field geologists. ‘lo such an extent has this hypothesis been taken, that on several oil-fields the converse process of reasoning has been adopted and the presence of the oil been regarded as suflicient proof of the occurrence of the anticline. It is by no means suggested that the anticlinal occurrence of oil and gas is not of great importance, but the promulgation of the idea of its exclusive Reviews—Ore Deposits, Rossland, British Columbia. 39 importance is to be deprecated, while the beautifully simple diagrammatic representation of the successive occurrence of water, oil, and gas in the arched strata is at its best but a crude and partial statement of the whole story. The tendency of modern investigation has been to prove that the original nidus of the hydrocarbons is the fine-grained sediments, and that the migration into the coarser and permanently more porous horizons takes place at an early stage as the result of compacting. | Many of these porous horizons are quite limited in their lateral extent, so that the later migration as a result of tilting and folding movements is often limited, unless abnormal conditions such as faults and joints produce planes of egress for the gas or oil. Hence it is found that as a result of variations in porosity and of irregular deposition of sandy horizons, the primary migration due to com- pacting is often of more importance in the differentiation of oil into pools than the later earth movements, which merely localize the oil and gas in the higher portions of the more porous strata. Of course, in many cases, the coarse horizons are sufficiently widespread to allow the anticlinal hypothesis to hold, but the reverse is more common in nature than is usually suspected. ~ AORN be V1II.—Geotocy anp Ore Deposits oF Rosstanp, Bririsk ConumBta. By Cartes Wares Dryspate. Memoir 77 of the Geological Survey. Ottawa, Government Printing Bureau, 1915. pp. xiv + 317, with 6 maps in pocket, 25 plates, and- 26 figures in the text. fJ\HE rich district of Rossland, which is situated in the Trail Creek mining district of the West Kootenay district of British Columbia, about 6 miles west of Columbia River and 5 miles north of the International Boundary, produces gold, silver, and copper. It was discovered in 1890, and has been worked continuously since 1894. In this memoir the region is very fully described. The -geological features and the mineral enrichment, which present many points of interest, are discussed in some detail. The district appears to have been covered by sea during at least part of the Carboniferous age, and upheaved at the end of the Paleozoic era. An intrusion of augite porphyry occurred during the Triassic period, and at the close of the Jurassic period the rock formations were invaded by the Trail granodiorite batholith, this being the first period of mineralization. Erosion took place throughout Cretaceous times, and at the end the whole Cordillera was uplifted and the present ranges were outlined. The second main period of mineralization occurred in Miocene time. During the Pleistocene a change to a glacial period took place. The ore consists of pyrrhotite, chalcopyrite, pyrite, and marcasite, with a little arsenopyrite, molybdenite, and bismuthinite, in a gangue of altered country rock, containing some quartz and locally a little calcite. The deposits resemble in many respects the well- known ones at Namaqualand, Cape Colony, and possess some structural features in common with those at Butte, Montana. 40 Reports & Proceedings—The Royal Society. VIII.—Unirep Sratzs Survey: Ruopr Istanp Coat. N Bulletin 615 of the U.S. Survey, Mr. George H. Ashley gives an account of Rhode Island Coal, the interest of which is mainly economic, the conclusion being drawn that the coal cannot compete with that produced by New England and Pennsylvania. The coal has an unusually large range, character, and quality, varying from anthracite to graphite, and contains a high percentage of ash and moisture. The coal beds, which were originally of moderate thickness, have been so folded and compressed that, while in places large pockets have been formed, elsewhere they have been nearly altogether squeezed out. The coal ignites slowly and with difficulty, and makes so hot a fire as to destroy stove tops and furnace linings. REPORTS AND PROCHEHDINGS- LY oe Re I.—Tne Royat Socrery. November 2,1916.—Sir J.J. Thomson, O.M., President, in the Chair. ‘‘On the Photographic Spectra of Meteorites.” By Sir William Crookes, O.M., F.R.S. Thirty rare earthy meteorites, mostly acquired through the courtesy of the British Museum Trustees, have been examined. The paper first deals with a few novel features in the construction of the spectrograph. The instrument has a train of five double quartz prisms of the Cornu type, and an explanation of their action in preventing double refraction is given. The jaws of the slit are formed of transparent quartz prisms, cut and mounted in such a manner that the edges appear opaque to light. A device, called the fixed slit system, is described, by which all uncertainty caused by variation in the width of the slit in various experiments is removed. The aerolites were all examined for occluded gases, especially with negative results for any inert gases that might be present. The spectrum tubes showed only compounds of hydrogen, carbon, and sulphur, and a little free hydrogen. The are spectrum of each aerolite has been photographed from the region of the ultra-violet to the end of the visible. The aerolite was powdered, mixed with powdered silver of known purity, and formed into a cake by hydraulic pressure. This gives sufficient cohesion for manipulation and enables it to conduct the current. The resulting spectrum contains, in addition to the lines of the aerolite constituents, only those due to silver, which are comparatively few. Examples of these spectra were exhibited. All the lines given in the are spectra of the thirty aerolites have been identified, and were shown in the spectrum photographs. The examination has revealed the presence of unexpectedly large traces of chromium in all the specimens, a condition quite different to that found in the siderites or meteoric irons, where chromium is practically absent. The proportion between chromium and nickel remains constant in twenty-six out of the thirty aerolites, and is clearly shown in the photographs. In three only nickel is almost absent. Reports & Proceedings—Zoological Society of London. 41 From the experience gained it has been possible to make a mixture containing known quantities of nickel and chromium, which with the addition of iron produces a spectrum in the neighbourhood of the chromium group that is practically identical with that produced by the aerolite Aubres. II.—Zooroetcat Socrery or Lonpon. November 21, 1916. —Dr. S. F. Harmer, M.A., F.R.S., Vice-President, in the Chair. “On the development from the matrix of further parts of the skeleton of the Archeopteryx preserved in the Geological Department of the British Museum (Natural History).”’ Dr. B. Petronievics and Dr. A. Smith Woodward, F.R.S., V.P.Z.S., read a paper on some new parts of the pectoral and pelvic arches lately discovered in the London specimen of Archeopteryx. ‘The coracoid bone most closely resembles that of the ratite birds and the Cretaceous Hesperornis. The pubic bones are twice as long as the ischia and meet distally in an extended symphysis, gradually tapering to a point, which seems to have been tipped by a mass of imperfectly ossified cartilage. IiI.—Epiypuren Geotocican Socrery. November 15, 1916.—Professor Jehu, Vice-President, in the Chair. The following papers were read :— 1. ‘‘A New Locality for Triassic Reptiles, with Notes on the Trias found in the Parishes of Urquhart and Lhanbryde, Morayshire.” By Mr. William Taylor, J.P., Lhanbryde. Mr. Taylor recorded the discovery, in sandstones about a mile north of the village of Urquhart, of a nearly complete specimen of Telerpeton, somewhat smaller than the example described by Huxley in 1866. On account of lithological resemblances he correlated the sand- stones, etc., of Bearshead, Stonewells, Meft, Lhanbryde, and New Elein with the fossiliferous rocks of Lossiemouth and Spynie, and concluded that the Trias of Morayshire was cul more extensive than formerly supposed. The paper was illustrated by a map siowine the distribution of the Triassic rocks in the area extending from Lossiemouth and Bearshead southwards to New Elgin and Lhanbryde. On the map were recorded ae genera of reptiles found at the various fossiliferous localities. . ‘*Voleanie Necks in North-West Ayrshire”? (with lantern ill Bi, By G. V. Wilson, B.Sc., H.M. Geological Survey. The area between Dalry, i sires and Largs contains the sites of about thirty volcanoes. In the north the large volcanic centre of Misty Law is most probably of Calciferous Sandstone age, and gave rise to the lava-flows of that period in the district. The area to the south is studded with a number of volcanic necks, all of which contain ash of a type similar to the interbedded ashes which occur about the _ position of the Dalry Blackband Ironstone; it was suggested that some of the necks gave rise to these beds ‘of ash. One neck was 42 Reports & Proceedings—Geological Society of London. described in which occurred a fallen mass of a coal-seam which had been large enough to work; fragments of charred wood and rounded pebbles of biotite, hornblende, and augite also occur in this neck. In another case marine shells—of a type not later than Millstone Grit—had been found in the ash of a neck, probably washed into the crater of a submarine volcano or into one on low-lying ground liable to submergence. This phase of volcanic activity probably started soon after the deposition of the Lower Carboniferous Limestones, and continued intermittently till Millstone Grit times, with quiescence during the deposition of the Coal-measures; but farther to the south we have the remains of great volcanic activity during the Permian. It was suggested that the district at its period of volcanic activity may have resembled, in some ways, the San Franciscan Volcanic Field of Arizona. IV.—Geotocicat Soctery or Lonpon. 1. November 22, 1916.—Dr. Alfred Harker, F.R.S., President, in the Chair. The following communication was read :— ‘‘Characeee from the Lower Headon Beds.” By Clement Reid, F.R.S., F.L.8., F.G.8., and James Groves, F.L.S. The investigations here recorded have been made at Hordle Cliffs (Hampshire), where the strata, below the superficial gravel, belong entirely to the Lower Headon Beds, and consist of freshwater and brackish-water (more or less calcareous) deposits, laid down ap- parently in wide shallow lakes and lagoons. Such habitats are the most favourable to the growth of Characez, and several of the beds have yielded numerous remains of these plants. There is a great diversity in the fruits of Chara found, representing evidently a number of species, belonging to several different sections or genera. With the exception of a few, which are possibly abnormal variations, the fruits can be roughly grouped under the following types :— I. Tuberculate series. (Type of C. tuberculata, Lyell = Kosmogyra, ‘Stache, emend.) (a) Spherical. (6) Obovoid or pyriform, with distinctly prolonged base. II. Non-tuberculate series. (c) Large spherical, diam.c. 1mm. (type of C. medicaginula, Brongn.). (d) Large ellipsoidal (type of C. helicteres, Brongn.). (e) Medium-sized, subglobose, tapering more or less at both ends. (f) Cylindric-ellipsoidal, showing more numerous striz. (9) More or less pyriform: that is, definitely tapering towards the base. (h) Minute, subglobose-ovoid (long. = c. 350 to 500 u). It is difficult to determine the exact number of species found, on account of the extreme variability of some of the forms, but the authors consider that at least twelve may, for the present, be con- veniently treated as distinct. The vegetative remains are comparatively few, consisting of minute portions of stems and branchlets of different diameters, and these it is impossible at present to connect with any particular types of fruit. Reports & Proceedings—Geological Society of London. 43 Though investigations of some earlier formations have shown that there are extinct forms of Characew exhibiting important points of difference from their living representatives, the remarkably distinct and characteristic oogonium of five elongated spirally twisted cells has remained constant certainly as far back as the Inferior Oolite, and it is only in earlier formations that any doubt arises as to whether bodies are or are not Chara fruits. Characez are found in still fresh or brackish water all over the world, under widely different conditions as regards heat, ete., and may therefore be expected to occur in almost all freshwater forma- tions. For these reasons it is suggested that the fruits of this group of plants, when more widely collected, may prove of considerable value as zonal fossils for the correlation of lacustrine deposits lying in isolated basins. Doubtless, on account of their small size, the Characez have in the past often been overlooked. 2. December 6, 1916.—Dr. Alfred Harker, F.R.S., President, in the Chair. Mr. G. C. Crick, A.R.S.M., F.G.S., gave an account of some recent researches on the Belemnite animal. He stated that it was not his intention to deal that evening with the homologies of the Belemnite shell or with the phylogeny of the Belemnite group, but to confine himself to the restoration of a typical Belemnite animal and its shell, as shown particularly by examples in the British Museum collection. He first demonstrated, by means of a rough model, the construction of the Belemnite shell, including the guard or rostrum, the phragmo- cone with its ventrally situated siphuncle, and its thin envelope the conotheca, with its forward prolongation and expansion (on the dorsal side) known as the pro-ostracum. He then exhibited photo- graphic slides of examples in the British Museum collection showing these various characters, and noted the abrupt termination of the chambered cone on the lower part of the pro-ostracum, of which the dorsal surface may have been partly or almost completely covered by a thin forward extension of the guard. To illustrate what was known of the complete body of the animal as found associated with the guard, he then showed photographic slides of two of the examples figured by Huxley in his Memoir on the Structure of the Belemnitide published in 1864. Each of these exhibited the guard associated with portions of the pro-ostracum, the ink-bag, and the hooklets of the arms. The form of the hooklets with their thickened bases was discussed, this feature in a great measure justifying the attribution to the Belemnite of certain Cephalopod remains (found practically at about the same geological horizon) that included uncinated arms associated with an ink-bag, and frequently also with nacreous portions of (presumably) the pro-ostracum. Of the remains of uncinated armed Cephalopods from the Lias, each exhibiting the same form of hooklets as those figured by t 44 Reports & Proceedings—Geologicul Society of London. Huxley, he said that the British Museum collection contained seventeen examples, all from the neighbourhood of Lyme Regis and of Charmouth, in Dorset. Kach specimen exhibits a number of uncinated arms associated usually with an ink-bag, sometimes also with nacreous matter, and in two instances also with the guard or rostrum. ‘These two examples were those to which he had already referred as having been figured by Huxley, and unfortunately the arms are not well preserved in either of these specimens; in one (B. bruguiervanus, from the Lower Lias near Charmouth) there are only a few scattered hooklets, while the arms of the other (2B. elongatus, from the Lower Lias of Charmouth) are represented only by a confused mass of hooklets.. Of the other fifteen examples, in one there are a few solitary hooklets; in another the number of the arms is very indistinct; in two the remains of only two arms are preserved ; in one there are traces of three arms; in two there are indications of three, or possibly four, arms; in one there is a confused mass of possibly four arms; and in one there are the remains of four, or possibly of five, arms. In each of the remaining siX specimens six arms can be more or less clearly made out, while there is not a single example in which more than six uncinated arms are displayed. Of the six examples that exhibit six uncinated arms four are — stated to be from the Lias of Lyme Regis; one is from the Lias of Charmouth; and one was obtained from the Lower Liassic shales between Charmouth and Lyme Regis. From a consideration of these specimens, the speaker concluded that the Cephalopod represented by these uncinated arms is the animal known as the Belemnite, and that the six uncinated arms were arranged in three pairs of unequal length, of which the longest pair was lateral, the medium- sized pair probably dorsal, and the shortest pair probably ventral. He considered the presence of tentacular arms to be doubtful. These observations were in accord with those of Huxley, who, in his Memoir already cited, stated that he had ‘‘not been able to make out more than six or seven arms in any specimen, nor has any exhibited traces of elongated tentacula, though the shortness of the arms which have been preserved would have led one to suspect their existence ’’. Mr. Crick regarded certain markings sometimes to be seen on the guard as indicating that during the life of the animal the guard was almost, if not entirely, covered by the mantle, in which case it was highly improbable that the guard was pushed into the soft mud of the sea-bottom in order to act as an anchor. He considered the animal to have been a free swimmer, swimming forward ordinarily, but when desirable, capable also of sudden and rapid propulsion backwards. V.—Liverpoot GrotocgicaL Socrery. 1. The first meeting of the fifty-eighth session of this Society was held on October 10 last, Mr. J. H. Milton, F.G.S., F.L.S., President, occupying the chair. The report on the work of the past session Reports & Proceedings—Liverpool Geological Socrety. 45 showed that in spite of present adverse circumstances there had been a slight increase in the membership, and that the activities of the Society had been well maintained. The President in his annual address dealt with ‘‘ The Coral Types of the Carboniferous Limestone”, and gave a very valuable and helpful résumé of the principal diagnostic characters of the different genera. The lines of their evolution were traced, and their value as zonal indices clearly shown. In this connexion a warm tribute was paid to the work of the late Dr. Arthur Vaughan. ‘The address was fully illustrated by a beautifully drawn series of sections of the chief types, and an exceilent collection of specimens from North Wales and elsewhere. 2. November 14, 1916.—J. H. Milton, F.G.S., F.L.S., President, in the Chair. The following paper was read :— ‘‘The Pebbles of the Middle Bunter Sandstones of the Neighbour- hood of Liverpool.’’ By T. A. Jones. The author described the results of an investigation into the nature of the rock types represented amongst the pebbles, which he roughly classified under the following heads: Quartzites and Grits, Granites, Mica Schist, Felstones, Tourmaliniferous Quartzites, Grits, Schists, etc., Fossiliferous Pebbles, and Miscellaneous. Attention has been given chiefly to those bearing tourmaline, which collectively were present in greater abundance than those of any other group, with the exception of the Quartzites and Grits. The mineral was present in great variety and quantity, and on the whole the rocks showed marked similarity to those surrounding the granite masses of Devon and Cornwall, with which they were perhaps still more strongly linked by the discovery of a pebble of granite containing abundant tourmaline in slender prisms, and small pinkish garnets. This rock when crushed yielded splintery fragments of dark indigo blue tourmaline, closely resembling those found amongst the heavy density minerals of the finer material of the Triassic sandstones of the district. A light ash-grey friable schist was also described, which contained irregular grains of brown and blue tourmaline apparently of clastic origin, which was also considered competent to have furnished some of them. Three other varieties of biotite granite were found, two of them with micropegmatitic structure. Twelve varieties of felstones had been examined, all of acid type. Four contained tourmaline plenti- fully, and two seemed to be tuffs rather than lavas. Among the fossiliferous pebbles one of reddish quartzite containing a single specimen of a small Orthis was recorded, the only example so far known to the author from the local pebble beds. On the whole the assemblage of pebbles seemed substantially identical with those of the Midlands as described by Professor Bonney, although the tourmaliniferous group was judged to be of greater importance. The paper closed with a brief discussion of the possible sources of the pebbles, and the method of transport. \ 46 Reports & Proceedings—Liverpool Geological Society. 3. December 12, 1916.—J. H. Milton, F.G.S., F.L.S., President, in the Chair. Mr. H. C. Beasley and Professor J. W. Gregory, D.Sc., F.R.S., were unanimously elected honorary members. Mr. Beasley has been an ordinary member for the last forty-six years, during which period he has been one of its foremost working members, and it has been a great pleasure to his fellow-members to recognize his great services to the Society and to local geology. The recent announcement of the gift of a Chair of Geology to Liverpool University by Professor and Mrs. Herdman, as a memorial to their son, was referred to with much interest and sympathy, and the following resolution was approved: ‘‘That this Society has learned with much satisfaction of the intended establishment of a Chair of Geology in the Liverpool University, and has special pleasure in the fact that the establishment is due to the generosity of one of its members and past presidents, Professor Herdman, and Mrs. Herdman, by whose action the long-felt need for the due recognition of this subject in the University scheme will at length be satisfied.” Mr. C. B. Travis, in a ‘‘ Note on Terminal Curvature at Billinge Hill’’, described an interesting example to be seen near the summit of the hill, where the outcropping beds of the Lower Coal-measures are curved over in a remarkable manner by the onward pressure of the Irish Sea ice-sheet invading the district from the west. This section has not previously been described. Mr. F. T. Maidwell followed with an account of recent geological rambles about Liverpool, in which he threw fresh light on some old sections, The correlation of the coal-seams in the collieries at Neston, Cheshire, was dealt with at some length, also the lttle- known outcrop of Permian strata at Skillaw Clough near Bispham. VI.—Tuz Wertineron, New Zzatanp, Paitosopuican Sociery (GroLogicaL Sxcrron). The annual meeting of the Wellington Philosophical Society (Geological Section) was held last evening, September 20, 1916, at the Dominion Museum. Mr. G. Hogben, C.M.G., F.G.S., ’ presided. The Annual Report stated that during the year seven meetings had been held, with an average attendance of fourteen. The following We have been read: ‘A Phase of Shore-line Erosion,” by . J. A. Bartrum; ‘‘ Terminology for Foraminal Development in Tees eae ” by "Mr. 8. S. Buckman, F.G.S.; ‘‘ The Continental Shelf” and “The Motion of Water in Waves”, by ; Dr CL Ae Cotton, F.G.S.; ‘‘ The Geological Occurrence and Origin of Petroleum,” by Meas W. Gibson and M. Ongley; ‘‘ The Structure of the Paparoa Range,” by Dr. J. Henderson; ‘‘An Artesian ‘Trial Bore at the Westshore, Napier,’? by Mr. R. W. Holmes; ‘“‘ Notes of a Visit to Marlborough and North Canterbury,” by Mr. P. G. Morgan, F.G.S.; ‘‘Stage Names applicable to the Divisions of the Tertiary in New Zealand,” by Dr. J. A. Thomson, F.G.8.; ‘‘ The Volcanic Rocks of Oamaru,”’ by Mr. G. Uttley, F.G.S. Obituary—Clement Reid. 47 The election of office-bearers for the ensuing year resulted as follows: Chairman, Dr. C. A. Cotton, F.G.S.; Vice-Chairman, Dr. J. Henderson; Hon. Secretary, Mr. KE. K. Lomas; Committee, Messrs. Morgan, F.G.S., Ongley, Uttley, F.G.S., Holmes, and Dr. Thomson, F.G.S. During the evening Dr. J. Allan Thomson read papers: (1) ‘‘ On the so- cailed ‘Drift Formation’ of Hawera” ; (2) ‘* The Geology of the Middle Clarence Valley, between the Bluff and Herring River.” —WNew Zealand Times, September 21, 1916. OS Ea WeASEuE = CHENENT REID: FR.S 4 Files. FLG.Ss Ere. Born JULY 6, 1853. DIED DECEMBER 10, 1916. Ir is with the deepest regret that we have to record the death of Mr. Clement Reid, late of H.M. Geological Survey, which took place at his residence, One Acre, Milford-on-Sea, on Sunday, December 10. He was buried at Milford on the following Wednesday. Mr. Reid was so deeply versed in all matters relating to the later Tertiary and more recent strata that all geologists interested in these deposits will feel that their science has lost a master and they a reliable co-worker. Only those who knew Mr. Reid intimately could appreciate his sterling abilities and intense devotion to his scientific work, characteristics in which he so much resembled his great-uncle Michael Faraday. Mr. Clement Reid joined H.M. Geological Survey in 1874 and started work, under the able guidance Gratis Be Woodward, in the South-West of England, but in 1876 was transferred to Norfolk, and there began, under the same genial leader, the detailed study of the Pliocene and Pleistocene deposits, including the ‘‘ Forest Bed” and “Contorted Drifts’’, of the Norfolk coast. The name of Clement Reid has ever since been intimately connected with the study of these formations; indeed, in all matters relating to the ‘‘ Norfolk Forest Bed” and the nearly associated strata he was regarded as the chief authority. His memoir on Zhe Geology of the Country around Cromer (Explanation of Sheet 68 E.), together with the maps and sections, is a model of careful work, and exemplifies the close attention to minute details as well as the broad grasp of his subject — _which has ever characterized his scientific work. Mr. Reid published numerous papers on geological subjects, many of which are of more than ordinary interest; but as an officer of H.M. Geological Survey his chief work was the preparation of maps and. of explanatory memoirs, and for this purpose after leaving Norfolk he was engaged in later years in Yorkshire, Tsncalneh ne. Sussex, Hampshire, Isle of Wight, Dorset, Wilts, Cornwall, and the London area. It is therefore in the publications of the Survey that the bulk of Mr. Reid’s work will be found, and these chiefly relating to Tertiary and more superficial deposits. Whatever Mr. Reid undertook to do he did thoroughly. He was 48 Obituary—Clement Read. ‘ \ always a most careful and untiring worker, and even his times of relaxation were devoted to some collateral aspect of his work. The paleontological side of his investigations ‘always gained his close attention. Quite early in his career he made botany a special study. Certain seeds found in the ‘‘ Forest Bed” needed determination, and he began, for comparison, to collect the seeds of wild plants, which seem at that time to have been strangely neglected, with the result that he became perhaps the first authority on the subject, and showed how much information regarding the climate of former times was to be obtained from fossil seeds. The painstaking work of himself and Mrs. Reid in the investigation of seeds laboriously washed out from certain deposits has resulted in the joint publication of memoirs which may be regarded as monumental 7‘The Fossil Flora of Tegelen-sur- Meuse,” Verhandl. d. Ko. “Akad. y. Wetenschappen te Amsterdam, 1907; ‘‘The Preglacial Fauna of Britain,’”? Journ. Linn. Soc. Botany, 1908; Zhe Pliocene Floras of the Dutch-Prussian Border, published by the Institute for the Geological Exploration of the Netherlands, The Hague, 1915). Mr. Reid’s report upon the Pleistocene deposits at Hoxne was largely based upon the seeds found in the more peaty parts of these beds. An exceedingly interesting study of fossil Characez was in progress by Mr. Reid at the time of his death in conjunction with Mr. J. Groves, but the results have only just begun to be published. This work seems to have been initiated by the examination of silicified slabs of Purbeck rock showing beautifully preserved sections of Chara stems, which led Mr. Reid to try artificial weathering by weak acid on some impure limestones, and this led to important discoveries in regard to anomalous structures in some of these fossils (see Proc. Roy. Soc., B, vol. lxxxix, p. 252, 1916). More recently, also in co-operation with Mr. J. Groves, the Chara seeds from the Headon Beds, near his home at Milford, were investigated, and a most important paper on the subject was read before the Geological Society oat a week or so ago, and will, we hope, be published before jong. Mr. Clement Reid was elected a Fellow of the Geological Society in 1875, was awarded the Murchison Geological Fund in 1886, and the Bigsby Gold Medal in 1897. He served for two periods on their Council, and was Vice-President in 1913-16. He was elected a Fellow of the Linnean Society in 1888, and served two periods on the Council. In 1899 he was elected a Fellow of the Royal Society. The Royal Geological Society of Cornwall awarded him the Bolitho Gold Medal in 1911. Mr. Reid, having joined H.M. Geological Survey in 1874, was advanced to the post of ‘‘Geologist’’ in 1894, became ‘‘ District Geologist’’ in 1901, and retired in January, 1913.. Mr. Reid married Miss KE. M. Wynne Edwards in 1897, and upon his retirement went _to live at his new residence at Milford-on-Sea, where, after only three short years, he passed peacefully away in the closing month of the year 1916. 1 See Reports and Proc. Geol. Soc. Lond., ante, p. 42. ‘LIST OF BOOKS OFFERED FOR SALE DULAU & CO., LTD., 37 SOHO SQUARE, LONDON, W. BATHER (F. A.). Studies in Edrioasteroidea, I-IX. Reprinted, with additions, from the Geological Magazine, 1898-1915. London, 1915. pp. 136, 8vo, and 13 plates. 10s. BAYLEY (W. 8.). Minerals and Rocks: the Elements of Mineralogy and _ Lithology for the use of Students in General Geology. London, 1916. | — pp. viii + 227. 8vo. Illustrated. Cloth. 6s. CHAMBERLIN (Lf. C.). The Origin of the Earth. Chicago, 1916. pp. 271. ne 8vo. Illustrated. Cloth. 6s. | DANA. Thi Appendix to the Sixth Edition of Dana’s System of Mineraloe.4’ by William E. Ford. Completing the Work to 1915. New : ‘York, 1915. pp. xilii+ 87. 8vo. Cloth. 6s. 6d. ECKEL (E. C.). Iron Ores: their occurrence, valuation, and control. New a York, 1914. Illustrated. Syo. Cloth. 17s. FARRINGTON (O. C.). Meteorites: their Structure, Composition, and errestrial Relations. Chicago, 1915. pp. x + 333. S8vo. Ilustrated. | Cloth. 8s. 6d. | FINLAY (G. 1.). Introduction to the Study of Igneous Rocks. London, 1913. pp. 228, crown 8yo, with 3 coloured plates and numerous illustrations. oe Flexible leather. 8s. 6d. | HEATH (G. L.). The Analysis of Copper; and its Ores and Alloys. New < York, 1916. pp. 292. S8vo. Illustrated. Cloth. 12s. 6d. HOWE (H. M.). The Metallography of Steel and Cast Iron. New York, ‘| «1916. pp. 641, 8yo, with 45 plates. Cloth. £2 2s. | KEITH (A.). The Antiquity of Man. London, 1915. 8yo. With 189 " E. W. Hughes—Geology of Part of Carnarvonshire. 75 Priem! described and discussed similar fossils from the Upper Silurian of 8. Felix, Laundos, Portugal, and decided that Plectrodus- proper at least was a jaw, although Selerodus pustuliferus was undoubtedly part of the cornu of the Cephalaspidian Aukeraspis. Later studies have convinced me that the true Plectrodus (as typified by P. mtrabilis) is indeed a jaw, and that it most closely agrees with the toothed jaws of the Lower Devonian Acanthodian Ischnacanthus.* 1 am, therefore, much indebted to Mr. W. Wickham King, F.G.S., for the opportunity of examining the microscopical structure of an unusually large specimen, probably of a new species, which he has recently found in the Downtonian of Baggeridge, S. Staffordshire. ‘The hard base to which the teeth are affixed proves to consist of almost structureless translucent calcified tissue in which there are occasional streams of elongated cellular spaces, irregular in shape, and sometimes with traces of ramifying canaliculi. It thus agrees exactly with the corresponding tissue in /schnacanthus. In this connexion it is interesting to add that both in Oesel and in Portugal separate whorls of teeth such as occur in front of the lower jaw of Ischnacanthus,* have been found in the same rocks as Plectrodus.* On the other hand, no typical dermal tubercles of Acanthodian fishes have hitherto been recognized in any Upper Silurian formation, and the occurrence of Acanthodian fin-spines is uncertain. We may, therefore, conclude that the toothed Acanthodians of the Lower Devonian were preceded in the Silurian by fishes with similar jaws, but the precise nature of these earlier fishes still remains to be determined. VI.—On rae Grotoey or tar Disrricr From Cuin-y-Coxmp 10 tHE St. Awnes—Luanttyrnt Ripe (CaRNARVONSHIRE).” By E. WYNNE HUGHES, M.Sc., F.G.S. (Concluded from January Number, p. 25.) B. Pre-Camprian, Rayotrric Sertms.—(i) At the south-west end of the Craig-y-Dinas mass we find exposed a rock similar in every respect macroscopically to that which is found at Cil-y-Coed. Unfortunately it cannot be followed far, as the land is ‘completely under drift, the top of Craig-y-Dinas itself being capped by a thick layer of drift. 1 F. Priem, ‘‘Sur des Poissons et autres Fossiles du Silurien supérieur du Portugal’’: Communic. Serv. Géol. Portugal, vol. viii, p. 3, pl. i, figs. 7-10, 1910. ; 2 A. S. Woodward, Catalogue of Fossil Fishes in the British Museum, pt. ii, 1891, p. 20. B. Dean, ‘‘ Notes on Acanthodian Sharks’’: Amer. Journ. Anat., vol. vii, p. 209, figs. 1-10, 1907. HE. S. Goodrich, in Lankester’s Treatise on Zoology, pt. ix, 1909, p. 190, fig. 160. 