IDictorfa Ibistot^ of the (Counties of JEnglanb EDITED BY H. ARTHUR DOUBLEDAY A HISTORY OF HERTFORDSHIRE VOLUME I A HISTORY OF THE COUNTY OF HERTFORD IN FOUR VOLUMES EDITED BY WILLIAM PAGE, F.S.A. THE VICTORIA HISTORY OF THE COUNTIES OF ENGLAND : •"% HERTFORDSHIRE , V WESTMINSTER ARCHIBALD CONSTABLE AND COMPANY LIMITED This History is issued to Subscribers only By Archibald Constable &f Company Limited and printed by Butler y Tanner of Frame and London INSCRIBED TO THE MEMORY OF HER LATE MAJESTY QJLJEEN VICTORIA WHO IN HER LIFETIME GRACIOUSLY GAVE THE TITLE TO AND ACCEPTED THE DEDICATION OF THIS HISTORY THE ADVISORY COUNCIL OF THE VICTORIA HISTORY His GRACE THE DUKE OF DEVONSHIRE, K.G. SIR HENRY MAXWELL-LYTE, K.C.B., M.A., F.S.A., Chancellor of the University of Cambridge ETC. His GRACE THE DUKE OF RUTLAND, K.G. Keeper *f tbe Public Records His GRACE THE DUKE OF PORTLAND, K.G. CoL- SlR J- FARQUHARSON, K.C.B. His GRACE THE DUKE OF ARGYLL, K.T. SIR Jos. HOOKER, G.C.S.I., M.D., D.C.L., F.R.S., THE MOST HON. THE MARQUESS OF SALISBURY, K.G. SIR ARCHIBALD GEIKIE, LL.D., F.R.S., ETC. Chancellor of the Unt-versity of Oxford Rgv j CHARL£S Cox> LL-D., F-S.A., ETC. THE RT. HON. THE EARL OF ROSEBERY, K.G., £ T LIONEL CUST, ESQ., M.A., F.S.A., ETC. Director of the National Portrait Gallery THE RT. HON. THE EARL OF COVENTRY President of the Royal Agricultural Society DR. ALBERT L. G. GtJNTHER, F.R.S. _ _ T m » r T-* President of the Linnean Society THE RT. HON. THE VISCOUNT DILLON President of the Society of Antiquaries CoL. DuNCAN A. JOHNSTON Director General of the Ordnance Survey THE RT. HON. THE LORD ACTON Regius Professor of Modern History, Cambridge PROF. E. RAY LANKESTER, M.A., F.R.S., ETC. rri n TT «T» T T Director of the Nat. Hist. Museum. South Kensington THE RT. HON. THE LORD LISTER President of the Royal Society REGINALD L. PooLE, ESQ., M.A. SlR FREDERICK POLLOCK, BART., LL.D., F.S.A., University Lecturer in Diflomatic, Oxford ETC. F. YORK POWELL, ESQ., M.A., F.S.A., ETC. Corpus Professor of Jurisprudence, Oxford Regius Professor of Modern History, Oxford SIR EDWARD MAUNDE THOMPSON, K.C.B., D.C.L., i HORACE ROUND, ESQ., M.A. LL.D., F.S.A., ETC. „, Director of the British Museum WALTER KYE, tsQ. SIR CLEMENTS R. MARKHAM, K.C.B., F.R.S., F.S.A. W. H. ST. JOHN HOPE, ESQ., M.A. President of the Royal Geographical Society Assistant Secretary of the Society of Antiquaries General Editor — H. ARTHUR DOUBLEDAV GENERAL ADVERTISEMENT THE VICTORIA HISTORY of the Counties of England is a National Survey showing the condition of the country at the present day, and tracing the domestic history of the English Counties back to the earliest times. Rich as every County of England is in materials for local history, there has hitherto been no attempt made to bring all these materials together into a coherent form. There are, indeed, histories of English Counties ; but many of them — and these the best — are exceed- ingly rare and costly ; others are very imperfect ; all are out of date. THE VICTORIA HISTORY will trace, county by county, the story of England's growth from its prehistoric condition, through the barbarous age, the settlement of alien peoples, and the gradual welding of many races into a nation which is now the greatest on the globe. All the phases of ecclesiastical history ; the changes in land tenure ; the records of historic and local families ; the history of the social life and sports of the villages and towns ; the develop- ment of art, science, manufactures and industries — all these factors, which tell of the progress of England from primitive beginnings to large and successful empire, will find a place in the work and their treatment be entrusted to those who have made a special study of them. Many archaeological, historical and other Societies are assisting in the compilation of this work, and the editor also has the advantage of the active and cordial co-operation of the National Trust, which is doing so much for the preservation of places of historic interest and natural beauty throughout the country. The names of the distinguished men who have joined the Advisory Council are a I vii b guarantee that the work will represent the results of the latest discoveries in every department of research. It will be observed that among them are representatives of science ; for the whole trend of modern thought, as influenced by the theory of evolution, favours the intelli- gent study of the past and of the social, institutional and political developments 01 national life. As these histories are the first in which this object has been kept in view, and modern principles applied, it is hoped that they will form a work of reference no less indispensable to the student than welcome to the man of culture. Family History will, both in the Histories and in the supplemental volumes of chart pedigrees, be dealt with by genealogical experts and in the modern spirit. Every effort will be made to secure accuracy of statement, and to avoid the insertion of those legendary pedigrees which have in the past brought discredit on the whole subject. It has been pointed out by the late Bishop of Oxford, a great master of historical research, that ' the expansion and extension of genealogical study is a very remarkable feature of our own times,' that ' it is an increasing pursuit both in America and England,' and that it can render the historian useful service. Heraldry will also in this Series occupy a prominent position, and the splendours of the coat-armour borne in the Middle Ages will be illustrated in colours on a scale that has never been attempted before. The general plan of Contents, and the names of the Sectional Editors (who will co-operate with local workers in every case) are as follows : — Natural History. Edited by AUBYN B. R. TREVOR-BATTYE, M.A., F.L.S., etc. Geology. By CLEMENT REID, F.R.S., HORACE B. WOODWARD, F.R.S., and othert Palaeontology. Edited by R. L. LYDEKKER, F.R.S., etc. ' Contributions by G. A. BOULENGER, F.R.S., F. O. PICKARD-CAMBRIDGE, M.A., H. N. DIXON, F.L.S., Flora Fauna G. C. DRUCE, M.A., F.L.S., WALTER GARSTANG, M.A., F.L.S., HERBERT Goss, F.L.S., F.E.S., R. I. POCOCK, REV. T.R. R. STEBBING, M.A., F.R.S., etc., B. B. WOODWARD, F.G.S., F.R.M.S., etc., and other Specialists Prehistoric Remains. Edited by W. BOYD DAWKINS, D.Sc., F.R.S., F.S.A. Roman Remains. Edited by F. HAVERFIELD, M.A., F.S.A. Anglo-Saxon Remains. Edited by C. HERCULES READ, F.S.A., and REGINALD A. SMITH, B.A. Ethnography. Edited by G. LAURENCE GOMME, F.S.A. Dialect. Edited by JOSEPH WRIGHT, M.A., Ph.D. Place Names "\ Folklore V Contributed by Various Authorities Physical Types J Domesday Book and other kindred Records. Edited by J. HORACE ROUND, M.A. Architecture. By Various Authorities. The Sections on the Cathedrals and Monastic Remains Edited by W. H. ST. JOHN HOPE, M.A. Ecclesiastical History. Edited by R. L. POOLE, M.A. Political History. Edited by W. H. STEVENSON, M.A., J. HORACE ROUND, M.A., PROF. T. F. TOUT, M.A. JAMES TAIT, M.A., and C. H. FIRTH, M.A. History of Schools. Edited by A. F. LEACH, M.A., F.S.A. Maritime History of Coast Counties. Edited by J. K. LAUGHTON, M.A. Topographical Accounts of Parishes and Manors. By Various Authorities History of the Feudal Baronage. Edited by J. HORACE ROUND, M.A., and OSWALD BARRON, F.S.A. Family History and Heraldry. Edited by OSWALD BARRON, F.S.A. Agriculture. Edited by SIR ERNEST CLARKE, M.A., Sec. to the Royal Agricultural Society Forestry. Edited by JOHN NISBET, D.Orc. Industries, Arts and Manufactures "j Social and Economic History !• By Various Authorities Persons Eminent in Art, Literature, Science J Ancient and Modern Sport. Edited by the DUKE OF BEAUFORT Hunting ~\ Shooting V By Various Authorities Fishing, etc. J Cricket. Edited by HOME GORDON Football. Edited by C. W. ALCOCK Bibliographies Indexes Names of the Subscribers viii With a view to securing the best advice with regard to the searching of records, the Editor has secured the services of the following committee of experts : — RECORDS COMMITTEE SIR EDWARD MAUNDE THOMPSON, K.C.B. WM. PAGE, F.S.A. SIR HENRY MAXWELL-LYTE, K.C.B. J. HORACE ROUND, M.A. W. J. HARDY, F.S.A. S. R. SCARGILL-BIRD, F.S.A. F. MADAN, M.A. W. H. STEVENSON, M.A. F. MAITLAND, M.A., F.S.A. G. F. WARNER, M.A., F.S.A. ILLUSTRATIONS Among the many thousands of subjects illustrated will be castles, cathedrals and churches, mansions and manor houses, moot halls and market halls, family portraits, etc. Particular attention will be given to the beautiful and quaint examples of architecture which, through decay or from other causes, are in danger of disappearing. The best examples of church brasses, coloured glass, and monumental effigies will be depicted. The Series will also contain 1 60 pictures in photogravure, showing the characteristic scenery of the counties. CARTOGRAPHY Each History will contain Archaeological, Domesday, and Geological maps ; maps show- ing the Orography, and the Parliamentary and Ecclesiastical divisions ; and the map done by Speed in 1610. The Series will contain about four hundred maps in all. FAMILY HISTORY AND HERALDRY The Histories will contain, in the Topographical Section, manorial pedigrees, and accounts of the noble and gentle families connected with the local history ; and it is proposed to trace, wherever possible, their descendants in the Colonies and the United States of America. The Editor will be glad to receive information which may be of service to him in this branch of the work. The chart family pedigrees and the arms of the families mentioned in the Heralds' Visitations will be issued in a supplemental volume for each county. The Rolls of Arms are being completely collated for this work, and all the feudal coats will be given in colours. The arms of the local families will also be represented in connection with the Topographical Section. In order to secure the greatest possible accuracy in the descriptions of the Architecture, ecclesiastic, military and domestic, a committee has been formed of the following students of architectural history, who will supervise this department of the work : — ARCHITECTURAL COMMITTEE J. BILSON, F.S.A., F.R.I.B.A. W. H. ST. JOHN HOPE, M.A. R. BLOMFIELD W. H. KNOWLES, F.S.A., F.R.I.B.A. HAROLD BRAKSPEAR, A.R.I.B.A. J. T. MICKLETHWAITE, F.S.A. PROF. BALDWIN BROWN ROLAND PAUL ARTHUR S. FLOWER, F.S.A., A.R.I.B.A. J. HORACE ROUND, M.A. GEORGE E. Fox, M.A., F.S.A. PERCY G. STONE, F.S.A., F.R.LB.A. J. A. GOTCH, F.S.A., F.R.I.B.A. THACKERAY TURNER A special feature in connection with the Architecture will be a series of coloured ground plans showing the architectural history of castles, cathedrals and other monastic foundations. Plans of the most important country mansions will also be included. The issue of this work is limited to subscribers only, whose names will be printed at the end of each History. ix • THE VICTORIA HISTORY OF THE COUNTY OF HERTFORD EDITED BY WILLIAM PAGE F.S.A. VOLUME ONE WESTMINSTER 2 WHITEHALL GARDENS I9O2 DA 670 H5V6 v. I County Committee for 1bertforo0btre THE RT. HON. THE EARL OF CLARENDON Lord Lieutenant, Chairman THE MOST HON. THE MARQUESS OF SALISBURY, K.G. THE RT. HON. THE EARL OF ESSEX THE RT. HON. THE EARL COWPER, K.G. THE RT. HON. THE EARL BROWNLOW THE RT. HON. THE EARL OF VERULAM THE RT. HON. THE EARL OF STRAFFORD THE RT. HON. THE VISCOUNT CRANBORNE THE RT. HON. THE VISCOUNT HAMPDEN THE RT. REV. THE LORD BISHOP OF ST. ALBANS THE RT. HON. THE LORD ROTHSCHILD THE RT. HON. THE LORD MOUNT-STEPHEN THE RT. HON. THE LORD ALDENHAM THE HON. FREDERICK WILLIAM ANSON THE REV. THE HON. EDWARD LYTTELTON SIR ARTHUR P. D. LUSHINGTON, BART. SIR EDMUND HARDINGE, BART. SIR WALTER GILBEY, BART. SIR JOHN BLUNDELL MAPLE, BART., M.P. SIR JOHN EVANS, K.C.B. THE VERY REV. THE DEAN OF ST. ALBANS T. ARMSTRONG, ESQ., C.B. PERCEVAL BOSANQUET, ESQ., D.L., J.P. SAMUEL B. BOULTON, ESQ., D.L., J.P. JAMES W. CARLILE, ESQ., D.L., J.P. LIEUT. RICHARD B. CROFT, R.N., D.L., J.P. THE REV. CANON DAVYS FRANCIS DELME-RADCUFFE, ESQ., J.P. LEWIS EVANS, ESQ., F.S.A. EDWARD S. FORDHAM, ESQ., M.A., LL.M., D.L., J.P. ERNEST GAPE, ESQ. THE REV. G. H. P. GLOSSOP, M.A. H. R. H. GOSSELIN, ESQ., J.P. T. F. HALSEY, ESQ., M.P. W. J. HARDY, ESQ., F.S.A. DR. E. LIPSCOMB, J.P. FREDERICK MACMILLAN, ESQ., D.L. G. N. MARTEN, ESQ., J.P. F. H. NORMAN, ESQ., J.P. C. T. PART, ESQ., J.P. R. C. PHILLIMORE, ESQ. WILLIAM PAUL, ESQ. WILLIAM RANSOM, ESQ., F.L.S., F.S.A. ABEL H. SMITH, ESQ., M.P. ARTHUR L. STRIDE, ESQ., J.P. THE REV. OWEN C. WHITEHOUSE, M.A. CHARLES W. WILSHERE, ESQ., D.L., J.P. E. N. Wix, ESQ., M.A. WILLIAM H. WODEHOUSE, ESQ., D.L., J.P. WILLIAM PAGE, F.S.A., EDITOR OF THE HISTORY OF HERTFORDSHIRE xiii CONTENTS OF VOLUME ONE Dedication ..... The Advisory Council of the Victoria General Advertisement The Hertfordshire County Committee Contents ..... List of Illustrations .... Preface ...... Natural History Geology ..... Climate ..... Palaeontology .... Botany ..... Introduction .... Phanerogamia (Flowering plants) . Notes on the Botanical Districts Cryptogamia (Non-lowering plants) Filices (Ferns') Equisetaceae (Horsetails) . Lycopodiaceae (Clubmosses) Musci and Hepatic* (Mosses and Liverworts') Characeae (Stonettiorts) Algae Lichenes (Lichens') . Fungi ..... Mycetozoa .... Zoology Mollusca (Snails, etc.) Insecta (Insects) Introduction Coleoptera (Beetles) Lepidoptera (Butterflies and Moths) .... Orthoptera (Grasshoppers and Neuroptera (Dragon/lies) History . By JOHN HOPKINSON, F.L.S., F.G.S, Assoc. Inst.C.E. >» » »» »» By RICHARD LYDEKKER, B.A., F.R.S., F.G.S. Edited by JOHN HOPKINSON, F.L.S., F.G.S. By JOHN HOPKINSON, F.L.S., F.G.S. By A. E. GIBBS, F.L.S., F.R.H.S. By JOHN HOPKINSON, F.L.S., F.G.S. By JAMES SAUNDERS, A.L.S. By B. B. WOODWARD, F.G.S., F.R.M.S. Edited by A. E. GIBBS, F.L.S., F.R.H.S. By A. E. GIBBS, F.L.S., F.R.H.S. By E. G. ELLIMAN .... By A. E. GIBBS, F.L.S., F.R.H.S PAGE V vii vii xiii XV xvii xix I 33 4' 43 44 5' 60 61 62 62 62 65 66 69 7° 80 81 83 83 no 1 68 xv CONTENTS OF VOLUME ONE Trichoptera (Caddisflles) and Hymenoptera (Bees, etc.) Diptera (FRa) Hemiptera (Bugs, etc.) and Aphides .... Arachnida (Spiders, etc.) Crustacea (Crabs, etc.) . Pisces (Fishes) Reptilia and Batrachia (Reptiles and Batrachians) . Aves (Birds) .... Mammalia (Mammals) Early Man ..... Anglo-Saxon Remains Introduction to the Hertfordshire Domesday .... Text of the Hertfordshire Domesday Sport, Ancient and Modern Introduction .... Foxhunting .... Hertfordshire Hounds Puckeridge Hounds . Old Berkeley Hounds Harriers ..... Staghounds ..... Shooting ..... Fishing ..... Hawking ..... Steeplechasing .... Racing Coursing ..... Pugilism ..... Cockfighting .... Bullbaiting .... ' Bob Grimston ' ... Cricket . By A. E. GIBBS, F.L.S., F.R.H.S. By F. O. PlCKARD-CxMBRIDGE, M.A. By the Rev. T. R. R. STEBBING, M.A., F.R.S., F.L.S. By G. A. BOULENGER, F.R.S., F.Z.S. . By A. F. GROSSMAN, F.L.S By SIR JOHN EVANS, K.C.B., F.R.S., etc. By REGINALD A. SMITH, B.A. By J. HORACE ROUND, M.A., D.L. By the REV. F. W. RAGG, M.A. . By CHARLES T. PART, M.A., D.L., J.P. Football Association Rugby Index of the Hertfordshire Domesday By HOME GORDON, assisted by J. EARL NORMAN, M.A., LL.D., C. J. REID, M.A., P. H. LATHAM, M.A. and A. J. GARTON Edited by C. W. ALCOCK By A. J. MILLAR By C. J. B. MARRIOTT PAGE 169 I/O 171 181 189 191 "93 217 "3 151 300 345 349 350 3S2 355 357 358 359 36. 363 364 366 368 369 37° 37' 37' 37* 383 387 XVI LIST OF ILLUSTRATIONS PAGE St. Albans Cathedral. By William Hyde frontispiece Implements from the Caddington District. Figs I to 5 . . . . • .226 Implement found near Hitchin. Fig. 6 .......... 228 Arrowhead found near Ash well. Fig. 7. . . . . . . . • •23I Arrowhead found near Tring. Fig. 8 *3J Knife found at Widdington. Fig. 9 . . . . . . . . • • 235 Coin, Philippus. Fig. 10 237 British Coins developed from the Philippus. Figs, n, iz • 237 Ancient British Coins, Verulam full-page plate, facing p. 240 Ancient British Coins, Verulam ....... „ ,, », 242 Anglo-Saxon Remains . . . . . . . . . „ ,, „ 253 The Marchioness of Salisbury ........ » » »> 349 St. Albans Steeplechase. The Start . . . . • • • » » >» 35* „ „ Coming into the Second Field . . . „ „ »» 355 „ „ Coming into the Last Field . . . „ » » 35^ „ „ The Finish ...•••»»» 3°' Coursers taking the Field at Hatfield Park coloured plate, facing p. 368 The Hon. Robert Grimston . . full-page plate, facing p. 370 LIST OF MAPS Geological Map between pp. xxii, I Orographical Map » 22» 23 Botanical Map ........••••» 42» 43 Pre-Historical Map • » 222> 223 Anglo-Saxon Map » 25°» 25' Domesday Map > 3°°. 3°l xvn PREFACE FOR the design and scope of the History of Hertfordshire the reader is referred to the General Advertisement of the Victoria History. While it is intended in the earlier portion of each History to keep to a chronological order as far as possible, the conditions obtaining in some counties make it desirable to depart slightly from the general rule. In the case of Hertfordshire the break in continuity is made by omitting the Romano-British chapter from this volume. Although our knowledge of Saxon times as far as this county is concerned is very imperfect, there is at present no such activity of research in this department as to encourage the hope that important facts may be brought to light if publication be delayed. But the excavations which are proceeding at Verulamium may add something to the very scanty material available for reconstructing the story of the county at the time of the Roman occupation, and Mr. Haverfield's contribution will there- fore be reserved for a future volume. It may be questioned by some whether there be any need for another History of Hertfordshire^ seeing that three histories of the county have been issued already at various times. But it may be pointed out that in none of them is there to be found a general view of the county and its life such as is projected in the present work ; nor has the true foundation of modern county history — the Domesday Survey — been examined by previous historians with the care it deserves. In this respect the Victoria History claims to supersede its predecessors ; and while the public must ultimately judge whether the ideals of the editors be in any degree realized, it is believed that in the manorial history, which will follow in two of the three succeeding volumes, the student will find a greater measure of accuracy than in the earlier histories. A particular statement of the plan upon which the topographical history has been compiled will be given in the preface to the next volume, in which the first portion of this section will find a place. The fourth volume will contain general articles on Ecclesiastical, Political, Social and Economic history and other subjects, as announced in the prospectus. XIX PREFACE In the compilation of this volume the Editors are much indebted to the assistance of Sir John Evans, to whom their thanks are also due for the loan of illustrations. For help in organizing the contributions on Natural History and for revision of the proofs of these articles they are under great obligations to Mr. John Hopkinson. The Editors also desire to acknowledge the courtesy of the Marquess of Salisbury, the Headmaster of Harrow School, Mr. G. N. Marten, the Society of Antiquaries, and the committee of the St. Albans Museum in making available for publication some of the illustrations which appear in this volume. XX 3 A HISTORY OF HERTFORDSHIRE HISTORY OF HERTFORDSHIRE GEOL EXPLANATION OF COLOURING RagsluX Beds London. Clay Woobrick and RtaAly Beds THE VICTORIA HISTOR'l \L MAP. E COUNTIES OF ENGLAND County Boundary shown thus J.&. Bartholomew GEOLOGY I geological structure of Hertfordshire attracted the attention of our earliest county historian long before geology became a science. 'Concerning the Soyle:' said Norden in I597,1 'It is for the most part chalkie, though the upper cruste in the South and West parts be for the most part of redde earth mixed with gravell, which yet by reason of the white marie under it yeeldeth good wheat and oates . . .' Norden here makes a definite geological observ- ation, that the Chalk, which forms the main stratum of the county, is overlaid in the south and west by a mixed soil of red earth (or clay) and gravel. This is correct so far as it goes, but it appears to have es- caped his notice that in the east a loamy clay (boulder-clay) overlies the Chalk, and that in the south-east a stiff clay (the London Clay) com- pletely alters the character of the soil, so effectually covering up the Chalk which lies underneath it that it is more suitable for root-crops and pasture than for raising ' good wheat and oates.' Norden also quaintly says that in the north part of the shire ' the soyle is very apt to yeeld corne and dertie wayes,' and in his account of Hitchin 8 he speaks of ' a kinde of chalke ... a stonie Marie, more fit to make lime than to soyle the grounde.' Chauncy, in his account of the soil of Hertfordshire, does little more than copy and amplify Norden. 'The upper Cruste,' he says,3 'in many Places consists of red Earth, mixt with Gravel ; most of the Meadows are dry ; the Hills wet and cold, for they are Clay, therefore barren ; and for divers Parts it contains Chalk within a Foot or a Fathom of the Surface of the Ground . . .' Salmon merely says of ' the Earth ' : 4 ' The Soil is none of the fruitfullest . . . The Arable hath generally too much Gravel or too much Clay.' In his account of Moor Park, however, in referring to alterations to ' More House,' 5 he says that ' in digging were found Veins of Sea Sand with Musscles in it.' This is the earliest mention of the finding of fossils in Hertfordshire, and must have created some astonishment in his day. Even in 1756 the finding of ' a petrified Echinus ... at Bunnan's Land in the parish of Bovingdon ' was considered worthy of record in the Philosophical Transactions of the Royal Society. 1 Speculum Britannia Pars, ' The Description of Hartfordshire,' p. I (quoted from the 1723 edition). 3 Op. cit. p. 1 8. 3 Historical Antiquities of Hertfordshire, p. I (1700). 4 History of Hertfordshire, p. i (1728). 6 Of. cit. p. HO. I I B A HISTORY OF HERTFORDSHIRE Clutterbuck is our first historian who gives any precise information on the geology of the county. Under the heading of ' Natural History and Climate ' l he gives a brief description of the Totternhoe Stone and of the Hertfordshire Conglomerate. This appears to be the earliest notice of the latter except the following curious account in a work dated 1756, relating to the Natural History of the county, as quoted by Young Crawley,2 who gives neither the title of the work nor the author's name. ' The surface of every ploughed field is covered with innumer- able small Stones of the flinty kind generally, and many of them inimit- ably variegated with various Colours and Figures. The Plumb Pudding stone may also be called a native of this County. Many of this kind which are found here will weigh twenty or thirty pounds, and will bear as fine a polish as Glass, and far exceed in beauty all the Marble I ever saw. In many of their gravel pits are also found clear, transparent peb- bles, generally not exceeding the size of chestnuts, and seldom less than a pea, but as clear as a drop of water, and extremely hard. These cut and polish as fine as a Diamond, and when set upon a good foil appear extremely brilliant, and are capable of being made into Rings, Buttons, and other Toys.' The geological formations represented in Hertfordshire,3 with their chief lithological characters and approximate thickness, are given in the following table, in descending order, the names of the formations which do not come to the surface in the county being printed in italics.4 1 History of Hertfordshire, vol. i. p. iii. (1815). 2 Guide to Hertfordshire, 'Introduction,' p. 9 (1880). 3 For a complete account of these formations reference should be made to the Memoirs of the Geological Survey, especially The Geology of London and of Part of the Thames Basin, by W. Whitaker, B.A., F.R.S., 2 vols. (1889). 1 The coloured section with the map shows the escarpment of the Chalk and the out- crop of the underlying Secondary rocks beyond Pitstone Hill, with the false escarpment of the Upper and part of the Middle Chalk at Moneybury Hill, the hollow between these two hills being a dry valley. The Chalk Rock at the summit of the Middle Chalk and the Melbourn Rock at its base are shown by double lines, and so is the Totternhoe Stone near the base of the Lower Chalk. Outliers of the Eocene Beds over the Chalk are illustrated by the one at St. Albans, and inliers of the Reading Beds underneath the London Clay by that at Cough's Oak. A slight anticline in the Chalk is indicated here. The dip of the Chalk from the swallow-holes at Potterells near North Mimms shows how water sinking in there will find its way along the interstices in the layers of flints into the valley of the Lea rather than into that of the Colne. The plain section in the text (p. 4) shows the position and dip of the Silurian and De- vonian rocks where proved to be present beneath an uneven under-surface of the Gault. It is evident that the Devonian rocks must rest unconformably upon the Silurian nearly 1,000 feet beneath the surface somewhere between Hertford and Turnford. The unconformity between the Secondary and the Palaeozoic rocks is seen to be rather greater than that between the Silurian and Devonian. The thinning-out of the Lower Greensand towards the south- south-west and the thinning-out of the Upper Greensand in a north-north-easterly direction are indicated. As in the other section, the Chalk Rock, Melbourn Rock, and Totternhoe Stone are represented by double lines. An Eocene outlier near Bennington has inadvertently been omitted to be shown. The horizontal line through the section (appearing by an optical illusion to dip to the left) indicates Ordnance datum. In each section the vertical scale is twelve times the horizontal, the latter being the same scale as that of the map, on which the trend of each section is indicated by a thin black line. 2 GEOLOGY Period Formation Character of the strata Approximate thickness in feet Alluvium Peat clay loam etc I to I O Recent Valley gravels .... Gravels of existing rivers .... 5 to 20 River Drift Older river-gravel and sand . 5 to 'Jo Clay-with-flints . . . Brickearth .... Reddish clay with angular flints Loamy and sandy clay .... lu yj i to 25 c to 60 Pleistocene Chalky boulder-clay i o to 4.0 Glacial Drift . . . .| Gravel and sand I O tO 20 Westleton Shingle . . . Pebbly gravel I to IO Lower London Clay .... Brown or bluish clay, with base- ment-bed of brown clay and pebbles 20 to 1 70 Eocene Reading Beds .... Sands, mottled and plastic clays, and pebbles 25 to 40 Thanet Sands .... Grey and black sand o to i o Upper Chalk .... Soft white chalk, twith layers of flints about ^oo ' Chalk rock — very hard, cream- coloured I to 4. Upper Cretaceous Middle Chalk . . . .- Lower Chalk . Upper Greensand . White chalk, with few flints Melbourn rock — hard, nodular . Grey and white chalk .... Totternhoe stone — hard, white . Chalk marl — grey marly chalk . Soft marly sandstone 200 to 350 IO 65 to 90 6 to 12 2O to 60 Gault Stiff blue clay . Lower Cretaceous Lower Greensand . Iron-sands and ' carstone "... o to 10 Upper Jurassic Purbeck Beds .... Portland Beds .... Kttneridge Clay .... Clays and argillaceous limestone Sands and shelly limestone . Dark-coloured clay — Devonian Upper Devonian Dull-purple shale Silurian Wenlock Shale and limestone .... — The existence of Devonian and Silurian rocks at a great depth under the surface in this area is only known to us from borings made by the New River Company in the valley of the Lea. These very old rocks must for ages have formed a land-surface stretching right across Hert- fordshire, and probably giving rise to rivers flowing to the north and to the south. The shore-line of the Lower Greensand sea on the south apparently ran through the north of London, and that of the contem- poraneous northern sea through the north of Hertfordshire, trending north-east and south-west, and communicating in that direction, through 3 \ ClolJuJl ' Benningtun A HISTORY OF HERTFORDSHIRE Oxfordshire, with the southern sea. Silurian rocks formed the highest land. At a depth of 797 feet beneath the surface (685 feet below Ord- nance datum) the Wenlock Shale with bands of limestone was found at the boring between Hertford and Ware, where is now the Broad- mead well, dipping about i° west of true south ?at an angle of 41° with the horizon.1 Upon these Silurian rocks, after some earth-movements had taken place, disturbing their original hori- zonal position, Devonian rocks were deposited. At a depth of 980 feet beneath the surface (872 feet below Ordnance datum) Upper Devonian shale was met with at Turnford near Cheshunt, a few miles south of the Ware boring, dipping about 17° west of true south at an angle of 25° with the horizon.2 Devonian rocks have also been found under London at an increasing depth as we proceed from north to south. They were therefore deposited unconformably upon the Silurian rocks, and the old land-surface grad- ually became lower from Ware southwards.3 South of London it was much lower, as shown by the great depth to which the Netherfield boring in Sussex was carried without reaching it. After the deposition and upheaval of the Devonian rocks a very long interval supervened before Hertfordshire was undoubtedly again beneath the sea, and considerable earth-move- ments took place, as shown by the angle of dip of these rocks. During this interval the whole of the Carboniferous, Permian, and Triassic, and nearly the whole of the Jurassic rocks were de- posited in other parts of England ; at least if any older rocks than the Upper Oolites ever existed in our area, no trace of them has yet been found. At Puttenham, in the extreme north-west of the county, beyond the Tring reservoirs, near the bottom of a bore-hole carried to a depth of 225 feet from the surface, the Kimeridge Clay was met with. The well was carried to a depth of 1 1 5 feet entirely through Gault clay, here about 1 50 feet thick ; the boring was commenced in this clay and passed 1 Francis, 'On the Dip of the Underground Palaeozoic Rocks at Ware and Cheshunt.' Rep. Brit. Assoc. for 1895, p. 451 (1896). 2 Op. cit. p. 452. 8 ?x7Pk'nSn' '.°n the Recent Discove<7 of Silurian Rocks in Hertfordshire,' Trans. t^atfird Nat. Hist. Soc., vol. ii. p. 241, see pi. ii. (1880). 4 (Turnford GEOLOGY through either Lower Greensand or Portland Sand, most probably the latter, as it comes to the surface at Hulcot in Bucks, four miles to the north-west. Below this the Kimeridge Clay is described as ' dark clay, with waterstones ' [probably septaria], but the search for water was futile.1 The Kimeridge Clay is a marine formation, as are the Silurian and Devonian rocks reached so far beneath the surface in the east of the county, but there is evidence, in its lignites and in the presence of coni- ferous wood in considerable quantity, of the proximity of land. The Portland Beds are also of marine origin ; but immediately above them, and coming to the surface at Liscomb Park near Soulbury, thirteen miles north of Puttenham, are Purbeck Beds, which are ofestuarine and fresh- water origin. It therefore seems probable that towards the close of the long interval unrepresented in our county after the Devonian beds became dry land — perhaps many millions of years — a submergence here took place, and rivers brought down from a not far-distant land-surface the mud of which the Kimeridge Clay consists ; that by the gradual eleva- tion of this land-surface the sea became shallower, the sands of the Port- land series then being deposited ; and that, the elevation still continuing, estuarine and fresh-water conditions prevailed, these being characteristic of the Purbeck Beds. The three formations here mentioned — the Kim- eridge Clay and the Portland and Purbeck Beds — form the Upper Oolites, the highest division of the Jurassic rocks. Within twenty miles from Puttenham, in a north-north-westerly direction, the whole of the lower divisions of the Jurassic series are met with — the Middle Oolites, the Lower Oolites, and the Lias — the axis of elevation having thus been on the north or north-west. After the beds were raised from their original horizontal position, so as to dip towards Hertfordshire away from this axis, they were planed down by denudation, the edges of the strata thus successively cropping out. It is this tilting- up which brings the older and originally lower rocks to the surface so that they crop out from underneath the newer rocks which have been de- posited upon them. When the tilted-up edges of the newer rocks offer a greater resistance to denudation than those underneath them they terminate in an escarpment such as that of the Chalk ; when a less re- sistance, in a valley, which may be extended into a plain such as that of the Gault. We now come to the third great division of the Secondary rocks, the Cretaceous System. Its lowest member represented in Hertfordshire is the Lower Greensand. Whilst the Hastings Sands and Wealden Beds were being deposited in the south-east of England, there was probably dry land here, but this was gradually submerged, and the Lower Green- sand was deposited over the Kimeridge Clay with a slight uncon- formity, its phosphatic-nodule bed at Potton, just outside our county boundary, showing, in the numerous water-worn fossils derived from the Jurassic rocks, what a great amount of denudation they must have 1 Whitaker, ' Hertfordshire Well-sections,' and paper, Trans. Herts Nat. Hist. Sac., vol. vi. p. 60 (1890). 