3 A.S. Woodward, Presidential Address, Quart. Journ. Geol. Soc., vol. xxi, p. lxvi, 1915. * Campylodus sigmoides, J. V. Rohon, loc. cit., p. 52, pl. i, fig. 25, 1893 ; G.(?) delgadoi, F. Priem, loc. cit., p. 5, pl. i, figs. 11-15, 1910. * Plates I and II and two maps, which illustrate this paper, will be found with the first part in the January Number, pp. 13 and 15. 76 B. Wynne Hughes—Geology of (1) Five hundred yards almost due north of Craig-y-Dinas, near the farm of Eithinog-Wen, a small amount of solid rock is present. A careful examination shows that this rock again compares closely with the rhyolitic series of Cil-y-Coed. Porphyritic quartz and pink — felspars can be seen even in hand specimens. ‘lhe groundmass is fine-grained, compact, and felsitic, differing only from the Cil-y-Coed rhyolites in its pink eoloration. Beyond EKithinog- Wen a close search of the slope of the ridge, that runs in a northerly direction here, disclosed no further exposures. ‘he large amount of debris, however, that is present everywhere at the foot of the ridge suggests the presence of the rhyolitic rock. Qu) At Bryn-mawr, 1,500 yards to the N.N.E. of Craig-y-Dinas and 1,000 yards from Kithinog- Wen, several rock masses are exposed. The distance between the first and last of these exposures is fully 600 yards. They all occur near the top of the ridge, and are undoubtedly portions of the same mass, The line of outcrop, if continued in a southerly direction, would pass through the exposures at Eithinog-Wen and Craig-y-Dinas. The largest of these exposures is the quarry near the roadway close to Glyn-Llifon Park. It is at present being worked for road-metal. In some cultivated land on the north side of the road further exposures of this rock are also to be seen. In hand specimens all the rocks compare closely with one another, showing porphyritic crystals of quartz and felspar in a fine- grained and compact groundmass. Several microscopic sections were examined, and they bring out the close resemblance between these rocks and the rhyolitie series at Cil-y-Coed. They show the presence of porphyritic crystals of quartz and both orthoclase and plagioclase. The quartz crystals are much more numerous than the felspars, but many of the latter still show multiple twinning. The groundmass is, cryptocrystalline, with patches sometimes coarser and sometimes finer-grained, and it frequently shows good fluxion structure. GPTS cles io te) We have here, then, a rock very similar, both macroscopically and microscopically, to the rhyolitie rocks of Cil-y-Coed. C. Summary oF tHE Successton.—We have, then, in the area between Pentwr and Bryn-mawr:—(i) Cambrian: (@) green slates at Ysgubor-Wen, (4) green grit band at Pentwr, (c) purple slates at Llech-y-dwr, (d) fine and coarse grits at Craig-y-Dinas, and also (e) a much cleaved conglomerate at Craig-y-Dinas, all with a dip of 50° $.S.E., lying upon (ii) Pre-Cambrian, (/) rhyolites and tuffs exposed at Craig-vy-Dinas, Eithinog- Wen, and Bryn-mawr. D. Retartioy vo rae Surrounping ARnEAS.—(i) South-east of Pentwr we have already noted the occurrence of Ordovician slates on Y Foel. These can be traced through Tai-lon to Pen-y-garreg and beyond. (ii) Unfortunately the Cambrian slates and grits cannot be similarly traced to Cil-y-Coed. The strike of the beds in the two localities suggests the presence of a fault in the intervening country, but no other evidence of it could be obtained, though this is the direction of the fault marked on the Survey map (1850). Part of Curnarvonshire. T7 (il) To the west and north-west the country is flat and low-lying. No solid rock was found anywhere in this direction. (iv) The most northerly exposure of the Pre-Cambrian rhyolite series 1s within 400 yards of the boundary assigned to the St. Annes— Llanllyfini ridge in the Geological Survey map (1850). The nearest locality on this ridge where solid rock is exposed is at Pare Pant-dy, 800 yards due east of Pen-y-groes and a mile and a half east of Bryn-mawr. Referring to the rocks at this end of the ridge, the Survey memoir states :— ‘Further south the conglomerate forms the highest points of Moel Tryfan and Mynydd Cilgwyn, where it is partly metamorphosed into a sort of talcose schist and conglomerate. Beyond this it has been either completely obliterated, or, curving round to the east near the crest of the hill, it is cut off by a fault which throws the superincumbent purple slate directly against the porphyry. It is seen that the grits and lower conglomerates disappear at Mynydd Cilgwyn, but the purple slates that are interstratified with these follow an unbroken line to the neighbourhood of the turnpike road near Llanllyfni. The general character of the porphyry is that of a felsitic rock with an amorphous grey felspathic base containing small crystals of quartz, which are often somewhat eranular, sometimes hexagonal, and sometimes they seem to be four-sided prisms. * . . . Italso contains small distinct crystals of glassy telspar. The base of the conglomerate is highly felspathic and sometimes crystalline, enclosing pebbles of felspathic trap, quartz, quartz rock, purple and black slate, and jasper. The whole mass is altered, and it is easy to note first: the disappearance ot the granular structure in the conglomerate or sandy matrix and its gradual assumption of a porphyritie character, with small crystals of felspar embedded, while the enclosed pebbles still retain their distinctive form; and again, approaching the recognised porphyry the hard outlines of the pebbles in the conglomerate gradually melt away till they become undistinguishable in the general fusion of the rock, and the view that the porphyry is not an intrusive mags is aided by the fact that it is impossible to define any line of demarcation between conglomerate and porphyry.’’ ! Evidently, then, we have on the St. Annes—Llanllyfni ridge a succession very similar to that at Craig-y-Dinas and Cil-y-Coed. ’ In consequence, the south-west portion of the ridge between Moel Tryfan and the village of Llanllyfni was carefully examined. 3. Tue Sr. Annes—LiANLLYFNI Riper. A. Moret Trrran.—The conglomerate at the top of Moel Tryfan seems outwardly identical with that at Cil-y-Coed. The pebbles are well rounded and of various sizes, though seldom more than 3 inches long. They are mainly of volcanic origin and are enclosed in an argillaceous matrix. There are also quite a number of quartzose pebbles of a type which is of rare occurrence in the conglomerate at Cil-y-Coed and Craig-y-Dinas, and the matrix is distinctly more argillaceous. On the top of Moel Tryfan there are no exposures of the quartz-porphyry or the quartz grit, but not more than 200 yards to the east of the conglomerate we find, at the Alexandra Slate Quarry, a great thickness of purple slate. From this quarry an adit has been driven east and west right through the mountain. An examination of the rocks in this adit shows that a quartz grit occurs here on the eastern side of the 1 Mem. Geol. Stirv., vol. ii, p. 143, 1866. 78 E. Wynne Hughes—Geology of conglomerate. Both the conglomerate and the quartz grit dip steeply to the south-east. A. further point of interest is the existence of several well-marked faults, running north-east to south-west. These faults have the same direction as the fault between the grits and the Ordovician slates on the south-east side of Cil-y-Coed. } Several thin sections from the conglomerate in the adit were examined ; they show that the conglomerate bears a close resemblance to that at Craig-y-Dinas and Cil-y-Coed. Thin sections of the grit from the two localities are also very similar, though perhaps the Moel Tryfan grit approximates more closely to a true quartzite. The adit shows that the whole mass has undergone great dis- turbance, there being at least six faults visible in the adit, with the result that the structure is highly complicated. The conglomerate, for instance, is only 12 feet thick in the adit, whereas on the moun- tain top it has an outcrop fully 120 feet wide. Between the conglomerate and the porphyry at the west end of the adit, is a thickness of fully 200 vards of green slate, grit, gritty slate, and a green chloritic rock. Whether these slates and grits are Lower Cambrian or Pre-Cambrian is a question of some difficulty which I hope to investigate at a future date. An examination of the adit then shows that— (a) The conglomerate and quartz grit here bear a close resemblance to those at Cil-y-Coed and Craig-y-Dinas. (6) They are in the same relative position. (c) Their dip, although steeper, is inthe same direction. (d) As at Craig-y-Dinas, they are overlain by purple slate. (ec) The conglomerate in the adit does not lie directly on the quartz-porphyry- (f) The matrix of the conglomerate is more argillaceous than that at Craig- y-Dinas and Cil-y-Coed. ‘ B. Bwicu-y-tiyy anv Citgwyy.—The conglomerate was traced in a south-westerly direction. At Bwlch-y-llyn the quartz grit also’ comes to the surface, and is again lying directly upon the con- glomerate on its south-east side. An examination of microscopic sections cut from specimens in this locality again brings out a close resemblance between the grit here and that at Cuil-y-Coed and Craig-y-Dinas. Like the latter, the grit at Bwlch-y-llyn ranges from fine to coarse, becoming more quartzitic from north-west to south-east. (PI. II, Figs. 4, 6.) From this point on, the conglomerate forms the high ground on Mynydd Cilgwyn, and it persists in a south-westerly direction along the whole length of the mountain. On the south-west slopes of the mountain, however, it disappears in the manner indicated in the Survey memoir. The pebbles in it, on this portion of the ridge, are certainly less numerous, but they are decidedly larger than at Moel ‘Tryfan, and, what is still more interesting, the matrix is distinctly more felspathic. In hand specimens and under the microscope this gritty matrix could hardly be distinguished from the gritty matrix of the conglomerate at Cil-y-Coed. (PI. II, Figs. 1, 2.) - Owing to the presence of several quarries on the east side of the ridge, the purple slate can easily be traced in a 8.S.E. direction from Moel Tryfan to Cilgwyn. At Cilgwyn it is exposed at the 4 Part of Carnarvonshire. eae Old Cilgwyn and Veingoch quarries. ‘The former of there two quarries lies only 250 yards away from the conglomerate, but does not expose the grit. On Mynydd Cilywyn, moreover, the quartz-porphyry is exposed in several places, always to the west of the conglomerate, but the exact line of junction could not be seen. Several microscopic sections of the quartz-porphyry were examined, and here again the resemblance to the rhyolitic rocks of Bryn-mawr and Cil-y-Coed is most. marked. The rocks contain porphyritic crystals of quartz and feispar embedded in a eryptocrystalline matrix which grades to microcrystalline in a patchy manner. It will be interesting to record here Bonney’s description of microscopic sections from this ridge. He states :— .‘*The general type is a compact dull felsite with porphyritic crystals of felspar and grains of quartz closely resembling some modern rhyolites. On Moel Gronw angular fragments of a pinkish tint are scattered through the general mass. Again, some parts are crowded with quartz grains, while others are comparatively free of these, and occasionally a spherulitic structure is observed. ‘The rock was probably originally vitreous, and there are abundant fresh examples of the most perfect flow-structure in the rock.’’ ' This description compares very closely with that already given of the Cil-y-Coed and Bryn-mawr rhyolitic rocks. C. Crogwyn Metyn ‘to Carr Encan.—On the southern s!opes of Mynydd Cilgwyn the conglomerate stops abruptly. All the lower slones of the hill on this side are composed of rhyolitic rocks very badly sheared. A careful examination of the area disclosed no exposure of either conglomerate or grit, although a large amount of solid rock is exposed, all of which is massive rhyolite becoming more and more sheared towards the east. As indicated in the Geological Survey Map the rhyolite in this area is brought up against the purple slates. The rhyolite was traced through Pare Pant-dy to the lower roadway going from Pen-y-groes to Talysarn. Here it stops abruptly. But asmall area of the rhyolite is exposed again at Caer Engan, 500 yards to the south-east of the nearest exposure in the main mass. In addition, a very narrow band of the conglomerate is found on the south-east side. It is badly crushed and the pebbies almost unrecognizable. The matrix is similar to that at Moel Tryfan, being argillaceous rather than felspathic. The greater portion of the hill, however, is composed of a felsitic rock, which both in hand specimens and in microscopic sections resembles the light variety at Cil-y-Coed ; but whatever fluxion structure it may contain is obscured by shearing. Furthermore, 200 yards to the east of Caer Kngan there is a small quarry in purple slates, but there is no exposure of grit in the intervening area. D. Sommary oF tHe Succession.— We have, then, on the St. Annes— Llanllyfni ridge— - (i) Rhyolitic rocks, conglomerate, and quartz grit at Moel Tryfan. (ii) Conglomerate and quartz grit at Bwlch-y-llyn. (iii) Rhyolitic rocks and conglomerate at Mynydd Cilewyn. (iv) Rhyolitic rocks and conglomerate at Caer Engan. (v) Purple slates all along the eastern side of the ridge. 1 Q.J.G.S., vol. xxxv, p. 312, 1879. 80 Reviews—Dr. John Ball— IV. Conclusion. The different formations at all the above localities on the St. Annes— Llanllyfni ridge lie in the same relative position to one another as the purple slates, grits, conglomerate, and rhyolitic series at Craig-y- Dinas, and the grits, conglomerate, and rhyolitic series at Cil-y-Coed. Further, the different formations are each to each lithologically similar. This resemblance is well brought out in Plate II, showing microphotographs of the conglomerate: Fig. 1, from Cil-y-Coed; Fig. 2, from Mynydd Cilgwyn; the fine grit: Fig. 3, from Cil-y-Coed ; Fig. 4, from Bwlch-y-llyn; the coarse grit: Fig. 5, from Cil-y-Coed ; Fig. 6, from Bwlch-y-llyn. The evidence seems, therefore, conclusive that the series at Cil-y-Coed and Craig-y-Dinas are of the same age as those of the St. Annes—Llanllyfni ridge. Accepting the view, usually held, that the porphyry on this ridge is pre-Cambrian and that the conglomerate is basal Cambrian, we have— 1. At Cil-y-Coed—Lower Cambrian grits and conglomerate lying on Pre- Cambrian rhyolites and tufts. 2. At Craig-y-Dinas—Lower Cambrian green and purple slates, grits, and basal conglomerate lying on Pre- Cambrian rhyolites. 3. At Bryn-mawr—Pre-Cambrian rhyolites and tufts. Pre-Camprran Rayotrres ano ‘T'urrs.—l'o sum up, the solid rocks exposed in the area between Cil-y-Coed and the village of Pen-y-groes comprise a volcanic series of rhyolitic type, probably Pre-Cambrian, overlain by a series of conglomerates, grits, and slates of Lower Cambrian age. This sequence represents substantially the succession which obtains in the main portion of the St. Annes—Llanllyfni ridge to the north-east ; and it is clear that the solid rocks of the St. Annes— Llanllyfni ridge extend at least 3 miles further south-west than is represented in the Geological Survey Map. In conclusion, I desire to express my indebtedness to Mr. C. J. Edwards for suggesting the work on Cil-y-Coed and for several photographs, to Dr. Cox for reading through the manuscripts and for various suggestions during the course of the investigation, and to Dr. Gordon for his help in connexion with the microphotographs. REVIEBwWwS- I.—Tur Grocrapay and Geronrocy or West-Cenrran Sryar. By Joun Batt, Ph.D., D.Sc., F.G.8., A.R.S.M., Mem. Inst. C.E. pp. ix, 219, with two geological maps printed in colour, 22 plates, and 54 text-figures. Cairo: Government Press, 1916. Price 30 P.T. fW\HIS important work owes its origin to the discovery of ores of manganese and iron in the Sinai Peninsula by the late Mr. Thomas Barron during his reconnaissance survey of a vast area in Western Sinai in the years 1898-9. Prospecting followed, the Sinai Mining Co. was formed to exploit the deposits, and Dr. Ball was deputed by the Director of the Geological Survey of Egypt to Geology of West-Central Sinai. 81 earry out a detailed topographical and geological survey of the area in which the more important deposits occur. He has produced an accurate map of an area of 3880 square miles limited by the parallels of 29° 15’ and 28° 56 20" N. lat. and by the meridians of 32° 9’ 35” and 838° 27' 380” KE. long. on a scale of 1:50,000, on which the distribution of the various geological formations, ranging from the granite and gneiss of pre-Carboniferous age through the Carboniferous, Cretaceous, and Tertiary to the Pleistocene and Recent deposits of alluvium and blown sand, is laid down. ‘The topographical and geological details were recorded simultaneously, and as an illustration of Dr. Ball’s skill and neatness as a surveyor it may be mentioned that the maps are based on direct photographic reproductions of the field-sheets. In addition to the general map, the work is illustrated by a larger scale map (1: 25,000) of the environs of Um Bogma, where the chief mines are situated, a plate of sections, numerous photographs, and a large number of text-figures, including pen-and- ink sketches of the most typical fossils drawn by the author from actual specimens. After describing the general features of the district, which consist of highly dissected tablelands and assemblages of rugged granitic peaks, with occasional more open areas, the author gives an account of the survey operations, of the methods adopted in laying out the base-line, in determining its geographical position, and in connecting up the triangulation with that of Egypt proper. ‘Then follow chapters dealing with the topographical features—the wadis, the mountains and the plains—and with the geology. In the centre of the area lies a broad sandy plain at a height of about 500 metres above sea-level, on which the base-line was laid down. This is bounded on the north by the formidable escarpment of Gebel el Tih, the edge of which is from 500 to 600 metres above the plain and extends from east to west in a somewhat sinuous curve. The base of the escarpment is formed of Nubian Sandstone, then follow 200 metres of fossiliferous Cenomanian clays, marls and lime- stones, which are capped by beds of Turonian limestone. The escarpment forms the southern termination of a deeply dissected plateau which stretches far to the north, and it is a remarkable fact that although the valleys descend rapidly from the edge in that direction, none appears to have been beheaded by the recession of the escarpment. Many points on the edge have been accurately fixed. South of the central plain is a wild country with only relics of plateau structure, in which many mountains rise to heights of 700 or 800 metres above the sea and one to over 1 ,000 metres. It consists of the pre-Carboniferous complex of eranite and metamorphic rocks, on the planed-down surface of which rest strata of Carboniferous age. The time available did not admit of any attempt to separate the rocks of the complex, which is presumably Archean. The Carboniferous rocks consist of a lower sandstone (130),! a middle limestone with fossils, similar to those occurring in Derbyshire and Yorkshire (40), and an upper sandstone with ZLepidodendron (130). To the west of the central plain this upper sandstone underlies the Nubian Sandstone, 1 The figures in parentheses represent thicknesses in metres. DECADE VI.—VOL. IV.—NO. I. 6 82 Reviews—Dr. John Ball— which it closely resembles. This point is one of great interest on account of the discussion which has taken place as to the age of the Nubian Sandstone. In the region we are considering the vast period of time separating the Carboniferous Limestone from the marine Cenomanian clays is represented by 650 metres of sandstone, which are conformable to the rocks below and above, and in which no break can be detected. Dr. Ball separates the lower portion of this series (130) under the name of Upper Carboniferous Sandstone, on account of the occurrence of fossils of the Lepzdodendron type, from the upper portion (500) to-which he restricts the name of Nubian Sandstone. The only traces of fossils found in the upper portion are a piece of silicified wood ‘‘ similar to that which occurs in the Nubian Sandstone of Egypt’’, and a thin layer of very impure coal. Owing to the discovery of Jnoceramus in the Nubian Sandstone of Aswan and the intercalation of the sandstone with the overlying marine Cretaceous in other parts of Egypt this formation is now generally regarded as being of Cretaceous age. Until quite recently no trace of marine fossils of Triassic or Jurassic age has been found either in Egypt or Sinai, but Dr. Ball refers to a discovery of Jurassic deposits in the northern portion of the peninsula, and suggests that part of the Nubian Sandstone may be of the same age. Details of this important discovery do not appear to have been made public. So far we have been referring to about three-fourths of the area covered by the map. This portion is bounded on the west by a series of important faults following a general direction a little east of south, roughly parallel to and at an average distance of about ten kilometres from the Gulf of Suez. The remaining portion consists principally of Campanian strata, but contains also representatives of the Eocene and Miocene periods. At one point Miocene rocks are faulted against the Lower Carboniferous Sandstone, and the throw is estimated at probably not much less than 2,000 metres. The faulting is regarded by the author as belonging to the close of the Miocene period; but the possibility of its having commenced at an earlier period must not be overlooked. Campanian strata (300?) form a highly dissected hilly country of a dazzling white aspect. Eocene strata appear to rest conformably on the Campanian. They are much thinner than those on the opposite side of the Gulf of Suez and in the Nile Valley. The Miocene rocks occur in detached patches and comprise conglomerates, gritty limestones, clays, and chalky rocks often impossible to distinguish from Eocene or Cretaceous in the absence of fossils. The author sums up his observations on the Miocene deposits in this part of Sinai by saying that ‘‘ the more easterly portions are characterized by great accumulations of conglomerates and grits, indicating that the old shore ran approximately along the line of the great fault already referred to, while farther to the west there is increasing predominance of limestones, clays, marls, and gypsum, indicating deeper water conditions for certain beds”’. The geological history of Egypt during post-Hocene times is of great interest, but it is difficult to correlate the available information. The prolonged hydrocratie movement which lasted during the 3 . { i Geology of West-Central Sinar. 83 Cretaceous and Eocene periods was followed by a geocratic movement in Oligocene times, when the fluvio-marine beds of the Fayum were formed with the remarkable deposits containing mammalian remains at their base. To this succeeded another hydrocratic movement in Miocene times. Miocene deposits occur in northern Egypt, on the borders of the Gulf of Suez, and in the neighbourhood of Ras Mohammed. ‘They occur at different levels and sometimes have the character of beach deposits. Did the earlier Miocene deposits advance over a planed down surface of older rocks? ‘This is suggested by Dr. Ball’s work, for it is impossible to avoid the conclusion that the Cretaceous and Eocene deposits once extended over the whole area. Moreover, a small patch of Miocene strata, wedged in between two faults just north of Gebel Sarbut el Gamal, is represented on the map as resting both on Nubian Sandstone and on Cenomanian, whereas Miocene rests on Campanian, without any intervention of Eocene on the mountain itself, of which it forms the summit. . As evidence of the great differences of level at which Miocene rocks occur, it may be pointed out that the boring for oil at Gebel Zeit! ended at a depth of about 1,100 metres below sea-level in rocks which are supposed to be of Miocene age, whereas the top of Gebel Sarbut el Gamal is 642 metres above the sea, making a difference of 1,742 metres. How far these differences of level are to be accounted for by deposition at different times while geographical evolution was going on, and how far they are due to movements of elevation and depression affecting large areas or to faults subsequent to deposition, cannot be determined with precision at present, but the last-mentioned cause has certainly played an important part. Basalt sills and dykes occur at many points in the district. They are all referred by the author to the Miocene period. The ores of manganese and iron (pyrolusite, psilomelane, wad, and hematite) occur at the junction of the Carboniferous Limestone and the underlying sandstone in certain places. They form irregular deposits which are only found in the neighbourhood of faults and become thicker and richer as the faults are approached. Where they occur certain dolomitic limestones, containing small amounts of manganese and iron, have partially or wholly disappeared, and it is suggested that the circulation of water along the fault fissures has removed the carbonates of lime and magnesia from the limestones and left behind the manganese and iron as oxides. The principal objection to this theory is that the amount of manganese in the dolomites which have been analysed is very small—less than 3 per cent. Is it possible that beds much richer in carbonate of manganese, like those occurring in Merionethshire, are present but not exposed ? In these days, hes. there is a marked recrudescence of old superstitions, not confined to geology, it is interesting to note that Dr. Ball, so far as this district is concerned, attributes the surface inequalities directly to erosion. After pointing out that valleys _] Explanatory notes to accompany the Geological Map of Egypt by W. F. Hume, Cairo, 1912. 84 Reviews—Prof. C. Schuchert’s Text-Book of Geology. sometimes coincide with faults he says: ‘‘It is important to note that the same fault which coincides with a deeply eroded wadi along one part of its course may cut across a high mountain tract in another part, and frequently at the latter place there is not the slightest change in the contour of the surface to mark the line of fault. ‘Nothing of the nature of a ‘rift’ is anywhere visible; faults have governed the position of drainage lines in places, but erosion alone has removed the material from the valleys.’ In _discussing the relation of the faults to the Gulf of Suez, which has been regarded as a trough subsidence, he refers to his papers in the Gnotogican Magazine! in which he has brought forward arguments in favour of the view that it is a submerged land valley. Enough has been said to show that this clearly written, beautifully illustrated, and well-printed monograph is an important contribution to our knowledge of the geography and geology of the Simai peninsula.—J. J. H. T. IJ.—A Texr-Book or Gronogy. Part Il: Hisrortcan Guronoey. By Cuartes Scnucner?. pp. vill + 405-1026, xxxyii plates printed in text, text-figures 312-522, and Geological Map of North America. New York, John Wiley & Sons, Inc.; London, Chapman & Hall, Ltd. 1915. Price 12s. nett. INHE first part of this text-book, dealing with Physical Geology, was reviewed in the Guotocicat Macazrne for September, 1916. Physical Geology is much the same the world over, though certain aspects may be more studied, or certain theories more favoured, in one country than in another. Historical Geology on the other hand, unless it be treated from the view-point of that observer in space whom Suess imagined, almost inevitably takes its colouring from the native country of the historian. This tendency is accentuated, and naturally so, when the exposition is based on lectures to the students of a single university. Above all is the difference marked between an American and a European treatment of the subject. We are therefore not surprised. to find in Professor Schuchert’s book, embodying as it does a course delivered to undergraduates of Yale, a presentation of historical, or at any rate of stratigraphical, geology, which to one brought up on Sedgwick, Murchison, Geikie, and Prestwich, might almost seem to be the account of another world. We do indeed find such familiar names as Cambrian, Carboniferous, and Cretaceous (and we must rejoice that Professor Schuchert’s publishers or his own better judgment have not permitted him to — _use the Cambric, Carbonic, and Cretacic, which he has long sought to introduce ); but even these household words have a novel content. The name Carboniferous has long been restricted by American geologists to the equivalent of our Coal-measures. Then this gave place to ‘‘Pennsylvanian’’, the Lower Carboniferous becoming ‘¢ Mississippian ’’; and now the latter is split into an upper system, the ‘‘Tennesseian’”’, including all formations from the Kaskaskia 1 “Origin of the Nile Valley and the Gulf of Suez,’’ Gnon. MaG., 1910, p. 71, and ‘‘ The Gulf of Suez’’, Gkou. MAG., 1911, p. 1. Reviews—Prof. C. Schuchert’s Text-Book of Geology. 85 down to the Warsaw, and a lower ‘‘ Waverlian”’, continuing from the Keokuk to the unfamiliar Chattanooga. These rather uncom- tortable system-names are adopted from Mr. E. O. Ulmch, who, however, spelt them differently. In similar fashion the name “Cretaceous” is restricted by Mr. Schuchert to formations corre- sponding to our Upper Cretaceous, i.e. down to the beginning of Cenomanian time; the preceding ages, from Albian to Neocomian inclusive, are erected into the Comanchian period, at least so far as North America is concerned. It may be gathered from the preceding paragraph that, except for the Eras, and to an incomplete extent for the Epochs, Professor Schuchert does not attempt to overcome the difficulties inherent in geographical treatment by any use of universal 'Time-names. For him such ages as ‘ Tournaician ’ [see] or ‘Cénomanian ’ [s?c] are just as local as ‘the Elizabethan period or the Carlovingian epoch. No living geologist is better fitted to discuss questions of correlation, at all events for the Palaeozoic era, than is Professor Schuchert, and the fact that ke is deliberately provincial may be held to indicate that in his opinion the time is even yet not ripe for comparison of the isolated histories with any universal Time-standard. Such an opinion does not well harmonize with the widely held view that the rhythmical movements of the earth’s crust are at the base of the whole march of the world and its varying tempo, or with the knowledge we already have of those movements—a knowledge so well illustrated by Professor Schuchert’s numerous maps, and emphasized by the varied names that he provides for uplufts and disturbances, such as the delightfully christened Shickshockian. No doubt, as he says, we have still much to learn in Europe as in America; and the more we know the more impossible will be exact correlation of far distant strata. But the practical application of a Time-scale will always help us over many difficulties, and will at least show just where our knowledge is defective. The book is meant to be a guide for American students, and for ‘such a purpose it seems well adapted. Apparently the students of geology at Yale are not expected to have any knowledge of - elementary zoology and botany, and so the lecturer has ever and anon to break the thread of his discourse in order to impart information concerning the anatomy of Mollusca, the origin of lungs, the classification of Pteridophyta, the physiology of Amphibia, ampiotic development, human embryology, and other matters properly belonging to other branches of study. However well Professor Schuchert deals with these subjects, the space devoted to them has necessarily to be taken away from stratigraphical geology, and the part that suffers is, as already indicated, the history of other countries. For us on this side of the Atlantic, therefore, the book must serve, not as a text-book for our students, but as a useful conspectus of American geological history. Here the rapid advance has of late introduced so many changes that one is grateful for a handy volume in which to follow the succession of geographical forms, and from which to extract the meaning of Appalachicola, Arikaree, Swearinger, Bertie, Cannonball, Kittatinny, 86 Reviews—O. C. Farrington’s Meteorites. and Mauch Chunk. One must also be grateful for some admirably written sections on the beginnings of earth-history by Professor Barrell, and for a well-illustrated chapter on Dinosaurs by Professor Rk. 5S. Lull. In brief, this is an original and stimulating book, where fact and theory are happily mingled, and the tangled threads of many complicated series of events reduced to an orderly and attractive pattern. I{1.