5 A HISTORY OF HERTFORDSHIRE undergone. It is present in our area only beneath the surface, the whole of its outcrop being outside the county, trending in a south- westerly direction from the neighbourhood of Potton, through Shefford, to Leighton Buzzard. In a well-boring at Long Marston, six miles south of the latter place, it was met with about 10 feet in thickness, after 215 feet of Gault clay had been passed through. It thins out to nothing in the south-east, being absent where the Gault was passed through at Ware and Turnford. The Lower Greensand is the highest bed of the Lower Cretaceous Series. Hitherto only the rocks which do not come to the surface in the county have been considered. The oldest formation which does so is of Upper Cretaceous age. This is the Gault, the earliest of that age, being next in succession to the Lower Greensand. Before its deposition there was a considerable disturbance of the strata previously deposited, result- ing here in a subsidence which even brought beneath the sea the Palaeo- zoic ridge that for ages had formed a barrier across our county between the seas on the north and on the south. While on the north-west the Gault reposes on the Lower Greensand, on the south-east it rests directly on Silurian and Devonian rocks. At Cheshunt it is 153 feet thick, at Ware 166 feet, and it increases in thickness towards the north and west, being 180 feet thick at Radwell near Baldock and at Hinxworth, about 200 feet at Ashwell, 210 feet at Hitchin, and 215 feet at Long Marston. It consists of calcareous marls and dark bluish-grey clays, with concre- tionary and phosphatic nodules. Owing to its soft and easily-weathered character it forms a plain and sometimes a depression at the foot of the Chalk escarpment, partly along, but chiefly beyond, the north-western margin of Hertfordshire. It enters the county from Cambridgeshire at the extreme north, in the Cam district, between the River Rhee and the Ruddry Brook ; continuing just within the margin of the county, it passes into the Ivel district ; it is again seen near Radwell north of Baldock, and again north-west of Pirton. The Thame district is in great part on it, and here it occupies the spur of the county beyond the Mars- worth, Startups End, and Tringford reservoirs, the Wilstone reservoir being the only one which is actually on the Gault. Although in great part a stiff impermeable clay, the soil upon it is extremely fertile, having been rendered so by a covering of drift from the Chalk. This Gault plain has, indeed, long been known as a fine corn-grow- ing district. The greater part of it not under arable culture is well wooded with oaks, a characteristic feature of the formation, as the name ' Oak-tree Clay,' which has been given to it as well as to the clays of Kimeridge and Wealden age, indicates. The Gault suffered much from denudation before the deposition of the next bed upon it, and its surface is very irregular. Towards the north-east it thins out greatly through the upper beds having been eroded. While in that direction it is immediately followed by the Chalk Marl, the lower beds of which are even sometimes wanting, towards the south-west the Upper Greensand is present ; but by whatever 6 GEOLOGY bed in our area the Gault is followed there is in that bed evidence that its lower layers at least were formed chiefly from the waste of the Gault underlying them, for they contain phosphatic nodules and worn fossils derived from it. The so-called ' coprolite bed ' which has mainly re- sulted from the denudation of the upper beds of the Gault, does not there- fore mark a distinct geological horizon, but may at one place be of Upper Greensand age and at another may represent the lower, or even sometimes the higher beds of the Chalk Marl. When the Upper Greensand is present it appears as a thin bed of soft marly sandstone passing up in places into a chloritic marl, which may represent the higher beds of the same formation, but is generally the lowest bed of the Chalk Marl there represented. This bed of phosphatic nodules and worn Gault fossils, whether it be of Upper Greensand or of Chalk Marl age, is of considerable economic value, being extensively worked for the production of artificial manure, but the only ' coprolite ' pits within the county are those at Ashwell. While there is a decided physical break between the Gault and the Upper Greensand, and a change of conditions took place from a rather deep and quiescent sea to comparatively shallow water, probably with shifting currents, there is no distinct line of demarkation between the Upper Greensand and the Chalk Marl, and it is sometimes difficult to say to which a certain bed should be assigned. The Upper Greensand is about 40 feet thick in the south-east of the county, but thins out to nothing in the north. In the extreme west only does it come to the surface, in a thin band between Marsworth and Buckland, just beyond the Wilstone reservoir. It is 44 feet thick at Cheshunt and 40 feet at Ware, its position at the former place being from 675 to 719 feet below Ordnance datum, and at the latter place from 478 to 518 feet below this datum. It consists of fine greenish sands with hard calcareous sandstone and chert, the typical green beds usually being charged with glauconite, and it contains sponge-spicules, Foraminifera, and other fossils. It ap- pears to have been laid down in a sinking sea-bed, the deposit in which gradually changed from one of mechanical origin, from erosion of adjacent land, to one of almost entirely organic origin, the great Chalk formation having been formed by and from the remains of the animals, mostly of microscopic size and lowly nature, which lived and died in and on the surface of the deep Cretaceous seas. The Lower Chalk rests upon the eroded surface of the Gault, or gradually takes the place of the Upper Greensand. It usually has for its basement-bed either the Chloritic Marl or the Cambridge Greensand, homotaxial deposits the lower beds of which contain phosphatic nodules and numerous fossils mostly derived from the Gault, many being phos- phatized. Whichever is present is followed by the Chalk Marl, a soft marly chalk with no flints but a considerable amount of silica. The Chalk Marl varies from about 20 to 60 feet in thickness, and the whole of the Lower Chalk from about 100 feet (Great OfHey) to 180 feet or thereabouts (Cheshunt). At Bushey its thickness has been given as 255 7 A HISTORY OF HERTFORDSHIRE feet, but its limits are not clearly defined in well-borings, and it is almost certain that too great a thickness has been assigned to it there. This may also be the case at Cheshunt. From the softness of the Chalk Marl the Lower Chalk at first forms a continuation of the Gault plain, and then a gentle upward slope along the denuded edge of its escarpment up to its junction with the Tottenhoe Stone. This is a hard, rather sandy chalk, from 6 to 1 2 feet thick, and often occurs in two beds, each 3 or 4 feet thick, and separated by a few feet of marly chalk. From its hardness the Totternhoe Stone stands well out above the plain of softer strata, usually forming a distinctive feature in the landscape. It enters the county in the Cam district, at Ruddry Spring near Ashwell, passes through the Ivel district north of Baldock, near Cadwell north of Hitchin, and by Pirton and Hexton. It then enters Bedfordshire, in which county it forms the ridge of Sharpenhoe Knoll, and it has long been extensively worked at Totternhoe as a building-stone, but has not been quarried there for some years. It decays rapidly when exposed to frost and other effects of the weather, as the present state of the west front of Dunstable Priory Church, which is built of it, testifies. It should not be employed for exteriors, but it is admirably adapted for interior decorative work, being at first soft and easily manipulated, and hardening and becoming whiter as the moisture dries out of it. The last which is seen of the Totternhoe Stone in Hertfordshire is in the Thame district north-west of Tring, where it crops out near the summit-level of the Grand Junction Canal south-east of the reservoirs, then forming the ridge of the hill which extends for some distance along the south-eastern side of the Wendover Canal. Nearly all along the outcrop of the Totternhoe Stone there are springs at frequent intervals which give origin to deep combes in the north-western escarpment of the Lower Chalk. The water in several instances soon disappears from the surface, being absorbed into the Chalk Marl ; the combes then being formed, or perhaps merely deepened, by underground denudation. The rest of the Lower Chalk consists of about 60 to 90 feet of hard grey and white chalk, followed by 4 or 5 feet of grey marly chalk. There are two other hard beds in the Chalk of Hertfordshire, the Melbourn Rock and the Chalk Rock. The most recently expressed view is that the former divides the Lower from the Middle Chalk, and the latter the Middle from the Upper Chalk ; but this gives so many divisions to the Chalk that it is best here to consider the Middle Chalk as having the Melbourn Rock at its base and the Chalk Rock at its summit. The Melbourn Rock is a hard, yellow and white, bedded nodular chalk, about 10 feet thick. It may be well seen in a small pit just below Willbury Hill, and it partly surrounds Ravensborough Castle, which is not really a castle but an ancient camp, five miles west of Hitchin. A bed of white chalk, which varies in thickness from about 200 to nearly 350 feet, follows. It is more silicious in composition than the Upper Chalk, but has only a few flints irregularly distributed through 8 GEOLOGY it. It forms a rather steep escarpment to the north-west, from half a mile to two miles in breadth. At its summit is the Chalk Rock, a very hard bed of chalk, which varies from about i foot to 4 feet in thickness, and is sometimes, like the Totternhoe Stone, divided into two beds with a foot or more of the softer chalk between them. It is cream-coloured, much jointed, and has layers of green-coated nodules of equally hard chalk at the top, which is somewhat irregular, as if it had been exposed or subject to slight denudation before the next layer of chalk was deposited. Owing to its hardness, it has so far resisted denudation as to be usually found at or near the top of the Chalk hills which form the water-part- ing between the catchment-basins of the Ouse and Lea on the north and those of the Thame and Colne on the north-west. Owing also to its hardness it is a very difficult rock to work for fossils, but it is one which better repays the labour than any other in Hertfordshire. It forms the top of the Chalk escarpment south of Royston and north of Kensworth, and nearly all the tributaries of the Colne and Lea cut through it. There is a good exposure close to Markyate Street on the banks of a lane cut into it, and there was one in a chalk-pit south-east of Airley Green near Caddington ; but this has now been covered in. The best exposure, however, is in the Midland Railway cutting at Chiltern Green, but that is just outside our county, in Beds. Collections of fossils from these localities may be seen in the Hertfordshire County Museum at St. Albans. The Chalk Rock was first described by Mr. Whitaker,1 partly from a collection of fossils made by Sir John Evans in the Boxmoor chalk-pit. It has recently been more fully described by Dr. Morison, and a list of its fossils found in the Chiltern Green cutting has been given by him.2 Its Mollusca have been described, and many species have been figured by Mr. Henry Woods.3 At the junction of the Middle and Upper Chalk are the highest hills of Hertfordshire, forming part of the north-easterly prolongation of the Chiltern Hills, and attaining an elevation, along the Royston, Luton, and Dunstable Downs, of from 400 to 600 feet generally ; and at Kensworth Hill, the highest point on the Dunstable Downs, of 8 1 o feet, being the greatest elevation in the county. The Upper Chalk, or chalk-with-flints, occupies much the largest area in Hertfordshire (at least three-fourths of the county). The general direction of the rivers of Hertfordshire is from north-west to south-east, and this corresponds with the slope of that portion of the county which is on the Upper Chalk. This generally forms an inclined plane, sloping downwards, with an inclination roughly coinciding with the dip or line of bedding of the Chalk, from the Chiltern Hills on the north-west to the valley of the Colne on the south, and that part of the valley of the 1 'On the Chalk Rock,' Quart. Journ. Geol. Sac., vol. xvii. p. 166 (1861). 2 'Notes on the Chalk Rock,' Trans. Herts Nat. Hist. Soc., vol. v. pp. 192-202 (1889). 3 ' The Mollusca of the Chalk Rock,' Quart. Journ. Geol. Sac., vol. lii. pp. 68-98 (1896) ; vol. liii. pp. 377-404 (1897). 9 A HISTORY OF HERTFORDSHIRE Lea which extends from Hatfield to Hoddesdon on the south-east. Into this inclined plain the valleys have been cut, for the hills of this part of Hertfordshire ' are not ridges elevated above the general level of the surface ; but appear to be such only when viewed from the valleys of the rivers, whose waters have cut and furrowed deeply below the general level.'1 Here and there these rivers have cut through the super- ficial deposits and the Upper Chalk into the Middle Chalk, exposing the Chalk Rock, which may thus be seen in the Bulbourn Valley as far south as Rough Down near Boxmoor. There are a few exceptions to the almost uniform slight dip of the Chalk towards the south-east. South of Royston the dip is reversed, a line of flexure having been traced for a distance of five miles along the escarpment. In the Memoir on Sheet 47 of the Geological Survey2 there are sketches of chalk-pits north of Barkway and on Reed Hill, showing a dip at about the junction of the Middle and Upper Chalk which gradually increases from zero to as much as 60° to the north. This appears to be merely a local disturbance, and the conjecture may be hazarded that it may have been caused by undermining resulting from the erosion of lower beds of the Chalk along the face of the escarp- ment. Other flexures in the Chalk will be noticed in the account of the Eocene beds when treating of the outliers and inliers to which they appear to have given rise. The Upper Chalk is a very permeable bed, and wherever it comes to the surface it forms a dry porous subsoil. Only about 300 feet of the lower portion of it are present in Hertfordshire. While the highest beds were being deposited elsewhere, this part of England was probably above the sea ; but the Chalk which has been deposited here has under- gone an immense amount of waste, continuous from its final if not from its first upheaval from the sea to the present time, and still going on. There may, however, have been a time when the Chalk, or at least the Upper Chalk, was entirely covered as it still is in the south-east of the county, by the Tertiary beds, the clays of which would protect its sur- face to some extent from disintegration. The great waste which it has undergone is due, more perhaps than to actual denudation, to the gradual dissolving of the carbonate of lime by water holding in solution carbonic acid (or carbon dioxide) derived from the air or from decaying vegetable matter. By this chemical action, which is continually going on, the flints and insoluble clay in the chalk are left on its surface, and form a deposit called ' clay-with-flints.' This covers a considerable area of the Upper Chalk, chiefly in the western part of the county. By the same chemical action also the so-called 'pipes' are formed, lines of weakness in the Chalk allowing of the more rapid percolation of water in certain places. Wherever it is not covered by an impermeable bed of clay, these c pipes ' occur, and as their funnel-shaped mouths are some- times of considerable extent, they give a very uneven surface to the 1 Coleman, Flora Hertfordiensis, p. xxxi. (1849). * Geology of the North-west part of Essex and the North-east part of Herts, p. 8 (1878). IO GEOLOGY Chalk, and alter the character of the surface-soil. There are better examples of such ' pipes ' in the Harefield chalk-pits just across our county boundary, in Middlesex, than anywhere in Hertfordshire, but fine examples have at various times been seen in the cuttings of the three main railway lines which pass through the county ; nearly all are, however, now grassed over. While the Lower and Middle Chalk frequently have but a thin covering of surface-soil, chiefly owing to their outcrop being usually in escarpments formed by comparatively recent denudation and having a steep slope, the Upper Chalk seldom comes to the surface except quite in the valleys where it and the superficial deposits upon it are subject to the erosive action of our existing rivers. While ' clay-with-flints ' pre- dominates on the west — in the Colne district — there are also, on high as well as low ground, thick beds of gravel and sand, formed either by glacial or river action. But on the east — in the Lea district — the Chalk is almost entirely covered with boulder-clay, except where the rivers have cut through this clay, exposing beneath it the glacial gravels and sometimes the Chalk. The close of the Cretaceous epoch must have been marked by considerable changes in the distribution of land and sea. Great Britain during the deposition of the Chalk was but an archipelago, the islands of which it was composed existing only west of a line running north and south from the extreme north of England to Somerset and Devon. East of this line all was sea, deepening eastwards ; west of it our present mountains in Scotland, Ireland, the English Lake district, and North and South Wales, with the highest land in Devon, were islands