—Merrorrres: rHeir Structure, Composrrion, AND TERRESTRIAL Retations. By O. C. Farrrneton. pp. x, 233, with frontispiece and 65 figures in text. Chicago: published by author, 1915. Price 8s. 6d. fJ\HE absence of a comprehensive and up-to-date book on meteorites has undoubtedly been a factor in confining the interest in this subject to a comparatively small number of geologists. he admirable introduction to this study in the handbook to the collection in the Natural History Museum is of course limited in scope, while Cohen’s Meteor itenkunde, which was intended to cover the full ground of the subject, was unfortunately little more than half finished at the author’s death. Dr. Farrington’s book, therefore, fills a gap in scientific literature and will be indispensable to the student who desires a general knowledge of the subject. The book opens with a discussion of the criteria whereby meteorites may be distinguished from terrestrial material, and emphasis is laid on the superficial and chemical characteristics by which the former may be discriminated when, as is generally the case, the fall has not been observed. Several chapters are devoted to the fall of meteorites, while the succeeding sections are concerned with the form and size of these bodies. As is to be expected, the discussion of the composition and structures is very full, the explanation of the octahedral structure so common in ‘irons’ and the account of the structures found in ‘stones’ being admirably lucid. In the description of the mineral species a large amount of space is devoted to the three types of nickel- iron, but this constitutes the least satisfactory portion of the book. Thus plessite is explained by analogy with the system silver-copper, as a eutectic developing probably from solid solution, but no mention is made of the recent metallographic work on the system iron-nickel.' ‘The investigations of Osmond and Cartaud, Tammann, and particularly Ruer have shown that y-iron and #-nickel are isomorphous and that this solid solution on cooling undergoes a number of changes in the solid state. a-iron and a-nickel, the low-temperature forms, also give solid solutions, and kamacite is to be regarded as a nearly saturated solid solution of a-nickel and a-iron, and not, as Dr. Farrington hints, as a compound of constant composition, Ni Feyy. The only compound in the system has the composition Fe Ni, and tanite is considered to be a solid solution of a-iron and this compound, while plessite is a eutectoid of kamacite and tenite, separating from solid solution. ' A useful summary of this is given by Desch, Metallography, 2nd ed., 1913, pp- 383-5. ae : | | ee a ee Reviews—H. J effreys Radvoactivity. 87 The author uses Rinne’s term ‘eutropic’ in place of ‘eutectoid’, but this is inadvisable as ‘eutropic’ had previously been used in another crystallographic sense by Linck in 1896, while ‘eutectoid’, first suggested by Howe in 1908, has also priority over ‘eutropic’ (suggested by Rinne in 1905) and has been generally adopted. _ For a long time the structure of meteorites was regarded as metastable, as it could be destroyed by annealing and a granular texture—occasionally found naturally—obtained. Recently, however, Benedicks, by very slow cooling, has obtained plessite and reproduced the octahedral structure. Hence the granular structure is to be regarded as metastable, and the difficulty in reproducing the usual meteoric structure is to be ascribed to the low rate of diffusion inhibiting changes in the solid state. ; In tie chapter on classification the only system given is Brezina’s modification of the Rose-T'schermak classification. It would have added to the interest of the book if the author had given his own interesting classification based on the American quantitative system for igneous rocks, and Berwerth’s rational system founded on the synthetic work on nickel-iron. The recent genetic one, devised by Prior, was, of course, published after this book appeared. The illustrations are excellent and the letterpress very clear, though there is a misprint in figure 53 and another on p. 189. The use of such a contraction as ‘A.N.H. Wien’ is by no means clear. Nevertheless the book can be confidently recommended as the best general introduction to the study of meteorites which has yet appeared, and should be in the possession of everyone interested in the subject. pau ALIS): LV.—Raproactivity AND Mounvrarn Boinpine. Tux Compression or THE EKartH’s Crusr 1x Coomne. By Harorp _Jerrreys. Phil. Mag., xxxul, pp. 575-91, December, 1916. f{VHE view that mountain-building owes its principal cause to the contraction of the earth has been widely adopted by geologists. ‘The subsidiary view that the alleged contraction is due to loss of heat has not met with equal success. The calculations of T. Mellard Reade, made before the discovery of radioactivity, indicated that the cireum- ferential shortening of the globe (in cooling from a molten state to its present condition during a period of 100 million years) could not exceed 10°5 miles. ‘his figure is only a small percentage of the shortening implied by the existence of great mountain ranges. Moreover, various calculations of the Jevel of no strain by Fisher, Reade, Davison, and G. H. Darwin gave results varying between 0:7 and 7:8 miles. ‘That is to say, compressional deformations of the earth’s crust must, on the older hypotheses, have been limited to a thin superficial shell which could never have accumulated the enormous stresses required for periodic mountain-building. ‘Thus, in two directions, the thermal’ contraction theory was shown tv be hopelessly inadequate to meet the facts. Consequently other causes of contraction have come to be invoked in recent years; among them, 88 Reviews—Mineral Resources of the United States. — a molecular rearrangement of compounds in the earth’s interior, which under high pressure may be supposed to involve a decrease in volume. With the discovery of radioactivity and the realization of its fundamental importance in dynamical geology it became evident that the thermal contraction theory stood in urgent need of re-examination. The mathematical skill required for this task is of an order far beyond. the attainments of most geologists, and Mr. Harold Jeffreys has come to our assistance by working out, in the light of our later knowledge, the group of problems involved. Using the thermal and radioactive data adopted by the present writer in a series of papers which have appeared in the pages of this Magazine, he has arrived at the following results :— (a) The level of no strain is now at a depth of 79 km. (uniform distribution of radioactivity) or of 76 km. (exponential distribution). (6) Every great circle of the earth has been shortened by 227 km. (uniform distribution of radioactivity) or by 133km. (exponential distribution). ‘To arrive at the radial shortening, these figures should be divided by 6°28. (c) The surface of the earth has been diminished by crumpling by 56 X 10° sq. km. (uniform distribution of radioactivity) or by 3°3 X 10° sq. km. (exponential distribution). In order to test these results Mr. Jeffreys has calculated from the mean height of existing mountain ranges the approximate diminution of the surface by crumpling. He finds the amount to be about 1:8 X 10° sq. km., which is little more than half of the amount implied by the thermal contraction hypothesis in its new form (exponential distribution). It should be pointed out, however, that Mr. Jeffreys’ calculation of the actual amount of diminution of the surface by crumpling gives only a minimum result, for it does not take into consideration the former existence of ranges that are now submerged or denuded to insignificant elevations. Most of the ranges measured are of post-Carboniferous age, and may therefore represent only a third or a quarter of the total crumpling since geological history began. The maximum circumferential shortening demanded by Chamberlin is about 3800 km., corresponding to a surface diminution by crumpling of 7-6 x 10° sq. km., more than twice as much as that found theoretically on an exponential distribution of radioactivity. Nevertheless, in spite of the fact that complete accordance has not yet been attained, itis evident that the theoretical and observed compressions are of the same order of magnitude, and it may confidently be asserted that the much abused thermal contraction hypothesis, thanks to radioactivity, has now been set firmly on its feet. ’Arravur Hommes. V.—Minerat Resources of THE Unirep Srares For 1914. (TVHIS is the 33rd of the admirable series of reports which was started in the early years of the United States Geological Survey. Year by year they give carefully prepared statistical —aee eo Reports & Proceedings—Geological Society of London. 89 information of the output of minerals in the country and of the imports from outside. As usual this report is divided into two main parts, of which the first deals with metallic and the second with non-metallic, substances, the latter including fuels, structural materials (other than metals), chemical minerals, and precious stones. Each chapter is entrusted to a different writer, and each is issued separately as soon as it isready. ‘The date of publication of the several chapters is given on the wrappers, but disappears in the bound-up volume ; the pagination is continuous, but separate throughout each part of the report, including the summary. The series is so well known that detailed criticism is uncalled for; it is sufficient to say that the present report is well up to the high standard of its predecessors. REPORTS AND PROCHHDINGS.- $< — I.—GeroLtocicaL Soctery or Lonpon. 1. December 20, 1916.—Dr. Alfred Harker, F.R.S., President, in the Chair. Marie C. Stopes, D.Sc., Ph.D., gave an account of some recent researches on Mesozoic ‘ Cycads’ (Bennettitales), dealing particularly with recently discovered petrified remains which reveal their cellular tissues in microscopic preparations. To make the significance of the various fossil forms clear, Dr. Stopes first showed some lantern-slides of living Cycads, and then pointed out that it was in their external features and in their vegetative anatomy only that the fossil ‘Cycads’ -were like the living forms; the most important features, the repro- ductive organs, differ profoundly in the two groups, and the fossils were fundamentally distinct, not only from the living Cycads, but from all other living or fossil families. The fossils representing the group that are most frequently found are (@) trunks, generally more or less imperfect casts or partial petrifactions, and sometimes excellent petrifactions preserving anatomical details and cell-tissues; (6) impressions of the foliage. Not infrequent are the detached impressions of incomplete ‘flowers’ _ or cones, of one cohort (the Williamsone), while petrified fructi- fications are numerous in some of the well-petrified trunks of the Bennettitee. The described species of the group run into hundreds, but probably many of these duplicate real species, because the foliage, trunks, pith-casts, various portions of the fructifications, ete., have often been separately found and named. In very few cases have the different parts been correlated. The species of the foliage are the most generally known, as they are the most readily recognized with the naked eye; they have been described under a variety of generic names, The following table gives the proved, or probable, associated parts of some members of the group :— 90 Reports & Proceedings—Geological Society of London. FOLIAGE. TRUNK. FRUCTIFICATIONS. Zamites spp. Bennettites spp. Bennettites spp. Zamites gigas. Attached, no separate Weallaamsonia gigas. : name. Otozaniites sp. = Williamsonia spectabilis. Ptilophyllum pectinoides. = Williamsonia whitbiensis. Anomozamites mmor. (Only slender branches Wielandiella angustifolia. known, no name.) Teniopteris vittata. — Williamsoniella coronata. Dr. Stopes exhibited slides of microphotographs of the stem and leaf-base anatomy of the group, including some unpublished details of Bennettites maximus. The roots of the group have hitherto been entirely unknown, and a slide was exhibited for the first time showing rootlets penetrating the leaf-bases of a petrified specimen (represented by a section in the Geological Department of the British Museum— Natural History). These roots probably belong to B. sawbyanus : they are covered with wonderfully petrified root-hairs, running uncollapsed through the silica matrix. They raise interesting questions concerning the possible chemical conditions of the infiltra- tion of the silica. Illustrations were also exhibited of the famous complex ‘flower’ and cone-structures, and of Wieland’s brilliant restorations of the same. Microphotographic slides were exhibited of the seed-cone of an interesting unpublished new species from the British Gault. This is beautifully petrified, and adds to our know- ledge of the finer anatomy of the seeds and associated structures. It is also the largest cone of the Bennettitales yet known, though it occurs in the Gault, by which time the group appears to have begun rapidly to die out. The following table indicates the distribution of a few of the most interesting representatives of the Bennettitales (including the cohorts Bennettites and Williamsonez) :— UppER CRETACEOUS. Very fragmentary and uncertain records; apparently the group is nearly or quite extinct. MIDDLE CRETACEOUS : The new large-sized seed-cone. Gault. B.morverei 2 (? described originally from the J urassic). LOWER CRETACEOUS: Well-petrified trunks with fructifications. Lower Greensand. 2B. gibsonianus (type-species of the Bennettitex). Potton Sands. Wealden. JURASSIC: Purbeck. B. maximus. Trunks, e.g. Colymbetes edwardsi. Trunks (casts and petrifactions), foliage. B. saxbyanus. Trunks (casts and semi-petrifac- tions). Buckland’s original Cycadeoidea Throughout these periods in © America, trunk- remains very ; abundant, often petrified and with fructifications, particularly from spp. the Black Hills, C. gigantea. : South Dakota, Oolites. Trunks, pith-casts, etc. Much}and Maryland. foliage of various types. Wil-| C. jenneyana, liamsonia gigas and other fruit-| C. mgens, C. impressions. wielandt, ete. W. scotica. Williamsoniella coronata. | Richimpressionsin Mexico Lias. Foliage and Williamsonia of Williamsonia and many fruits (India). Wicchiaceecacrs Rhetic. Wielandiella angustifolia and foliage. | Reports & Proceedings—Geological Society of London. 91 The group is by far the most characteristic of all the plants of the Jurassic and Lower Cretaceous, during which periods its distribution was almost world-wide. It was locally, if not universally, dominant, and was the most highly evolved plant-group of the epoch of which we are cognizant. Three chief points of interest are to be noted in the geological distribution of these plants: ~ (a) that the most numerous highly specialized trunks reach their maximum in the Jurassic and Lower Cretaceous Periods, when their distribution was practically world- wide ; (4) that the oldest and therefore presumably the most primitive type, Wielandiella, is externally less like the living Cycads than the commoner later forms, while these latter are utterly unlike the living genera in their fructifications; (¢) that the geologically youngest cone is the largest yet discovered, occurring in the Gault when the extinction of the group appears already to have set in. Contrary to what might have been anticipated from their external likeness to the living Cycads, coupled with their great geological age, the fossil ‘ Cyeads’ are much more complex and on a higher level of evolution than the living group. It seems to the author to be extremely unlikely that the fossil and the living forms have any direct phylogenetic connexion nearer than a remote, unknown, commonancestor. The mooted connexion between the fossil ‘ Cycads’ and the Angiosperms is highly suggestive, but lacks data for its establishment. A short discussion followed, and the thanks of the Fellows present were accorded to Dr. Stopes for her lecture. 2. January 10, 1917.—Dr. Alfred Harker, F'.R.S., President, in the Chair. ee following communications were read :— On the Paleozoic Platform between the London Basin and esau Areas, and on the Disposition of the Mesozoic Strata upon it.” By Herbert Arthur Baker, BSc., F.G.S. With an Appendix by Arthur Morley Davies, D.Sc., F.G.S. The author carries on the work of Dr. A. Strahan and Dr. Morley Davies in tracing the contours of the Paleozoic platform of the South-East of England. By comparing these with the contours of the base of the Gault, he determines the probable boundaries of the areas -of the platform that were only submerged finally under the Gault sea. He analyses the effects of post-Cretaceous tilting and warping, and presents a map illustrating the contours of the Palzo- zoic floor at the end of the Lower Cretaceous Period. He next discusses the successive Mesozoic overlaps on the platform, the probable areas that they respectively cover, and the relation of these to the tectonics of the platform itself. He claims that there is evidence for a second Charnian axis, parallel to that traced by Professor P. F. Kendall, proceeding south- eastwards through Norfolk and Suffolk, east of Kent, to the North of France. He further suggests that the area between these two geo-anticlines is a geo- syneline, which in Mesozoic times, in consequence of the accumulation 92 Reports & Proceedings—Geological Society of London. of sediments within it, and the continued operation of Charnian movement, became converted into an anticline (as in the case of the ‘Wealden area). In an Appendix, Dr. Morley Davies discusses the interpretation of the Saffron Walden boring, and its bearing on the supposed inter- Charnian trough; he also points out evidence of a post-Cretaceous Charnian anticline under London. 2. ‘‘ Balston Expedition to Peru: Report on Graptolites collected by Captain J. A. Douglas, R.E., F.G.8.” By Charles Lapworth, LL.D., M.Sc., F.R.S., F.G.S. The specimens of graptolites were collected from the rocks of the Inambari district in Peru by Captain Douglas, under whose. name the collection has been placed in the Geological Department of the University Museum, Oxford. These fossils were forwarded by Professor W. J. Sollas to Professor C. Lapworth, who embodied the results of his study in a Report, of which the following is a brief abstract. The specimens are recorded as all occurring in the same locality, but it is not known whether they were obtained from a single zone. The majority of the rock-specimens in which the graptolites occur are black and somewhat pyritous carbonaceous shales, usually well bedded and uncleaved, and the graptolites are in general well preserved. The lithology of the containing rocks and the mode of preservation of the graptolites are similar to those obtaining in the richest graptolite-bearing strata of Britain, Europe, and North America. The forms apparently represented in the collection are Logano- graptus logani, Hall, a new species of Goniograptus (?), Didymograptus stabilis, Elles & Wood, and D. bifidus, Hall, Phyllograptus angusti- folius, Hall, Glossograptus acanthus, Elles & Wood, Cryptograptus tricornis, Hall, var. Amplexograptus confertus, Lapworth, and A. celatus, Lapworth. Taken as a whole this graptolite fauna may best be compared with that of the Upper Arenig formation of Britain and its North American equivalents, answering to the Lower Llanvirnian of Hicks & Marr, and the Didymograptus bifidus zone of Elles & Wood and H.M. Geological Survey. The assemblage of graptolites discovered in Bolivia a few years ago by Dr. J. W. Evans corresponds very closely with this Peruvian fauna, and was probably derived from the southward continuation of the same Andean graptolite band. The Peruvian forms in the Douglas Collection, like those from Bolivia, admit almost as close a parallelism with those of the Arenig—Llandeilo graptolite beds of Australia and New Zealand as with their representatives in the Northern Hemisphere. Not only is the Douglas Collection of Peruvian graptolites instructive and valuable from the paleontological point of view, owing to the number and good state of preservation of the species represented, but it is of especial interest from the paleeographical aspect, as affording additional proof of the identity (in general facies) of the graptolite fauna of the sea-waters of Lower Ordovician times Reports & Proceedings—Edinburgh Geological Society. 93 in those regions of the globe which are now occupied by some of the dry lands of Britain, Eastern North America, Peru, Bolivia, Victoria, and New Zealand. Thus it greatly strengthens the inference that in Arenig—Llandeilo times there was open-sea communication admitting of the circulation of sea currents along some as yet un- determined line or lines, connecting the above-mentioned regions, which must have extended across the Equator and apparently throughout a length nearly equal to that of half the circumference of the globe. II.—Epinsurce GroLiocicaL Socrery. December 20, 1916.—Dr. Flett, F.R.S., President, in the Chair. The following papers were read :— 1. ‘‘Igneous Intrusive Phenomena at Upper Whitfield, near Macbiehill; and at Raveirig and Kaimes Hill Quarries, Balerno.”’ By T. Cuthbert Day, F.C.S. - The intrusive nature of the Upper Whitfield hasalt was established by the discovery of upper and lower contacts with the sedimentary deposits. Jetails of a xenolithic structure in the igneous rock at the point of contact were given, and a peculiar marmorized dolomite associated with chert was described. Mention was also made of a case of metasomatism in basalt through the action of a deposit of dolomitized calcite. A description was given of a peculiar tachylite in connexion with the intrusive olivine dolerite at Ravelrig and Kaimes Hill quarries, Balerno. _ 2. “Ona Section in a Bore-hole in the Calciferous Sandstones, Upper Old Red Sandstones, and Lower Old Red Sandstone Lavas in the Grange District, Edinburgh.” By D. Tait, H.M. Geological Survey. Mr. Tait said that the geological horizon of the beds in the upper _ part of the bore are on the boundary between the Carboniferous and the Old Red Sandstone formations, but, as no fossils had been found in the bore, no sharp line could be drawn at their point of junction ; possibly they form passage beds between them, since there were present, interbedded with each other, beds typical of both formations. At a depth of 284 feet a fault breccia was passed through. This probably indicates a fault, with a downthrow to the south-west, but its importance is not known. From 389 to 397 feet cornstone bands and nodules were found, interbedded with red marly clay. At 399 feet the bore passed through the unconformity between the Upper Old Red Sandstone and the Lower Old Red Sandstone. The Lower Old Red Sandstone rocks are lavas of Blackford Hill Quarry type . and a bed, 47 feet thick, of volcanic agglomerate. The total depth of the bore from the surface was 475 ft. 6 in. Ill.—Tur GerotocicaL Sociery oF Giasgow. At a meeting of the Geological Society of Glasgow held on December 14, 1916, Mr. H. R. J. Conacher read a paper on ‘‘ Oil- shales and Torbanites”’. The rocks of these types which occur in 94 Reports & Proceedings—Geological Society of Glasgow. — ¥ the Lothians yield, on destructive distillation, a characteristic crude oil which consists chiefly of paraffins, olefines, and naphthenes. and they thereby differ from ordinary coals, the liquid products of which contain but small amounts of these hydrocarbons. This peculiarity has been variously ascribed to the presence of vegetable matter derived from alge or higher plants in a more or less decomposed state, animal matter from the fish, ostracods, etc., whose remains are abundant in the shales, to the presence of petroleum or other bituminous substances or to a hypothetical material called kerogen. The author described a series of experiments undertaken with a view to attaining a definite result, the method being to ascertain what material could actually be detected by means of the microscope, and to compare these constituents with the results of the distillation of the same samples. In those shales which contain animal remains, the yield and quality of oil is independent of the amount of animal remains, but varies in proportion to the quantity and nature of the vegetable matter present. The latter consists of two distinct types. One portion seems to be macerated and carbonized plant-material, similar to that of which coal is composed, while the other portion is _composed of certain yellow bodies which have been variously described as spores, fossil alge, or globules of dried-up petroleum. It is these yellow bodies which yield the distillation products of oil- shales and torbanites. The evidence is against these bodies being spores, alge, or petroleum, and it is shown that they are simply fragments of resin set free by the decay and oxidation of woody matter with which they had been originally associated, and that, by the physical action of pressure and shrinkage, structures had been developed simulating those of spores and alge. The failure to obtain appreciable amounts of extract by means of the usual solvents is inconclusive, as it is known that the solubility of resins rapidly diminishes with increasing age. Further it has recently been found that the resinous material extracted from coal yields on distillation just such products as are got from oil-shales and torbanites. The author’s view, therefore, is that both oil-shales and torbanites are derived from the same original materials as ordinary coals, but have reached a state of more complete elimination of the perishable parts, leaving the resins with a proportion of material derived from the decomposition of the woody substances, which in the case of oil- shales are mixed with a large proportion of mud. Mr. J. Neilson read a paper entitled ‘‘ The Auld Wives’ Lifts, an Ancient Monument”’. He objected to the view that these stones had reached their present position through natural agencies by the subaérial weathering of a ridge, as the position of the stones in the centre of a shallow amphitheatre rendered the action of erosion negligible, while the surrounding rocks show little sign of alteration since Glacial times. The theory that their origin is due to ice-action is equally untenable, while there are likewise difficulties in the hypothesis that the structure is a ‘‘tor’’. The explanation advanced by the author is that the “ Lifts”’ did not attain their present position by natural agencies, but that they were placed there by man, the Correspondence—J. W. Gregory. 95 blocks having been taken from the nearest escarpment. The whole structure belongs to the type of monument known as cromlech or dolmen, and the irregular form and small dimensions are probably to be explained by the fact that the chief consideration was the feat of raising the enormous blocks, the utility of the chamber beneath being of secondary importance. CORRESPONDEHNC#E. PROFESSOR LOEWINSON-LESSING.? Srr,—It was arranged in January, 1914, that a German translation of Professor Loewinson-Lessing’s important memoir on the volcanoes of the central Caucasus should be published in T'schermaks Mitteilungen. Owing to the strike of the printers in Vienna the publication of the memoir was delayed till the summer, and before its issue war was declared. It has subsequently been published, and Professor Loewinson-Lessing is anxious that it should be understood by his English friends and fellow-geologists that the publication of this memoir in Austria was arranged before the War and that he has since then had no share in its production. As Professor Loewinson-Lessing has asked me to explain why his memoir has appeared in an Alien journal during the course of the War, I shall be much obliged if you would issue this explanation. J. W. Greeory. GEOLOGICAL DEPARTMENT, UNIVERSITY, GLASGOW. January 17, 1917. (QiSTlAi Slr NAsySse ERNEST SWAIN. BoRN JANUARY 15, 1843. DIED DECEMBER 20, 1916. AurnoucH he never contributed to any scientific publication, Ernest Swain was well known to a past generation of geologists as a keen student of the science and a constant attendant at the meetings of the Geological Society and Geologists’ Association. Of the latter he remained a member till the last. He was born at Wood Lane, Shepherd’s Bush, and educated privately and at King’s College, of which he became an Associate. His life was passed in business in the West End, but all his spare time was devoted to scientific studies, and his museum and library were open to all friends and students, many of whom owed their start on a scientific career to his influence and aid. He was an active member of the quondam West London Scientific Association and the succeeding Western Microscopical Club. He devoted much time to the compilation of commonplace books, of which he kept some 140 going on the subjects that interested him. Unhappily he latterly met with bad times and retired to Chorley Wood, where he died at the close of last year. 1 Professor of Mineralogy. and Geology in the Polytechnic Institute, Sosnovka, Petrograd, Russia. Laat Obituary. : REGINALD COOKSEY BURTON, B.Sc., F.G.8., Assistant Superintendent Geological Survey of India. Born MARCH 10, 1890. DIED OF WOUNDS APRIL 9, 1916. Tuer name of R. C. Burton has to be added to the ‘‘ Roll of Honour ” of geologists who have given their lives for their country in the present War. Dr. H. H. Hayden, the Director, writes: ‘ ME: Burton joined the Department in January, 1912, and was posted to the Central Provinces, where, during his short period of service, he did admirable work in helping to solve the question of the origin of the calcareous gneisses which constitute such an important element of the Archean group of that area. His investigations into the origin of the bauxite of Seoni and adjoining districts also gave evidence of marked ability, and by his death the Geological Survey has lost one of the most promising as well as one of the most popular of its younger members. Mr. Burton joined the Indian Army Reserve of Officers early in April, 1915, and after a short training in India was attached to the 104th Rifles in Mesopotamia, where he died on April 9, 1916, from wounds received in action on the previous day. His loss is keenly felt by all his colleagues.” (Records of the Geological Survey of India, vol. xlvii, pt. 111, p. 143, August, 1916.) SIR EDWARD BURNETT TYLOR, Kn.’ J.P., D.C.L., LL.D., F.R.S., Hon. Fellow of Balliol College, and Emeritus Professor of Anthropology, University of Oxford. BORN OCTOBER 2, 1832. DIED JANUARY 2, 1917. ‘'a1s famous Anthropologist was born at Camberwell October 2, 1832, and educated at the school of the Society of Friends, Grove House, Tottenham, to which Society his family belonged. He was one of the sons of the originator of the old firm of Tylor and Sons, Brass-founders, Newgate Street, K.C., of which his brother Alfred Tylor, F.G.S., was for many years chief. Abandoning business E. B. Tylor devoted himself to the study of the races of mankind, their history, languages, and civilization, and had the advantage, at 24 years of age, to accompany his friend Henry Christy on a journey in Mexico in 1856; the archeological objects then collected now form part of the Christy Collection in the British Museum. His researches are embodied in Anahuac, or Mexico and the Mexicans (1861), Researches into the History of Mankind (1865), and Primitive Culture: Researches into the Development of Mythology, Philosophy, Religion, Art, and Custom (2 vols., 1871; 8rd ed., 1891). He was elected a Fellow of the Royal Society in 1871, Honorary LL.D. St. Andrew’s (1878), and D.C.L. Oxford (1873). In 1883 he was appointed Keeper of the Oxford University Museum, Reader, and in 1896 the first Professor, in Anthropology. In 1858 he married Anna, daughter of the late Sylvanus Fox, of Wellington, Somerset. to which place he retired after resigning his post at Oxford. 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Watson’s Microscopes for } Geology. WATSON & SONS wmanvfacture a special series of Microscopes for Geo- logical work. All have unique features, and every detail of construction has been carefully considered ‘with a view to meeting every requirement of the geologist. All Apparatus for Geology supplied. WATSON’S Microscopes are guaranteed for 5 years, but last a lifetime, and they are all BRITISH MADE at BARNET, HERTS. W. WATSON & SONS, Ltd. (ESTABLISHED 1837), 313 HIGH HOLBORN, LONDON, W.C. Works:—HIGH BARNET, HERTS. Manufacturers of Optical and Scientific instruments, MICROSCOPES | 3 ‘ 4 ities ee Ee H oa Fan ane ae AN a uf Ce i atk x Ae ca) Grou. Maa., 1917. Prate VI. 1, VIEW OF LODMUNDARFJORD, EAST ICELAND. 2 GREAT FALLEN BLOCK OF LIPARITE, JAFNADAL. THE GEOLOGICAL MAGAZINE NEWoseRleS ) DECADE Vile VOLS IM. No. III.—MARCH, 1917. . fs. Cogs (x MAR 26 191. ORIGIN AL ARTICLES. aae < y I.—A Remarxaste Rock Srream in Hast Icenan Non ee ea lisse: By LEONARD HAwkgss, M.Sc., F.G.S. tenons acne (PLATE VI AND TEXT-MAP.) N his account of the volcanoes of Iceland, Thoroddsen describes two types of acid lavas which have been extruded in post- Glacial, prehistoric times. First are the lavas of the Torfajokull district, of the usual nature of acid flows, building up a compact mass of bluish-grey rock with an outer casing of obsidian and pumice. These lavas have been poured out in the post-Tertiary country, but the second type of stream is found most frequently in the older parts of the island, which otherwise have witnessed no volcanic eruptions since Tertiary times. This type of flow results from eruptions of a peculiar character in which ‘‘ vast outflows of half- melted and unmelted masses of liparite, poured out from cauldron- shaped depressions, stretch down into the lowlands” (1, p. 503). The best example of these ‘‘ Liparitische Blockstrome”’ occurs in the Lodmundarfjord district, E. Iceland, and is especially described by Thoroddsen (2, pp. 159-161). In this paper the contention is put forward that the Lodmundarfjord blockstream is not a lava-flow but an unusual type of glacial moraine. Unfortunately the magnificent topographical map of Iceland in preparation by the ‘‘ Generalstaben”’ of Copenhagen does not yet include the Lodmundarfjord district, and no claim of special accuracy is made for the rough sketch-map of Fig. 3, which is given to render the description below more intelligible. The Lodmundarfjord, running approximately east and west, is bounded on both sides by ramparts of Tertiary plateau-basalts from two to three thousand feet in height. The fjord is continued inland in a broad flat valley, the Bardarstadadal, and a raised beach, 23 metres high, after Thoroddsen (2, p. 103), shows that the sea formerly stretched far up the valley. The only notable breach in. the southern wall occurs at 800 feet, the mouth of a broad hanging valley which forms part of the pass (the Hjalmadalshe1%i, czrca 2,000 feet) leading over to the Seydisfjord. On the north side, near the end of the fjord proper, a broad valley, the Hraundal, leads up from sea-level to the inland plateau in a north-westerly direction.. The mountains of the Lodmundarfjord are built up exclusively of basalts and red tuff partings, but a thick series of acid rocks is exposed in the cliffs bordering the upper reaches of the Hraundal, being the southern extension of the largest area of DECADE VI.