of small size, except in Scotland ; there was open sea to the south, extending over the north of France, but north of Scotland there was land, where is now a deep sea. It was not, however, from the denudation of this northern continent that the Chalk was formed ; it was built up by the animals which lived in the Cretaceous sea — animals most of which were of microscopic size. The larger fossils which we now find in the Chalk, numerous though they are in some places, formed but a minute fraction of the number of living creatures which teemed in those deep seas or sported on the surface. The great mass of the Chalk consists of Foraminifera (Globerigina, etc.), and other microscopic Rhizopoda, or rather of their calcareous shells or siliceous external skeletons, either whole or reduced to fragments. It was minute creatures such as these which built up nearly the whole of the groundwork of our county, living and dying until their remains accumulated to a thickness of at least 800 feet. The land then rose, the western archipelago becoming a continent, and the sea covering only the midland, eastern, and southern counties of England as far west as Devon, and of course including in its depths the whole of Hertfordshire. The break between the Secondary or Mesozoic period and the Tertiary or older Cainozoic period is the most important of any in ii A HISTORY OF HERTFORDSHIRE Europe, being a very decided physical as well as pateontological one. In both Cretaceous and Eocene strata the most abundant fossils are Mollusca, but the Protozoa, Rhizopoda, Crustacea, and Polyzoa which abounded in the Cretaceous seas were very sparsely represented in Eocene times ; on the other hand there were but few Cretaceous plants and no Cretaceous mammals, while plants, and especially Dicotyledons, are fairly well represented in Eocene strata, and the Tertiary era has been termed the Age of Mammals. The break however is not so much in the classes of plants or animals represented as in the fact that not a single species passes from Secondary to Tertiary rocks, indicating an enormous lapse of time, with perhaps a complete change of conditions. Physically the difference in the strata consists in the fact that hard, distinctly-bedded rocks, and especially those of a calcareous nature, cease with but few exceptions at the close of the Secondary period, giving place in the Tertiary to clays, sands, and gravels. This great break is very well marked in Hertfordshire, for we have neither the highest beds of the Chalk nor the lowest of the Eocenes. There are higher beds of the Chalk, though not the highest known, and lower Eocene beds, south of London than we have here. As the Cretaceous sea must have been continuous north and south of London, the inference is that our Chalk must have suffered a greater amount of denudation than that of Surrey, Sussex, Hants, and Kent. That much erosive action has taken place is proved by the great irregularity of the surface of the Chalk in this county and by the enormous quantity of flints and therefore great thickness of strata which must have been re- moved to form the sands and pebble-beds of the Reading Series. The Woolwich and Reading Beds are of two types : in the one, best represented in the Woolwich district, loamy beds with many fossils prevail ; in the other, or Reading type, the beds are more pebbly and sandy, with but few fossils, and it is a significant fact that a greater denudation of the Chalk has taken place where the Reading type is present, as in Hertford- shire, than where the beds are of the Woolwich type, as in Kent. In our area the term ' Woolwich ' is dropped because we have no beds of that type. Although such a long interval elapsed of which we have no record, it does not appear that any earth-movements except subsidence then took place within our area, the eroded surface of the Chalk, although uneven, having been approximately horizontal when the earliest Eocene beds were deposited upon it. When the Chalk is covered by a bed of sand through which water can percolate, there is on its surface a layer of unworn green-coated flints usually considered to form the base of the Thanet Sands, but it should rather be regarded as a reconstructed Cretaceous bed, for the formation is not due to the deposition of sedi- ment, the layer of flints being merely the insoluble residue of the Chalk, and its formation being a process probably continuous from or even before the upheaval of the Chalk to the present time. Why this layer seems to form the base of the Thanet Sands is due to the nature rather 12 GEOLOGY than the age of that formation, for it is also present when sands of the Reading Beds rest upon the Chalk, as in the Bushey chalk-pit near Watford. When fully developed, as in Kent, the Thanet Sands are 50 or 60 feet thick, but they thin out under London to 20 feet, and are only known to occur in Hertfordshire from their presence in the Cheshunt boring, where their thickness is reduced to about 10 feet and they consist of grey and black sand.1 They are of marine origin. South-east of a line preserving a general north-east and south-west trend, but very irregular, crossing the Lea and Colne districts from a point about half a mile south of Stocking Pelham near Bishop Stortford to Woodcock Hill near Rickmansworth, the Chalk is overlaid by the Reading Beds and London Clay, the escarpment of which follows, at a distance varying from less than a quarter of a mile to a mile and a half, the river Ash downwards from Furneaux Pelham to Amwell Magna, the river Lea upwards from Hoddesdon to Hatfield, and the river Colne downwards from North Mimms to Harefield. Of the Reading Beds there is normally a narrow outcrop along this line, wider in the east than in the west owing to the difference in the slope of the ground ; and the London Clay reposes upon them, forming a range of hills along its escarpment generally from about 300 to 400 feet in height, and, at its highest point, Stanmore Common, between Watford and Elstree, rising to 500 feet. The Reading Beds are represented in Hertfordshire by a very variable series of sands, mottled clays, and pebble-beds, there usually being at their junction with the Chalk the layer of green-coated flints already mentioned. They are here of estuarine origin, thus differing from all the formations already considered, which are of marine origin. From their small thickness, which varies from about 25 to 40 feet, and the usually rather steep slope of the ground at their outcrop, they do not occupy any great extent of country, and in most places have but little effect upon the surface-soil. Where their sands and clays predominate and get mixed with the London Clay, the soil is usually fertile, but where their beds of rounded flint-pebbles are much developed, as in the neighbourhood of Hatfield and North Mimms, the soil is particularly sterile. At Radlett and near North Mimms the principal pebble-bed is consolidated by a silicious cement into a conglomerate, well known as the Hertfordshire conglomerate or ' plum-pudding stone.' Although it is only known to occur with certainty in situ in this part of Hertfordshire at the present time, it has probably at some former period had a much greater extent, for masses of the conglomerate are strewn here and there nearly all over the county, and are also found beyond it. In a gravel-pit north of St. Albans there are large unwaterworn masses of it apparently but little disturbed from their original position, for they seem to form part of too extensive a bed to have been shifted horizontally ; indeed, in 1 Whitaker and Jukes-Browne, ' On Deep Borings,' etc., Quart. Journ. Geol. Soc., vol. 1. (50), p. 508 (1894). 13 A HISTORY OF HERTFORDSHIRE most places where there is a large unwaterworn mass it has probably been merely let down into its present position by the removal by denuda- tion of the softer strata beneath it. Large boulders of this rock are frequently found in our rivers, and one such was dredged up from the Ver and erected on the green opposite Kingsbury, St. Albans, in 1887, as the Victoria Jubilee memorial of the village of St. Michaels. The Reading Beds are cut into and their sands and clays are worked in many of our brickfields. Good sections may be seen in the brick- fields near Harefield, at Bushey, in Hatfield Park, and in others along their line of outcrop. Their sands are frequently cross-bedded, indicating shifting currents. They are so very variable that it is impossible to construct a general section. In some places, for instance, there is a thick bed of pure white sand which is altogether absent in others. Of the London Clay only the lower portion is represented ; the basement-bed of brown sandy clay with layers of flint-pebbles, which varies from about 6 to 1 2 feet in thickness, and is perhaps more truly a passage-bed between the Reading Beds and the London Clay than an integral member of the latter ; and a few feet of the lower portion of the true London Clay. This is here a stiff clay rather brown than blue in colour, appearing when freshly cut somewhat like the blue clay under London when that has been exposed for some time. The London Clay is usually capped on the highest points only by a pebble-gravel of Lower Glacial or of pre-Glacial age, in either case the remnant of a bed of gravel once of great extent. Elsewhere it is generally uncovered by superficial deposits, but in the valley of the Stort it is overlaid by chalky boulder-clay. Except in the valley of the Lea below Hoddesdon, where there are sandy loams and low-lying peaty marshes, and also where it is capped by pebble-gravel, the surface-soil upon it is a clay. The area over which the Eocene beds extend presents a marked contrast to the Cretaceous area. Its soils, its agriculture, and its flora are of an essentially Middlesex type. In the Colne and Brent districts it forms grass-lands devoted to hay-farming and grazing, interspersed with woods chiefly of oak, ash, elm, and fir trees ; in the Lea district, on the south, owing to the rich alluvial soil, nurseries and market-gardens pre- dominate ; while on the east, owing to the covering of boulder-clay, the land is chiefly under arable culture, partaking of the character of the corn- growing districts of the adjoining county of Essex. Outliers of the Eocene beds are spread over a considerable area of the Upper Chalk, but there is not one to be seen beyond its limits. Most of these outliers extend in an irregular line which is roughly parallel with the line of outcrop of the main mass with which they have at one time been continuous. As a general rule the larger outliers are towards the north-east, and as they decrease in extent towards the south-west they become more scattered. The largest of these outliers occupies an area of 3! square miles between Braughing and Much Hadham, and consists only of the Reading Beds ; the Colliers End and Sacombe outliers, of less extent, follow near together, the latter of Reading Beds only, the former M GEOLOGY with London Clay also ; then, at a little greater distance from the main mass, there is an outlier between Bennington and Watton, followed by a larger outlier on which Datchworth is situated, and a smaller at Ayot, these two being in the general direction, and the three having London Clay over the Reading Beds. All these are in the river-basin of the Lea, and their united area is about twelve square miles. In the Colne river-basin there is first an outlier at St. Peter's, St. Albans; there are three small outliers near together at Leverstock Green, Bedmond, and Abbot's Langley, the first of these being beyond the general line ; three small outliers near Sarratt follow ; and there is a small one near Chorley Wood, Rickmansworth. Most of the outliers in the Colne river-basin are of the Reading Beds only, and their united area is about three square miles. For some distance this string of outliers roughly coincides with a tolerably well-marked ridge of hills stretching from Watton south-west- ward by Welwyn, Sandridge, and St. Albans, where it exceeds 400 feet in height, to Hemel Hempstead. This ridge probably indicates a line of flexure in the Chalk, which, while dipping elsewhere in a regular manner from the Chiltern Hills towards London, is slightly depressed along this line. The Eocene beds upon it may have thus been let down below the plane of denudation, allowing patches of them to be preserved. Their clays being better able to resist subsequent sub-aerial denudation than the surrounding chalk, which also is constantly being chemically dissolved, by the gradual wearing down of the surface of the Chalk they would in course of time be left as hills. These outliers completely change the character of the soil overlying the Chalk district. Some appear as well-wooded eminences on which the oak and elm flourish best ; others, chiefly where the sands of the Reading Beds are more developed than their clays, or where the London Clay upon them is capped by pebble-gravel, are sandy, gorse-covered com- mons. Nearly all are worked for brick-making. Far away to the north-west there are three very small outliers of the Reading Beds, of three or four acres each, following each other in a line from near Kensworth to Berkhamsted Common, the last of these only being in Hertfordshire. The presence of these outliers is important as showing the former great extent of the Eocene Beds, of which they furnish more conclusive evidence than do the boulders of Hertfordshire conglomerate which are found at even a greater distance from their parent bed. To another line of flexure — an uprise of the Chalk — the existence of a series of inliers in the London-Clay area is probably due. Inliers are patches of lower beds exposed by the removal of the higher strata which once covered them. In Hertfordshire the Reading Beds are thus exposed beneath the London Clay in two inliers between Cough's Oak and Northaw, and if this presumed line of flexure be continued parallel with the outcrop of the Reading Beds into Middlesex, an inlier will be met with extending from Pinner, past Ruislip, to just beyond Ickenham. 15 A HISTORY OF HERTFORDSHIRE At the inlier half a mile north-east of Northaw the Reading Beds are cut through as well as the London Clay, and the Chalk is laid bare, showing an anticlinal axis, or axis of elevation. The Chalk hill on which Wind- sor Castle is situated is an inlier on the same line of flexure, but that is some distance from our county. The Eocene beds of Hertfordshire form part of the north-western margin of the London Tertiary Basin, usually designated ' The London Basin ' only, but it is not strictly speaking a basin. It is a shallow trough running nearly east and west, and tilted up slightly towards the west, thus giving it the form of a wedge with the apex on the west. It may be inferred from the lines of flexure which pass through the county that the slight crumpling of the strata which took place after the de- position of these beds, affecting them as well as the Chalk beneath them, was due to lateral pressure exerted from the north-west or the south-east, which might either be caused by shrinkage of the earth from its loss of internal heat, or by volcanic activity, or by both these actions combined. This shrinkage is continually going on, and has been in progress ever since the earth commenced to be formed into a sphere of molten matter from its original incandescent nebulous state. It is the chief initial cause of volcanic outbursts, and we know that such outbursts occurred in the British Isles on the close of the Eocene period, that is in Oligocene and Miocene times. It is not improbable therefore that these flexures were caused by pressure from the north-west during the period when volcanoes were pouring out lavas and throwing out ashes upon the Chalk and older rocks of the north-east of Ireland and the west coast and western islands of Scotland. How soon after the close of the Lower Eocene period Hertford- shire was upheaved from beneath the sea we do not know, for what remains of the London Clay may be but a small fragment of the strata which have been deposited in our area and removed by denudation. The proximity of outliers of the Lower Bagshot Beds, as on Harrow Hill, indicates that the southern portion of the county, if not the whole, continued beneath the sea until at least the commencement of Middle Eocene times, but it may have risen before the end of the Eocene epoch, and have been dry land while the fluvio-marine (Oligocene) series of southern Hampshire was in course of formation, continuing to be a land-surface during Miocene and Pliocene times. In that case its surface would then have become greatly diversified by sub-aerial denudation, under perhaps a tropical rainfall ; but it was shortly to be subjected to the levelling action of a great sheet of ice. The fossils of the London Clay indicate a tropical climate, and the climate continued tropical or sub-tropical during Middle and Upper Eocene, Oligocene, and Miocene times. It then became cooler, and during the long interval which elapsed between the close of the Miocene and the commencement of the Pliocene period it reached the temperate stage, the molluscan fauna of the earliest Crag deposits being similar to that at present inhabiting the Mediterranean. Britain then stood high 16 GEOLOGY above the sea ; no German Ocean and no English Channel then existed ; and animals were free to roam and plants to spread across the land which connected our country both on the south and on the east with the con- tinent of Europe. A period of gradual depression followed, the cold at the same time increasing, and during Pliocene times at first temperate and then boreal or arctic Mollusca teemed in the shallow seas and estuaries of the eastern counties, while remains of Mammalia, in grad- ually increasing quantities, were brought down by rivers from adjacent land. In all probability there then roamed over our county animals of the same species as those whose remains we thus find in the Crag (a Suffolk term for a shelly gravel or sand), but there is no evidence that our rivers flowed in that direction and contributed their sediments to any of the existing Crag strata. It is more probable that the rivers of Hertfordshire then flowed to the north, and removed thence vast quan- tities of Cretaceous and Tertiary strata, cutting off our Chalk from that of Yorkshire and Lincolnshire, and commencing to form the Chalk escarpment across the north-western margin of the county, its present features being due to subsequent erosion by the springs which form the sources of the Great Ouse. What was the cause of this gradual refrigeration of our climate, culminating in the Glacial epoch, has given rise to a vast amount of controversy. This is not the place to discuss it, but it may be mentioned that, without bringing in cosmical changes, a very great alteration in climate might be produced by a different distribution of land and sea. A deflection of the Gulf Stream which might be brought about by changes in the distribution of land so far off as the continent of America, might at any time give to our islands almost an arctic climate. It is necessary to look a little beyond our boundaries, for the student of Hertfordshire geology alone might be justified in assuming that there was a great gap between the Tertiary and Quaternary epochs, the greater part of the Eocene and the whole of the Oligocene, Miocene, and Plio- cene deposits being unrepresented in our county ; but in the eastern counties there is an almost unbroken sequence between the two, the Forest-Bed series, which is the newest of the Pliocene deposits, passing upwards almost imperceptibly into the oldest of the Pleistocene strata. The justification for the change of name from Tertiary to Quaternary lies more in the alteration in the nature of the deposits than in any decided physical or palasontological break, for we have no longer to deal with regularly stratified beds which can easily be correlated over wide areas. In the Pleistocene period marine gravels were being formed at one place while rivers were accumulating gravel of somewhat similar com- position in another not far distant ; mud was being deposited in the estuary of a river while on the sea-shore near it the wind was piling up heaps of sand, as in the present day. This great diversity of operations carried on at the same time makes the study of the Pleistocene period one of great difficulty, and our chief authorities vary greatly in their views. Much of the following attempt to show how this period is i 17 c A HISTORY OF HERTFORDSHIRE represented in our county must therefore be considered as open to con- troversy and liable to modification from future research. The Quaternary era is usually divided into two periods, Pleistocene or Post-Pliocene, and Recent, the Pleistocene being equivalent to the Glacial period, and being divided into Lower, Middle, and Upper Glacial, and the Recent period being divided into Prehistoric and His- toric. 'The oldest Pleistocene gravels in Hertfordshire and the south of England generally are however of pre-Glacial age ; the Till or Lower Glacial boulder-clay is not represented here ; and later in the Pleisto- cene period arctic conditions did not prevail uninterruptedly. Our two chief beds of gravel Professor T. McKenny Hughes long ago distinguished as ' Gravels of the Upper Plain ' and ' Gravels of the Lower Plain,' the former being the older of the two, and having been deposited by the sea which levelled the county into a plain of which we now see the remnants in the highest ground of the area of the London Clay.1 These older gravels have been investigated by several other geo- logists, and especially by the late Sir Joseph Prestwich,2 who has given to the greater part of them the name ' Westleton Shingle,' separating under the term 'Southern Drift' the gravel which caps our most southern London Clay hills and also occurs south of the Thames, this being considered of earlier formation than the pebble-gravel of Westleton and the eastern counties generally. The largest patch we have of this oldest shingle-gravel spreads over Stanmore Heath from Little Bushey to Bentley Priory at a height of 400 to 450 feet, and there are smaller patches on the hill between Pinner and Watford, and east of Stanmore on Elstree and Brockley hills, nowhere less than 380 nor more than 450 feet in height. The great ice-sheet of Norway and Britain, approaching from the north-east, does not appear to have extended farther to the south than these hills, but it is more probable that this was due to the melting of the ice than that the hills, or the range or plateau of which they then formed a part, created a barrier against its further progress. According to the views of Professor Hughes they are the remnants of an extensive plain which then existed, having been formed into hills by subsequent erosion of valleys on the north and on the south. A little to the north of these hills are others capped by true Westle- ton Shingle. All these are Tertiary hills, either forming a part of the London Basin, in which case the shingle rests directly on the London Clay, or being outliers of Reading Beds with or without London Clay. We have no Westleton Shingle lying directly on the Chalk, which seems to show that the erosion of the Tertiaries from the surface of the Chalk had not taken place when this marine pebble-gravel was deposited. Mr. 1 ' On the Two Plains of Hertfordshire and their Gravels,' Quart. Journ. Geol. Sac., vol. xxiv. p. 283 (1868). 8 In three papers on the Westleton Beds read before the Geological Society, Quart. Journ. Geol. Sac., vol. xlvi. pp. 84-119, 120-154, and 155-181 (1890). 18 GEOLOGY Whitaker gives expression to the same view from other evidence when he says : ' From its occurrence on the tops of the hills, whilst the Middle Glacial gravel often lies at their base or on their flanks, it would seem that the pebble-gravel is the older of the two, and was deposited long before those hills were cut into their present form — a process which must have been somewhat advanced before the other gravel was laid down.' ] The Westleton Shingle caps the London Clay hills between Hat- field and Hertford Heath, where they form a conspicuous range between 320 and 380 feet high, and rests on the London Clay at Shenley Hill towards the south-west. Most of the Tertiary outliers, whether of Reading Beds and London Clay or of Reading Beds alone, are also capped by this shingle. It may be well seen on the Reading outlier at Bernard's Heath, St. Albans (406 feet), where it is from 8 to 10 feet thick, and on the Reading and London Clay outliers of Ayot Green (406 feet) and Datchworth (407 feet). At a lower level it caps the outliers of Collier's End (348 feet), and Sacombe Green, north of Ware (362 feet), and at a much higher level the small outlier at Bennett's End near Hemel Hempstead (465 feet), which is partly covered by brick- earth. On the borders of Hertfordshire and Middlesex the Westleton Shingle rests on the London Clay ridge which extends from Potter's Bar to Bell Bar (380 to 400 feet), and a little to the west caps the London Clay in Mimms Wood, a mile and a half north of South Mimms (400 feet). Within a mile of our border the Reading and London Clay outlier of Tyler's Hill or Cowcroft has a small capping of this shingle at a height of about 600 feet above sea-level, and much farther to the south-west, on what was once an outlying portion of our county, the shingle caps the Tertiary outlier of Penn near Beaconsfield, at the same elevation. It is thus seen that the Westleton Shingle generally occurs at a higher level as we proceed from east to west, showing that the existing elevation of the land in that direction took place after its deposition. This inference would not follow with Glacial deposits which may have been dropped from icebergs, and occur at very different levels. Nearly all our London Clay hills and Tertiary outliers are thus seen to be capped by gravels of pre-Glacial age, remnants of a bed once of great extent. Although at one time a continuous sheet, the Westleton Shingle varies much in its composition at different places, but the greater part of it in our district is composed of well-rounded Tertiary flint-pebbles ; white quartz-pebbles and subangular flints come next in different proportions, but together usually about equal in quantity to the flint-pebbles, and the rest consists of subangular fragments of chert and ragstone of Lower Greensand age, and pebbles of white and yellow quartzite, Lydian stone, etc., with a few old-rock pebbles. In the foregoing description of the hill-gravels of the south of 1 Guide to the Geology of London, yA -d. p. 57 (1880). 19 A HISTORY OF HERTFORDSHIRE Hertfordshire the views of Sir Joseph Prestwich have been adopted, but it should be mentioned that they are not universally accepted. The correlation of these gravels with the Westleton Shjngle of Westleton has been disputed, and Mr. Clement Reid 1 now believes that the Stanmore gravel ' presents all the characteristics of an Eocene deposit.' He also remarks that ' It now seems doubtful whether outside the glaciated area any plateau gravels (i.e. gravels more than about 150 feet above the Thames) are to be found that are not either of Eocene age or derived wholly from Eocene deposits at a higher level.' A gravel derived from Eocene deposits may be of Westleton or any age subsequent to Eocene, but the higher the level the older is the gravel likely to be, and Prest- wich considered the 'southern drift' of Stanmore Heath to be older than the Westleton Shingle. After the deposition of this high-level shingle, which, with the Tertiary strata beneath it, then extended at least nearly to the edge of the present escarpment of the Chalk, the land gradually rose and the cold gradually increased until arctic conditions prevailed. A great ice- sheet spread over the Scandinavian peninsula and crept southwards over northern Britain, covering the whole of Scotland and nearly the whole of Ireland and the north of England, and extending over the Midland and Eastern counties including nearly the whole of Hertfordshire. Here it planed off the Chalk, cut away the Tertiaries, and carried off most of the Westleton Shingle, devastating the county as far south as the hills of Brockley, Elstree, and Stanmore. At the period of its greatest advance the ice-sheet terminated just north of these hills ; snow-fields rested on the highest points in North Wales, Ireland, and northern Britain, glaciers descending from them and adding their quota to the field of ice ; and here and there where evidence of ice-action is wanting there appears to have been an exposed surface of land. Eng- land was then joined to the continent of Europe, perhaps only between Kent and Normandy except by means of the ice-sheet on the north, the English Channel even then dividing the south of England from Brittany, while the Atlantic Ocean existed on the west. The climate becoming milder, the ice-sheet receded, and as the ice melted, liberating a vast volume of water, the resulting rivers took its place as a denuding agent, excavating the valleys of the Colne and Lea. It was also probably soon after the retreat of the ice-sheet that, with a very heavy rainfall, the greatest deepening of the valleys of the Thames and Ouse took place, and the present general features of the escarpment of the Chalk were impressed upon it, but in quite a different manner from that in which the Tertiary escarpment was formed. The Chalk escarpment has been and is still being cut back by the springs which issue from the Totternhoe Stone at its base, mostly at right angles with the strike of the Chalk ; the cutting back of the Tertiary escarpment is effected by the rivers which flow along its foot 1 Summary of Progress of the Geological Survey for 1899, p. 140 (1900). 20 GEOLOGY nearly parallel with the strike of the rocks (Chalk and Tertiaries). The Lea was then probably flowing off the high land of which the remnant still left is now known as part of the Chiltern Hills ; between Hatfield and Ware it has followed the trend of the Tertiary escarpment, cutting it back ; and at Amwell it has cut through this escarpment. It would appear that a vast amount of denudation must have taken place on the north-west of the present range of the Chilterns in this district since the Lea commenced to flow towards the south-east, for its source must then have been very much higher than it is now, other- wise it would have flowed in the opposite direction ; but whether this so-called ' Luton gap ' was caused by river- or ice-action is uncertain. The river which takes the name of Ver above Bricket Wood Common and of Colne below it, flowed from the same hills near Kensworth, but only from the south-east, not the north-west side of the present range, and meeting with the Tertiaries south of St. Albans has almost ever since been eating back the Tertiary escarpment past Watford and Rick- mansworth, increasing its steepness, and at Harefield it has cut through it. The chief tributaries of these rivers also flowed from the Chilterns and helped forward their erosive work, especially at the points of juncture. Although some of the main features of the county may date from Pliocene or even Miocene times, when its surface may have been even more diversified than it is at present, there can be little doubt but that many of those features were much modified over the greater part of the area during Lower Glacial times, and that it is only to the period immediately following the recession of the great ice-sheet that we can with certainty trace back the origin of our present river- valleys in the Chalk, the rivers then flowing at a higher level than they do now, but in the same general direction. The land then sank and the sea gradually encroached upon it, the extent of the submergence being much greater in the north than in the south of Britain. In the Lake district of Cumberland stratified gravels of this period are found 1,600 feet above the level of the sea, and on Moel Tryfaen in North Wales there were then deposited sands and gravels since raised 1,350 feet, containing shells of species of Mol- lusca still living in the seas around Britain. There is a similar assem- blage at Macclesfield 1,200 feet above the sea, and from the height at which the flint-gravel sand, and clay of this the Middle Glacial period are found in the south of England we may infer that Hertfordshire was depressed at least 500 feet below its present level. During this period of greatest submergence in Pleistocene times the British Islands formed a scattered archipelago ; the highest mountains of the north of Scotland were the only islands with their summits above the snow-line, for with the submergence the climate became milder, this period being an in- terglacial one ; and in Hertfordshire portions of the Chiltern Hills appeared as islands probably nowhere exceeding 200 feet in height. These Middle Glacial gravels are the ' Gravels of the Lower Plain ' first described by Professor Hughes. They vary much in composition 21 A HISTORY OF HERTFORDSHIRE and arrangement, and contain many sub-angular flints and some un- broken and almost unworn ones, with drifted Oolitic and Liassic fossils, chiefly gryphasas and belemnites, and echinoderms and other fossils de- rived from the Chalk. Much false-bedded sand also often occurs, and sometimes a bed of loam or clay. ' These deposits are exposed and may be examined in nearly all the valleys south of the Chalk escarp- ment. They may be seen in the railway-cutting north of Hatfield, and in a pit on the hill-side east of Horn's Mill. They can be traced all along the hill-side from that place to Hatfield, near Cole Green station, and south of the Mimram near Tewin. In the road-cutting south of Broad Oak End Farm, and along the west side of the Beane between that place and Hertford, some boulder-clay, with glaciated stones, occurs at the base of the gravels. In the gravel-pits near Ware, some finely-laminated brick-earth, belonging to the Mid-glacial series, is seen to be folded and crumpled up and then covered by horizontal beds in the way usually ascribed to ice-action. At Camp's Hill there is also a brick-earth in the Mid-glacial beds, beneath which bones of reindeer, mammoth, and rhinoceros have been found. Mr. S. V. Wood found at Stevenage, in the brick-earths intercalated in the Middle Glacial series, several specimens of Ostrea edulis, a non-arctic shell . . . the only instance of [contemporaneous] fossils being found in the Mid- glacial of the county.' ' The Middle Glacial beds are thus seen to be widely spread over the county, and to be very variable in their origin as well as in their nature. Possibly the prevailing impression with regard to this period does not quite accord with the facts, the term Interglacial which has been applied to it being to some extent misleading. Although the only con- temporaneous fossils known indicate a temperate climate, there are in- dications that the seas of the period were not free from icebergs. The (so-called) ' foreign rocks ' found in our Mid-glacial gravels, which must have been carried a great distance from the north, being fragments of much older rocks than occur in Hertfordshire, and the fossils derived from distant formations, indicate some other transporting agent than rivers or ocean-currents, while the presence of local patches of boulder- clay with glaciated stones, confirms the view that ice-action was not entirely absent. A temperate climate is not incompatible with the occasional presence of icebergs drifting from the north ; but the more likely explanation of the anomaly is that this period was one of long duration, generally cold but with mild intervals when a temperate molluscan fauna migrated to the seas of the British archipelago from the warmer southern waters. Such milder intervals would be most likely to occur when the depression of the land was greatest, and the 1 Elsden, 'The Post-Tertiary Deposits of Hertfordshire,' Trans. Herts Nat. Hist. Sac., vol. i. p. 105 (1881). Prestwich has recorded the finding of pieces of the tooth and tusk of an elephant in gravel, which he believed to pass under the boulder-clay, at Bricket Wood near Watford, but there is some doubt as to the position of this gravel. — Geologist, vol. i. p. 241 (1858). 