—VOL, IV.—NO. III. 7 98 Leonard Hawkes—Rock Stream in East Iceland. acid rocks in Iceland. Especially noteworthy is the mountain Skimhéottur, cerca 3,000 feet high, into which a huge cirque extends. The cirque walls are very steep, falling to a broad gravelly plain about 750 feet high, over which a river—the Hrauna—meanders in a south-easterly direction till it cuts through a rise of about 50 feet, the beginning of the blockstream, and takes a rapid course through a gorge to the fjord. The blockstream is a chaotic assemblage of large angular blocks of liparite, a great number being twelve or more feet in diameter, with an extremely uneven hummocky surface, forming a wilderness known as the ‘‘ Hraun”’. ‘‘Hraun” is an old Norse word meaning ‘‘a rough place”, ‘Ca wilderness’, but in Iceland it came to signify ‘‘a lava field when 4 1 ivi, Skumhotlut %q silty Fn) WTP Y % ny ay, tin & ? “e TY, Sally Ss, 4 | iit Ty Y PIE fy) ty ( Oxy Ais) Typ pHa ae Dh at sia Ce es = = = = = = > — = = S SS S \ ez PEG ~”A oy r.) —— S Ox a 8 Fic. 3.—Sketch-map of the Lodmundarfjord District. H=the Hjalmadal ; B=the Bardarstadadal; Se=the farm Severendi; St=the farm Stakkahlid. cold”, ‘‘a burnt place’’, being so used in the Sagas as well as in modern times (3). Thoroddsen regards the blockstream as a lava-+ flow extruded from Skumhottur. ‘The rough block surfaces of some acid lavas are well known and cited as a parallel, albeit the exceptional unevenness of the ‘‘ Hraun”’ is taken as an indication that the lava was exceptionally viscous, and the daring suggestion is made that the liparite was first intruded into the Tertiary basalts and cooled down so slowly that when the plateau was dissected by dislocation and erosion the still hot magma flowed out as a stream of half-melted blocks (2, p. 161). A closer examination of the district reveals little to support this hypothesis. It is clear that the greater Leonard Hawkes—Rock Stream in Hast Iceland. 99 part of the material composing the ‘‘ Hraun”’ comes from Skiimhottur, but I am not satisfied that ‘‘the lparite is for the greater part intrusive here” (2, p. 276). The acid series is estimated to have a maximum thickness of 1,800 feet, and though the actual junction was covered with snow (June month) the basalts did not show any signs of disturbance commensurate with that to be expected if the main part of the series were intrusive. The acid rocks here are similar to those which the author has described from the neighbouring Seydisfjord (4, pp. 391-2), consisting of tuffs, breccias, obsidian, and liparite. One breccia underlying the main mass contains large fragments of liparite, pitchstone, and obsidian, and the farmer at Stakkahh’% has some petrified tree trunks which were obtained here.. Thus with proof of the extrusive nature of part of the series, and in the absence of indications of intrusion with the exception of some dykes, it seems probable that the main mass was extruded in ' Tertiary times, as is the case with so many occurrences of acid rocks in Kast Iceland (5, p. 468). The chief objection to the hypothesis of a lava origin is the nature of the ‘‘Hraun”’ itself. Examination revealed the fact that the rock stream is not, as has been stated, exclusively composed of spherulitic liparite, but contains pitchstone, obsidian, pumice, and basalt. A beautiful mahogany obsidian is especially noteworthy, and all the rocks mentioned are to be seen in situ in the Skumhottur mountains. In the gorge of the Hrauna the ‘‘ Hraun”’ is seen to be fragmental and composite to the base and to contain much gravelly material. I saw no sign of a liparite dyke in the gorge, or any evidences of fumarolie action in situ as reported by Thoroddsen. Perhaps the most interesting part of the rock stream, which is about one and a quarter miles in length, is its termination in the main fjord valley. Near the fjord the blocks become smaller until the final fan of fine fragmental material is reached, resting on the floor of the Bardarstadadal, north of the FjarSara. These deposits are seen in Pl. VI, Fig. 1. South of the river, at and to the west of Severendi, are a number of conical mounds commonly composed of liparite fragments, with obsidian and basalt less frequently. One of the largest mounds was elliptical in plan, 100 feet by 80 feet, with a maximum height of 23 feet, and contained a block of liparite 7 feet in diameter. Proceeding westwards the mounds become fewer and further between until about half a mile from Severendi the last one occurs close to the southern wall of the valley. Many of the mounds are exclusively formed of one type of rock, some of obsidian and others of liparite, and they furnish the clue to the problem of the origin of the ‘‘ Hraun’’. Owing to its jointing 1 In connexion with the lava hypothesis as advanced by Thoroddsen it is of interest to note that the block surface of some lavas in the Cordilleras of South America was taken by Humboldt and de Boussingault as evidence of eruption in fragmentary form, but Scrope considered this an ‘‘ improbable hypothesis’’, pointing out that the fragmentary nature of lava streams is a property restricted to their upper and under surfaces, the main mass being compact (6, p. 70). 100 Leonard Hawkes—Rock Stream in Hast Iceland. liparite commonly weathers out in very large blocks. A striking demonstration of this is to be found at the head of the Jafnadal, StoSvarfjord, 8.E. Iceland. The valley ends in a large cirque, the walls of which are chiefly composed of liparite. The plain about a thousand feet below the top of the cirque wall is dotted over with blocks of liparite which have rolled from above over the steep snow slopes. The largest of these blocks, measuring 90 feet by 46 feet by 40 feet, has split in two at its final resting-place (see Pl. VI, Fig. 2). The complete weathering down of such a block would give rise to a mound like the largest of those in the Lodmundarfjord valley. The mounds clearly result from the weathering of large blocks in situ, and the only agency which can be imagined to have brought them to their positions so far west is that of ice floating in the sea, which once stretched far up the valley as evidenced by the raised beach deposits. Thus the ‘‘Hraun’”’ is. of raised beach age and was not formed subsequently (2, p. 159), and it dates from the end of the last Ice Age, when the glacier of the fjord valley had retreated. he raised beaches along the fjords of the Folden district, Salten, N. Norway, are considered by Rekstad to be formed of morainic debris, and to date from the time when glaciers flowed down side valleys to the shores of the fjords (7, pp. 10-11). A similar explanation suffices for the deposits described in the Bardarstadadal, and thus the “‘ Hraun”’ is to be regarded as the moraine of a glacier flowing down Hraundal. The morainic theory is rejected by Thoroddsen on two main grounds. These are (1) that ‘‘ the whole mass of debris and blocks consist exclusively of one particular rock, spherulitic liparite, whilst a moraine must contain both’’, and (2) ‘‘no ice scratches are found on the blocks”’ (2, p. 160). As mentioned above, besides obsidian basalt does enter into the composition of the ‘‘ Hraun”’, though to a remarkably small extent. This is partly understood when we consider the brittleness and fissility of liparite as contrasted with the toughness of basalt, whereby the former succumbs more easily to erosive agencies than the latter. The readiness with which lparite breaks up would itself account for the absence of ice-scratches on the blocks. During a field examination, extending over several weeks, of the acid rocks of East Iceland, the writer never saw an ice-scored surface of liparite. I regard the ‘‘ Hraun”’ as a surface ‘“‘ block-moraine”’, andit would not bear ice-scratches. The material probably did not fall slowly on to the glacier as a talus stream, but descended in great landslides, as has been suggested for some of the rock streams in the San Juan Mountains, Colorado, which are characterized by ‘‘the remarkable quantity of relatively coarse material comprising them, and the fact that the ereater part of this must have been carried on the surface of the ice”’ (8, p.25). The ‘‘ Hraun”’ presents many analogies to the rock streams of the San Juan Mountains. These latter are comparable in size, the hummocky surface is similar, they are often composed of Tertiary acid volcanic rocks, and the topography of the district is that of a “dissected and glaciated plateau of more or less horizontally bedded volcanic rocks” (9, p. 11). Leonard Hawkes—Rock Stream in Hast Iceland. 101 An interesting case of a landslide on to a glacier, which illustrates what has probably taken place in the formation of the ‘‘ Hraun”’, is recorded by Freshfield from the Caucasus. ‘‘ The Shikildi Glacier presented itself as an advancing mound of huge blocks of grey eranite. .. . In 1866 a noise as of thunder was heard by the shepherds of the Baksan, and a great cloud of smoke or dust was observed to issue from the recesses of the chain under Ushba. . . After a time it was ascertained that a great rock had crashed down from the cliffs on the east side of the Shikildi Glacier. . . . We saw next day the gap in the mountain side which had provided the enormous masses now strewn over the lower glacier. . . . I neversaw such a goods-train of aglacier. . . . The immense size of the single blocks and the complete burial of the ice under them are the features which give their extraordinary character to the moraines of the Shikildi’’ (10, pp. 137-8). It is interesting to note that in the Saga _ relating the colonization of the Lodmundarfjord, crea 900 a.., mention is made of a landslide, and whilst this cannot refer to the main mass of the “ Hraun”’, there is little doubt that we here have evidence that sliding has taken place in historic times.’ Many of the San Juan rock streams are regarded as landslides which had no connexion with glaciers. It would be possible to regard the ‘* Hraun’’ as such, and the mounds in the Bardarstadadal as being formed from blocks transported by the shore ice-foot when this broke up. But apart from the fact that the general aspect of the ‘‘ Hraun”’ is rather that of a moraine than a landslide, it is very probable that under the severer climatic conditions giving rise to an ice-foot, a glacier would exist inthe Hraundal. Strictly the term ‘‘ moraine”’ should be used only of material which has been actually transported by a glacier, rock debris which falls on to a stationary or retreating glacier being termed ordinary talus accumulations or landslide material according to degree. There will be cases which stand near the border-line between these two classes which will only be correctly placed after very careful investigation. Whilst reserving a final decision until the writer can make a more thorough examination, he is inclined to the opinion that the ‘‘ Hraun”’ has been transported to some extent by a glacier and is therefore a true glacial moraine. The rejection of the ‘‘lava-flow’’ hypothesis removes an exception to an important generalization, i.e. the post-Glacial instances of voleanic activity in Iceland are confined to the Quaternary Formation districts, so that the post-Glacial vulcanism is to be regarded as the direct continuation of the Quaternary and not the Tertiary activity (12, p. 18). It may be considered remarkable that the same 1 ‘* Todmund the Old was the name of a man, and another was Beowolf his sworn brother. They came to Iceland from Thule-ness in Vors. Lodmund east his porch-pillars overboard while he was at sea, and said that he would settle where they were drifted ashore. And the sworn-brethren made Kast-frith, and Lodmund took in settlement Lodmund-frith, and dwelt there three winters. Then he heard of his porch-pillars being inthe south of the country. And with that he put on board his ship all that he had. . . . And when he had been a little while, there was a great rumbling noise, and they saw a great earth-slip fall upon the homestead which Lodmund had set up and dwelt in.”’ Landndamaboc, iv, 9 (11 102 Dr. D. Ellis—A Jurassic Fossil Fungus. : rock-stream should be regarded by one observer as a lava-flow and by another a glacial moraine, but a similar case is on record in the history of Icelandic geology. Anaccumulation of liparite blocks and debris in the Vatnsdal, Hunafjord, North Iceland, was thought by Schmidt to result from a post-glacial volcanic eruption (18, pp. 764-5), but it is now considered to date from the end of the Ice Age and to represent a great fall of rock on to a glacier (2, p. 271). REFERENCES. 1. TH. EHORODDSEN, ‘* Explorations in Iceland, 1881-98’: Geogr. Journ., Lond., vol. xiii, 1899. 2. TH. THORODDSEN, ‘‘ Island. Grundriss der Geographie und Geologie ”’ : Erganzungsheft No. 152 und 153 zu Petermanns Mitteilungen, 1905. CLEASBY & VIGFUSSON, Icelandic and English Dictionary, Oxford, 1874. LL. Hawkes, ‘‘ The Building up of the North Atlantic Tertiary Volcanic Plateau ’?: Gmhou. MAG., Dec. VI, Vol. III, pp. 385-95, 1916. 5. Ib. Hawkes, ‘‘ The Acid Rocks of Iceland’’: Abstract, GEou. MaG., 1916, pp. 468, 469. . G. P. ScropE, Volcanos, London, 1862. J. REKSTAD, ‘‘ Om Strandlinjer og Strandlinjedannelse ’’: Norsk. Geol. Tids., Bd. iii, No. 8, Kristiania, 1915. 8. W. Cross & BE. Howe, Silverton Folio, No. 120. U.S. Geol. Sury., 1905. 9. Kh. Howe, ‘‘ Landslides in the San Juan Mountains, Colorado’’: Prof. Paper No. 67. U.S. Geol. Sury., 1909. bel “1D 10. D. W. FresHFiELD, The Exploration of the Caucasus, vol. ii, London, - 1896. 1l. Vierusson & POWELL, Origines Islandice, Oxford, 1905. 12. H. Pserurss, ‘‘Island’’: 2. Hand. d. Reg. Geol., Heidelberg, 1910. 13. C. W. Scumip7, ‘‘ Die Liparite Islands in geologischer und petrographischer Beziehung’’: Zeits. d. Deut. geol. Ges., xxxviii, p. 737, Berlin, 1885. EXPLANATION OF PLATE VI. Fria. 1.—General view of the Lodmundarfjord ‘‘ Hraun’’, looking north from Severendi. The Skimhéttur cirque is seen in the middle background. The main fjord valley and the ‘‘ Hraun’’ deposits north of the River FjarSar4 occupy the foreground. , Fig, 2.—A great fallen block of liparite, now split into two, in the Jafnadal, StéSvarfjord, East Iceland. A hammer may be distinguished on the face of the nearer block, not far from its base. 11.—On run Jurassic Fosstzr Funeus, Puvcouycires l’ropINGHAMII ) (inxs), By Davin Evuis, Ph.D:, D.Sc. ‘ (WITH PLATE VII AND A’ TEXT-FIGURE.) [* a recent paper! the writer described structures which he had _ found in the Frodingham Ironstone of Lincolnshire. The claim that these structures are fossil fungi is one of more than usual interest, for fossil fungi have not hitherto been recorded from the Jurassic rocks, and, further, the decomposition established by this fungus must have been carried out under marine conditions. Since the publication of this paper criticisms as to the conclusions contained in it have not been wanting, and it is proposed in the present paper to deal with these criticisms and further to furnish a few additional data to. supplement those that have already been given. * “Fossil Micro-organisms from the J urassic and Cretaceous Rocks of Great Britain ’’?: Proce. Roy. Soc. Edinburgh, vol. xxxv, pt. i, No. 10, 1915. ee Grou. Maa., 1917. Pirate VII. oe el Se A JURASSIC FOSSIL FUNGUS. Phycomycites Frodinghamti, cc. 2 i ai\y a aet ghey é oe ; ie a sty \ 4 Row al J oe ah fees i « ‘ ? pei 4 Li t ‘ raps ‘ ; - ¢ me 0) y AGN: ‘ P € i Ny ic : \ f fe Hs! ¥ ek os mes : R 1 i La aaa f t & f * ‘ Ps Dr. D, Hlus—A Jurassic Fossil Fungus. 1038 Before dealing with the criticisms it must be borne in mind that the conclusions arrived at in the former paper were based on biological grounds. The structures were such as a biologist recognizes to be characteristic of fungi. They take the form of tubes coated with ferric oxide and conform to fungal structures in the following respects :-— Sketch of animal remains in Dunliath Ferruginous Limestone (Jurassic), N.W. Scotland, found in association with fungal hyphe. x 1400. - 1. The tubes are cylindrical and possess a membrane comparable to the membranes of modern fungi. 2. The diameter of the tubes is 2 to 4 (s45— sto mm.). 8. They branch and interweave in the manner characteristic. of modern fungi. (In addition they also form whorled branches: 104. Dr. D. Ellis—A Jurassic Fossil Fungus. whilst not characteristic of modern fungi this feature is characteristic of other plants.) 4. They are uniform in size. 5. They form terminal dilatations which are comparable to the sporangia of modern fungi. This is particularly so with regard to their size as compared with the tubes which bear them, to their shape, and to their terminal position. In all respects they suggest the development of terminal reproductive organs on hyphe (Pl. VII, Hp), 6. In two instances, one of which is shown in Pl. VII, Fig. 2, rounded structures have been noted inside the terminal dilatations which in every essential particular suggest the spores which are formed inside the sporangia of modern fungi. 7. The structures in question are found in an organically formed rock (Pl. VII, Fig. 3). The circumstantial evidence upon which alone the whole case naturally rests seems thus, from a biological standpoint, to be complete enough to allow of little doubt as to the matter. The points with which we shall now be dealing have had their inspiration in the minds of those accustomed to regard such matters more from the geological and mineralogical than from the biological standpoint. 1. The structures in question may be of mineral and not of organic origin. —Throughout the history of this subject mineral secretions have been repeatedly mistaken for organic remains. So far as the imitation of plant organs is concerned the structures imitated are leaves and cellular tissues. But from the nature of the case the plant patterns executed by these secretions are of a simple form and their variety of a very limited order. Whilst such secretions may imitate a cellular or a tubular structure, it is difficult to see how the whole atmosphere in which a phycomycetous fungus lives can be simulated so very faithfully by a mineral secretion that not only are hyphee and hyphal membranes reproduced but also sporangia (Pl. VII, Fig. 1) and even spores (Pl. VII, Fig. 2). Further, the relative dimensional proportions of the parts are so faithfully adhered to that even when examined with the highest powers of the microscope, a trained eye cannot detect any details of structure inconsistent with the structural plan of phycomycetous fungi. Such wonderful fidelity in detail would demand strong evidence of an opposing nature to dismiss the claim that the structures in question are fossilized fungal remains.’ The slides have been submitted to several competent mineralogists for their opinion of the structures from the minera- logical standpoint. In no single case was evidence forthcoming to suggest that a mineral interpretation of these tubes and expansions would fit the facts of the case. Among those to whom the slides were submitted was Dr. Flett, of the Geological Survey, Edinburgh, whose opinion on this point will command respect. Dr. Flett stated that he was prepared to accept the organic origin of the structures indicated to him and that he knew of nothing in the mineralogical world that approximated to them. From the mineralogical standpoint no single positive fact has been brought to light which invalidates the claim for organic origin made from a study of the biological data. Dr. D. Hllis—A Jurassic Fossil Fungus. 105: 2. The structures may have been caused by insect borings.—If the causation of these threads and vesicles is not to be ascribed to a mineral infiltration, and an organic origin is granted, there still remains another possible origin, viz. that the tubes were due to insect borings. This possibility has been suggested to account for the tubes and vesicles. This criticism would have weight were it not for the extreme smallness of the tubes. These measure only =t+smm. In previous cases where this criticism had weight, as for example in the case of the Rhizomorpha Sigillariee of Lesquereux, the tubes under consideration were 2—3 mm. in diameter, and the claim was made that they were rhizomorphal cords of fungal hyphe. Being commensurate in size with known insect borings, the criticism that they might have been produced by insects was quite legitimate. We are here, however, dealing not with cords of hyphe, but rather with the individual strands such as are commonly found in the woody tissues of many plants. he possibility of their preservation need not be discussed, as their appearance in the tissues of fossil wood is too common and too well known to admit of any doubt on the matter. It is not conceivable that any insect either during Mesozoic times or at any time could make borings which simulated the biological characteristics of a fungus on such a minute scale. It is the more incredible when we reflect that these supposititious borings would be excavated in the body of some animal fragment, the natural habitat of many phycomycetous fungi, and not in the harder tissues of trees in which insect borings are usually found. 3. Criticisms arising from the fact that whilst the parasite (or sapro- phyte) has been preserved the details of structure of the host in which vt lived have not been preserved.cIn answer it may be stated that the discovery of this organism was not entirely due to an accidental circumstance, but was rather the successful issue of a specific search. In the author’s researches on modern iron-bacteria, the membranes of which are impregnated with the highly resistant ferric oxide, he was led to the conclusion that if iron-bacteria or their representatives existed in former ages the chances of their preservation in fossil form were very strong. When the opportunity occurred ironstones and ferruginous limestones of various ages were carefully searched for iron-absorbing micro-organisms. ‘The tough- ness and hardness of such membranes can be observed by anyone who cares to examine the dead membranes of the modern ochre-bacillus (Leptothria ochracea). The search did not reveal fossil iron-bacteria as was expected, but it did bring to light a fungus possessing the same characteristic of absorbing iron-compounds from the surrounding water. An organism thus protected would obviously stand a much better chance of preservation than the soft tissues of the animal fragments inside which a fungus of this character must necessarily abide. The slides containing these structures consist of fragments of organic matter embedded in a calcite matrix (Pl. VII, Fig. 3). The threads and vesicles were invariably found inside the organic fragments and not in the matrix. An example is shown at a in Pl. VIi, Fig.3. Thisfragment is seen photographed on a higher scale of magnification in PI. VII, Fig. 4. In the latter case the threads 106 °—s éD) rr. VD. Ellus—A Jurassic Fossil Fungus. under discussion are plainly revealed. It cannot be reasonably doubted that the fragment marked ain Pl. VII, Fig. 3, is an organic fragment similar to the other obviously organic fragments that are to be seen in the same field. It is unfortunate that in the Frodingham Iron- stone in which these were found no traces of the internal structure of the animal host could be discerned, whilst the details of the structure of the parasite contained in it were so clear. This point, however, is capable of an easy explanation if it be assumed that the threads and vesicles represent a fossil fungus which during tts lifetime had the same power of absorbing iron salts that the iron- bacteria possess at the present day. Under these circumstances the membranes of the fungus would be impregnated with ferrie oxide during its lifetime, a circumstance which would render these membranes much more resistant to disrupting forces than the soft tissues in which they were embedded. Further, it is possible to conclude with a fair approach to certainty that the iron on the threads was laid down for the greater part during their lifetime. The reason for this conclusion is as follows: A study of the iron-bacteria has brought to light the fact that the deposit of iron on their membranes varies in consistency according to the age of the thread. Young threads have a sharply contoured membrane of a brownish-yellow colour. In older threads the nature of the deposition and of the membrane is quite different. The colour of the iron changes to a deeper brown, the quantity of it is greater, and the membrane, instead of being a continuous sharply outlined structure, is a discontinuous irregular line and wanting in sharp lines of demarcation. All gradations can be observed by a close study of the membranes of Leptothrix ochracea, the best known of the iron-bacteria. It is surely a significant fact that the same gradations ean be observed on the membranes of the threads which we are now discussing. ‘The appearance of these gradations is easily explicable if we assume that the tubes are the remains of an iron- absorbing fungus, but on the assumption that all the iron in these rocks, including the iron on these tubes, resulted from a subsequent infiltration of iron-ckarged water, the explanation is not so easy. It cannot be doubted that the bulk of the iron in these rocks arrived there by subsequent infiltration, but it is at least highly probable that some of it has never been absent from the material from which these rocks were formed. If the iron on these tubes had got there solely by infiltration, it would naturally be expected that all the tubes would have a deposit of a uniform nature; the tubes, on the other hand, show those changes which come about when iron enters the living cell, and after undergoing changes due to metabolism is thrust out again and deposited on the outer part of the membrane. We muy assume that the presence of the iron covering isa sufficient explanation of the preservation of these threads and vesicles. Whilst a search among the organic particles of the Frodingham Ironstone containing the fungus failed to reveal traces of the structure of the host, a measure of success was achieved by searching the similar Jurassic ferruginous limestone at Dunliath in the north-west of Scotland. In Pl. VII, Fig. 6, for example, we see an organic Dr. D. Ellis—A Saerasene Fossil Fungus. 107 fragment showing traces of animal cells (@), and also a few hyphe of some unknown fungus (6). Again, in others inside similar organic fragments structures like those represented in the T’ext-figure and in Pl. VII, Fig. 5 were met with. These are obviously the remains of some animal cells, although in this condition it is impossible to specify any further with regard to their nature. The point of the matter lies in this, that these organic fragments from Dunliath contain the remains of both animal cells and fungal threads, both very incomplete and very indefinite: in the Frodingham Ironstone the disruption of the animal cells has been complete, whilst the fungus, thanks to its protective covering, has been particularly well ‘preserved. 4. Doubts arising from the fact that the threads and vesicles were Sound in material known to have suffered decomposition in sea-water.— . Whilst it is true that no fossil fungi have so far been found of which it could be definitely stated that they had effected decom- position in salt water, the reason for this does not le in the fact that there is anything inherently impossible in the idea, for that would imply that decomposition of organic matter cannot take plave in salt water, which is contrary to experience. It is true that the vast bulk of marine decomposition is due to the activity of bacteria, but even in this field a large proportion of the organisms which carry on this decompesition belong to the sulphur bacteria, several species of which group are composed of long threads, thus approximating in their habits to the threads of which the aquatic fungi are composed. — In the artificial cultivation of many of the thread-forming sulphur bacteria success attends the attempt only if sea water instead of fresh water be employed. A still more powerful argument is the fact that in the cultivation of some of the Saprolegnias, a group of phycomycetous fungi, the use of sea water is recommended in making up the nutrient medium. So that even in the case of modern plants . of the same group we meet with fungal decomposition under marine conditions. Anyone who has studied the shores of Denmark can satisfy himself of the extent to which marine decomposition can operate in the scavenger work of Nature. The shallow Jurassic seas must have had huge shallow lagoons in which of necessity scavenger work on a large scale must have been in operation. It would be an extremely rash statement to assert even apart from our experience of modern fungi that no thread fungi could have contributed to this ‘ work. - For even if such fungi did not exist at the present day, there are so many closely allied forms that effect decomposition in salt water that marine fungi in a fossil form would not have been a matter for surprise. Conclusion.—Vhe study of the tubes and vesicles classed under Phycomycites Krodinghami had revealed their organic nature by the closeness with which their structures followed those of modern fungi. The resemblances extended even to minute points of structure, and were so great that from a biological standpoint no doubts were enter- tained as to the fact that we were dealing with fossil fungi allied to the modern Phycomycetes. It remained to inquire whether any positive evidence could be adduced, or any facts brought forward on 108 Professor Yakovlec—On Rugose Corals. mineralogical or geological grounds, which could impair the position taken up. The criticisms on theoretical grounds which have been brought forward have not invalidated the claim for these structures which the writer has brought forward. It is proposed to present the slides to the British Museum, so that they can be made available for inspection and reference. EXPLANATION OF PLATE VII. Fic. 1.—Frodingham Ironstone from Jurassic rocks of Lincolnshire. From interior of fossilized organic fragment. Shows hyphe, one bearing a fully developed terminal sporangium. a=sporangium, 6=hypha, c=calcite matrix. x 530. 2.—Frodingham Ironstone from Jurassic rocks of Lincolnshire. Shows two sporangia of Phycomycites Hrodinghamw. In the left sporangium (c), partially extruded from it, is seen a spore (b). q@ is a portion of a small oolite. » 166. ., 3.—Organic remains in Frodingham Ironstone. Atqais shown a fragment in which fungal hyphe were found. x 18. 4.—The organic fragment marked a in Fig. 3 shown on a larger scale. The fungal hyphe are distinctly visible. x 116. ., 5.—From Dunliath Ferruginous Limestone (Jurassic, N.W. Scotland). Remains of animal cells. x 466. ., 6.—A semi-diagrammatic sketch of a portion of an organic fragment in the Dunliath Ferruginous Limestone. Inside the fragment are seen the remains of animal cells and of fungal hyphe. The branched tubules are the hyphe and the dark rounded fragment the animal cells. IJ1.—Own rue Orcanization or THE Rugosr Corats anD THE ORIGIN OF THEIR CHARACTERISTIC PECULIARITIES. By Professor N. N. YAKOVLEV, Petrograd, Russia. (PLATE VIII AND FOUR TEXT-FIGURES.) URING the last ten years I have published a series of memoirs ' on different questions concerning the morphology and biology of the Rugose Corals. In these memoirs I have elucidated the ground-form of the polyparium of the solitary Rugosa, the mode of its attachment to the substratum, the origin of the characteristic arrangement of the septa, and the origin of the fossule in dependence on this form and attachment. I have established the connexion between the form of the polyparium of the Rugosa (including that of the fossule) and the life of these corals in definite environmental conditions. 1N. Yakovlev, ‘‘Die Fauna der oberen Abtheilung der palaeozoischen Ablagerungen im Donetz-Bassin. II. Die Korallen’’: Mém. Com. géol. St. Petersbourg, N.S., livraison xii, 1903.- ‘* A contribution to oe Characteristic of Corals of the group Rugosa’’: Ann. Mag. Nat. Hist., VII, vol. xili, pp. 114-17, 1904. ‘ Ueber die Morphologie und Morghacenie ‘abe Rugosa ”’ : Ver. Russ-k. Min. Ges. St. Petersbourg, vol. xli,, pp. 394-415, 1904. ‘* Die Entstehung der charakteristischen Higentiimlichkeiten der Korallen Rugosa”’ : Mém. Com. géol., St. Petersbourg, N.S., livraison Ixvi, 1910. ‘‘ Les récifs coralliens existent-ils dans le paléozoique?’’: Bull. Com. géol. St. Petersbourg, vol. xxx, No. 10, pp. 847-57, 1911. ‘‘ Studien tiber die Korallen Rugosa ”’ : Mém. Com. géol. St. Petersbourg, N.S., livraison xevi, 1914. Professor Yakovlev—On Rugose Corals. 109 Referring to the colonial Rugosa, I have explained how the characteristic forms of the colonies are correlated with the mode of multiplication, and demonstrated the part played by these corals in reef-building. Here and there I have pointed oyt differences between the Rugosa and the Hexacoralla, which do not admit the former to be considered as the progenitors of the latter, though this is probably claimed by the majority of paleontologists and zoologists. This examination (pursued by me for many years) of the form and functions of the Rugose Corals and of the questions they raise, I now look upon as sufficiently complete to render desirable a review of the results of my work, which throws fresh ight on the Rugosa as well as providing a causal explanation of the origin of the peculiarities of this specialized group. In conformity with the character of the present paper, the exposition will be given concisely, without citations and references, without criticism of other authors, without any details; those who are interested will find all this in my previous publications. The shape of the Rugose polyparium is considered to be, typically conical. Herein the Rugosa differ from the Hexacoralla, which mostly have a cylindrical polyparium; and this difference of body- form may be seen in the soft-bodied Actinize now living. The Rugosa are first found in Silurian rocks, but doubtless existed previous to this, and before Silurian times the Rugose polyparium had already departed from the fundamental simply-conical shape. It had acquired, near its proximal end, a lateral attachment to the substratum, unlike the basal attachment of the Hexacoralla (see Pl. VIII, Figs. 1-4). This lateral attachment was correlated with their life in epicontinental seas. The basal attachment of the cylindrical (or, in rare cases, conical) polyparium of the Hexacoralla living in deeper, calm water, as much satisfies the requirements of solidity as the lateral attachment of the Rugose conical polyparium living in a zone of the sea characterized by comparatively rough or at least agitated water. The lateral attachment, then, of the Rugose polyparium is an adapta- tion to definite environmental conditions. It has modified the original form of the simply-conical polyparium and has imposed upon it a definite orientation correlated with the direction of the prevailing currents. For a conical polyparium lying on one side on the sea-bottom must of necessity turn away its mouth from the mud of the sea-bottom in order to avoid suffocation. Thus thesimple cone with a straight axis becomes one with its axis curved in one plane—a form resembling the horn of an ox, and suggesting such trivial names as cornu, _ corniculum, cornucopia, cornu-bovis, ceratites, buceros, etc. Moreover, all the individuals of one locality were orientated in the same direction, namely, with their convex sides towards the direction of the prevailing current (see Text-fig. 1). Only thus will a polyparium of such a shape offer the maximum resistance to wave- and current- action tending to tear it from the substratum. Now the scar formed by the attachment of the polyparium to the substratum as well as the root-like processes serving the same purpose necessarily occur as a rule on the convex side of the corallum. 110 Professor Yakovlev—On Rugose Corals. And in this respect, as well as in its general form, the coral already shows an external bilateral symmetry. Scars of attachment and root-like processes, both on the convex side, and a general external bilateral symmetry, characterize all the known Rugosa from the Silurian rocks, the earliest in which they have yet been found, to the Permian in which the last Rugosa occur. Further, when, owing to the character of the sea-bottom, there is no possibility of attach- ment and the coral consequently is free, the polyparium, whether _ of a Rugose or Hexa-coral, takes on a flat, discoid shape (Palgocyclus, \ Microcyclus, ete.) But, in spite of its not leaning over, the Rugoase Coral retains its bilateral symmetry, shown externally chiefly by the apex which lies excentrically, while that of the Hexacoral is central. That is to say, in spite of the removal of the conditions producing bilateral symmetry, the discoid Rugose Coral exhibits it. Is not this an example of the inheritance of acquired characters ? Another form showing the tendency to retain bilateral symmetry after the conditions which caused it have been removed is that ‘y taken by unattached genera such as Calceola, Platyphylium, and other operculate corals. These are curved, flat on the lower side, and YEXT-FIG. 1.—Diagram representing two polyparia of solitary Rugosa growing side by side. ‘The arrows outside the polyparia indicate the direction of the prevailing current, and those within the calices that of the water along the channels formed by the fossule. H, G, S, the positions of the Main, Counter, and Alar fossule respectively. Nat. size. provided with an operculum whose function is to prevent the penetration of mud into the coral’s calice. Operculate corals are probably polyphyletic in origin, and, as would be exe occur only among the Rugosa. The last external character dealt with is the fr equently occurring phenomenon of ‘‘Rejuvenescence”’. The term is inappropriate, since young individuals also are subject to it. Rejuvenescence consists of a periodically repeated retraction of the calice as if by shrinking or by the appearance of a daughter coral produced by intracalicinal budding. Rejuvenescence, especially in the broadly conical forms, is easily explicable, in fact only to be expected, when it is con- sidered how inconvenient and disadvantageous from a mechanical point of view a considerable upward expansion of the polyparium would be to the Rugosa with their typically conical. polyparium. Turning from the external to the internal characters of the Rugose skeleton, we shall find that they are determined by the curved condition of the conical polyparium. We shall consider, first of all, the characteristic arrangement of the secondary septa and their Professor Yakovlev—On Rugose Corals. 111 relation to the primary septa—a condition peculiar to the Rugosa. The works of Duerden, Carruthers, and others have shown that the secondary septa develop in four adjoining (and in four only out of s1x) primary interseptal chambers, and are bilaterally symmetrical in their arrangement. ‘Two of the primary septa lie in the plane of bilateral symmetry of the coral. About one of these—the Main- septum—the secondary septa (as seen at their outcrops on the wall TEXT-FIG. Z.—Diagram showing the arrangement of the outcrops of the septa on the surface of the polyparium, according to whether the mouth is at right angles to the concave side (above), to the convex side (below, on the left), or to neither (below, on the right). The mouth is always at right angles or nearly at right angles to the Counter-septum. S, Alar-septum. aa, a'a’, the edges of the polyparium at different periods of its growth. (After Yakovlev, 1904.) of the polyparium) are arranged pinnately; while on each side of the other—the Counter-septum—the secondary septa lie parallel both to it and to each other (see Text-fig. 2). Two other primary septa—the Alar-septa—lie somewhat at right angles to the Main- and Counter-septa, thus dividing the calice into four quadrants, two Main- and two Counter-quadrants. As seen at their outcrop on the 112° Professor Yakovlev—On Rugose Corals. wall of the polyparium, the secondary septa are pinnately arranged with regard to the Alar-septa in the Counter-quadrants and ne parallel ‘to the Alar-septa in the Main-quadrants (see Text-fig. 2 above Swok an arrangement of the secondary septa appears to be the natural outcome of the mechanical conditions imposed by the curved state of the conical polyparium. For the mouth of the conical polyparium is generally in a plane perpendicular to its concave side (Text-fig. 2 above); and the secondary septa have a tendency to grow (as in all Anthozoa) in a plane perpendicular to that of the mouth of the calice. Since the primary septa are already existent in a curved polyparium, the secondary septa can grow in a manner just stated, and unimpeded, in two only of the four Primary quadrants, namely in the two Counter-quadrants. In the two other quadrants, namely the Main-quadrants, the secondary septa cannot grow in a plane perpendicular to that of the mouth, because, at least in part, they would be impeded by the convex surface of the Alar- septa (see the dotted line ¢-¢ in Text-fig. 2 above). Therefore they grow, as may be observed, so that their outcrops on the coral-wall are parallel with those of the Alar-septa. But the Main-septum, sometimes, though comparatively rarely, lies on the concave side of the coral. When this is so, the plane of the mouth of the calice is perpendicular to the convex side of the coral (see Text-fig. 2, below and on the left). Applying to this case the principle that the secondary septa tend to lie at right angles to the es of the mouth, we see that they can only thus grow unimpeded in the quadrants lying on the convex side of the coral (now the Counter-quadrants), whilst in the other pair of quadrants the growth of secondary septa perpendicular to the plane of the mouth would be impeded by the concave face of the Alar-septa. A third, intermediary type also occurs (‘'ext-fig. 2, below and right-hand side) in which the plane of the mouth is inclined approxi- mately equally to the convex and concave side of the polyparium. In this case the Main-septum occurs on the convex side of the coral as it did in the first instance. The fossule arise as a necessary consequence of ‘the primate arrangement of the secondary septa. For there is always a com- paratively broad space left between the youngest secondary septa and the Main-septum in the two Main-quadrants, and between the youngest secondary septa and the Alar-septa in the Counter- quadrants (R, R, of Text-fig. 2 on the left) into which the soft tissues settle doen and contribute to the widening of these spaces, converting them into permanent cavities. These spaces are the Main- and the Alar-fossule. The Main-fossula placed on the convex or concave side of the corallum, according to the position of the Main-septum, is really two juxtaposed fossule, but appears as one, because of the shortness of the Main-septum. Consequently it is wider than the Alar-fossule and is more constantly conspicuous than these. ‘The shortness of the Main-septum is caused by the soft tissues settling down into the Main-fossula. This sagging of the soft tissue, pressing also against the sides of the fossula, caused Professor Yakovlev—On Rugose Corals. 113 the deviation of the free edge of the secondary septa towards the one preceding it, so as, finally, to fuse with it (@ with S, and Z, and 6 with a, in Text-fi fig. 3), giving the appearance (it is, of. course, only an appearance) of repeated branching of the primary septa. The septal fusion occurs in young individuals as well as in mature ones. The older parts of many polyparia become cylindrical and straight instead of conical and curved. In these there are no wide spaces between the primary and secondary septa, and consequently there is less development of the fossulz, and the fusion of the septa disappears— in a word, radial symmetry, doubtless existent in the progenitors of the Rugosa, is re-established. Since the fourth fossula, that lying on each side of the Counter- septum, is rarely visible in the Rugose skeleton, its origin must be different from that of the other fossule. Its presence is due to the fact that there are no secondary septa adjacent to the Counter- septum. A study of the functions of the other fossule (of course TEXT-FIG. 3.— Diagram of the calice of Hadrophyllum pauciradiatum, Edwards & Haime. H, G, S, Main, Counter, and Alar septa respectively. a-e, secondary septa. , F, F, Fossule. (After Duerden, 1905.) Nat. size. a purely hypothetical consideration, dealing, as it does, with the soft parts of an extinct group of animals) may help to explain the origin of the Counter-fossula. It appears to me that the function of the Main- and Alar-fossule was to bring water to the axial part of the coral, This is partly corroborated by the fact that all three lie in one general direction, since the Alar-septa make an acute angle with the Main-septum. I have established the hypothesis that the solitary, curved polyparia of the Rugosa, during their life, were orientated on the sea-bottom with their convex sides towards the prevailing currents, a position most advantageous from a mechanical point of view (see Text-fig. 1). This orientation itself would cause the water to flow along the Main- and Alar-fossule towards the axial parts of the coral; and the water would naturally find its exit on the opposite side, namely along the Counter-fossula, which doubtless arose for this purpose. For, though not constantly expressed in the DECADE VI.—VOL. IV.—NO. III. 8 114 Professor Yakovlev—On Rugose Corals. skeleton, the Counter-fossula would then be too important not to be constantly expressed in the soft parts of the coral. If this were so, the presence of the Counter-fossula in the soft tissues might actually impede the formation of secondary septa in the loculi adjacent to the Counter-septum (Text-fig. 4). A last peculiarity of the solitary Rugosa correlated with the curved, conical polyparium, is the fact that the number of secondary septa present in the quadrants on the convex side, is sometimes greater than the number of secondary septa on the concave side (Text-fig. 4). Consequently, the position of the axis of the coral, as defined by the point of meeting of the primary septa within the polyparium, appears displaced towards the polyparium’s concave side. This phenomenon is no doubt due to retardation of development on the concave side, as though under the influence of contraction of the coral here at its curved part; on the convex side, on the other TEXT-FIG. 4.—Diagrammatic sections of Lophophyllum proliferum, McChesney- The section on the left is a Russian and on the right an American specimen. In both cases the upper side of the section is on the convex side of the polyparium (after Yakovlev & Duerden, 1903). H, G, S, Main, Counter, and Alar septa respectively. S;, the fourth pair of primary septa. a, b, secondary septa. % nat. size. hand, the development is accelerated, as though under the influence of distention. Colonial Rugosa are characterized by intracalicinal budding, resulting in a bush-like appearance, and causing a limited growth of the colony. Hexacorals, on the other hand, multiply by division and build colonies which spread far from their initial point on the surface of the substratum. Colonial Rugosa also differ from Hexa- corals in the greater size of their individual corallites. The Rugosa, consequently, do not possess the plasticity necessary for producing the variety of colonial forms that we find among the Hexacorals, e.g. Madrepora. ‘lo the small dimensions of the colonies and to the monotony of form probably was due the small share they took in building Paleozoic reefs. The Rugosa became extinct at the close of Paleozoic time, probably in consequence of an unfavourable environment, which may have 7 ae ie pie yyy: Wake io. ~ Grou. Maa., 1917. Prate VIII. 2 t LATERAL ATTACHMENT OF RUGOSE CORALS. A. Holines—Classification of Igneous Rocks. 115 been due to the following causes. The end of Paleozoic time coineides with a worldwide period of mountain-building—the period of the so-called Appalachian revolution of American authors, and that of the building of the Ural and Donetz ranges of Russia (where the change of facies is surprisingly abrupt—the limestone strata of the Upper Carboniferous giving way to the Permo-Carboniferous characterized by great expanses of sandstones). When the limestones, laid down in shallow and comparatively calm waters, were deposited, the environment was favourable to the life of Rugosa Corals. But the mountain-building uplifts, causing great quantities of clastic material removed by denudation to be brought down and deposited in the sea, created conditions the reverse of favourable to the corals. In the Permo-Carboniferous the Rugosa are already rare, and after that time are extinct; and nearly the same fate befel the Tabulate corals. When suitable conditions again arrived, a new race of corals arose—the Hexacorals—replacing the Rugosa. The above explanation of the organization of the Rugese Corals results from considering the simple primary factors of morphogenesis. I think that it is only for such simply organized animals as the Coelenterata that such a complete and harmonious explanation is possible; and that it is not possible to give an all-embracing expression, reduced to a mathematical formula, of the strueture of higher animals, because of their complex organization. In a few cases, however, such expressions have been found for isolated organs _of higher animals; for instance, in the case of the development of the feet and teeth of Vertebrates. EXPLANATION OF PLATE VIII. THE LATERAL ATTACHMENT OF RUGOSE CORALS. Fie. 1.—Cyathophyllwm ceratites, Goldfuss, attached to a branch of C. cespi- tosum, Goldfuss. Devonian: Timan Range, River Uehta. », 2.—Pseudocaninia conica (Fischer de Waldheim), attached to a spine of Archeocidaris. Upper Carboniferous: Mjatshkovo village, Govern- ment of Moscow. ; », 3.—Petraia permiana, Nechaev, attached to the dorsal valve of Stropha- losia. Permian :. Gorodistshe village, Government of Vjatka. A. V. Nechaev’s specimen. », 4.—Cyathophyllum heterophyllum, Edwards & Haime, attached by a highly developed, sole-like appendage. Devonian: Paffrath, Rhenish Prussia. IV.—A Mrwneratoeicat Crassirication oF Igneous Rocks. By ARTHUR HOLMES, A.R.C.S., D.1.C., B.Se., F.G.S. | URING the past two years the teaching collection of rocks in the Geologival Department of the Imperial College has been under re-arrangement, and in the course of the work the writer has had occasion to consider very carefully the principles on which igneous rocks should be classified. He is aware that in the present state of our knowledge any such classification must be tentative and experi- mental. and should be judged according to its general convenience, both for teaching purposes and for understanding the various problems that arise from petrological studies. The following article summarizes 116 =A. Holmes—Classification of Igneous Rocks. the conclusions arrived at, and while the writer must be held entirely responsible for all expression of opinion, he wishes to acknowledge his gratitude and indebtedness to Professor Watts and Dr. Evans, both of whom, in numerous discussions, have freely offered suggestions and criticism which have proved to be of the greatest value. In recent years the chief criteria on which systematic classifications of igneous rocks have been based are (a) mineral composition, (d) chemical composition, and (¢) texture, or (c’) mode of occurrence (Cross, 1910, p. 473). Although the two latter factors have often been considered interdependent, it is now becoming generally recognized that they are by no means wholly so, and modern custom tends more and more to relegate each of them toa subsidiary position in classifica- tion. For the working petrologist, the mineral composition of an igneous rock is, in a great majority of cases, its most important characteristic. Unfortunately, many minerals, such asthe pyroxenes and amphiboles, are capable of a wide range in composition. More- over, a small percentage of igneous rocks are incompletely crystallized. It has therefore to be recognized, and accepted as at present an unavoidable limitation, that the whole field of igneous rocks cannot be reliably classified on a mineralogical basis that will also faithfully reflect the chemical composition. On the other hand, a chemical classification, whether founded on normative minerals, or otherwise, demands far more analyses than can in practice be obtained. In addition to the requirements of field-work, it is therefore necessary to have at least two systems of classification, one mineral, the other chemical. Clearly, for purposes of comparison, the two systems should be arranged as closely as possible along parallel lines. In the Quantitative Classification of Cross, Iddings, Pirsson, and Washington, the chemical composition is expressed, not in oxides, but by a series of standard minerals known as the norm, as opposed to the mode, which is the actual mineral composition. ‘he first division, into Classes, is based on the relative proportions of the salve and femic groups of minerals in the norm (corresponding terms for the mode are felsic and mafic). As Mr. G: W. Tyrrell (p. 63) has pointed out, the five classes that are adopted correspond in principle, though in greater detail, to Brogger’s division of igneous rocks into leucoeratic and melanocratic types. The second division, into Orders, is based in the first three classes on the ratio of quartz, or if quartz be absent of felspathoid, to felspar. he orders thus correspond partially to Professor Shand’s division of igneous rocks into oversaturated, saturated, and under- saturated types (1918, p. 518, and 1915, p. 340). One of the most serious defects of the C.I.P. W. Classification, to which attention was drawn by Tyrrell in 1914 (p. 68), lies in the fact that the method of subdivision into orders in Classes IV and V is based on ratios of the femic minerals, thereby introducing a most confusing break and lack of parallelism between the subdivisions of Classes I to III, and those of TVand VY. - Tyrrell urges that the salic divisions should ‘be carried on through all the classes and for the same reason the femic divisions of the later classes might, if desired, be carried back through the early classes,. thus providing each rock analysed with a double symbol. A. Holmes—Classification of Igneous Rocks. Tay) It also seems to the present writer that Order 5, embracing as it does rocks with normative quartz and felspar, felspar alone, or felspar and felspathoid, is of too broad a character. It traverses one of the few natural lines of distinction available for classification, the line between the antipathetic minerals quartz and felspathoid. Certainly the norm indicates which of these is present, but in the symbol it might advantageously be expressed by suffixes such as the following :— 5q (accessory normative quartz present), 5 (no quartz nor felspathoid present; in this case normative olivine would generally be present), 5, (accessory felspathoid, or lenad, present). The division of orders (of Classes I to III) into Fangs is based on the ratio of the molecular proportions of alkalies to lime, only those ehtering into the salic minerals being employed for comparison. Mineralogically, this is practically the ratio of orthoclase plus albite to anorthite, it being understood that felspathoids, where present, are to be expressed in terms of the amounts of orthoclase and albite to which they are equivalent. The ratio, however, tells us very little about the rock to which it is applied beyond expressing in a general way its alkalicorcalcic character. It issuggested below that a more useful method of division would be afforded by the ratio of the molecular proportions of soda to lime in the felspars, or better, of the direct ratio by weight of albite to anorthite. Such a ratio would express the normative soda-lime felspar, and in many cases the latter would not materially differ from the actual soda-lime felspar of the rock. The division of rangs into Sub-rangs is based on the molecular ratio of salic potash to salic soda, and is useful in distinguishing rocks with minerals like orthoclase, muscovite, leucite, and biotite, from those containing albite, analcime, nepheline, ete. It has frequently been a matter for surprise that the sub-rangs of the C.I.P. W. Classification (of which in the first three classes there are 675) do not always contain rocks of closely similar types, and that adjacent sub-rangs may sometimes enclose rocks that are much more closely related to one another than they may be to other rocks falling within their own sub-rang. The latter possibility is illustrated by the following analyses, taken from Iddings’ Jgneous Rocks, vol. i1:— A. 1B C. D. EK. SiQg . 75-04 75:17 74-37 73-05 64-57 AleO3 .. 13-12 12-66 13-12 14-67 16-80 Fes O3 5 2-12 0-23 0:73 0-89 0:97. FeO : n.d. 1-40 0-87 n.d. 3:02 MgO . 0-34 0-05 0-35 0:26 1-69 CaO... 0-40 0-82 1-26 0-97 3°53 Na,O . 2-44 2-88 2-57 3-99 3-81 K,0 : 6-32 5-75 6-09 5-11 4-01 H.0 0:76 0-82 0-30 0-91 1-28 ihaglls >, — O47 0-45 — = _ Total . 100-54 100-26 100-11 99-85 99-68 Symbol: 1,4,1,2 I, 4,1,3 I, 4, 2,3 I, 4,2,3 I, 4, 2,3 Omeose. lLiparose. Toscanose. Toscanose. Toscanose. 118 Cal@raes 4 3) 2 1 K20 In the above diagram the rectangular spaces represent subdivisions of the C.1.P.W. Classification formed by ranges and sub-rangs. The spaces between the curved lines represent the distribution of the different soda-lime felspars across the C.I.P.W. Classification in Classes I-III, Orders 1-4 and part of 5. In the case of other orders, the curves occupy other positions which may be obtained approximately by swinging them upwards about the north-east corner through an angle depending on the amount of felspathoid present in the norm. Actually, the classification is, as generally used, in four dimen- sions, and consequently sixteen sub-rangs meet in the theoretical point determined by the intersection of four super-planes. Thus it would be possible for sixteen closely similar analyses to fall into sixteen adjacent pigeonholes, whereas sixteen analyses distributed evenly through any one of the pigeonholes would show considerably more variation. Obviously, this is not a serious fault in the classification unless it can be shown that there is a natural grouping of rocks. If there were, and the existing modal nomenclature is A. Holmes—Classification of Igneous Rocks. 119 I. OVERSATURATED ROCKS: CHARACTERIZED BY QUARTZ. Org SODA Orig.s ROCKS. Ors7.; SODA-POTASH ROCKS. Orgo.5 POTASH Org7.5 ROCKS. Orjoo ALBITR. OLIGOCLASE- ANDESINE. LABRADORITE- = ANORTHITE. § & 3 Felspar absent or accessory. SODA-GRANITE. Rockallite. PEGMATITE. SODA-POTASH GRANITE. POTASH-GRANITE. Hkerite. Muscoyite granite. Grorudite. Muscovite biotite granite. PEGMATITE. PEGMATITE. Granophyre. SODA-QUARTZ PORPHYRY|SODA-POTASH Q. PORPHYRY| POTASH QUARTZ PORPHYRY. Quartz bostonite. Aplite. Paisanite. SODA RHYOLITE. Comendite and Pantellerite. SODA-POTASH RHYOLITE. POTASH RHYOLITE. QUARTZ- GRANO- DIORITE. DIORITE. Tonalite. 5 ADAMELLITE. GRANITE. Quartz monzonite. Biotite-granite. Hornblende granite. Augite granite, etc. PEGMATITE. Granophyre. QUARTZ PORPHYRITE. QUARTZ PORPHYRY. Nevadite. Aplite. DACITE. RHYO-DACITE. RHYOLITE. / Quartz latite. Liparite. Dellenite. QUARTZ GABBRO. QUARTZ MONZONITE (in part). Labradorite Quartz anorthosite. ‘Quartz norite. QUARTZ DOLERITE. Quartz diabase. QUARTZ BASALT. Bandaite. granite. QUARTZ TRACHY-DOLERITE. QUARTZ PYROXENITE. Quartz hornblendite. 120 ) S Ss Felspar: absent or ACCESSOry. Felspar absent. OLIVINE ALKALI-SYENITES. Laurvikite (in part). Rhomb-porphyry (in part). OLIVINE-ALKALI-TRACHYTES. Skomerite. Olivine kenyte. | OLIVINE DIORITE. OLIVINE ANDESITE. Mugearite. OLIVINE GABBRO. Olivine anorthosite. Olivine norite. Olivine hyperite. OLIVINE DOLERITE. Olivine diabase. OLIVINE BASALT. OLIVINE MONZONITE ! (in part?). OLIVINE TRACHY- ANDESITE. Olivine latite. OLIVINE MONZONITE. Kentallenite. Absarokite. OLIVINE TRACHY-DOLERITE. Ciminite. PICRITE. Olivine pyroxenite. LIMBURGITE. Picrite-basalt. PERIDOTITE. Wehrlite. Lherzolite. Cortlandite. Dunite. MICA-PERIDOTITE. Kimberlite. 1 See footnote on p. 121. 124 =) or rc) LABRADORITE- ANORTHITE. “ Anioo Felspar absent. or accessory. NEPHELINE SYENITE. Mariupolite. Laurdalite. Borolanite. Foyaite, Ditroite. : Leucite syenite. Litchfieldite. Covite. Kudialite syenite. Shonkinite. Leucite shonkinite. NEPHELINE-SYENITE PORPHYRY. Tinguaite porphyry. Tinguaite. NEPHELINE PHONOLITE. LEUCITE PHONOLITE. ESSEXITE (in part). Shonkinite (in part). Marosite. Vicoite. Kulaite (in part). | THERALITE. | Essexite (in part). Nepheline monzonite. TESCHENITE. Analeime dolerite. Camptonite (in part). | NEPHELINE TEPHRITE.| LEUCITE TEPHRITE. Analcime tephrite. Kulaite (in part). IJOLITE. Jacupirangite. Bekinkinite. MONCHIQUITE (olivine LEUCITE MONCHIQUITE (olivine free). free). Fourchite. Ouachitite. Nepheline monchiquite NEPHELINITE. LEUCITITE. 126 A. Holmes—Classification of Igneous Rocks. three divisions are necessary, those corresponding to albite (up to ANj5), to oligoclase and andesine (from An), to An;9), and to labradorite to anorthite (from Ansy to Anjoo). Symmetry seems to demand an anorthite division, and in some cases it would be useful to distinguish oligoclase rocks. Probably the five rang divisions of the soda-lime felspars would give somewhat better results, the present objection to using them being merely the lack of an appropriate nomenclature. In particular, the boundary between andesine and labradorite at An, is preferable to that at An, ). However, these are extensions of the method which will fall naturally into place as more rocks are quantitatively examined and described. Secondly, it is proposed to divide the rocks further according to the ratio of orthoclase to albite, or, stating it more generally, according to the molecular ratio of potash to soda. The ratio is conveniently expressed by the percentage of orthoclase in total orthoclase plus albite. In order to give the felspathoid minerals and the micas due weight in the classification, these may also be expressed in terms of the amounts of orthoclase and albite to which they are approximately equivalent. The chief factors required for this conversion are given approximately in the following table :— ORTHOCLASE=1°0 ALBITE =1°'0 Anorthoclase = 0°4 Anorthoclase =0°6 Leucite =1°4 Analeime = 5 Muscovite =0°7 Nepheline =1°6 Biotite =0°6 Some petrologists may object to the inclusion of biotite as a mineral comparable to orthoclase, but since it may be regarded as containing a leucite-like molecule, it seems desirable to take it into considera- tion. The writer is aware that at this stage the classification ceases to be purely mineralogical, but it is difficult to avoid some such grouping of minerals if the classification is to be one that can readily be tabulated and memorized. To employ every important mineral as a classificatory co-ordinate would demand more dimensions than can be printed or mentally visualized. The point raised touches the question of the objects of the classification, and these may be stated as follows :— (a) To attain parallelism with a chemical classification as far as possible. (6) To form compartments which shall largely define and limit the types of rocks falling within them. (c) 'To express the relations of rocks to one another ; linear in a chemical and mineralogical sense, and genetic as far as this can be done by a division of space into compartments. (d) To enable students of the subject oye to memorize the ever increasing list of rock names. (e) To indicate to petrologists where new names are necessary, and where they may, with advantage, be avoided. Returning from this digression to a consideration of the actual subdivisions adopted on a potash to soda basis, we may consider those that have already been used. In the C.1.P.W. Classification the five sub-rangs would give limiting positions at Or,.;—Ors7.;—Or¢2.s— A. Holmes—Classification of Igneous Rocks. V 27 UNDERSATURATED ROCKS: CHARACTERIZED BY FELSPATHOIDS AND OLIVINE. Oro SODA Orjo.s ROCKS. Org7.; SODA-POTASH ROCKS. Org.; POTASH Ofg7.5 ROCKS. Oriog ALBITE. ba =) x OLIGOCLASE- ANDESINE. > ee S LABRADORITE- ANORTHITE. Ani00 Felspar absent or accessory. OLIVINE ESSEXITE (in part). Olivine shonkinite. OLIVINE THERALITE. SOMMAITE. Olivine essexite (in ‘ part). OLIVINE TESCHENITE. ; Olivine camptonite (in part). NEPHELINE BASANITE. LEUCITE BASANITE. Olivine kulaite. Olivine jacupirangite. Olivine bekinkinite. OLIVINE MONCHIQUITE. LEUCITE OLIVINE MONCHIQUITE. Missourite. Alnoite. NEPELINE BASALT. LEUCITE BASALT. Nepheline melilite basalt. Melilite basalt. 128 A. Holmes—Classification of Igneous Rocks. Ory,.;, Some authors have used 1/3—2/3 (Or;s—-Or,,) as the limiting ratios of orthoclase to total felspar in certain groups of rocks such as monzonite (Hatch, 1916, vol. i, p. 192). This procedure, however, compares orthoclase to soda-lime felspar, and as the composition of the latter varies according to its occurrence in (say) granites or gabbros, adamellites or labradorite-monzonites, it follows that the same factors are not used throughout. Iddings in his modal classification (vol. ii) adopts 3/8-5/8 as limiting ratios, with a still greater possibility of variation in the factors, since for orthoclase he substitutes alkali felspar. Until we know whether there be a natural grouping of rock types about certain points (and relative abundance of the types concerned must, of course, be the chief test applied), the precise value of the limiting ratios adopted does not seriously matter. Those here employed are the ratios of the C.I.P.W. Classification, using in general only three of the five divisions. The separation of grano- diorite from quartz-diorite and adamellite demands a fourth sub- division. According to the definition of Lindgren, the orthoclase limits for granodiorite are about Or,) — Orgs, consequently the C.I.P. W. limits Or,).;—Ors,., will serve equally well. In the other direction, a fifth subdivision is necessary to accommodate the labradorite- monzonites which, starting at Or.,;, may be allowed to pass over the Org, dividing-line as far as the Or,,; limit. These limits are broader than are actually required, but as they do no violence to the definition of a gabbro, there can be no objection to their adoption. The writer does not wish to insist on rigidly fixed lines of division, for it is his opinion that a really valuable quantitative classification can only emerge when thousands of modes have been measured and statistically examined. ‘The mode is the only ‘“‘symbol”’ that can at present usefully be given to a rock. Nevertheless, for a tabular statement to be possible at all, lines must be drawn somewhere, and those adopted seem to enclose all accepted rock names without changing their current significance. There remain to be considered rocks without actual felspar. Logically, the five divisions here made on successive pages should be * repeated for rocks free from felspar, the divisions giving in respective order: Quartz rocks, Pyroxenites and Hornblendites, Peridotites, Felspathoid rocks, and Olivine-felspathoid rocks. It is much more convenient, however, to treat each group as a limiting case of the felspar group to which it most clearly belongs. This is done in the tabulation by placing some of the rocks in question below the corresponding felspathic rocks. In each division of the tabular scheme, the coarse-grained rocks (eneially those of major intrusions, to use Dr. Evans’ convenient term for ‘ plutonic’ masses) are used as types, and allied porphyritic, fine-grained, or aphanitic varieties (belonging generally to minor intrusions and lava-flows) are grouped with them. The classification is printed in three dimensions, in sheets super- imposed one on another as required. Of these dimensions, the first is based on degree of silica- saturation, and since it valnes lines of variation from saturated types in the directions respectively of quartz, A. Holives—Classification of Igneous Rocks. 