22 HISTORY OF HERTFORDSHIRE OROGRAPK 45' 3O 2" 10' REFERENCE NOTE above 800 feet 600 to 800 feet 400 to 600 feet 200 to 400 feet 100 to 200 feet nelow 100 feet 3O' THE VICTORIA HISTORY OF VL MAP. •ill Wymiucllcy n.iii,, i:r-...-n l.i.-i i.i.h.ill ' &•'• i:r.\ Tl^tVltn^''' .;i- str-'j'\^^ COUNTI ES OF ENGLAND County Boundary shown thus GEOLOGY only evidence in our county of such a mild interval is the presence of Ostrea edulis where the land must have been submerged at least 300 feet, for Stevenage now stands higher than that above sea-level. The land rose and the cold increased ; the snow-line gradually extended southward from the northern islands of Scotland to the south of Ireland and South Wales ; and glaciers descended from the snow- fields and ploughed up the land at least as far south as the Chalk of the eastern counties. The debris was deposited in the depths of the valleys and on the slopes of the hills, and even up to the top of the escarpment of the Chalk, as on Reed Hill near Royston, but none is to be seen on the higher part of the escarpment towards the west, which would then be an island in the Glacial sea. This is but one of many views which are held as to the conditions under which the ' great chalky boulder- clay ' was deposited, and it seems to be the most likely, but it has been well said : ' Where, as is too often the case with Glacial deposits, there is room for much diversity of opinion, geologists fully avail themselves of it. Hence it is best to picture the Glacial period in a general way, and to admit that glaciers and ice-sheets, icebergs and coast-ice, have all had their share in the production of the phenomena, although we cannot always localize their action.1 The Upper Glacial boulder-clay (Middle Glacial of S. V. Wood) is generally known as the ' great chalky boulder-clay,' owing to the numerous boulders of chalk which it contains. It is usually a rather dark bluish-grey calcareous clay, containing chalk in all forms — ground up with it, as small pellets or pebbles, and in all gradations of size up to very large masses, most of the larger chalk boulders being so hard as to have preserved, with the protection afforded by the clay in which they are imbedded, the scratches and grooves made by contact with harder rocks whilst they were being carried along imbedded in ice, this being the meaning of the somewhat misleading term 'ice-grooved rocks.' Imbedded in the boulder-clay are also many chalk-flints ; boulders from various formations, chiefly of rocks of Jurassic age, but also of much older and more distant strata, such as Carboniferous Limestone, deeply ice-grooved ; pebbles of quartz and small boulders of granite derived from formations still more distant both in time and space ; and fossils derived chiefly from the Lias and Oxford Clay. No fossils contempora- neous with its formation have been found in it. Boulder-clay is spread over the greater part of north-east Hert- fordshire as a continuous bed except where it has been cut through by the rivers ; it covers most of the higher ground in the centre of the county where the rivers have cut more deeply into it than on the east ; and the most south-westerly patch is at Bricket Wood between St. Albans and Watford. Sections of it may be seen there and at Little Berkhamsted, Bayford, Hertford Heath, Buntingford and several other places. 1 H. B. Woodward, The Geology of England and Wales, and ed. p. 486 (1887). 23 A HISTORY OF HERTFORDSHIRE It is evident that boulder-clay once filled up most of our valleys as well as covered all but our highest hills. In the east of the county the sources of our rivers are upon it ; the rivers then cut through it in places into the Chalk ; and lower down their valleys the boulder-clay has been completely cut through by them, exposing the underlying Glacial gravel and sand. After the deposition of the boulder-clay the land again rose, but not for some time to its present level, the old shore-lines which pass through the southern counties, where they have left their mark in beach-shingle and sea-cliffs, being evidences of successive elevations of the land, at one time up to 140 feet below its present level, and subsequently to within a few feet of it.1 The shingle-beaches at various levels indicate pauses in the upheaval, and by the time the sea had receded (or rather the land had risen) so far as to form a shingle-beach at least 100 feet higher than that now forming on our coasts, the arctic climate had given place to one milder than that which now prevails. This period of upheaval marks the time when marine gravels finally ceased to be formed above the present sea-level, giving place to estuarine, alluvial, and lacustrine deposits. An instructive example of the latter is the ancient Hitchin lake-bed, for the most complete knowledge of which we are indebted to Mr. Clement Reid,8 although it has also been investigated by Sir John Evans, Mr. William Hill, Mr. William Ransom, and other Hertfordshire geologists and archsologists ; for the formation of this lake-bed and the overlying deposits embraces the period during which the study of geology gives place to that of archasology, bringing Man upon the scene. The alluvial or lacustrine deposits known as the Hitchin lake-bed lie in a channel or trough running nearly north and south, which appears to have been excavated, or re-excavated, after the deposition of the boulder-clay, the geological position of the lake-bed being between the great chalky boulder-clay, representing the close of the Glacial period in this neighbourhood, and the brick-earth in which Palasolithic flint implements are of frequent occurrence. The deposit is very variable in character, consisting of sandy, marly, and loamy beds, white, yellow, brown, and black, sometimes, from the abundance of decomposed plant- remains, even forming a lignite. It contains the teeth and bones of several mammals and fishes, remains of a few insects, the shells of many molluscs, the leaves and seeds of numerous flowering plants, several mosses, and a few charas. Most of the species still exist with us, but all the mammals have long been extinct in Britain in a wild state, and two, the mammoth and woolly rhinoceros, are altogether extinct. Their remains have all been found in a whitish marly silt which occurs locally above the deposits from which all the other fossils have been obtained. On this silt rests the Paleolithic brick-earth, which until recently yielded 1 Clement Reid, Victoria History of Hampshire, vol. i. p. 23. ' The Paleolithic Deposits at Hitchin and their relation to the Glacial Epoch,' Prac. Royal Soc., vol. Ixi. p. 40 (1897) ; Trans. Herts Nat. Hist. Sac., vol. x. p. 14 (1898). 24 GEOLOGY here the earliest traces of man ; but since the lake-bed was visited by Mr. Clement Reid a few species of mammals have been added to his list and a few flint implements have been found associated with them in this silt. It therefore seems probable that primaeval man lived on the shores of this lake and there fashioned his rude implements of flint, but we cannot be certain that this was the period of his arrival in Britain. We do not find the remains of man in these deposits, but only the results of his handiwork in rudely-chipped flints. If, therefore, man existed in Britain before he became a tool-maker we should have no trace of such existence. In a somewhat similar situation near Caddington Mr. Worthington Smith has found a workshop of Palaeolithic flint implements ; he has found the cores from which chips have been struck, and he has found the chips struck ofF them and pieced them together again. Here there are also other indications of human habitation, and, as at Hitchin, by the side of a lake. With the advent of man the geological record ceases and the archaeological begins, but there are other superficial deposits which have not yet been noticed. Such are the detritus of existing rivers, whether gravel or alluvium, sometimes much higher than their present level, showing how deep they have cut down their beds ; and accumulations of peat resulting from vegetable growth on boggy land. There are also deposits to which no definite age can be assigned, in addition to those of which the age is a subject of controversy. The formation of ' pipes ' in the Chalk has been going on ever since the Chalk was raised above sea-level and water percolated into it ; and ever since the Tertiary beds were removed from the surface of the Chalk, that surface where exposed has been ' weathered ' into clay-with-flints, this bed, which covers much of the Chalk in western Hertfordshire, being the result of surface-disintegration of chalk. Much of our brick-earth has also been forming for an indefinite period. A brief summary may now be given of the foregoing attempt to trace the history of Hertfordshire before the advent of man, from which period the story will be continued by Sir John Evans. The scene opens with a deep sea in which a calcareous deposit was forming — a sea teeming with the abundant life which characterized the Upper Silurian period. The nearest land-surface was a plateau of Cambrian rocks in the centre of England, the sea extending on the south to western France, where it washed a shore of Cambrian and Lower Silurian rocks. The sea-bed rose, and the calcareous mud, consolidated into shale and limestone, became crumpled up into folds running east and west, and on the southern flank of one of these folds there was sea in Upper Devonian times, also replete with life. This sea-bed rising, its sediment, consolidated into shale, remained for long ages a ridge of land stretching across Middlesex and the south of Hertfordshire, the highest part of this land being the Silurian hills on the north. Further crumpling or folding in nearly the same direction as before affected this Devono-Silurian tract so that the portion of it which has been dis- 25 A HISTORY OF HERTFORDSHIRE covered nearly 1,000 feet beneath the surface in south-east Herts has the Devonian rock tilted 25° from the horizontal, and the Silurian about 40°. Whilst great changes in the relative distribution of land and sea were taking place elsewhere in Britain during Carboniferous, Permian, Triassic, and earlier Jurassic times, we have no evidence that this tract sank entirely beneath the sea until we come to the Upper Cretaceous period ; but the submergence of its north-western flanks began in Upper Jurassic times ; in Lower Cretaceous the sea had reached almost to its highest point ; and it was entirely submerged during the whole of the Upper Cretaceous period, except perhaps towards the close of the deposition of the Chalk. Whether it was a land-area whilst the higher beds of the Upper Chalk were forming in the south of England, and still later whilst the Maestricht Beds of Germany were being deposited, we have no evidence to decide, but we do know that a vast amount of chalk has been carried away. Most probably it is the higher beds of the English Chalk only which have been removed by denudation, Hertfordshire, with the rest of the British region, being above the sea when the Maestricht Chalk was deposited. In early Eocene times Hertfordshire was again beneath the sea, but not at first deeply submerged. Scotland, Ireland, Wales, and the north and extreme west of England formed parts of a land-area from which sediment was brought down by rivers flowing towards the west, and for a time the climate was tropical. As the land again rose the climate became temperate, and in the Miocene period there was much volcanic activity in the north-west of Britain which probably caused some disturbance of the strata in our area. In the Pliocene period the county was apparently subjected to a vast amount of sub-aerial denudation, and then the sea encroached upon it and its diversified surface was levelled to a considerable extent into a plain of marine denudation. With the next rise of the land the climate became of arctic severity and a great ice- sheet came from the north as far as the range of London Clay hills, still further levelling the land by its erosive action. Submergence followed, and the climate became milder, but only to again become arctic with partial emergence. As the land continued to rise however, and the surface began to assume its present aspect, the climate gradually became temperate, and the most important event of all in the history of the county came to pass — the advent of man by migration from the south. It was at about this time also that England was finally severed from the continent of Europe by the formation of the Straits of Dover. The rainfall then was heavy, much of our present land was under water, our rivers rose higher up their valleys and were often in flood, streams ran down our present dry valleys or combes, and most of the county was densely wooded. Man then, probably naked and living much in trees by the margins of lakes or swamps, had to contend with the wild beasts for existence with no other weapons than such as might be made by chipping one flint with another; or perhaps to seek safety first in climbing trees, and then, gaining some insight into constructive art, by 26 GEOLOGY driving piles into the beds of lakes and building his dwellings upon them. By this time he began to take a pride in chipping his flint weapons more carefully than was necessary for the use to which they were put, and then, with infinite patience, finely polishing them. At this stage Geology merges into Pre-historic Archaeology.1 HYDRO-GEOLOGY The Chalk is our great water-bearing stratum ; firstly owing to its pervious nature, the whole of it being permeable, but its permeability or water-bearing capacity decreasing towards its base ; and secondly because the water contained in it is held up by the Gault clay on which it rests, the Upper Greensand, which usually in other districts separates these two formations, either being absent or reduced to a thin bed. The permeable Chalk and the underlying impermeable Gault dip from north- west to south-east, the gradient being at least 60 feet to the mile in the north-west and 30 feet to the mile in the south-east. The inclination of our valleys, and consequently of our rivers and of the surface of the underground water in the Chalk, is less than this, varying from about 24 feet to the mile in the north-west to about 12 feet to the mile in the south-east. In each valley the plane of permanent saturation in the Chalk, whilst sloping downwards along the course of the river, or longitudinally, with an inclination at least equal to that of the river, also slopes downwards to the river from the limit of its watershed above its source and on either side, or transversely, with an inclination less, and usually much less, than that of the sides and head of the valley. Water therefore stands lowest in the Chalk along the rivers, wherever there are springs which feed the rivers, or where the plane of saturation is artificially lowered by the water being pumped up from wells, or, generally speaking, wherever there is an outlet for it, and highest along the water-partings of the various catchment-basins, but not always exactly along them, for wherever there is a large abstraction of water from the Chalk, the plane of saturation must be lowered and the sub- terranean basin enlarged, causing the water-parting underground to recede beyond the water-parting above ground. Nearly all our rivers derive most of their supply of water from the Chalk, instead of from surface-drainage as do rivers flowing over clay or other impermeable strata, and therefore they are not dependent upon a continuous rainfall, but throughout almost the whole of the year mainly upon the rain which falls during the winter months. From experiments with percolation-gauges at Nash Mills near Hemel Hempstead, and at Lea Bridge, it has been ascertained that in the six summer months about 6 per cent, of the rain which falls finds its way through three feet of soil or chalk with grass growing on the surface, and in the six winter months 1 The author desires to express his indebtedness to Sir John Evans, Mr. Richard Lydekker and Mr. H. B. Woodward for their kindness in reading the proof of this article. 27 A HISTORY OF HERTFORDSHIRE about 46 per cent., these figures being the average results of a soil- and a chalk-gauge at Nash Mills and a soil-gauge at Lea Bridge, and the greatest difference between the average values given by either of the three gauges being 2 per cent, in the summer and 3 per cent, in the winter. The average annual percolation is therefore 26 per cent, of the rainfall. Assuming the average annual rainfall in Hertfordshire to be 26 inches, this being the average for half a century ending 1892, and also that this is equally divided between summer and winter, which it is very nearly, we have 0-78 inch percolating in the summer and 5-98 inches in the winter, giving an annual percolation of 6*76 inches. The difference between the summer and the winter percolation is due to so much of the rain being evaporated and absorbed by vegetation in the summer. It cannot be said that the whole of the water which goes down three feet into the soil reaches the plane of saturation, but the moisture which is brought up from a greater depth by absorption into the roots of trees or by capillary action cannot be so great as to materially affect these figures. It might be thought that our rivers would be highest in the winter and lowest in the summer, but such is not the case. Owing to the slowness of the percolation the surface of the plane of saturation rises for a considerable time after the rain has fallen, and consequently our rivers have in them the greatest volume of water in the spring and the least in the autumn. To the amount of rain which percolates through the Chalk should be added that which runs off the surface of the impermeable strata. It is very difficult to form any estimate of this. There must be much more evaporation from the surface of impermeable beds than from the surface of permeable beds, for wherever water stands it must be exposed much longer to evaporating influences than when it sinks beneath the surface. If it be assumed that impermeable beds yield with ordinary or not very heavy rainfall, half the amount of water that permeable beds do, we shall probably be very near the mark. The yield of the catchment-basins of the two principal rivers of Hertfordshire, the Colne and the Lea, is a question of much importance in connection with the water-supply of London. It would occupy too much space to go fully into this matter here, and for a detailed exami- nation of it reference should be made to a paper by the present writer.1 It has there been shown that, irrespective of our county boundary, the area of permeable strata in the basin of the Colne above Harefield is about 148 square miles and of impermeable strata about 87 square miles, and that the area of permeable strata in the basin of the Lea above Feilde's Weir is about 224 square miles and of impermeable strata about 1 86 square miles ; also that the probable yield from percolation through the Chalk is about 45 million gallons per diem in the Colne basin and 54 million in the Lea basin, and from water running off the surface of impermeable beds about 1 2^ million gallons per diem in the Colne basin 1 Hopkinson, ' Hertfordshire Rainfall, Percolation, and Evaporation,' Trans. Herts Nat, Hist. Soc., vol. ix. pp. 33-72, pi. i. (1896). 28 GEOLOGY and 20^ in the Lea basin, giving a total average yield for the two basins of about 132 million gallons of water per diem. Also that in three successive years the average annual supply from these two catchment- basins may be from 35 to 40 per cent, less than this average, and in six successive years about 25 per cent. less. In the same paper the inference is drawn that too much water is being taken by the New River and East London Water Companies from the basin of the Lea for the welfare of our county, and that the same would be the case in the basin of the Colne if water were supplied to London from near Harefield as has been proposed. That the plane of saturation in the valley of the Lea is being unduly lowered artificially, which can only be by excessive pumping from the deep wells of these companies, is shown by the following table which gives the average rainfall in Hertfordshire and average flow of the Chadwell Spring near Ware for twenty-four years in six-yearly periods, with ratios to the rainfall of 1842 to 1899 (April to March), and to 3,600,000 gallons per diem as the accepted mean flow of the spring up to at least the year 1874. The last column shows how the flow is rapidly decreasing in relation to the annual rainfall. RAINFALL IN HERTFORDSHIRE AND FLOW OF THE CHADWELL SPRING COMPARED Hertfordshire Mean Rainfall Spring Period Flow of to Chadwell Spring Rain- Summer Winter Year fall ins. ratio ins. ratio ins. ratio gals, per diem ratio ratio 1875-81 16-85 129 H'57 I II 31-42 I2O 3,640,000 101 84 1881-87 12-77 98 14-71 112 27-48 105 3,073,000 85 81 1887-93 13-10 IOO 12-07 92 25-17 96 2,644,000 73 76 1893-99 11-15 85 13-52 103 24-67 94 2,056,000 57 61 Some of our rivers vary greatly throughout the year, and from one year to another, in the position of their source. After a winter of heavy rainfall the inclination of the plane of saturation in the Chalk is raised, and cuts the bed of the river near the head of its valley ; but after a winter of small rainfall, and in the summer and to a greater extent in the autumn, the inclination of this plane is less, and cuts the bed of the river some distance down its valley ; and wherever the plane of satura- tion rises into or cuts a river-bed on the permeable Chalk, there is the source of the river for the time being. The Ver is a good example of these variable rivers, in some years rising above Markyate Street, and in others below Redbourn. Rivers which are called ' bournes ' are merely extreme instances of this phenomenon. Such rivers only flow occasionally after a very heavy rainfall, and especially when a wet winter is preceded by a prolonged wet period. They usually begin to flow in the spring, as soon as the rain has had time to percolate through the Chalk to its plane of satura- 29 A HISTORY OF HERTFORDSHIRE tion and to raise this plane to a steeper inclination than that of the bottom of their usually dry valleys, this frequently happening some time after all heavy rain has ceased ; they cease to flow when they have conveyed away a sufficient quantity of water to reduce the level of the plane of saturation to that of their beds. Our Hertfordshire Bourne1 is a tributary of the Bulbourne, into which it flows, occasionally, at Bourne End, a small hamlet about half-way between Berkhamsted and Boxmoor. It sometimes has its source about four miles up its valley, and it has been known to run in such a powerful stream as to overflow the usually dry culvert under the road at Bourne End, and to flood this road. The Bourne flowed about once in every seven years between 1852 and 1873, and about once every alternate year from 1873 to 1883. It has only flowed since then in 1897, after an interval of quiescence of fourteen years. On each of these occasions the mean rainfall in Hertfordshire for the twelve months ending 3151 March of the year of flow exceeded 30 inches. The ' bourne,' if such it may be called, which occasionally forms the source of the Colne, is one of a very different kind. For a certain distance it flows over the London Clay and therefore always runs with or after rain, but where it leaves this impervious bed for the Chalk it usually ends, at least on the surface, giving to that place the name of ' Waterend.' It disappears in a ' swallow-hole ' in the Chalk. If this cannot take it all there is another ready a little farther on, and so on as far as the swallow-holes at Potterells near North Mimms. Seldom does any water get beyond these great chasms, down one of which at least a man might be carried ; but sometimes they cannot take it all, not because they have not sufficient capacity, but because they are full owing to the plane of saturation having risen in the Chalk up to their capacious mouths. Then there is a flood, the river forms a lake hiding the swallow-holes from view, and the bed of the Colne, dry for some distance below this point year after year, is unable to carry off all the water, its banks overflowing, submerging the meadows, and rendering some of the roads between Colney Heath and Smallford impassable. The water which sinks into these swallow-holes is probably conveyed in channels in the Chalk into the lower part of the valley of the Lea, for that would be its direction if it follows the dip of the Chalk. There are several interesting questions connected with this phenomenon which have been discussed elsewhere.2 We have also many valleys, sometimes several miles in extent, down which rivers have not been known to run in historic times. Such dry valleys are merely elongated Chalk combes. They were probably formed when the impermeable Tertiary beds extended over the permeable 1 Evans, 'The Hertfordshire Bourne,' Trans. Watford Nat. Hist. Soc., vol. i. p. 137 (1877) ; Littleboy, 'The River Bourne,' Trans. Herts Nat. Hist. Soc., vol. ii. p. 237 (1883); Hopkinson, ' The Chadwell Spring and the Hertfordshire Bourne,' op. cit. vol. x. p. 69 (1899). The above explanation of the flowing of the Bourne is from the paper by Sir John Evans. 8 Hopkinson, 'The River Colne and the Swallow-holes at Potterells,' Trans. Herts. Nat. Hist. Soc., vol. vi. p. xxix. (1892). 30 GEOLOGY Cretaceous, at which time a great part of the rainfall would collect on the clay and form into streams which would cut deep channels in it and through it into the underlying Chalk, instead of a small part of the rain percolating through the Chalk and the greater part evaporating or being absorbed by vegetation, as at the present time ; or perhaps later, after the Tertiaries had been removed, when the moister climate and consequent higher plane of saturation of the Chalk would suffice, as under the former supposition, to cause rivers to flow in our now dry valleys. But since the removal of the Tertiaries by denudation, or the lowering of the plane of saturation by the drier climate and the artificial abstraction of water by means of wells sunk into the Chalk, these valleys have prob- ably been and are still being deepened by the Chalk being dissolved and carried away by percolation in the manner previously mentioned. In some instances the plane of saturation occasionally rises to the bottom of these valleys, when a little water may be found in them in places, as in one near Watford on the west of The Grove and Cassiobury Park, but as a rule the water-level in the Chalk is now permanently below the lowest points in these valleys. Under natural conditions in any Chalk area there must be a slight tendency for the plane of saturation to become lower, owing to the loss of internal heat by our earth allowing of water percolating further into it, and to the gradual reduction in the rainfall from causes which need not be considered here, but these are secular changes which must be altogether imperceptible to us. The removal of the forests which once covered most of our county was the first artificial aid which man, far too prone to interfere with his Maker's provident arrangements for his comfort and welfare, gave to the acceleration of this natural process ; the deep drainage of the land followed, causing water to flow away more rapidly, and thus giving it less time to sink into the Chalk ; but nothing could possibly have a more prejudicial effect upon our enjoyment of the country and upon such of our industries as are dependent upon a plenti- ful water-supply, than the folly of which certain water companies are guilty of taking water out of our underground Chalk reservoir more rapidly than it flows into it. By thus emptying it from the bottom a void is created which must be filled up from the top, and the certain result follows that our watercress-beds, which should yield our most valuable natural produce next to agriculture which is also prejudicially affected, become dry, our water-power decreases, and our rivers cease to flow in the higher part of their courses. The water companies are thus continually adding to the extent, and may eventually add to the number, of the dry valleys of Hertfordshire. CLIMATE SOME of the principal elements of the climate of Hertfordshire may be ascertained by examining maps in a meteorological atlas, such as the Meteorological Atlas of the British Islands issued by the Meteorological Council, or the splendid Atlas of Meteorology recently published which forms volume iii. of Bartholomew's Physical Atlas.1 Here for instance may be ascertained approximately the monthly as well as the annual temperature and rainfall of the county, with the advantage of easy comparison with the same elements of the climate of other parts of the British Isles, of Europe, or of the world. But climate is such a complex phenomenon that any views thus formed must be wanting in definiteness. Not only have we to consider the rainfall, temperature, humidity, amount of cloud, and direction of the wind, but also the nature of the soil, the extent of water, of woods, of barren heaths and cultivated land, and the presence or absence of manu- facturing districts. More than three centuries ago Norden said of Hertfordshire : ' The ayre for the most part is very salutarie, and in regard thereof many sweete and pleasant dwellinges, healthfull by nature and profitable by arte and Industrie, are planted there.' 2 Sixty-five years later Fuller remarked : ' It is the garden of England for delight, and men commonly say that such who buy a house in Hertfordshire pay two years' purchase for the aire thereof.' 3 Thus the salubrity of Hertfordshire had by then become proverbial, and the county is certainly favoured from a hygienic point of view, having a dry soil, being hilly though not mountainous, with a great extent of surface considerably elevated above sea-level, being well watered with numerous rivers deriving their supply chiefly from springs in the Chalk, and therefore pure, being well wooded, having many parks and country seats, a fair proportion of uncultivated land forming gorse-covered commons, and wide stretches of grass on each side of many of its roads (roadside wastes), and also by the absence of manufacturing towns. There is no industry which interferes with the purity of the air, and the only manufacturing process by which the rivers are contaminated is that of paper-making. There are several 1 The Physical Atlas, byj. G. Bartholomew, F.R.G.S. (London: Archibald Constable & Co., Ltd.). In progress. ! The Description of Hartfordshire, p. 2 (1597). 3 The Worthies of England, part 2, p. 17 (1662). 