129 felspathoid, and olivine, it really constitutes a classification on three co-ordinates. to make quantitative’ divisions the ratios of quartz to felspar, felspathoid to felspar, and of olivine to felspar or mafic minerals, could be employed. In particular it should be pointed out that in the table of oversaturated rocks, quartz-syenites have been squeezed out by the granites, and only consideration for space has deterred the writer from inserting a second sheet to include rocks with small amounts of quartz (on which such rocks as quartz-gabbro would then have properly appeared). The fourth and fifth co- ordinates, printed as second and third dimensions, are quantitative, and depend respectively on the ratios of albite to anorthite (expressed by percentages of anorthite), and of orthoclase (including other potash minerals suitably weighted) to albite (including other felsic soda minerals suitably weighted). A remaining feature, unexpressed in the tables, is the ratio of felsic to mafic minerals. The classification and nomenclature arising from this ratio have already been described ; and in practice the ratio constitutes a sixth co-ordinate that may often be of great service as a further means of subdivision. The seventh and last co-ordinate is textural. Vogt (see Harker, p.373) has pointed out that in the peridotites the atomic ratio of magnesium to iron gradually increases as the amount of alumina decreases. Dr. Prior has also used the ratio of Mg 0O/FeO with excellent results in a recent and illuminating classification of meteorites (Ain. Mag., p. 42, 1916). It may be worthy of notice that in the mineralogical classification of this paper, the same ratio increases from the north-east corner of each sheet to the south-west corner, for rocks having a normal ‘colour ratio”’ or felsic/mafic ratio. Indeed, for all such rocks (as far as can be tested by ‘‘average”’ analyses) the chemical variation in any direction is approximately regular. Glassy rocks are necessarily incapable of treatment, as indeed they must be by any system of classification by minerals. Similarly, most, altered rocks, whether they be altered by pneumatolytic or other processes arising from the consolidation of their parent magma, or by weathering processes, must also be excluded. A classification appropriate to express their characters would be based on the processes by which they have been.altered, and the mineral and structural changes whereby their new features have been developed. REFERENCES. CROSS, Tones! PIRSSON, & WASHINGTON. ‘‘ Quantitative Classification of Teneous Rocks”? - Journ. Geol., x, p. 555, 1902. In book form, 1903. 5 Modifications of the Quantitative System”? : Journ. Geol., xx, p. 550, 1912. Cross, W. ‘“‘ The Natural Classification of Igneous Rocks’’: Q.J.G.S., Ixvi, p- 470, 1910. ““The Use of Symbols in expressing the Quantitative Classification ”’ Journ. Geol., xx, p. 758, 1912. “Problems of Petrographic Clas-ification’’: Journ. Geol., xxii, p. 791, 1914. Evans, J. W. ‘‘ The Quantitative Classification of Igneous Rocks ’’: Science Progress, No. 2, October, p. 258, 1906. HARKER, A. The Natural History of Igneous Rocks, ch. xv, 1909. Hatcu, F. H. ‘‘ The Classification of the Plutonic Rocks’’: Science Progress, No. 10, October, 1908. Text Book of Petrology, vol. i, 1916. DECADE VI.—VOL. IV.—NO. III. 9 130 Reviews—Thrust Movements in Norway. IDDINGS, J. P. Igneous Rocks, vol. i, 1909; vol. ii, 1913. LINDGREN, W. Amer. Journ. Sci., ix, p. 269, 1900. SHAND, S.J. ‘‘On Saturated and Unsaturated Igneous Rocks’’ : GEOL. MAG., (V) X, p. 508, 1913 ; (VI) I, p. 485, 1914; (VI) II, p. 339, 1915. ‘“A Recording Micrometer for Geometrical Rock Analysis’’: Journ Geol., xxiv, p. 394, 1916. TYRRELL, G. W. ‘‘A Review of Igneous Rock Classification’’: Science Progress, No. 33, p. 60, July, 1914. REVIEWS. I.—New Lieur on THE Careponran Tarust Movements 1n Norway. Vor IV, part i, of the Norsk Geologisk Tidsskrift, just published, contains a summary of an exceptionally interesting paper on the tectonics and formation of the Norwegian mountains, read before the Geological Society of Norway by Professor V. M. Goldschmidt, of Christiania University.’ As the Norwegian and Scottish Highland rocks are of similar age and nature and exhibit the same type of tectonic structure, the discoveries in one region cannot fail to be of interest to the workers in the other: the chief points of the paper are here noticed without any attempt to offer criticism. The main conclusions advanced are of a novel character and have more than a local significance, for the author uses them to elucidate the problems offered by the rocks and structures of other great mountain ranges of the world. The paper deals with the central Norwegian mountain region in which great masses of eruptive gabbro and granite have been thrust over Ordovician phyllites. A series of arkoses, conglomerates, and schists, known as the ‘“‘ Hoifjeldskvarts”’ (high-mountain quartz) is usually present overlying the phyllites, and an attempt is made to elucidate the hitherto problematical origin and age of the series, to show its relationship to the high mountain eruptives which frequently overlie it, and to demonstrate the conditions under which the Caledonian mountain-building thrust movements obtained. The great difficulty experienced in unravelling the nature and origin of the ‘‘ Heifjeldskvarts’’ results from the extreme metamorphism to which a great part of ithas been subjected. Thus, if it were possible to classify its green schists and determine their origin, much light would be thrown on many problems, but as yet there is no means of doing this, for a tuff, an agglomerate, a conglomerate, an effusive or intrusive mass may all on alteration give the same kind of amphibolite schist. A district was therefore chosen for investigation in which the regional metamorphism is.a minimum, and there are fewest hindrances in the way of an indisputable identification of the rocks. Such a district was found in Central Norway to the east and west of Valdres, north-west from Christiania. . In the first tract discussed, that between Valdres and Gudbrandsdal, the sedimentary origin of the ‘‘ Heifjeldskvarts”’ can be established beyond doubt. The series here occupies an extensive area, and 1 VY. M. Goldschmidt, ‘‘ Om heifjeldskvartsen I og If’’: Norsk Geologisk Tidsskrift, Bd. iv, Hefte i, pp. 44-6, 49-53, Kristiania, 1916. Reviews—Thrust Movements in Norway. 131 interbedded in it are conglomerates essentially composed of gabbroid stones. ‘The problem is to determine the relationship of these conglomerates to some adjacent gabbro mountain masses which owe their present position to thrusting. In an early paper Bjerlykke held that the conglomerate was derived from the gabbro, and was thus the younger ‘formation. In a later communication, however, the contrary opinion is expressed that the gabbro is younger than the ‘‘ Heifjeldskvarts’’, and was intruded between it and the underlying phyllites. Professor Goldschmidt has made a thorough microscopic investigation of these rocks. The massive gabbro is a very characteristic rock composed of very fresh augite, less fresh biotite, and a wholly decomposed plagioclase ; hor nblende varieties also occur. The pebbles of the conglomerate exhibit all the varieties of the massive mountain gabbro, from which they are clearly derived. Thus the ‘ Heif- jeldskvarts”’ cannot be older than the mountain-building movements, since these conglomerates were laid down after the gabbro masses had reached their present position. Again, the conglomerate can be followed to places where it is overlaid by the gabbro and has been strongly pressed, often almost out of recognition. Thus the ‘‘ Hoifjelds- kvarts”’ cannot be younger than the thrusting movements, seeing it has been metamorphosed during, and as a result of, their evolution. It is not pre-Caledonian ; it is not post-Caledonian ; it is Caledonian —a conclusion of great significance, for it shows that the thrusting took place at the earth’s surface, a conglomerate being laid down during the process. The gabbro was eroded in front, whilst it was being “pushed forward from behind. The second tract examined lies between Valdres and Hemsedal. Here we have a similar type of structure, only the Ordovician phyllites are overlaid by thrust masses of granite instead of gabbro. In the south of the district the conglomerate beds are seen overlying the granite as a normal basal deposit, with no evidences of pressure action. In the north, on the other hand, the conglomerate has been overridden by the eranite, and its pebbles lave been pressed and drawn out by the movement. Here also the derivation of much of the conglomerate from the granite which now overlies it is established. Thus the investigations in both of these districts lead to the conclusion that the sedimentation of the ‘‘ Hoeifjeldskvarts”’ took place whilst the great eruptive masses were being driven forward, and with deposition of material from the erosion of the selfsame masses. By the continuance of the thrusting movements the sediments were covered and metamor phosed. On this interpretation, and in opposition to the orthodox view that the great thrust move- ments have obtained at a considerable depth, it must be admitted that great mass-thrusting can take place ‘“‘in daylight”? at the surface, so that a mass can be driven forward and be subject to erosion at one and the same time, in such a way as to ride over its own debris. After mentioning the great amount of work which yet remains to be done before all the problems of the ‘‘ Hoifjeldskvarts can be solved, and the flood of light which a full understanding of this series must throw not only on the formation of the Norwegian mountains but on the general principles of tectonic geology, it is 1382 Reviews—Cretaceous Brachiopoda, West Africa. confidently affirmed that ‘‘ the old dogma limiting the great thrust movements to a great depth stands no more”’. Professor Goldschmidt parallels the Flysch with the ‘‘ Heifjelds- kvarts’”’ formation. Just as the ‘‘ Heifjeldskvarts”’ is Caledonian, so the Flysch is Alpine in age, being formed contemporaneously with the mountain - building movements, though the petrographical similarity between the two formations is very small, one obtaining its material from forward-thrust eruptives and the other from forward- thrust Mesozoic sediments. In the discussion following the reading of the paper Professor Brogger expressed his approval of the original views set forth, and the further work of the Norwegian geologists in the light of the new theory will be followed with great interest. L. Hawxrs. I{.—Own somre Cretacrous Bracutopopa anp Motiusca From ANGOLA, PortuguEsE Wusr Arrica. By R. Burten Newron. ‘Trans. Royal Soc. Edinburgh, vol. li, pt. i, No. 15, August, 1916. [J\HE fossils described in this paper were collected by Professor J. W. Gregory and Mr. E. Robins from a cream -coloured limestone in the neighbourhood of Lobito Bay, north of Benguella in Angola. Most of the specimens are poorly preserved, but the author considers that there is sufficient evidence to refer the fauna to the Vraconnian stage, and this view receives support from the Cephalopods which have been examined by Mr. G. C. Crick. Twenty species are varieties only is of a purple-brown tint. A peculiarity of the olivine basalts is their comparative richness in alkalies, a feature that brings them into relationship with the titaniferous-olivine basalts of the Western Mediterranean described and analysed by Washington. The Arctic province, however, is distinguished by the abundance of alkali-poor basalts, which in spite of the fact that their silica percentages are low are thoroughly over-saturated rocks. Professor H. Hilton: On the use of the Orthographic Projection in Crystallography. The method of preparing a projection and its use in the drawing of crystals were explained, and the advantages of this projection of the sphere were pointed out. J. V. Samojloff: Paleophysiology, the Organic Origin of some Minerals occurring in Sedimentary Rocks. In connexion with the exploration of the phosphate deposits of Russia, the occurrence of barytes has been noted over a wide area in the governments of Kostroma, Kazan, and Simbirsk, and also further to the north-east in the basin of the Pechora River. The mineral occurs as nodules in the clays and marls of the Upper Jurassic, and is confined to the Oxfordian—Sequanian horizon, though extending up to the Kim- meridgian in some of the districts. Nodules of barytes have been dredged from the séa-floor off the coast of Ceylon, and granules of barium sulphate have been detected in the bodies of certain marine organisms, namely the Xenophyophora. If, therefore, during the Upper Jurassic period such organisms, capable of extracting barium salts from sea-water, were more abundant, they would account for the accumulation of barium in these strata, where the barytes occur as a primary mineral. Similarly, the mineral celestite has been found over a very wide area in Turkestan in beds of Upper Cretaceous age. The presence of strontium sulphate has been detected in the skeletons of the Acantharia, a group of the Radiolaria. It is conceivable that \ 142 Reports & Proceedings—Edinburgh Geological Society. similar organisms were relatively more abundant during the Cretaceous period, and that their remains gave rise to the deposits of celestite. Although the iron compound hemoglobin plays an important function in the blood of present-day animals, yet cases are known amongst the Crustacea and Mollusca in which the copper compound hemocyanin performs the same function, and vanadium has been detected in the blood of the Ascidia. During former periods of the earth’s history — these, and perhaps some other, metals may have been predominant in the blood of animals then living. In this connexion the persistent occurrence in the Permian strata of copper minerals and ores associated with abundant animal remains is significant. Similarly, there may have been at different periods variations in the chemical composition of the ash of plants. The recurring presence of minerals of primary origin in certain sedimentary strata therefore suggests that there may have been varying physiological processes during past periods, and for this new branch of paleontology the name ‘‘ Paleophysiology”’ is suggested. E. S. Simpson: On Tapiolite in the Pilbara Gold-field, Western Australia. The mineral, which was discovered at Tabba-Tabba Creek and Greens Well, lying in a large area of granite intersected _ by pegmatite veins and greenstone dykes and bosses, occurs in fairly well-defined crystals, which analysis proved to contain little niobium. At the first locality the crystals displayed the forms 100, 001, 111, 101, 320, and were twinned as usual on 101 and often distorted; while at the second they displayed the forms 100, 111, 101, 520, and showed twinning about 106 and 301 as well as 101. A curve was prepared showing the specific gravity obtaining in the tetragonal isomorphous series of metatantalates and metaniobates of iron, manganese, and calcium. LV .—Epinpuren GEOLOGICAL SociEery. January 17, 1917.—Dr. Flett, F.R.S8., President, in the Chair. 1. ‘‘Low-level Kettle-holes in and near Aberdeen.” By Dr. Alexander Bremner. \ A number of kettle-holes, i.e. cup-shaped hollows due to the melting out of isolated masses of ice embedded in fluvio-glacial and morainic deposits, occur below the 100 ft. contour-line in the Aberdeen district. During marine submergence such hollows could not fail to be obliterated by wave action. Hence it may be inferred that in this district (1) there was no 100 ft. submergence, or (2) the submergence was anterior to or contemporary with the last advance of the local ice. 2. “The Glacial Geology of the Stonehaven District.” By Dr. Bremner. The district dealt with extends westward from the coast between Dunnottar Castle and Portlethen village to the Dee watershed and south-westward to the Bervie Water from Drumlithie upward. A description was given of the traces left by the ice which, in a phase Correspondence—R. Bullen Newton. 143 of the Ice Age succeeding the maximum glaciation, flowed north-east from Strathmore (Strathmore Ice), and of those left by the ice which, after the final or partial disappearance of the Strathmore Ice from the district, passed over the Dee watershed and brought with it a characteristic ‘‘ granite drift’’ (Dee Valley Ice). Striation (E. 32°S.) due to the latter ice was recorded from Beltcraig, near Portlethen. Many peculiar valleys (glacial overflow channels) were noticed, the largest being the gorge through which the Caledonian Railway runs for fully a third of the distance between Drumlithie and Stonehaven Stations. It was pointed out that at Stonehaven, as at Aberdeen, no beach deposits referable to the 100 ft. submergence have ever been observed, but that there is strong evidence in favour of the existence of a pre-glacial rock platform (now overlaid by glacial deposits) at a level of 75 to 100 feet above O.D. 3. ‘Notes on River Development in the East-Central Highlands.” By Dr. Bremner. Many instances of rearrangement of drainage in the East-Central Highlands were noted, and it was proved that in Sheets 64 and 65 there occurs no authentic case of recent (post-glacial) river capture ; in particular, capture of the Slugain by the Quoich was shown to be pre-glacial. (See also Scottish Geographical Magazine for November, 1915.) The complicated history of the River Muick was traced in some detail. By successive captures, its headwaters (Allt an Dubh Loch) have been diverted from their original course down Glen Mark so as to enter the Dee (1) by way of the Girnock Burn and the wind-gap west of the Coyles of Muick, (2) by way of the present lower Muick. The dismemberment of the original Tarf (Sheet 64) by the Bruar, Tromie, and Edendon, and possibly by the Mhaire, was also discussed. CORRERSPON DEHN CE. a FORAMINIFERAL LIMESTONES FROM NEW GUINEA. Sir,— When reviewing the literature on some Foraminiferal lime- stones from New Guinea, during the preparation of a paper published in May last as No. 20 of a series of ‘‘ Reports on the Collections made by the British Ornithologists’ Union Expedition and the Wollaston Expedition in Dutch New Guinea, 1910-18”’, issued in 1916, I regret having overlooked an important contribution to the subject by my friend Mr. Frederick Chapman, the paleontologist of the National Museum at Melbourne, entitled ‘‘ Description of a Limestone of Lower Miocene Age from Bootless Inlet, Papua” (Journ. Proc. Roy. Soc. New South Wales, vol. xlviii, pp. 281— 301, pls. vii-ix, 1914-15). The formsof Foraminifera referred to by Mr. Chapman are almost identical with those mentioned in my report as occurring in the limestones of Mount Carstensz, and, moreover, the stratigraphical results are exactly similar in each case. It is 144 Correspondence—J. B. Scrivenor. interesting, therefore, to note that although these New Guinea localities are so widely separated, being probably some 600 miles apart, there is distinct paleontological proof that the limestones of both regions belong to the later Aquitanian stage of the Miocene epoch. It becomes increasingly difficult for the paleontologist to keep pace with the vast amount of literature which is issued on almost every branch of his subject, a condition of things which at the present time is more than ever accentuated on account of the Geological Society having discontinued the publication of their annual list of ‘Geological Literature’’, which has been of such inestimable service to all research workers in geological science. R. Burten Newton. BRITISH Musrum (Nat. Hist.), SOUTH KENSINGTON. FEDERATED MALAY STATES. Sir,—Owing to the fact that copies of the Geological Society’s Proceedings have not been sent to me while residing abroad I have only just been made aware, by the appearance of No. 284 of the Quarterly Journal, that my name was unnecessarily introduced into the Discussion on a paper read on June 23, 1915, p. 622 (but only now printed and issued to Fellows, in February, 1917). The speaker, Mr. W. R. Jones, said that :— ; “The danger of examining ‘mountains under microscopes’ was illustrated in a striking manner, in the case of a rock which occurs at the summit of Gunong Bakau, in the Federated Malay States. This rock was described as occurring extensively, and as being of no value. [A reference introducing my name is given here.—J. B. S.] It was further stated that the rock was evidence of the existence in this part of the granitic magma of a great quantity of free hydrofluoric acid capable of attacking felspar without the precipitations of a previously combined base, such as tin. Subsequently, however, the rock was found to contain tin-ore, and it has now been worked on a considerable seale.’’ As the Society’s officers have published the above I will ask you to print the following brief reply. The rock in question was not described as occurring extensively. It was described as being of no value because neither the quartz nor topaz was saleable. The passage concerning free HF omits any reference to the following condition in my publication: ‘‘if indeed it be correct to assume that the Chinchong rock is an alteration product.”” Tin-ore has not been found in the rock. The rock has not been worked. The speaker’s imperfect knowledge of the locality and failure to digest the page of my publication that he quotes have made him oblivious of dangers greater than that which he describes. J. B. Scrivenor. ““A?? COMPANY, INNS OF CouRT O.T.C., BERKHAMSTED. February 2, 1917. LIST OF BOOKS OFFERED FOR SALE a iene NET PRICES AFFIXED BY “-DULAU & CO., LTD., 37 SOHO SQUARE, LONDON, wW. BAYLEY (W. S.). Minerals and Rocks: the Hlements of Mineralogy and Lithology for the use of Students in General Geology. London, 1916. pp. vii + 227. 8vo. Illustrated. Cloth. 6s. CHAMBERLIN (T.C.). The Origin of the Earth. Chicago, 1916. pp. 271. Svo. ane Cloth. 6s. ECKEL (E. C.). Iron Ores: their occurrence, valuation, and control. New York, 1914. Illustrated. Svo. Cloth. 17s. HEATH (G. L.). The Analysis of Copper; and its Ores and Alloys. New York, 1916. pp. 292. 8vo. Illustrated. Cloth. 12s. 6d. HOWE (H. M.). The Metallography of Steel and Cast Iron. New York, 1916. pp. 641, 8vo, with 45 plates. Cloth. £2 2s. ibs KEITH (A.). The Antiquity of Man. London, 1915. 8vo. With 189 illustrations. Cloth. 10s. 6d. LAHEE (Ff. H.). Field Geology. New York, 1916. pp. 508. Crown 8yo. Illustrated. Cloth. 12s. 6d. LEITH (C..K.) AnD MEAD (W. J.). Metamorphic Geology. A Textbook. 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Oil-field Development and Petroleum Mining. London, 1916. 8vo. Illustrated. Cloth. £1 5s. : WAGNER (F. H.). Coal and Coke. New York, 1916. pp. 431, 8vo, with 137 Illustrations. Cloth. 17s. WEINSCHENK (E.). Fundamental Principles of Petrology, translated from the third German edition by A. Johannsen. New York, 1916. pp. 214. Svo. Illustrated. Cloth. 10s. 6d. WEST (G.). », A-T,. i manonia. Portsdown, Hants. oy ett a transligata. Coltishall, Norfolk. mt - Vf Trimingham. », LO-12. Se pyramidalis. i Il.—On tue Inrecument or J@UANODON BERNISSARTENSIS, BOULENGER, AND oF J/OROSAURUS BECKLESI, MANTELL. By REGINALD WALTER HOoo.ey, F.G.S. (PLATE X.) InTEGUMENT OF [GUANODON BERNISSARTENSIS. (Y\HE Zguanodon has been known since 1825, when the genus was first described from teeth by Mantell.! Odd bones and various associated portions of the skeleton have been found in England, and in 1878 the skeletons of many individuals were discovered in the Wealden of Bernissart, near Mons, Belgium. No trace of the dermal covering has hitherto been observed. Owen? in 1885, when describing the bones of a ‘‘ young Jguanodon”’ from the Wealden of the Isle of Wight, mentions that ‘‘some portions of a layer of dark finely granulated carbonaceous matter were found embedded between the ribs, near the middle of the side of the trunk ”’, which he queried as the integument of Jyuanodon, but these remains were proved later to belong to Hypsilophodon. In 1914 I obtained from the Wealden Shales of Brighstone Bay, Isle of Wight, nearly the entire skeleton of a young individual of Iguanodon bernissartensis, with the exception of the greater part of the tail. “4 In July last, while clearing away the matrix from the preacetabular extremity of the left ilium, a portion of the epidermis (Fig. 1) was exposed. It covers an area 90 mm. long by40mm.wide. The impression of the integument is also discernible on another block 78 mm. long by 57 mm. wide, found in close proximity to the other. Fragments of skin were also discovered underlying two of the left thoracic ribs. On these latter specimens carbonaceous matter is to be seen. No scutes or dermal ossifications were found. ‘he skin is remarkably thin, and covered with small convex tubercles varying in diameter from 5mm. to 3mm. On the largest specimen there is an area, 8 mm. by 7 mm., where the tubercles are slightly larger and flatter, and 65 mm. distant occurs another patch with the same measurement, where the tubercles coalesce in such a manner that the tuberculation is almost invisible. The tubercles on the edge of the skin at the top 1 G. Mantell, Phil. Trans., 1825, p. 184. 2 R. Owen, Mon. Foss. Rept. Weald. Form., pt. ii, 1855, p. 51. es Grou. Mag., 1917. Pratze 1X. R. M. Brydone, Photo. Bemrose, Collo. Chalk Polyzoa. R. W. Hooley—Integument of Wealden Dinosaurs. 149 of Fig. 1 are also decidedly larger and flatter than the others. One plate-like tubercle, 10mm. in diameter, occurs on the smaller portion of the skin from the same inguinal region. It appears therefore probable that on those parts of the body exposed to the sun large flat tubercles would be found as in Zrachodon annectens,' and it is evident that the ‘‘ ground plan” of the epidermis is essentially similar, consisting of small, rounded tubercles, although in Jguanodon they are not so rounded or apical. Professor Osborn} thought that the iguanodonts from the Lower Cretaceous of Kurope would probably be distinct in their epidermal covering”’ from the trachodonts of the Upper Cretaceous of America, and it is interesting to find that at least they are alike in ground plan. Intecument or Uforosaurus BeckiEsu, MantELLb=WL. Brevis, OWEN. An impression of the epidermis of this reptile (Fig. 2) is well displayed on a block of rock removed from the hollow between the radial crest and the inner border of the left humerus. This humerus, with the radius and ulna, was found in the Wealden beds of | Hastings by 8S. H. Beckles in 1852. These specimens (No. R. 1870) are now in the British Museum. They were referred to by Mantell in a lecture given by him at the Royal Institution in that year. The report” of the lecture records that ‘‘A portion of the scaly cuirass which covered the limbs and is composed of hexagonal plates was exhibited’’. he integument was also noticed by Marsh,* when examining this fossil while still in the possession of its discoverer. He remarks that he ‘‘found attached to the humerus portions of the osseous dermal covering, the first detected in the Sauropoda, and known only in the present specimen”. It has not been further described, but by kind favour of Dr. A. Smith Woodward I am now privileged to give the details. The side of the matrix upon which the epidermal markings are shown is convex, well seen in Fig. 2, but this feature is entirely due to the concavity of the partieular) area of the humerus upon which it lay and not to the natural rotundity of the limb. There was no intervening matrix between the skin impression and the bone, therefore unless this portion of the integument was turned inside out after the decomposition of the muscles and before the matrix was deposited upon it, the under surface of the epidermis is exhibited. The only fact that supports the improbable theory of the reversal of the integument is that there is an apparent ornamentation of very small rounded tubercles displayed on some of the plates. The smallest plates, especially at the upper end of the specimen, are covered with them. It does not appear that they are due to oxidization subsequent to the removal of the block from the humerus. I have observed a somewhat similar result from chemical action after exposure to the atmosphere on matrix which at first had a smooth surface. However, it is more probable that they are papilliform 1H. Osborn, Mem. Amer. Mus. Nat. Hist., N.S., vol. i, pt. ii (June, 1912), PP. 46, 47. 2 Proc, Roy. Inst., vol. i, p. 34, 1852. 2 0. C. Marsh, GEou. Mac. [3], pp. 205, 206, 1889. 150 A. Holmes & H. F. Harwood—Picrite, Mozambique. protuberances of the epidermis into the dermis and that we are looking upon the inner surface of the former. There i is no sign of ossification, although Marsh* speaks “ aE the osseous dermal covering’’. The extent of the epidermal impression is 210 mm. long by 200mm. wide. It consists of hexagonal plates, convex and boss-like, which on their outer surface were probably flat. A group comprising eight of the largest plates covers an area 95mm. long by 68 mm. wide. The central plate of this group has a diameter of 26 mm. The plates surrounding this cluster gradually decrease in size, until they are only 9mm. in diameter. The plates do not overlap. The integument of MMorosaurus becklesit was tuberculate and the lessening in dimensions of the tubercles towards the axillary surface of the arm, where they probably became smaller and rounded, is after the manner of Zrachodon and Jguanodon. EXPLANATION OF PLATE X. Fic. 1.—Impression of a portion of the epidermis from the left ilium of Iguanodon bernissartensis obtained by the author from the Wealden Shales of Brighstone Bay, Isle of Wight, in 1914. », 2.—Impression of a portion of the epidermis of Morosaurus becklesi, Mantell, found by Mr. S. H. Beckles in 1852 in the Wealden beds of Hastings, now in the British Museum (No. R. 1870). J1I.—Picrite rrom tae Ampwini River, MozamBigur. By ARTHUR HotmgEs, A.R.C.S., D.I.C., B.Sc., F.G.S. (with an Analysis by H. F. Harwoop, M.Sc., Ph.D.). (PLATE XI.) LMOST due west of Mozambique Island, at a distance of about forty-two miles from the sea, the military road from Mosuril to Nampula crosses the Ampwihi River, an important tributary of the Monapo.? During the dry season the stream is reduced to a string of stagnant pools, separated by long reaches of sand and- gravel that here and there are interrupted by outcrops of the underlying formations. Throughout the greater part of its course the Ampwihi flows through a region in which gneisses persist with monotonous regularity, the only variation being that due to oceasional intrusions of granite and of still later pegmatite dykes. At the point where the military road crosses the narrow channel a welcome diversion is introduced by the presence of a dark compact dyke about 10 feet in thickness. ‘he dyke appears on the right-hand bank and crosses obliquely to the other side, taking a N. N.W.-S.8.E. course across the strike of the older rocks. Upstream, about seventy yards to the south-east, the Ampwihi bends to the south-west, so that it returns towards the dyke, which is again exposed across its sandy floor. The dyke was traced by Mr. E. J. Wayland in July, 1911, for a distance of altogether 200 yards, and was examined by Mr. D. Alex. Wray and later by myself during the same year. It is clearly the latest 1 Q. C. Marsh, op. cit., p. 206. 2 See A. Holmes & D. A. Wray, ‘‘ Mozambique: a Geographical Study ’’ : Geog. Journ., p. 143, Aug. 1913 (Map, p. 112). os Se rae ee ee Grou. MaG., 1917. PWVATE NG PORTIONS OF INTEGUMENT OF WHALDEN DINOSAURS. 4 a TA 1 y) . . =, : 4 * z) } Es x: 1 : A. Holmes & H. F. Harwood—Picrite, Mozambique. 151 rock of the district, and is intruded along a line of fault, for in two cases pegmatite dykes seen on the eastern side are broken across and reappear on the western side with a well-marked northerly displacement. PETROGRAPHY. The specimens collected were from the margin—evidently chilled— of the transverse dyke, and have a dark-grey colour, mottled with nearly black glassy phenocrysts of olivine. Here and there are minute white amygdales, the infilling consisting of an isotropic material that is probably glass. The weathered surface is creamy grey in colour with rusty patches corresponding to the phenocrysts. The average specific gravity of three fragments of the fresh rock is 3:08. In thin section the rock is found to consist of corroded phenocrysts of olivine in a fine-grained groundmass composed mainly of elongated grains of augite and enstatite, the former alternating with and sometimes intergrown with laths of soda-lime felspar. In places interstitial patches of pale brownish-grey glass appear, and where a minute amygdale is seen it is found to be composed of the same obscure material (Pl. XI, Fig. 1). The olivine phenocrysts are occasionally hyp-idiomorphic in outline, but generally they are deeply corroded, the resorption having sometimes divided a large crystal into a number of rounded fragments. Except around the edges and along cracks and cleavage planes, where serpentinization has begun, the crystals are still quite fresh. The serpentine is mainly of the fibrous variety, chrysolite, the fibres being arranged normally to the edges or cracks from which the alteration has developed. The only inclusions present are sparsely scattered grains of magnetite. In one section it was noticed that a shred of biotite had developed at the junction of an olivine erystal with interstitial glass. The most abundant mineral of the groundmass, and indeed of the whole rock, is a pale yellow-green augite occurring in granules that are generally slightly elongated along the c axis. ‘The average refractive index is 1:7; the optic-axial angle is low; and the specific gravity is nearer 3°2 than 3:1. These characters, when considered in relation to the chemical composition of the rock, indicate that the pyroxene approximates to the enstatite-augite variety.’ Among the augite granules there occur a few colourless grains generally of similar average dimensions, but occasionally slightly larger, having noticeably lower refractive index and double refraction, and giving straight extinction. They were at first thought to be wollastonite, but further optical examination showed that the optical character is positive and that the average refractive index is about 1-67. These properties lead to the conclusion that the mineral is enstatite. It is clear from its relations to the surrounding minerals that it crystallized after olivine and before augite. In Pl. XI, Fig. 2, a good example of enstatite can be seen adjoining the dark space on the right-hand side. 1 See J. V. Elsden, Q.J.G.S., vol. lxiv, p. 287, 1908. 152 A. Holmes & H. F. Harwood—Picrite, Mozambique. Between the grains of augite another colourless mineral, with prismatic habit, occurs. The optical characters indicate that it is a soda-lime felspar, approaching bytownite in composition. The average refractive index is about 1°57, and the maximum extinction angle is 40° measured from the direction of elongation of the microliths. As the specific gravity is estimated to be about 2°73, the composition of the felspar is approximately Abso Any, 1.e. that of a caleic labradorite. The relations between augite and felspar are illustrated in Pl. XI, Fig. 2. A casual glance would suggest that the augite crystallized before the felspar, but this appearance is due to the superior relief of the augite, and a careful examination shows that the two minerals crystallized together. This conclusion is corroborated by the fact that in places a micrographic intergrowth can be detected. The augite grains become more angular, and between them the minute interstitial labradorite can be traced in optical continuity from place to place. On the borders of the micrographic areas the felspar frequently becomes fibrous and tends to radiate.’ Becoming gradually more obscure the fibrous felspar dies away and an interstitial clearing of glass appears. The refractive index of the glass is 1°55, and its specific erawily is 2°5, indicating approximately the composts of syenite.? The relative proportions of the minerals were measured by the Rosiwal method. Under a 1 in. objective the proportions of olivine and groundmass were determined, and afterwards the groundmass was. analysed under a} in. objective. As it was not found possible to distinguish in every case between augite and enstatite, the two pyroxenes were estimated together. In order to determine the specific gravities of the various minerals, a diffusion column of methylene iodide and methylene iodide diluted with benzine was prepared so as to give a range from 3°38 to 2°3. Olivine and magnetite sank. A well-marked band of pyroxene formed between 3°1 and 3:2. Another band formed at 2°73 (labradorite), tailing out above and below owing to the difficulty of obtaining a clean separation from such fine-grained material. Finally, another layer formed at the level corresponding to 2°50. The results obtained are as follows :— Mineral Receaeo alae Glass 3 2 8 2-50 a Labradorite, ae F 17 2-73 Pyroxene . y : 45 3-15 (average) Olivine . : : 29 3-45 (?) Magnetite. : ‘ il 5-17 (?) Total . . 100 Average . 3-20 The actual specific gravity of the rock is 3:08, so that the figure assumed for olivine, 3-45, is probably a little too high. As the 1 See Iddings, Rock Minerals, 2nd ed., fig. 28, p. 215, 1911. 2 See J. A. Douglas, Q.J.G.S., vol. Isiii, p. 153, 1907, for relations between refractive indices and specific eravities of glasses. A. Holmes & H. F. Harwood—Picrite, Mozambique. 153 analysis indicates that the composition of the olivine includes nearly 80 per cent of forsterite, the specific gravity should be about 3:4. This figure would give for the rock a calculated specific gravity of 8°10, which agrees more closely with the observed result. CHEMICAL Composition. An analysis of the rock was made by Dr. H. F. Harwood, with the following results :— Percentages. nee. PEE eee ates SiO. . i 46-37 0-773 Al, O3 . : 10-82 0-106 Orthoclase . 3-33 Fe.O3 . ; 1-60 0-010 Albite . : 8-38 FeO . A 7-85 0-109 Anorthite . 23-33 MgO. i; 20-78 0-5195 CaO. : 7-94 0-142 Diopside . 12-82 Na,Q . 5 0-99 0-016 Enstatite . 16-41 K,O . : 0:57 0-006 H20+. 1-97 — Olivine . 380-30 H.,O-. f 0-82 — CO.n . Z none — Magnetite . 2-44 Ni@ awe P 0-13 0-002 Ilmenite A 0-30 P2O5 . a none — MnO . 5 0-16 0-002 97-36 Cr203 . 5 0-07 0-0005 Water . i 2-79 NiO. 5 0-07 0-001 Total . 100-14 ; ; Total . 100-16 Specific gravity (average of three specimens) = 3-08. Radium content (A. H. 1915) = 0-44 x 10—™ grams per gram of rock. The composition of the rock is of a type not very commonly found. Its nearest analogue is that of a Hawaiian picrite-basalt which was erupted in 1840.! A few other similar analyses are cited in the table below (p. 154), from which it may be seen that two British rocks, one from Anglesey and one from Loch Garabal, have a general chemical similarity to the picrite under discussion. The presence of nickel and chromium in every case in which it has been sought for is an interesting feature, and indicates the importance of making analyses as complete as possible. The association of these elements with olivine-rich rocks has been frequently pointed out,” and there is no doubt that by determining such relations in detail much may yet be learned concerning the genesis of igneous rocks and ore-deposits. Among African rocks the Mozambique picrite resembles most closely some of the mineralized picrites of the Insizwa Range. Owing to the presence of pyrrhotite and of copper and nickel sulphides in these rocks the analyses cannot be directly compared, but it is clear that 1 W. Cross, Prof. Paper 88, U.S.G.S., 1916, pp. 44, 77. The mineralogical composition of the Puna lava of 1840 is almost identical with that of the Ampwihi picrite. * H. S. Washington, Trans. Ann. Inst. Min. Eng., xxxix, p. 735, 1908. > W. H. Goodchild, ‘‘ Economic Geology of the Insizwa Range’’: Inst. Min. and Met. (read December 21, 1916). 154 A. Holmes & H. F. Harwood—Picrite, Mozambique. the two rock-types are very similar. In one case (sample No. 7) Mr. Goodchild remarks: ‘‘The felspars not infrequently show micrographic intergrowth with the pyroxene, but on the whole are interstitial,” and in the photo-micrograph of the rock (Fig. 9) it can be seen that the correspondence in texture goes even further, for the olivines are markedly porphyritic. From nickel-bearing rocks we may turn to chromium-bearing rocks, as exemplified by those of the Great Dyke of norite of Southern Rhodesia.’ Here, however, the picrites are coarse-grained, and are not comparable in detail, either texturally or mineralogically, with the Ampwihi picrite. A. B. C. D. EK. SiO, , 46-37 47-25 47-75 42-87 46-0 AleO3 . 10-82 9-07 10-56 10-93 6-8 Fe.03 . 1-60 1-45 0-74 , 3-44 3-0 FeO 5 7-85 10-41 8-34 10-14 7-5 MgO : 20-78 19-96 19-09 16-27 23-9 CaO : 7-94 7-88 9-62 9-11 8-1 Naz O : 0-99 1-38 1-32 0-92 0-8 K.0 j 0-57 0-35 0-12 0-13 0-9 H2,0+ 1:97 0-04 2-06 2-87 \ oo H,O- . 0-82 0-08 0-05 0-57 CO, f none — — 2-70 n.d. Ti Og i 0-13 1-61 0-37 tr. n.d. Pp. Os E none 0-21 0-03 tr. n.d. MnO : 0-16 0-13 0-10 tr. n.d. Cr203 0-07 0-13 0-24 n.d. 0-2 NiO : 0-07 0-12 0-07 n.d n.d. Total - 100-14 100-03 100-46 99-95 99-60 Picrite. Ampwihi Crossing, Mozambique (an. Harwood). Picritic basalt. Flow of 1840, Nanawale, Puna, Hawaii (an. Steiger). Diabase? Cathay Hill, Mariposa County, California, U.S.A. (an. Hillebrand). Hornblende picrite. Ty Croes, Anglesey (an. Phillips). Peridotite? Loch Garabal, Scotland (an. Player). HSat> Returning to the analyses cited above, there are three further relationships worthy of discussion, namely, the relation of. the Mg0O/FeO ratio to the percentage of alumina, the association of potash with magnesia, and that of soda with iron-oxides. Vogt has shown that in peridotites the ratio of MgO to FeO increases on an average as the percentage of alumina decreases. For percentages of alumina between 10 and 11 the atomic ratio of Mg0O/FeO averages 2°6. In the Ampwihi picrite there is consider- able divergence from this value, the ratio being 4. Thereisasimilar divergence in the case of the Cathay Hill Diabase, the ratio of which is 3°8. The three other rocks cited, however, give ratios that agree very well with Vogt’s generalization :— D. 18 BR. Als Os . c , : : 10-93 9-07 6:8 Atomic ratio MgO/FeO . 2-2 3-0 4-2 1 A. EH. Y. Zealley, Trans. Roy. Soc. S.A., p. 14, 1915. 2 See A. Harker, Natural History of Igneous Rocks, p. 373, 1909. A. Holmes & H. F. Harwood—Picrite, Mozambique. 155 _ Washington has recently pointed out the general sympathetic relation between potash and magnesia, and between soda and iron oxides in igneous rocks.1. The former relation is exemplified with one exception (C) by the analyses quoted :— E. A. B. C. D. MgO . 23-9 20-78 19-96 19-09 16-27 TO ee 0-9 0-57 0-35 (0-12) 0-13 indicating that the Ampwihi picrite is not different from its analogues in this respect. The soda-iron relationship does not hold within the narrow limits of the five analyses A~E. If soda and potash be compared with the Mg O/Fe O atomic ratio, however, it will be noticed that with one exception in each case potash increases, while soda decreases, with the ratio. Atomic ratio of K. : A. C. B. D. Mg O/Fe O . 4-2 4-0 3-8 3-0 2-2 KeO . 5 3 0-9 0-57 (0-12) 0-35 0-13 Naz O 0:8 0-99 1-32 1:38 (0-92) _ It may not appear that there can be any meaning in such results as these, drawn as they are from rocks without apparent genetic relations in either time or place. Such rocks may, neverthless, have genetic relations in virtue of the processes by which they were formed. By comparing similar igneous rocks, correspondences and discrepancies of the kind to which attention has been drawn may come to be used, when their significance is understood, to suggest the origin and differentiation of the magmas from which the rocks have crystallized. It is possible that magnesia-rich magmas do not readily part by crystallization with their potash, and that they may selectively absorb and accumulate potash from the rocks through which they pass in approaching the surface. Similarly, in proportion to their iron content, magmas may not readily part by crystallization with their soda, and they may selectively absorb and accumulate soda from the rocks through which they pass on their upward or lateral journeys. his digression has led us far from the picrite dyke of the Ampwihi River, to which we must now return to pick up afresh the lines of thought suggested by analytical results. The radium content of the rock, only 0°44-% grams per gram, is very low. Peridotites appear to average more than this amount, a composite analysis of ten varieties giving 0°51X10-" grams per gram.” ‘lwo dunites analysed for radium by Professor Strutt, however, gave 0°33" and 0:34-" grams per gram respectively.’ The slightly higher result for the picrite is probably due to the presence of felspathic constituents, which are generally far richer in radium than olivine or enstatite. ‘The result is of more than numerical interest merely, for it shows that the dyke cannot have 1 Proc. Nat. Acad. Sci., p. 574, 1915. 2 A. Holmes, Science Progress, 1914, No. 33, p. 16. 3 R. J. Strutt, Proc. Roy. Soc., 1906, A. 77, p. 479. 156 sdvjavho ajqowscfuosun anissedens Bumoys ‘ aSpiyy uvivivyy A) 4ajsve pepalyo sUy oJ s2/duv—4ybi4 40 Kayouirxcaddo Pui ey joe” wart 4¥BY 4509 830490 YoLDeG Cretaceous and Older Rocks in East Kent. 549 here. The finer portion must have been dropped further on in its course. Possessed of this corrasive power in Kast Kent, erosion of the Mesozoic area of its bed must have been inevitable, but doubtless the finer part of the eroded material was carried beyond the area. Rarity of Mesozoic débris is therefore to be expected in the Wealden of East Kent, and where Mesozoic fragments do occur they are probably of large size and marked angularity. Comparison of the details yielded by some of the borings suggests that the Mesozoics in Kast Kent underwent erosion in early Wealden times, although it must be borne in mind that allowance must be made for the general pre-Cretaceous denudation of the area. For example, the sites of the Tilmanstone shaft and the Barfreston boring both lie on the sub- Cretaceous outcrop of the Oxfordian, and since Tilmanstone lies a little to the north-east of Barfreston we should expect the thickness of Oxfordian passed through to be rather less there. In actuality, only 3 feet of Oxford Clay remain at Tilmanstone, whereas 102 feet were passed through in the Barfreston bore. It would appear, then, that the early Cretaceous strike-stream which traversed the outcrop of the Oxford Clay in the neighbourhood of Tilmanstone was responsible for a considerable amount of erosion. With continued submergence Weald Clay times approached, and delta conditions, ushering in the marine invasion of the Lower Greensand, began to prevail. The waters of the Wealden lake encroached northward upon Kast Kent, the velocity of the streams was checked, finer sediments began to be deposited in quantity, and base-level conditions were realized. The spreading waters united the streams into a single sheet. The evidence shows that the main stream and its two subsequent branches had become united into a single sheet of water before the commencement of Weald Clay times. Higher ground, separating the two subsequent streams from each other, appears to have existed in the neighbourhood of Fred- ville, yet 283 feet of Hastings Beds occur here. To the north-east, however, the velocity of the stream still remained such that deposition had not yet commenced. Probably in this area the stream was active in removing from the Paleozoic floor some of its Bathonian covering. With the advent of Weald Clay times, how- ever, deposition proceeded over the whole area under water, and the surface so long exposed to denudation was finally buried. In the neighbourhood of Deal a small area of Coal-measures remained uncovered until Lower Greensand times, and at and near Stodmarsh an area of Bathonian remained until Gault times. Norr.—After the proofs of this paper had been sent to the Editor additional information became available in consequence of the publication of the Summary of Progress of the Geological Survey for 1916 (Mem. Geol. Surv. 1917). Details concerning three additional borings (J. Pringle, Appendix II), viz., at Bere Farm (12 miles north-east of Dover), Elham (close to Elham Station), and Folkestone, are now to hand. The Bere Farm boring shows the sub-Cretaceous surface there to be composed of Corallian Limestone, as was expected, although the thickness of the Wealden (42 feet) is 550 Reports & Proceedings—The Royal Society. less than might have been expected. The Elham and Folkestone borings show the south-westerly thickening of the Wealden (158 feet and 218 feet respectively), but each apparently demonstrates the entire absence of both Purbeck and Portland rocks. Mr. G. W. Lamplugh (Appendix IV) discusses the underground range of the Jurassic and Lower Cretaceous rocks in East Kent, and is more fortunately situated than the present writer (who has been away at sea) in having information furnished by a further twelve borings to work upon. November 14, 1917. REPORTS AND PROCHEDIN GS. I.—Tue Royat Socrery. November 8,1917.—Sir J. J. Thomson, O.M., President, in the Chair. The following paper was read :— ‘The Structure, Evolution, and Origin of the Amphibia. Part I: The ‘Orders’ Rachitomi and Stereospondyli.”” By D. M. S. Watson, M.Se., Lieut. R.N.V.R. (Communicated by Professor J. P. Hill, F.R.S. In dis paper all known genera of Rachitomous and Stereo- spondylous Stegocephalia are reviewed, the brain-case and basi-cranial region, hitherto practically unknown, being described more or less completely, and much new information about other regions set down. It is shown that there are a series of characters which change steadily with time in all Labyrinthodontia. The more important of these changes are— 1. The gradual reduction and final loss of basi-oecipital, basi- sphenoid, and supra-occipital bones and cartilages. 2. The gradual replacements of basi-pterygoid processes of the basi-sphenoid by expansions of the para-sphenoid, and finally of the ex-occipitals with which the pterygoids articulate. 3. The gradual increase in size of the inter-pterygoid vacuities, and of the para-sphenoidal rostrum. 4. The gradual regression and final disappearance from the skull of a foramen for the hypoglossal nerve. It is pointed out that these characters, which are seen to arise within these two groups, are those which have always been regarded as the diagnostic features of the class Amphibia, and that it is certain that they have arisen independently in at least three great orders. Finally, it is shown that a hypothetical ancestor of the Rachitomi obtained by projecting backward the evolutionary trends shown in these and other series of characters which change regularly with time, is actually realized in the Embolomerous Amphibian Péeroplax. Il.—Geroxrocicatn Socrery or Lonpon. November 7, 1917.—Dr. Alfred Harker, F.R.S., President, in the Chair. The following is an abstract of a lecture on ‘‘ The Nimrud Crater in parish Armenia’! delivered by Felix Oswald, B.A., D.Sc., F.G.S. : Reports & Proceedings—Geological Society of London. 551 The Nimrud volcano, one of the largest volcanic craters in the world, is situated on the western shore of Lake Van, and was surveyed and investigated geologically for the first time by the speaker in 1898. The western half of the crater is occupied by a deep lake of fresh water, while the eastern half is composed of recent augite-rhyolites, partly cloaked in white voleanic ash. The crater wall is highest on the. north (9,908 feet), rising in abrupt precipices over 2,000 feet above the lake (7,653 feet). The southern wall is also precipitous, but only reaches the height of 9,434 feet (the south-eastern part). A large slice of the crater wall has slipped down on the south-west, so as to form a narrow shelf, 800 feet above the lake. The crater is nearly circular, 8,405 yards from west-south- west to east-north-east, while the transverse axis 1s 7,905 yards. The lowest points lie on the long axis, reaching only 8,139 feet on the western and 8,148 feet on the eastern rim. The crater wall has an external slope of 38° on the south and east, where it consists exclusively of overlapping lenticular flows of augite- rhyolite and obsidian. On the south-west, west, north-west, and north these are capped by thin sheets of cindery basalt which must have possessed great fluidity, extending for many miles to form wide plains of gentle slope and great fertility down to Lake Van on the east and into the Plain of Mush on the west. ‘These basalt-flows dammed up the north-east to south-west valley between the Bendimahi and Bitlis Rivers, and thus brought Lake Van into being. The history of the Nimrud volcano may be summarized as follows from the speaker’ s observations :— 1. Its forerunner was the Kerkur Dagh on its southern flank— a denuded mass of grey augite- trachyte, rising to 9,000 feet, and crowned by many peaks. It was probably erupted in the Pliocene Period, subsequently to the folding of the Armenian area, in which the latest folded rocks are of Miocene (Helvetian—Tortonian) age, occurring north of the Nimrud Dagh and consisting of limestones . with corals (Cladocora articulata, Orbicella defrancei, ete.), Litho- thamnion, Foraminifera (Lepidocycline Orbitordes, Amphistegina, etc.), beds of Pecten (P. urmiensis, etc.) and of oysters (Alectry yonia virletr). Nimrud and the other numerous volcanoes of Armenia came into existence at a period when the sedimentary rocks could no longer be folded, but were fractured along definite lines, and Nimrud is situated on the great fracture transverse to the Armenian folds at the apex of their bending round from the Antitauric (west-south- west to east-north-east) to the Persian (north-west to south-east) direction, and it also marks the point of intersection of this fracture with a great north-east to north-west fracture (Caucasian direction), which delimits on the south Lake Van and the faulted depression of the Plain of Mush, abruptly cutting off the Tauric horst of pre- Devonian marbles and mica-schists. 2. Numerous flows of augite-rhyolite built up the vast cone of the Nimrud Dagh, and the increasing pressure on the central vent became relieved by extrusions of augite-trachyte along radial fissures, forming the present promontories of Kizvag, Zighag, and Karmuch. 552 Correspondence—Professor W. W. Watts. , 3. A presumably long period of inactivity was followed by violent explosions destroying the summit of the cone, and from this crater (smaller than the present one) vast lava-flows of a very fluid basalt (crowded with phenocrysts of labradorite, pale-green augite, and some olivine) flooded the country and filled up the Bitlis and Akhlat valleys, which have since then been eroded a little below their former depth. The Sheikh Ora crater of basic tuff (now breached by Lake Van) probably belongs to this period. 4. Further explosions widened the crater, in which a large lake was formed, while the eastern half of the crater became filled by a succession of outflows of augite-rhyolite, in which numerous blow- holes were drilled, bringing to the surface large blocks of basaltic agglomerate and also affording sections showing the transition downwards from obsidian, spherulitic obsidian, and spherulitic rhyolite to banded augite-rhyolite (with sanidine and green augite in a micropeecilitic ground-mass). 5. The last eruption was recorded in 1441 by a contemporary Armenian chronicler, and resulted in the extrusion of a very viscous augite-rhyolite along a north-to-south zone of weakness, both inside the Nimrud crater, where it separated off part of the large lake to form the shallow, so-called ‘“‘ hot lake’’, and also to the north of Nimrud, where it rose up fissures and in a small crater. 6. A violent earthquake in 1881, which destroyed the village of Teghurt, at the eastern base of the crater wall, was the last sign of activity ; but earthquakes are still frequent in the Plain of Mush, at the western foot of the Nimrud Dagh, and recent fault-searps are clearly visible along the borders of this faulted depression. The speaker mentioned that he had presented his model of the crater to the Museum of Practical Geology (Jermyn Street) and the rocks and slides to the British Museum (Natural History), where his fossils from Armenia are already preserved.’ A short discussion followed, and the thanks of the Fellows present were accorded to Dr. Oswald for his lecture. CORRESPONDENCE. ae COAL IN THE SILURIAN AT PRESTEIGN. Srr,—Mr. Cantrill’s article in tie November number of this Magazine on the boring for coal in Silurian and Longmyndian rocks at Presteign (pp. 481-92) is interesting in throwing light upon one of the most flagrant examples of the ignoring of geological evidence in exploits of this nature. As there must have been some grounds for the impression in the locality that coal existed there, 1 Tantern-slides of many unpublished photographs and drawings of the Nimrud crater and its surroundings, a model coloured geologically (scale, 1 inch =1 mile), and a series of rock-specimens and rock-sections were exhibited by Dr. Oswald in illustration of his lecture. A Geological Survey map of the Maclean Umtata district, Cape Province, Sheet 27, scale 3-75 miles = 1 inch, 1917 (presented by the Geological Survey of the Union of South Africa), was also exhibited. r OG) Y Q, x Piatem il C7 Se Wee Ly Heol. Mag., 191 Obttuary—Professor Edward Hull. 5538 without which local money probably would not have been forth- coming, I may mention that on a visit to the section last August, with Professor Garwood (whose excellent conjoint paper with Miss Good- year, read at the Geological Society on June 6, and published in abstract in the Proceedings on June 13, 1917, has been overlooked by Mr. Cantrill in his account of work on the district), we learnt from an old quarryman, whose memory reached back many years, _ that it had been the custom in slack times to cart coal from the Clee Hills for lime-burning. In order to preserve the coal it was necessary to bury it, often in considerable quantities. Relics of these hoards are occasionally met with, and, as their history has been generally forgotten, it is very likely that these chance finds gave rise to the idea that coal-bearing beds exist in the locality. W. W. Warts. HILLSIDE, LANGLEY PARK, SUTTON, SURREY. November 12, 1917. (Gy SCA GFN ASyE SS PROFESSOR EDWARD HULL, F.R.S. (WITH A PORTRAIT, PLATE XXXYV.) Born MAy 21, 1829. DIED OCTOBER 18, 1917. By the death of Edward Hull, in the 89th year of his age, another of the links has been broken which connect the geologists of to-day with those of the earlier half of last century. He was born in Antrim, and came of a stock that had been settled in Ireland for at least four generations. Educated at Trinity College, Dublin, he took his degree in Arts there. It was there, also, that he was _ Inspired with a strong bent towards geology by the prelections of Professor Thomas Oldham. That eminent man gave him a letter of recommendation to Sir Henry De la Beche, Director-General of the Geological Survey, who without loss of time found a place for him in 1850 on his staff. From the time when Hull began field-work by running sections in North Wales under J. B. Jukes, he continued for seventeen years to be employed in England, first mapping tracts in Gloucestershire and the upper parts of the Thames Valley, and then in the coal-fields of Cheshire and Lancashire. During the winter months, when the members of the staff, quitting the field, repaired to London for indoor work in the office, Hull gained the good-will of his colleagues by his imperturbable good-nature, which, in sport, they would sometimes tax to its utmost limit. But he seemed never to bear any of them a grudge, taking it all as part of the routine of Survey life. They came to recognize that beneath his foibles of manner there lay a kindly heart, ever ready to respond to kindness. In 1867, on the separation of the Geological Survey of Scotland as a special branch, Hull’s good service was rewarded by his being 554 Obituary—Professor Edward Hull. appointed District Surveyor and second in command on the Scottish branch. Stationed at Glasgow, he was entrusted with the mapping of the Clyde coal-field. But he had not been more than two years in this new sphere when he received further promotion by being appointed to succeed Jukes as Director of the Geological Survey of Ireland—a post which he continued to fill until he retired from official life, after a service of forty years. The Irish Directorship was by no means a bed of roses. The staff included at least one fiery member, who, with characteristic Irish contempt for the ruling power, began opposition before the newly appointed official had set foot in Ireland, demanding that the appointment should be cancelled. When this demand was rejected, he commenced the same system of petty insubordination and opposition which had reduced poor Jukes to despair. Hull, however, as an Irishman, was probably not wholly unaccustomed to such tactics. He never succeeded in permanently silencing the malcontent, and made many an appeal to his chief in Jermyn Street for support. Indeed, no small part of his official correspondence with headquarters consisted in reports of fresh and unexpected devices of opposition. But his equanimity seemed never to be seriously ruffled. No higher testimony to his essential good-nature could be desired than the fact that he bore the perpetual worry. for two and twenty years without losing either his wits or his temper. During his reign in Ireland he had the opportunity of seeing the geology of every part of the island. This wide experience gave him material for the preparation of a convenient new general geological map of the country on the scale of 8 miles to an inch. While discharging his duties in the Survey he also held the Professorship of Geology in the Royal College of Science in Dublin. In 1891 Hull retired from official life. He was then little more than 60 years of age, and still in full possession of health and vigour. He determined to come to London and settle there in the expectation that he might find congenial employment as a practical geologist or geological engineer, especially in connexion with such matters as coal-mining and water-supply, in which he had often been consulted during his life on the Survey. He never allowed his pen to rust. The list of his memoirs, papers, and separate books is a monument of his industry. He was a voluminous writer on English geology from the beginning of his life in the Survey onwards. Some of his early papers are marked by a suggestiveness in the discussion of more or less theoretical questions which gave promise of distinction that was hardly fulfilled in his later work. His best known volume, Zhe Coal-fields of Great Britain, is a useful compendium of the subject of which it treats, and has passed through five editions. Reference should also be made to his contributions to our knowledge of the geology of Palestine. He was sent to that country in 1883 by the Palestine Exploration Society, as leader of an expedition which included the future Lord Kitchener as one of its staff, the object of research being to report on the region of Mount Seir, Sinai, and Western Palestine. In later years he devoted much time to tracing on Admiralty and other charts the Obituary—George O. Crick. | BBB submarine continuations of the river-valleys of Western Europe and Western Africa. In 1910 the retired Professor published a thin autobiographical volume, entitled Reminiscences of a Strenuous Life. His career, like that of many other public servants, was quiet, uneventful, and not unsuccessful. It included sufficient leisure for such work as he chose to undertake, outside the sphere of his official duties, and of this leisure he diligently availed himself in the preparation of his contributions to the scientific literature of the time. Though much of his writing may not be enduring, it must be admitted that he has left his mark on the records of English geology. . Those who knew Edward Hull best will always remember him as a leal-hearted friend, who through a long life maintained the honour of a gentleman and carried with him cheerfulness and good will wherever he went. ALG: Norr.—On June 1, 1914, Professor Hull was one of those friends who wrote and congratulated the Editor on the completion of fifty years of the Gronogican Macaztne, and was indeed one of the four famous geologists, then surviving, who had contributed to the 1864 volume of that journal, viz., the Rev. O. Fisher, M.A., F.G.S.; Sir Archibald Geikie, O.M., K.C.B., P.Pres.R.S., etc.; Professor W. Boyd Dawkins, M.A., D.Sc., F.R.S.; and Professor Hull, M.A., LL.D., F.R.S., etc., Professor Hull himself having during the fifty years made 119 communications to this Magazine. We had pre- pared a complete list of the titles of Hull’s books and papers, amounting in all to over 250. Asa selected series had already been published by Professor Hull at the end of his Reminiscences of a Strenuous Life in 1910, and the full list would have occupied more than ten pages, we could not devote so large a space in this number, and the intention had therefore reluctantly to be abandoned.— Epitor Grot. Mace. GEORGE CHARLES CRICK. BORN OCTOBER 9, 1856. DIED OCTOBER 18, 1917. Born at Bedford on October 9, 1856, the son of Dr. F. W. Crick of that town, George Charles Crick was educated at the Modern School there. Subsequently he passed through a course of studies at the Royal School of Mines, South Kensington, from 1875 to 1881. His career there was noteworthy, for he successively. passed 1st Class in Physics (1875-6), 1st Class in Biology (1876-7), 2nd Class in Chemistry (1877-8), 1st Class in Geology (1878-9), 1st Class in Mechanics, 2nd Class in Mineralogy, 2nd Class in Paleontology (1879-80), and 1st Class in Mechanical Drawing (1880-1), thus winning the Associateship. For some short time he acted as one of the curators to a notorious private collector, but on January 1, 1881, he entered on duty as Clerk and Assistant Secretary to ‘‘H.M. Commission to enquire into Accidents in Mines, ete.’’, of which Sir Warington W. Smyth was 556 Obitwary—George C. Crick. Chairman, and he continued to actin that capacity till the termination of the Commission in 1886. Meantime in November, 1881, he undertook work in a voluntary capacity in the Geological Department of the British Museum (Natural History), and was then employed as a temporary Assistant in 1882; on April 19, 1886, he was taken on the establishment as an Assistant of the Second Class. At the Museum he was given charge of the Fossil Cephalopoda, then much in need of attention, and throwing his whole heart into the work has left it one of the best arranged and indexed collections in the institution. This group was at that time in process of being catalogued by Mr. A. H. Foord, who writes as follows: ‘(I had the happiness of knowing the late Mr. G. C. Crick for many years, as I was intimately associated with him in the Geological Department of the British Museum. Our work running on similar lines we wrote several papers jointly for this Magazine and for the Annals and Magazine of Natural History. Great patience and minute attention to details were conspicuous in all his work, and his researches were therefore highly valued by students of paleontology in the branch which he made his own, viz. the Belemnites and the Ammonites. He will be greatly missed by all his colleagues.” Crick further assisted Foord largely with the first two volumes of the Catalogue of Fossil Cephalopoda in the British Museum, issued in 1888 and 1891, and was joint author with Foord of the third volume (Bactrites and Ammonoidea, pars), published in 1897: whilst he compiled the List of Types and Figured Specimens of Fossil Cephalo- poda in the British Museum (Natural History), which saw the ight in 1898, Sixty-seven papers, including seven written in association with A. H.Foord, and one with R. Bullen Newton, stand to Crick’s credit in various scientific publications. In the course of these, seventy-four new species are described and three new genera founded (_Amphoreopsis, Styracoteuthis, and Belemnocamaz). Thisis quite a moderate number for any student of fossil Cephalopoda, but his inclinations were ever toward the morphological side of his subject, and especially any feature of mechanical interest. This is very evident in his beauti- — fully constructed model of the Ascoceras shell, and of the guard and phragmocone of the Belemnite, as well as in the question of the attachment of the animal to its shell in Nautiloids and Ammonoids. The first instalment of his memoir on this last question, that dealing with the Ammonoidea, was brought before the Linnean Society of London in 1898, and appeared in their Transactions. This important communication was very highly esteemed, and led, in conjunction with his other work, to the award by the Geological Society in 1900 of a moiety of the Barlow-Jameson Fund. The second part of the memoir, that treating of the Nautiloidea, was practically complete at the time of his death, and it is hoped that, with other of his literary remains, this may yet be published. Indeed, it would have appeared before had it not been for the meticulous care he bestowed on all his writings, which led him to withhold them from publication until Obituary—George C. Crick. ee: satisfied that the last possible item of information had been obtained, whilst a contributing cause of delay was to be found in the state of his health. Never robust, he became on more than one occasion so seriously ill that his life was despaired of; still, he made marvellous recovery, and for some years had been so much better that he even participated for a time in Red Cross work. Whilst conscious himself of his precarious condition, he happily had no premonition of his sudden end, and the afternoon before was discussing with Dr. Kitson the geological age of some Ammonites from Nigeria, and making plans for future work. ‘The following morning he passed quietly away at his Wimbledon home, and a few days later was interred at Luton. Modest, quiet, and unassuming, ever ready to assist others, Crick endeared himself to all with whom he came in contact; even one who had not seen much of him writes ‘‘he always seemed a lovable little man”’. As such he will be sincerely mourned, not only by his widow, but by a very wide circle of friends. Crick was elected a Fellow of the Geological Society in 1881; he joined the Geologists’ Association in 1887; was one of the original members of the Malacological Society of London on its foundation in 1898; was elected a Fellow of the Zoological Society in 1896; and of the Royal Geographical Society in 1916. He was also a member of the Bedfordshire Natural History Society, of which his father was one of the founders, and frequently read papers before them. B. B. Woopwarp. LIST OF THE SCIENTIFIC WRITINGS OF G. C. CRICK. 1889. (In association with A. H. Foord.) ‘‘On the Muscular Impressions of Celonautilus cariniformis, J. de C. Sowerby, sp., compared with those of the Recent Nawtilus’’: GHou. MaG., Dec. III, Vol. VI, pp. 494-8, 2 woodcuts. 1890. (In association with A. H. Foord.) ‘*‘On the Muscular Impressions of some Species of Carboniferous and Jurassic Nautiloids compared with those of the Recent Nawtilus’’: Ann. Mag. Nat. Hist., ser. VI, vol. vy, pp. 220-4, 6 text-figs. (In association with A. H. Foord.) ‘‘Descriptions of new and imperfectly defined species of Jurassic Nautili contained in the British Museum (Natural History) ’’: ibid., pp. 265-91, 18 text-figs. (In association with A. H. Foord.) *‘On some new and imperfectly defined species of Jurassic, Cretaceous, and Tertiary Nautili con- tained in the British Museum (Natural History)’’: ibid., pp. 388- 409, 9 text-figs. 1893. (In association with A. H. Foord.) ‘‘On a New Species of Discites (Discites Hibernicus) from the Lower Carboniferous Limestone of Treland’’: Grou. MaG., Dec. III, Vol. X, pp. 251-4, woodcut. 1894. (In association with A. H. Foord.) “‘ On the Identity of Hllipsolites compressus, J. Sowerby, with Ammonites Henslowi, J. Sowerby” : ibid., Dec. IV, Vol. I, pp. 11-17, pl. (In association with A. H. Foord.) ‘‘On the Temnocheilus coronatus, M‘Coy, from the Carboniferous Limestone of Stebden Hill, near Cracoe, Yorkshire ’’: ibid., pp. 295-8, woodcut. ‘©On a Collection of Jurassic Cephalopoda from Western Australia— obtained by Harry Page Woodward, F.G.S., Government Geologist— with Descriptions of the Species’’: ibid., pp. 385-93 and 433-41, Pls. XII and XIII. 558 1895. 1896. 1897. 1898. 1899. 1900. 1901. 1902. 1905. ‘ Obituar ge C. Crick. (Review.) ‘‘ Nanno, a new Cephalopodan type,’? by J. M. Clarke: ibid,, pp. 561-2. “Ona New Species of Prolecanites [P. similis] from the Carboniferous Limestone of Haw Bank Tunnel, Skipton, Yorkshire’’: Trans. Manchester Geol. Soc., vol. xxiii, pp. 80-8, 4 pls. ““Notes on some Fragments of Belemnites from Somaliland ’’: Grou. MAG., Dec. IV, Vol. III, pp. 296-8. “On Goniatites evolutus (Phillips) and Nautilus elongatus (Phillips), ete.’’: ibid., pp. 413-19. ‘On a Specimen of Coccoteuthis hastiformis, Rupp., sp., from the Lithographic Stone, etc.’’: ibid., pp. 439-43, Pl. XIV. ““On the Aperture of a Baculite from the Lower Chalk of Chardstock, Somerset ’’: Proc. Malac. Soc., vol. ii, pp. 77-80, text-figs. ‘On the Pro-ostracum of a Belemnite from the Upper Lias of Alderton, Gloucestershire ’’: ibid., p. 117, pl. ix. ‘“On an example of Acanthotewthis speciosa, Miinster, from the Litho- graphic Stone, Hichstadt, Bavaria’’: GEOL. MaG., Dec. IV, Vol. IV, pp. 1-4, Pl. I and woodcut. ‘*On the Fossil Cephalopoda from Somaliland, collected by Dr. Donaldson Smith ’’: Appendix F in Dr. Donaldson Smith’s Through Unknown African Countries, pp. 426-9. ‘*On an example of Acanthoteuthis Ferussacii, Miinst., from the Litho- graphie Stone of Solenhofen, Bavaria’’: Proc. Malac. Soc., vol. iii, pt. i, pp. 57-60, pl. i, etc. ‘“On the Muscular Attachment of the Animal to its Shell in some Fossil Cephalopoda (Ammonoidea)’’: Trans. Linn. Soc., ser. 11, vol. vii, pt. iv, pp. 71-113, pls. xvii—xx. ‘* Descriptions of new and imperfectly known species of Nautilus, from the Inferior Oolite, preserved in the British Museum (Nat. Hist.) ”’: Proc. Malac. Soce., vol. iii, pt. iii, pp. 117-39, 15 illustrations. ‘On a deformed example of Hoplites twberculatus, Sby., from the Gault of Folkestone’’: GHoL. MaG., Dec. IV, Vol. V, pp. 541-2, text-fig. ‘Note on Ammonites euomphalus, Sharpe’’: ibid., Vol. VI, pp. 251-6, text-figs. ‘“On some new or little-known Goniatites from the Carboniferous Limestone of Ireland’’: Ann. Mag. Nat. Hist., ser. VII, vol. ili, . pp. 429-54, text-figs. ‘‘Notes on the Fossils from the Chilian Andes, collected by Mr. Fitz- gerald’s Expedition’’: Appendix B in E. A. Fitzgerald’s The Highest Andes, pp. 333-7. ‘‘Note on Ammonites calcar, Zieten’’?: GHoL. MAG., Dec. IV, Vol. VI, pp. 554-8, text-figs. “On the Horizon and Locality of Nawtilus truncatus, Sowerby ”’ : ibid., Vol. VII, p. 154. ‘‘Note on Nautilus (Hphippioceras) clitellariwm, Sowerby’’: ibid., . 560. Ne Note on Zieten’s type-specimens of Ammonites polygonius and Amm. discoides’’: ibid., p. 561. ‘*A Chalk Ammonite, probably A. Ramsayanus, Sharpe’’: ibid., Vol. VIII, pp. 251-3. “Note on a Dibranchiate Cephalopod from the London Clay of Sheppey’’: Proc. Malac. Soc., vol. iv, pp. 256-8. ‘On the type-specimen of Belemnoteuthis montefioret, J. Buckman ”’ ibid., vol. v, pp. 13-16, pl. i. Mh WNdditional Note on Ammonites calcar, Zieten’’: GEOL. MAG., Dec. IV. Vol. IX, p. 47. ‘‘Note on the genus 7megoceras, Hyatt’: ibid., pp. 127-8. ‘‘Note on Nautilus robustus, Fcord & Crick’’: ibid., pp. 342-6. ‘‘Note on Dr. J. E. Gray’s type-specimens of Jurassic Ammonites from India”’: Proc. Malac. Soc., vol. v, pp. 285-9. 1904. 1905. 1906. 1907. 1908. 1909. 1910. 1911. 1915. md Obituary— George C. Crick. 559 “On Ammonites robustus (R. Strachey, MS.), H. F. Blanford, from the Himalayas’’: ibid., pp. 290-5, text-fig. ““Notes on some specimens of straight-shelled Nautiloidea, collected by the Rev. Samuel Couling, M.A., Ching Chow fu, Kiachow, North China ’’: GEOL. MAG., Dec. IV, Vol. X, pp. 481-5, Pl. XXII. ““Note on Vestinautilus crassimarginatus, A. H. Foord’’: ibid., pp. 552-5. “Note on Pericyclus fasciculatus, F. M‘Coy, sp.’’: ibid., Dec. V, Vol. I, pp. 27-33. **Notes on the Cephalopoda belonging to the Strachey Collection from the Himalaya’’: ibid., pp. 61-70, 115-24. ‘‘Note on a remarkable Belemnoid from the Chalk of Flamborough Head’’: Proc. Geol. Assoc., vol. xviii, pp. 283-5, figs. “‘Note on Actinocamaz, Miller ; its identity with Atractilites, Link.”’: GEOL. MAG., Dec. V, Vol. I, pp. 407-10. ‘Note on two Cephalopods obtained by Lieut.-Col. Skinner, R.A.M.C.., from the Valley of the Tochi River on the N.W. Frontier of India’’: ibid., pp. 490-3. ‘“ Description. of a Nautiloid, Plewronautilus pulcher, n.sp., from the Carboniferous Rocks of England’’: Proc. Malac. Soc., vol. vi, pp. 15-20, pl. i. ‘“On a new form of Carboniferous Nautiloid (Amphoreopsis pauct- camerata) from the Isle of Man’’: ibid., pp. 134-7, pl. viii. ‘‘On a Dibranchiate Cephalopod, Styracoteuthis orientalis, n.gen. and n.sp., from the Hocene of Arabia’’: ibid., pp. 274-8. **Qn a specimen of Cyrtoceras (Meloceras) apicale [Foord] from the Carboniferous Limestone, Kniveton, Derbyshire’’: GEOL. MAG., Dec. V, Vol. II, pp. 62-5. “On some Fossil Cephalopoda from North Cornwall, collected by Mr. Howard Fox, F.G.S.’’: ibid., pp. 154-60. ‘‘Note on a rare form of Actinocamaz (A. grossouvrei) [Janet] from the Chalk of Yorkshire’’ : Naturalist, pp. 155-8, pl. xvi. ‘‘ Cretaceous Fossils of Natal’?: Third Report Geol. Surv. Natal, pp. 163-250, pls. x—xv. “‘The Cretaceous Rocks of Natal and Zululand and their Cephalopod Fauna ’’: Grou. MaG., Dec. V, Vol. IV, pp. 339-47. ‘‘Note on two rare forms of Actinocamax from the English Upper Chalk ’’: ibid., pp. 389-95. ‘On the Arms of the Belemnite’’: Proc. Malac. Soc., vol. vii, pp. 269-79, pl. xxiii. (In association with R. Bullen Newton.) ‘‘On some Jurassic Mollusca from Arabia’’: Ann. Mag. Nat. Hist., ser. VII, vol. ii, pp. 1-29, Is. i-ili. ue ee on two Cephalopods collected by Dr. A. P. Young on the Tarntaler Képfe, in Tyrol’’?: Grou. Mac., Dec. V, Vol. VI, pp. 443-6, Pl. XXVI. ‘*On Belemnocamax boweri, n.g. et sp.’’: Proe. Geol. Assoc., vol. xxi, pp. 360-5, pl. xxviii. ‘“Note on two Cephalopods from the Chalk of Lincolnshire ’’: GEOL. MaG., Dec. V, Vol. VII, pp..345-8, Pl. XX VII. ‘“Note on the type-specimens of Ammonites cordatus and Ammonites excavatus, J. Sowerby ’’: ibid., pp. 503-5. ‘‘ Snakestones’’?: Naturalist, pp. 145-6. ‘“Wotes on Carboniferous Cephalopoda from the neighbourhood of Exeter’’: Quart. Journ. Geol. Soc., vol. ixvii, pp. 399-413. “Note on Nautilus Mokattamensis, A. H. Foord, from the Eocene of Egypt’’: Proc. Malac. Soc., vol. xi, pp. 286-90, pl. and text-figs. ‘On a Dibranchiate Cephalopod (Plesiotewthis) irom the Lithographic Stone (Lower Kimmeridgian of Hichstaédt, Bavaria)’’: ibid., pp. 313-18, pl. 560 Miscellaneous. 1916. ‘‘Note on a gigantic Cephalopod Mandible’’: Grou. MaG., Dec. VI, Vol. III, pp. 260-4. ‘“Note on the Carboniferous Goniatite Glyphioceras vesiculiferwm, de Koninck, sp.’’: Proc. Malac. Soc., vol. xii, pp. 47-52. “On Ammonitoceras tovilense [n.sp.] from the Lower Greensand (Aptian) of Kent’’: ibid., pp. 118-20, pl. vi. 1917. ‘‘Note on the type-specimen of Crioceratites bowerbankwi, J. de C. Sowerby ’’: ibid., pp. 138-9, pl. vii. ““ Recent Researches on the Belemnite Animal’’: Abstr. Proc. Geol. Soc., Sess. 1916-17, pp. 12-13. MISCHLUANHOUS- Tuer Roya Soctery Mrpats: Awarps For Screntiric ResEARCH.— Of the two Royal Medals to be awarded this year by the President and Council of the Royal Society, the King has approved of one being awarded to Dr. John Aitken, F.R.S., for researches in cloudy condensations, and the other to Dr. Arthur Smith Woodward, F.R.S., F.L.S., V.P.G.S., Keeper of the Department of Geology in the British Museum (Natural History), and one of the Kditors of the GrotoaicaL Magazine, for his researches in Vertebrate Paleontology. We offer him our hearty congratulations on this well-merited honour. For his life and portrait see Grot. Mae. 1915, pp. 1-5, Pl. I. Tue WoopwaRrpIAN Proressor oF GEOLOGY IN THE UNIVERSITY or Campriper.—This Chair, founded by Dr. John Woodward in 1722, and rendered illustrious by Professor Adam Sedgwick, who held it from 1818 till 1872, when he was succeeded so happily by one of his former pupils, Professor T. McKenny Hughes (1873- 1917), is now followed by another well-known Cambridge geologist, John Edward Marr, Sc.D., F.R.S., who for thirty years or more has fulfilled the important post. of University Lecturer in Geology and College Lecturer in St. John’s. This election by the Senate has been received with great satisfaction not only by University men but by geologists at large, amongst whom Professor Marr is well known and universally esteemed. A sketch of his life and work, with a portrait, as an ‘‘ Eminent Living Geologist”’, appeared in this journal in July, 1916 (pp. 289-95, Pl. XI). Lennam Bens anp MiocenE Rock From tHE North SEA.— Mr. R. B. Newton, who recently described these interesting deposits in the Journal of Conchology, xv, 1916-17 (Guou. Mae., June, July, 1917), and Quart. Journ. Geol. Soc., Ixxii, 1916, respectively, has now arranged a temporary exhibition series of the two faunas. Those interested can see these specimens in the Gallery of Fossil Mollusea at the British Museum (Natural History), on request, during the next few months. INDEX. CLISINA and Aclisoides, 287. Alaria Suteri, sp. nov., C. T. Trechmann, 304. Albite-Granophyre and Quartz-Por- phyry, Carrock Fell, 403. Alexandrian Rock, N.E. Illinois, 135. Algal Development in Woolhope Lime- stone, 331. Alkaline Rocks, S.W. Afriea, S. J. Shand, 235. Ambrym Island, Volcanic Eruption (1913), 496, 529 ; Eruption of, 1894, 531. Amethyst, Colour of, 521. Ammonite Septum, Development and Morphology, 231. Analcite and Analcitization, 287. Aplustrum (?) Selwynensis, sp. nov., C. T. Trechmann, 337. Apractocleidus teretepes, 29. Arcas of Atlantic Slope, 224. Atlantis, 473. Auchenia lama, 516. Australia, Geology of Northern Terri- tory, 134. South, 329. —— West, 427, 428. AILEY, E. B., Ben Nevis and Glen Coe, 30. Baker, H. A., London Basin and Adjoining Areas, 91; Charnian Movement, EH. Kent, 398; Uncon- formity between Cretaceous and Older Rocks in East Kent, 542. Ball, J., West-Central Sinai, 80. Ball, L. C., Wolfram Mines, N. Queensland, 524. Balsillie, D., Geology of Kinkill Ness, Fife, 525. “Banket,’’ The, 285. Barrell, J., Origin of Tertiary Ape Man, 424. Base of the Camerate Monocyclic Crinoids, F. A. Bather, 206. Bather, F. A., Base of the Camerate Monocyclic Crinoids, 206; Salt Weathering and Worm Borings, 526. ‘* Batholiths’’ of Haliburton, Ban- croft Area, 286. _ Becker, G. F.,and Day, A. L., Linear Force of Growing Crystals, 225. Bedfordshire, Handbook, 518. DECADE VI.—VOL. IV.—NO. XII. Bell, A., Sub-Crag Boxstones, 407. Bell, Robert, Obituary of, 334. Ben Nevis and Glen Coe, Geology of, 30. Berry, E. W., Flora of Alum Bluff Formation, 226; Flora of Calvert Formation, 284. Bird, Giant Eocene, 469. Blatchford, T., Mineral Resources, Yilgarn Goldfield, 428. Boxstones,Sub-Crag, Hast Anglia, 407. Brachiopod, new, Poikilosakos, 212. Bremner, A., ‘‘ Kettle-holes,’’ Aber- deen, 142. Bretz, J. He: Oregon, 524. British Association Proceedings, 371, 384. Brown, C. Barrington, Obituary of, 235. Brown, J. Coggin, Catalogue of Meteorites, Calcutta. Museum, 219. Brydone, R. M., Chalk Polyzoa, 50, 145, 492; Chalk Zone of Holaster planus, 245. Bryozoa of Paris Basin, 283. South-West France, 282. Primitive works on, 283. Buccal Armature of Conulus albo- galerus, 433. Buckman, S.S., Jurassic Chronology, 332. Bunter Pebble-Beds of Notts, 288. Burton, R. C., Obituary of, 96. Burton, T. H., Bunter Pebble-Beds, 288. s Bury, H., Paleoliths of Farnham, 29. Butler, G. M., Handbook of Minerals, 378. Satsop Formation, ALCITH in Silicified Wood, 476. Caledonian Thrust Movement, Norway, 130. . Calvert Formation, Flora of, 284. Cambrian Geology and Paleontology, 25. Camerate Monocyclic Crinoids, Base of, 206. Canavari,. Mario, Dentition of Pty- chodus, 224. Cantrill, T. C., Presteign, 481. Canu, F., Tertiary Cheilostome Bryozoa, 282-4. Coal-boring at 36 562 Carbonate Springs, Regna-Verin, 475. Carboniferous Limestone, Leicester- shire Coalfield, 228. S. Wales Coalfield, 229. Carnarvonshire, Geology of part of, 12, 75. Cenomanian and Turonian Cheilo- stome Polyzoa, 256. Chalk Polyzoa, 50, 145, 492. Chalk Zone of Holaster planus, Isle of Wight, 245. Chamberlin, T. C., Origin of Earth, 279. Chambers, C. G., Bedfordshire, 518. Characesw, from the Lower Headon Beds, 42. Charnian Movement, East Kent, 398. Chrysostoma Selwynensis, sp. nov., C. T. Trechmann, 299. Cil-y-Coed to St. Annes, Llanllyfni, Geology of, 12, 75. Cladoselache clarkz, Upper Devonian, Ohio, U.S.A., 542. Clapp, F. G., Petroleum and Gas Resources, Canada, 36. Clark, W. B., Obituary of, 432. Classification of Igneous Rocks, A. Holmes, 115. Clyde Area, Tertiary Dykes of, 305, 350. Coal-boring at Presteign, shire, 481, 552. Coalfield, Central Scotland, 426, 475. Cockerell, T. W. A., New Tertiary Insects, 329. Cole, G. A. J.. Rhythmic Deposition of Flint, 64. Conacher, H. R. J., Oil-shales and Torbanites, 93. Conchological Features of Lenham Sandstone, Kent, 259, 320. Conulus albogqlerus, Buccal Arma- ture of, 433. Coolgardie and Kast Coolgardie, 428. Copper Sulphide, Secondary Reactions involved in Enrichment, 222. Coprolites, Spiral, not Saurian but Sharks, 541. Coral Octotremacis, 9. Corals, Rugose, 108. Correlation and Chronology in Geology, 285. Cretaceous Brachiopoda and Mollusca, West Africa, 132. Crabs from 8. Dakota, 225. —— Gasteropoda, 471. Mollusea, New Zealand, 294,337. Polyzoa, New, 492. —— Unconformity in Hast Kent with Older Rocks, 542. Radnor- Index. Cribrilina Bramfordensis, sp. nov., Brydone, 493. galanthis, nom. nov., Brydone, repleta, nom. noy., Brydone, 495. Seafordensis, sp. nov., 51. ~ —— T-formis, sp.nov., Brydone, 493. transita, sp. nov., Brydone, 492. tumuliformis, sp. nov., 51. Crick, G. C., Obituary of, 528, 555. Crystals and Crystal Forces, 223. Linear Force in Growing, 223. AVISON, C., Eruption of Sakura- jima (1914), 520. Day, T. C., Igneous Intrusive near Maebie Hill, 93. Dean, B., Bibliography of Fishes, 428. Deeley, R. M., Disturbed Gravels, 157. Detrital Andalusite i in Cretaceous and Eocene, 135. Diatryma, Skeleton of Giant Bird, 469. Diplodocus Carnegiet, suggested re- construction, 356. Discoides cylindricus, Girdle of, 389. Disturbed Gravels, R. M. Deeley, 157. Dithyrocaris tricornis and D. testu- dinea, Horizon of, 269. Dixey, F., and Sibly, T. F., Car- boniferous, S. Wales Coalfield, 229. Douvillé, H., Cretaceous and Hocene of Tibet, 429. Drysdale, C. W., Ore Deposits, British Columbia, 39. Dunstones of Plymouth, 282. Dupare et Grosset, Platiniferous De- posits of Spain and Russia, 176. et Tikanowitch, Pa of the Urals, 178. Perignathic ARLY Man, 1. Earth, Origin of, 279. Earthquake in Marsica, Italy, 474. East Kent, Charnian "Movement in, 398. Unconformity between Greiner and Older Rocks in, 542. Easter Island, 138. Eastman, ©. R., Fossil Fishes in U.S. Nat. Mus., 223. Echinoidea Holectypoida, 160, 196, 249, 342, 389, 433. Economic Geology, 181. Ellis, David, Jurassic Fossil Fungus, 102. Eminent Living Geologists: Alfred Harker, 289; Osborne, Professor Henry Fairfield, 193. Index. Hoanthropus, 1. Kocene Bird, Gigantic, 469. Htchegoin Pliocene, Mid-California, 328. fia. QO. C., Meteorites, 86 Fauna of Fernando, Los Angeles, 135. Federated Malay States, 144, 447, 503. Fishes, Bibliography of, 428. Fissure Eruptions, 534. Flett, J. S., Submarine Contours, 233; Swiney Geological Lectures, 514. Flint, Rhythmic Deposition of, 64. Floating Fen of Danube Delta, 133. Flora of Alum Bluff Formation, 226. Fox Hill Sandstones, 225. Foraminiferal Limestone, New Guinea, 143. Fossil Beetles, Florissant, Colorado, 379. Fishes in U.S. Nat. Mus., 223. —— Insects, American, 135. Plants, Text-book, 516. Foye, W. G., Magnetite Ores, Ontario, 286; Batholiths of Haliburton, Ontario, 286. Frater, M., Voleanic Eruption (1913), Ambrym Island, 496. Fungus, Jurassic Fossil, 102. ARDINER, C. I., Silurian Inlier of Usk, 472. Garwood, KE. J., Algal Development in Woolhope Limestone, 331. ’ Genotypes of some Polyzoan Genera, 169. Geological Factors in War, 284. Map, City of Dublin Area, 240. Maps as a Record of Geological Advance, 329, 380. Society, Edinburgh, 41, 93, 142, 233, 525. — —— Glasgow, 93. —— ——~ J,jondon, 42, 43, 89, 91,138, 140, 182, 185, 227, 228, 229, 231, 287, 330, 331, 380. —— Survey, Great Britain, Memoirs, 30, 180. Scotland, Memoirs, 426,475. ==: South Australia, 329. —— —— United States, 34, 40. —— —— WestAustralia Reports,427, 428. Geology, Textbook of, C. Schuchert,84. at the Seat of War, 68. Liverpool, 44, 137,234, 432. 563 Geology of Chitral, Gilgit, and Pamirs, 175. of the Urals, 178. Gilligan, A., Millstone Grit, York- shire, 137. Glacial Controversy, New Zealand, 241. Glastonbury Lake- Village, 425. Glossopteris Beds, Queensland, 135. Goldschmidt, V. M., Caledonian Thrust Movements, Norway, 130. . Grand’ Eury, F. C., Obituary of, 528, Graptolites, Peru, 92. Gravels, Disturbed, 157. Green, Upfield, Obituary of, 336. Greenwood, H. W., Secondary Rutile, Millstone Grit, 234. Gregory, J. W., On the Coral . Octo- tremacis, 9; Professor Loewinson- Lessing, 95; Geological Factors in War, 284; Volcanic Eruptions, Ambrym, New Hebrides, 529. |G Ree Oe es gen.nov., W.D. Lang, 256. arcuata, n.sp., W. D. Lang, 257. Harmeri,n.sp., W.D. Lang, 257. Harker, A., Eminent Living Geologists, 289. Harris, G. D., The Atlantic Slope Arcas, 224. Harwood, H. F., Picrite from Mozam- bique, 150. Hawkes, L., Rock Stream in Iceland, 97; Post-Glacial Uplifts in Norway, 174. Hawkins, H. L.; Morphology of Echinoidea and Holectypoida, etc., 160, 196, 249, 342, 389, 433; Perignathic Girdle of Pygasteride, 342; Discoides cylindricus, 389 ; Conulus albogalerus, 433. Hayden, H. H., Geology of Chitral, Gilgit, and Pamirs, 175. Hebrides, New, Volcanic Eruption, Ambrym, in 1913-14, 529; Earlier History to 1894, 530; Eruption of 1894, 531. Holaster planus, Isle of Wight, 245. Holectypus, Apical System of, 249. Holland’s reconstruction of Dzplo- docus criticized, 356. Holmes, A., Classification of Igneous Rocks, 115; Picrite from Mozam- bique, 150; Pre-Cambrian of Mozambique, 380; Albite-Grano- phyre and Quartz - Porphyry, Carrock Fell, 403. Hooley, R. W., Integument of Dino- saurs, 145. : 564 Hopkinson, J., Address to British Association Conference of Delegates, 371. Hughes, E. W., Geology of N.W. Car- narvonshire, 12, 75. Hughes, I’. McKenny, Obituary of, 334. Hull, Professor E., Obituary of, 528, 553. Hume, W. F., Oilfields of Egypt, 5, 315. Hutchinson, H. N., Reconstruction of Diplodocus Carnegier, 356. CELAND, East, A Rock Stream in, ie Ichthyosaurian Coprolites not Spiral, 540. Igneous Intrusive Phenomena, Macbie Hill, 93. Igneous Rocks, Classification of, 115. Iguanodont Dinosaurs, Integument of, 148. Illing, V. C., on Dr. Walcott’s Cam- brian Geology, 25. Illinois, Fossil Invertebrates, 132. Integument Iguanodont, R. W. Hooley, 148. Invertebrate Fauna, Oligocene, Georgia, 477. EFFREYS, H., Compression of Karth’s Crust in Cooling, 87; Distributions of Meteoric Bodies in Solar System, 222. Johnson, R. H., Oil and Gas Pro- duction, 38. i Johnston, W. A., Late Pleistocene Oscillations, Ottawa, 32. Jurassic Chronology, Correlation of, 332. Fossil Fungus, 102. 335. Kent, Hast, Charnian Movement in, 298; Unconformity between Cre- taceous and Older Rocks in, 542. Kettle-holes, Aberdeen, 142. Kinkell Ness, Fifeshire, 525. Knowlton, F. H., Flora of Fox Hill Sandstones, 225. i ENNEDY, H. T., Obituary of, ANG, W. D., Genotypes of Poly- zoan Genera, 169; Cenomanian and Turonian Cheilostome Polyzoa, 256. Lapworth, C., Graptolites from Peru, 92. Index. Late Pleistocene Oscillations, Ottawa Valley, 32. Leeds, Alfred N., Obituary of, 478. Lenham Sandstone, Conchological Features of, 259, 320; Lenham Fossils, Temporary Exhibition of, 560. Lies, E.G., Allen, E. T., and Merwin, H. H., Copper Sulphide Enrich- ment, 222. Liverpool Geological Society, 44, 137. University Geological Chair, 432. Loewinson - Lessing, Volcanoes of Central Caucasus, 95. London Basin and Adjoining Areas, 91. Geological Society, 42, 43, 89, 91, 138, 140, 182, 185, 227, 228, 229, 231, 287, 330, 331, 380. Longstaff, Aclisina and Aclisoides, 287. Lower Carboniferous Flora at Gullane, 28. Lower Devonian F'auna, United States, 179. ACNAIR, P., Horizon of Dithyro- caris, 269. Magnesite Deposits, Quebec, 522. Maitai Series, New Zealand, 53. Mammalian Bones, London District, 422. Man, Geological Theory of Origin, 424, Mancini, E., Earthquake in Marsica, 474. Marbles, British and Foreign, 328. Marr, Dr. J. E., appointed to Chair of Geology, Cambridge, 560. Matthew, W.D., Skeleton of Diatryma, 469... Membranipora bitubularis, sp. noy., 50. crateroides, sp. noy., 49. - —— Gabina, sp. noy., Brydone, 494. subcastrum, sp. noy., Brydone, 494. teniata, sp. nov., 50. Merrill, G. P., Cookeville and Whit- field Meteoric Irons, 221. Mesodon macropterus, 386. Meteoric Bodies, Distribution in Solar System, 222. and other Rocks, etc., Western Australia, 327. Meteorites, Catalogue from Calcutta Museum, 219. Collection in United States National Museum, 220. - Tron, Cookeville, Whitfield, 221. Index. Meteorites, New, 478. — Structure and Composition, 86. Millstone Grit, Yorkshire, 137. Mineral Production of Canada, 182. Resources, British Empire, 514. United States, 89. Yilgarn and Southern Cross, 428. ’ Mineralogical Society, 141, 232, 431. Minerals, Handbook of, 378. Mollusks, Choctawhatchee Marl, 477. Molybdenum, Natal, 475. Morphology or Hchinoidea Holecty- poida, 160, 196, 249, 342, 389, 433. Mozambique, Picrite from, 150. Murdoch, J., Opaque Minerals, 425. EHRITOPSIS(?)Speighti, sp.nov., C. T. Trechmann, 300. New Zealand, Age of Maitai Series, aon Cretaceous Mollusca, 294, 337. Glacial Controversy, 241. Newton, R.B., Cretaceous Brachiopoda and Mollusca, W. Africa, 132; Conchology of Lenham Sandstones, Kent, 259, 320; Exhibition of Lenham Fossils, 560. Nomland, J. O., Htchegoin Pliocene, California, 328. BITUARY Notices: Bell, Dr. B., 334; Brown, C. Barrington, 235, 241; Burton, R. C., 96; Clark, W.B., 432; Crick, G. C., 528, 555 ; Grand’EHury, F. C., 528; Green, Upfield, 336; Hughes, T. McKenny, 334; Hull, Edward, 528, 553; Kennedy, H. T., 335 ; Leeds, A.N., 478; Reid, Clement, 47; Swain, Ernest, 95; Tiddeman, Richard Hill, 238; Tylor, Sir EB. B., 96; Woodward, H. P., 239. Octotremacis, Structure, and Age, 9. Oil and Gas Production, 38. Oilfields of Egypt, 5, 315. Oil-shales and Torbanites, 93. Opaque Minerals, Microscopical De- termination, 425. Ore Deposits, Rossland, Columbia, 39. Oswald, Felix, The Nimrud Crater, Turkish Armenia, 550. Affinities, British AHANG Volcanic Series, Federated Malay States, 447, 503. Paleocene Bat, 516. Palsoliths of Farnham, 29. Paleontographical Society, 226. 565 Pallis, Marietta, Floating Fen of Danube Delta, 133. Parsons, L.-M., Carboniferous Lime- stone, Leicestershire Coal-field, 228. Perignathic Girdle of Pygasteride, 342. Petroleum and Natural Gas Resources, Canada, 36. Picrite from Mozambique, Holmes and Harwood, 150. Piltdown Gravel, 227, 480. Platiniferous Deposits of Spain and Russia, 176. Plectrodus, Jaw of, 74. Pliocene Cave, Doves Hole, 480. Poikilosakos, gen. et sp. noy., 212. Polymorpiites, Genus, 442. Polyzoa, New Chalk, 50, 145, 492. Polyzoan Genera, Genotypes of, 169. Post-EKocene and Post-Miocene, in Oilfields, Egypt, 5. Post-Glacial Uplifts in Norway, 174, 235. Pre-Cambrian and Rocks of Mozam- bique, 380. Presteign, Radnorshire, Coal-boring at, 481 ; Coal in Silurian at, 552. Ptychodus, Dentition of, 224. Pugnellus Marshalli, sp. noy., C. T. Trechmann, 302. Wawarensis, sp. nov., C. T. Trechmann, 303. Pyenodont Fishes, 385. Pygasteride, Perignathic Girdle of 342. UARTZ-PORPHYRY and Albite- Granophyre, Carrock Fell, 403. ADIOACTIVITY and Mountain Building, 87. Rathbun, Mary J., Cretaceous Crabs from Dakota, 225. Reid, Clement, Characer, Lower Headon Beds, 42; Obituary of, 47. Rhode Island Coal, 40. Rhythmic Deposition of Flint, 64. Rock Stream in East Iceland, 97. Royal Society, London, 40, 550; Award of Royal Medals, 550. Royal Society Club, 476. Rugby School Natural History Society, 329: Rugose Corals, 108. AKURA-JIMA Eruption (1914), 520. Salt-weathering and supposed Worm- borings, 526. Samoa Earthquake and Tidal Wave, 432. Satsop Formation, Oregon, 524. 566 Schuchert, C., Textbook of Geology, 84; Correlation and Chronology: in Geology, 285. Scott, Alexander, Primary Analcite, 287. Scouler, Dr. John, Dithyrocaris tri- cornis, Horizon of, 269. Secondary Rutile Millstone Grit, 234. Sederholm, J. J., Synantetic Minerals, 285. Seward, A. C., Fossil Plants, 516. Sharks’ Coprolites spirally formed, 541. Shells of Holderness Basement Clays, 477. Sheppard, T., British Geological Maps, 329, 380. Silurian Inlier of Usk, 472. Simpson, HE. 8., W. Australian Rocks and Meteorites, 327. Sinai, West-Central, 80. Smellie, W. R., Apractocleidus tere- tepes, 29. Smith, William, and his Maps, 380. South African Geology, 326. South Australia, Annual Report of Government Geologist, 329. —— Mining Operations, 523. Spilitie Facies, Lower Carboniferous Lava-flow, Derbyshire, 184. Spirifer, Silurian, Maine, 135. Stopes, M. C., Mesozoic Cycads, 89. Strahan, A., Geology at Seat of War, 68. Sub-Crag, ‘‘ Boxstones,’’ East Anglia, 407. Submarine Contours, Orkney Islands, 233. Swain, E., Obituary of, 95. Swiney Lectures, Geology, 514. Swinnerton, Professor H. H., Develop- ment and Morphology of Ammonite Septum, 231. Synantetic Minerals, 285. AYLOR, W., New Locality for Triassic Reptiles, 41. Termier, P., Atlantis, 473. Tertiary Cheilostome Bryozoa, Ameri- can, 282. Dykes of the Clyde Area, 305, 350. Insects, New, 329. Tibetan Paleontology, 429. Tiddeman, R. H., Obituary of, 238. Titaniferous Magnetite Ores, Ontario, 286. Trechmann, C. T., Zealand, 53; Maitai Series, New Glacial Controversy, Index. New Zealand, 241; Cretaceous Mollusca, New Zealand, 294, 337. Trench Geology, E. W. H., 431. Trias of New Zealand, 182. Triassic Crinoids from New Zealand, 3, 184. Triassic Reptiles, New Locality, 41. Trueman, A. E., Genus Polymor- phites, 442. Tungsten Deposits, Rhodesia, 374. Turonian Cheilostome Polyzoa, 256. Tylopora, gen. nov., W. D. Lang, 257. lorea, sp. nov., W. D. Lang, 258. rowet, sp. noy., W. D. Lang, 258. Tylor, Sir HE. B., Obituary of, 96. Tyrrell, G. W., Tertiary Dykes of the Clyde Area, 305, 350. Essex Vale, NCONFORMITY between Cre- taceous and Older Rocks in East Kent, 542. United States Survey, 34, 40. Upper Silurian Fish, Plectrodus, 74. ENTS at Stromboli, 519. Voleanic Eruption (1913-14), Ambrym Island, 496, 529. Necks in North-West Ayrshire, 4]. —— Series, 503. Voleano, the Nimrud, on Lake Van, Armenia, 550. Pahang, F.M.S., 447, ADE, B., Cretaceous Gastero- poda, 471. Wagner, P. A., South African Geology, 326. Walcott, C. D., Cambrian Geology and Palwontology, 25. War, Geology at Seat of, 68. ; Washington, H.S., VentsatStromboli, 519. Watson, D. M. S., Poitbilosanas, a new Brachiopod from Texas, 212; Structure, Evolution, and Origin of the Amphibia: the Rachitomi and Stereospondyli, 550. Watson, J., British and Foreign Marbles, 328. Watson, T. L., Colour of Amethyst, 521. Watts, W. W., Coal in the Silurian at Presteign, 552. Wellington, New Zealand, Phil. Soc., 46. West-Central Sinai, Geology of, 80. ! Index. Wherry, HE. T., Calcite in Silicified Wood, 476. Wickham, H. F., Fossil Beetles, Colorado, 379. Willbourn, E. 8., Pahang Volcanic Series, 447, 503. Williams, H. §., Lower Devonian Fauna, United States, 179. Wilson, G. V., Volcanic Necks, North- West Ayrshire, 41. Wilson, M. H., Magnesite Deposits, Quebec, 522. Wolfram Mines, North Queensland, 524. , Woodward, Arthur Smith, Award of Royal Society Gold Medal to, 560; Early Man, 1; Jaw of Plectrodus, 74; Piltdown Gravel, Second Skull of Hoanthropus, 227; Pycnodont Fishes, 385; Mammalian Bones, London, 422; So-called Coprolites of Ichthyosaurians and Labyrintho- donts, 540; Hybodus, Acrodus, 567 Lias, Lyme, etc., 541; Clado selache, Devonian, Ohio, 542. Woodward, H. P., Obituary of, 239. Woodwardian Chair of Geology in Cambridge given to Dr. J. H. Marr, F.R.S., 560. Worth, R. H., Dunstones of Plymouth, 282. Wright, F. E., Crystals and Crystal Force, 223. Wynne, HK. Hughes, Cil-y-Coed, 12, 75. AKOVLEYV, N. W., Rugose Corals, 108. Young, R. B., The Banket, 285. EKALLEY, A. HE. V., Tungsten - Deposits, Rhodesia, 374. Zincand Lead Deposits, United States, 181. Zoological Record, 380. Zoological Society, London, 41, 288. Stephen Austin and Sons, Ltd., Printers, Hertford. Cambridge Gniversity Press | Agricultural Geology. By R. H. RASTALL, M.A., late Fellow of Christ’s College and Demonstrator of Geology in the University of Cambridge. With 51 illustrations. Demy 8vo. 10s 6d net. Cambridge Geological Series. “Mr. Rastall very clearly defines the successive geological systems and their characteristics as” bearing on the cultivable soil of to-day, . . . and the interest of the book is increased by geological maps, sections, and diagrams of stratigraphical geology.’’—Cowntry Life : The Geology of the Lake District and the Scenery as influenced by Geological Structure. By J. E. MARR, Sc.D., F.R.S., Fellow of St John’s College, Cambridge. With a map, frontispiece, and 51 illustrations. Demy 8vo. 12s net. d British and Foreign Marbles and other Ornamental Stones. A Deseriptive Catalogue of the Specimens in the Sedgwick Museum, | Cambridge. By JOHN WATSON, Hon. M.A. (Cantab.). 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