1 33 D A HISTORY OF HERTFORDSHIRE paper-mills in the valleys, and by the refuse carried into the rivers their water is frequently rendered turbid and their fish have sometimes been killed. This does not occur however to any great degree, and no better gauge of the general purity of the rivers of Hertfordshire can be found than the extent to which watercresses are cultivated. For them to thrive the water must be clear, it must flow from gravel or chalk, and there must be a constant gentle stream. The chief elements of climate are rainfall and temperature. The mean temperature of a district of small area compared with that of the country in which it is situated is chiefly governed by its lateral or geographical position, the mean rainfall by its vertical or orographical position, both elements being greatly influenced by aspect. Thus a slope facing south will generally be warmer and have a greater range of temperature than a northern slope, and a slope facing west or south-west will generally have a greater rainfall than an eastern or north-eastern slope. The general south-eastern inclination of the surface of the county is perhaps too slight to affect the temperature, but the rainfall is greatly affected by the form of the ground, the southern and western hills at- tracting the rain, which chiefly comes from the south-west, so greatly that with a mean annual rainfall for the whole of the county of about 26 inches, there is a difference of 3! inches between the rainfall of the river-basin of the Colne on the west and that of the river-basin of the Lea on the east, the former having 28 inches and the latter 24! inches. (The mean of these is 26^ inches but that is reduced to 26 inches by the disparity of area, the Lea basin being much larger than the Colne.) There have been published annually in the Transactions of the Hert- fordshire Natural History Society some of the results of observations taken at five meteorological stations during the twelve years 1887 to 1898. It is believed that this period is a sufficiently long one, and that the stations are sufficiently numerous and widely-distributed, for the results of the observations to be of value in enabling us to arrive at a knowledge of the chief elements of the climate of the county except the rainfall. To deduce the average rainfall over an area of 630 square miles, and to form an idea of the extremes, five stations are inadequate, and the period of twelve years is much too short. Although therefore the rainfall is tabulated from these observations, additional tables will be given showing certain features of the rainfall at a much larger number of stations for periods varying from thirty to sixty years. The five meteorological stations are Royston, Berkhamsted, St. Albans, Bennington, and New Barnet, the first of these no longer exist- ing. At all these stations observations have been taken in a uniform manner with verified instruments similarly placed except as to the ex- posure of the thermometers for ascertaining the temperature of the air in the shade. At Bennington, St. Albans, and Berkhamsted the ther- mometers are in ' Stevenson ' louvre-boarded screens in accordance with the regulations of the Royal Meteorological Society ; at Royston and New Barnet under ' Glaisher ' open screens as at most of the stations 34 CLIMATE contributing to the Quarterly Weather Reports of the Registrar-General. The ' Stevenson ' screen affords a complete protection from the effects of radiation by which the thermometers under the ' Glaisher ' screen are cooled below the temperature of the air at night, and of reflection by which those in a ' Glaisher ' screen may be heated above the tempera- ture of the air on sunshiny days. The result is that while the observa- tions at Berkhamsted, St. Albans, and Bennington are strictly com- parable, the greater range of temperature shown at Royston and New Barnet is due, at least for the most part, to the exposure of the ther- mometers and not to any actual excess in the range at these two places. From experiments which have been made with the two kinds of screens it appears that it is only in the range of temperature that they give divergent results, the determination of the mean temperature not being sensibly affected. All the observations which are here utilized have been taken at 9 a.m., and entered to the day of observation, except the maximum tem- perature and the rainfall which are entered to the previous day. The regulation that the thermometers should be 4 feet above the ground and over grass has in all cases been adhered to. The position of the stations, and the names of the observers, etc., are as follows : — Royston (London Road). — Latitude: 52° 2' 34" N. Longitude: o° i' 8" W. Altitude : 301 feet. Observer : (the late) Hale Wor- tham, F.R.Met.Soc. Rain-gauge 8 inches in diameter, rim 6 inches above the ground. The observations were discontinued on the death of the observer early in the year 1899. The instruments were on the east side of, and not far from the house, the ground sloping down towards the east, and the exposure being sufficiently open. Berkbamsted (Rosebank}. — Latitude: 51° 45' 40" N. Longitude: o° 33' 30" W. Altitude : 400 feet. Observer : Edward Mawley, Sec. R.Met.Soc. Rain-gauge 8 inches in diameter, rim i foot above the ground. The instruments are some distance from the house on ground sloping down towards the south-west, the situation being quite open. There are numerous meteorological instruments, including several which are self-recording, this being one of the most perfectly equipped meteoro- logical observatories in this country. St. Albans (The Grange}. — Latitude: 51° 45' 9" N. Longitude: o° 20' 7" W. Altitude : 380 feet. Observer : John Hopkinson, F.R. Met.Soc. Rain-gauge 5 inches in diameter, rim i foot above the ground. Full particulars of this station, a very open situation, with a complete record of the observations from 1887 to 1896, have been given by the observer in a paper on ' The Climate of St. Albans ' in the Transactions of the Hertfordshire Natural History Society (vol. ix. pp. 215-228). The observations were discontinued here early in the year 1900 owing to the removal of the observer from St. Albans to Wat- ford. They are continued at the Hertfordshire County Museum, St. Albans, to which institution the thermometers, thermometer-screen, and 35 A HISTORY OF HERTFORDSHIRE rain-gauge have been presented, with the object of securing the per- manence of the station. Bennlngton (Bennington House). — Latitude : 51° 53' 45" N. Longi- tude : o° 5' 20" W. Altitude : 407 feet. Observer : Rev. J. D. Parker, LL.D., F.R.Met.Soc. Rain-gauge 5 inches in diameter, rim i foot above the ground. The instruments are a considerable dis- tance from the house and in a very exposed situation on the high ground overlooking a great extent of undulating country on the north and east. The situation is a very fine one and admirably adapted for showing what is the climate of the Chalk hills of the north of the county. There are numerous meteorological instruments. New Barnet (Gas Works). — Latitude : 51° 38' 5" N. Longitude : o° 10' 15" W. Altitude: 212 feet. Observer: T. H. Martin, M.Inst.C.E. Rain-gauge 8 inches in diameter, rim i foot above the ground. The instruments are near the office of the Barnet Gas Company, apparently in a rather damp situation. Although not an ideal one for the purpose, it well represents the London Clay district on the north of London. This is the only Hertfordshire meteorological station which is not on the Chalk. There is not one of the home counties which is better supplied, for its area, with meteorological stations than is Hertfordshire, not- withstanding the discontinuance of the Royston station, and the obser- vatories are wide apart, and represent hill and valley, and chalky, gravelly, and clayey soils. Tables I. to IV. give some of the results of observations taken at these five stations during the twelve years 188710 1898. The annual means, with extremes of temperature, are given in Table I. The mean temperature of 48*3° is very little departed from at any station, Royston only showing a greater departure than 0*3°. It is remarkable that this, the most northern station, should have a mean temperature o'7° higher than that of any of the other four places. There is a very close agreement between the mean minimum (or night) temperature at each station except New Barnet where it is i'9° below the mean of the other four : this is probably due in part to the kind of screen used, but chiefly to the low position and the nature of the subsoil, London Clay, which retains moisture and induces ground-fogs by which the air is rendered colder at night than it would be in a higher position and on a drier stratum. The clay is however here capped by a thin stratum of gravel. The mean maximum (or day) temperatures are in still closer agreement, the excess at Royston and New Barnet being fully accounted for by the ' Glaisher ' stand being used at these two places. This, as already mentioned, accounts for the greater range of temperature at Royston and New Barnet than at Berkhamsted, St. Albans, and Ben- nington. The only other point in this table calling for remark is the small number of rainy days registered at New Barnet owing to the omis- sion of the measurement of small falls of rain and snow, but this does not affect the amount registered. 36 CLIMATE TABLE I RESULTS OF CLIMATOLOGICAL OBSERVATIONS FOR EACH STATION, 1887-0 Temperature of the Air Hu- Rain Stations Means Extremes midity Cloud, Mean Min. Max. Range Min. Max. Per O— IO Amount Days deg. deg. deg. deg. deg. deg. cent. ins. Royston . 49-0 40-8 57-1 16-3 3'5 93-0 83 6-7 22-21 161 Berkhamsted 48-1 40-3 55-8 15-5 7'5 91-0 82 7-2 25-60 I76 St. Albans . . 48-3 41-1 55'4 14-3 IO-I 91-0 82 6-7 26-OO 181 Bennington . 48-0 40-7 55'3 14-6 9'5 90-9 81 7'3 23-89 182 New Barnet 48-1 38-8 57'5 18-7 I'O 94'5 83 6-2 2373 139 County . 48-3 40-3 56-2 15-9 i-o 94'5 82 6-7 24-29 168 Tables II., III., and IV. give the means at these five stations of the same elements of climate (air-temperature, humidity, cloud, and rain), with the extremes of temperature, for each of the twelve years, for the average of the twelve years in each season and in each month, and the annual results for the whole period, which of course are the same as in the first table. It will be seen that the second half of this period was much warmer than the first half, had a greater range of temperature, both mean daily and absolute, a drier air, a little brighter sky, and a rather smaller rainfall. TABLE II RESULTS OF CLIMATOLOGICAL OBSERVATIONS FOR EACH YEAR, 1887-98 Temperature of the Air Hu- Rain Year Means Extremes midity Cloud, Mean Min. Max. Range Min. Max. Per I-IO Amount Days deg. deg. deg. deg. deg. deg. cent. ins. 1887 47-0 38-9 SS'i 16-2 8-0 89-4 81 6-5 19-07 I$I 1888 47-0 39'9 54'i 14-2 14-6 86-5 85 7'4 24-94 !84 1889 47-8 40-5 55-2 147 12-7 85-0 85 7-0 27-09 179 1890 47'9 40-0 55-8 1.5-8 4-3 837 83 6-8 22-40 170 1891 47'5 397 55'3 I5'6 7-5 83-4 84 6-7 28-58 187 1892 47-0 38-9 55-0 16-1 I I-O 86-0 82 6-S 25-02 1 66 1893 50-0 41-0 59-1 18-1 I2'O 94'5 78 6-0 22-28 152 1894 49-0 41-4 56-6 15-2 4-0 85-0 83 6-7 27-58 192 1895 48-1 39-6 56-6 17-0 I'D 86-9 81 6-5 24-08 150 1896 48-9 41-0 56-9 15-9 15-0 89-5 82 6-9 26-09 165 1897 49-1 4i-3 56-9 15-6 15-0 88-8 82 7-1 24-76 163 1898 50-2 42-0 58-3 16-3 16-0 91-8 81 6-9 19-57 i55 Mean . 48-3 4°'3 56-2 15-9 IO'I 87-5 82 6-7 24-29 1 68 37 A HISTORY OF HERTFORDSHIRE TABLE III SEASONAL RESULTS OF CLIMATOLOGICAL OBSERVATIONS, 1887-98 Temperature of the Air Hu- Rain Seasons Means Extremes midity Cloud, Mean Min. Max. Range Min. Max. Per O— IO Amount Days deg. deg. deg. deg. deg. deg. cent. ins. Spring . . . 46-6 37'5 55-6 18-1 9-0 86-6 79 6-5 5-03 39 Summer . . . 60-2 50-4 70-0 19-6 29-0 94'5 75 6-6 6-93 40 Autumn . 49-2 41-8 56-6 14-8 I5-0 91-8 86 6-6 7-29 45 Winter . . . 37-2 317 42-7 I I'O 1-0 65-3 89 7-2 5-04 44 TABLE IV MONTHLY RESULTS OF CLIMATOLOGICAL OBSERVATIONS, 1887-98 Temperature of the Air Hu- Rain Months Means Extremes midity Cloud, Mean Min. Max. Range Min. Max. Per O-IO Amount Days deg. deg. deg. deg. deg. deg. cent. ins. January . 36-1 31-1 41-1 IO'O 4-0 59-8 90 7'5 •62 16 February . . 377 31-5 43'8 I2'3 I'O b5'3 «7 7-0 '31 12 March . 41-2 33'4 49.0 I5-b 9-0 68-0 83 67 '95 15 April. . . . 46-2 36-7 557 19-0 17-8 82-9 ?8 6-5 '31 12 May .... 52-3 42-4 62-2 19-8 2 I'O 86-6 75 6-3 77 12 June .... 59-0 48-8 69-3 20-5 29'O 90-0 75 6-6 73 II July .... 6ro SI'S 70-8 19-5 34'° 90-3 74 67 2-54 14 August . 60-6 51-1 70-0 18-9 33"! 94'5 76 6-4 2-66 15 September . 56-6 47-6 657 18-1 2S-8 91-8 82 6-0 1-91 12 October . . . 48-0 40-6 55'4 14-8 16-0 74'3 87 6-4 2-89 17 November . 43'° 37'3 48-7 11-4 15-0 64-0 90 7'5 2-49 16 December . 37'9 32-5 43'2 107 4'3 59-0 90 7-1 2'II 16 Year. . . . 48-3 40-3 56-2 15-9 I'O 94'5 82 6-7 24-29 168 In dividing the year into seasons, March, April, and May are con- sidered as spring ; June, July, and August as summer ; September, October, and November as autumn ; and December, January, and February as winter. Autumn is warmer than spring by 2*6°, almost entirely owing to the colder nights in spring, but the excess of temperature of summer over that of winter is much more due to the warm days in summer than to the cold nights in winter. Spring is 9 '4° warmer than winter, and summer is 13 -6° warmer than spring; autumn is ii'o° colder than summer, and winter is i2-o° colder than autumn. Thus the transition from spring to summer is the greatest, and that from winter to spring is the least. Autumn and winter are much more humid than spring and summer, but the rainfall is much greater in summer and autumn than it 38 CLIMATE is in winter and spring ; autumn and winter, however, have a greater number of wet days than spring and summer. January is on the average the coldest month, and July the warmest. Assuming that the mean temperature of each month occurs about the middle of the month, it would appear that the increase of temperature is most rapid during the month of May, and that the decrease is most rapid during September and October. In two months only, July and August, has the temperature never been below freezing-point (32°), and in two months only, December and January, has it never exceeded 62°. Tables V., VI., and VII. give particulars of the rainfall for the longest available period under each heading. A day of rain is one on which at least o-oi in. of rain falls, any fall of 0-005 "*• to °'OO9 in- being considered as o'oi in. TABLE V MEAN AND EXTREME RAINFALL FOR 60 YEARS (1840-99) Mean Rainfall Extreme TV/f «.U iviontfis I station 2 stations 7 stations I 2 stations 1 8 stations 20 stations Mean Min. Max. 1 840-49 1850-59 1860-69 1870-79 1880-89 1890-99 1840-99 1854 1852 inches inches inches inches inches inches inches inches inches January . 2'24 2'2O 2'8o 2-58 171 •8 1 2'22 1-68 4-85 February . 1-92 I-I9 i-67 1-82 1-95 '37 I-65 1-14 1-26 March 1-51 1-25 2-04 l-67 l-58 •82 I-65 •28 '31 April . i'S4 1-88 1-50 2'05 1-91 •26 1-69 77 76 May . . 2-08 2-22 2-18 2-13 2'06 •66 2'OD 3-58 2-14 June . . 171 2-06 2-39 2'34 1-99 79 2-05 •85 4-28 July . . 2'12 3-I5 r86 2-64 2-74 2-39 2-48 1-72 3-94 August . 2-30 2-55 2-55 2'6o 1-92 2-75 2-44 r§7 3'93 September 2-45 2'OO 2-47 2-64 2-60 1-96 2-35 •55 3-21 October . 3-34 3'22 2'39 2-56 3-i8 3-09 2-96 2-33 4-06 November 2-85 2-23 2-10 2-76 2-84 2-56 2-56 i'37 6-27 December 176 i-55 2-16 2-18 2-26 2*32 2*04 i-53 2-58 Year . . 25-82 25-50 26-II 27-97 26-74 24-78 26-15 17-67 37-59 TABLE VI MEAN NUMBER OF DAYS OF RAIN FOR 30 YEARS (1870-99) Months 1870-79 1880-89 1 890-99 1870-99 Months 1870-79 1880-89 1890-99 1870-99 January . 16 H 16 15 July . . '3 15 '3 14 February . IS '3 12 '3 August . 14 '3 15 H March . H 1 1 14 13 September 13 '3 12 *3 April . . 13 H 12 '3 October . 15 16 16 16 May . . 13 12 12 12 November 16 16 15 16 June . . H II 12 12 December 15 16 16 16 Year . . 171 164 165 167 39 A HISTORY OF HERTFORDSHIRE TABLE VII MEAN RAINFALL IN EACH DISTRICT, WITH ITS RELATION TO COUNTY MEAN River District 1860-69 1870-79 1880-89 1890-99 inches per cent. inches per cent. inches per cent. inches per cent. Cam : Rhee . . . 23-47 — IO 23'55 -16 23.50 - 12 22-37 — IO Ivel Hiz . . . . 23-89 -9 25-61 -8 25-27 -5 23-61 -5 Thame : Up. Thame — — — — — — 26-10 + 5 r Bulbourne 29-2O + 12 31-00 + ii 29-60 + IO 25-94 + 5 Gade . . . 26'29 + I 28-59 + 2 28-46 + 6 25-87 + 5 Colne{ Ver ... 27-45 + 5 29-56 + 6 28-44 + 6 26-35 + 6 1 Upper Colne . — — — — — 24-64 = v. Lower Colne . — 27-63 — i 30-98 + 16 26-54 + 7 ' Mimram — — 25-58 -4 23-82 -4 Beane . — 26-25 -6 — — 24-61 /-,_ , Rib .... — — — 25-04 -6 24-22 — 2 Lita • Ash .... — 26-24 -6 25-98 -3 24-82 = Upper Lea . . 25-OI -4 27-10 -3 24-69 -8 23-11 -7 ^ Lower Lea . — — 27-78 + 4 23-65 -5 During the last half-century there have been falls of rain of at least z\ inches in twenty-four hours on twelve occasions. On the lath of July, 1889, such a fall occurred at eighteen stations out of thirty then recording, and at least 3! inches at four of these. Falls of at least 3 inches have occurred on seven occasions, and of at least 3! inches on 30th June, 1878 ; I2th July, 1889, the day with the greatest average rainfall at all stations ; and iyth July, 1890, the day with the greatest fall of rain at any one station, viz. 4' 19 inches at Moor Park, Rick- mansworth. Two other elements of climate, viz., sunshine and wind, remain for consideration, but can only be very briefly noticed. The following are averages for the twelve years 1887-98 for wind at Berkhamsted, St. Albans, and Bennington, and for sunshine at Berkhamsted only. The prevailing direction of the wind is from S.W. (sixty-one days in the year) to W. (sixty-two days), and the next most frequent winds are N. to N.E. and S. (each about thirty-seven days). The least frequent are S.E. (twenty-five days). About forty-four days in the year are re- corded as calm. March is the most windy month, June the calmest. The duration of bright sunshine is least in December and greatest in May; December having rather more than an hour a day, and May nearly six and a half hours. Throughout the year the sun shines brightly for nearly four hours a day. 40 H PALEONTOLOGY ERTFORDSHIRE is a county singularly deficient in interest so far as the palaeontology of vertebrated animals is concerned. Not only does it lack any fauna of extinct vertebrates peculiar to itself, but it is extremely poor in vertebrate remains of any description ; its gravels being generally devoid of the teeth and bones of the larger mammals, while very few remains of the lower vertebrates appear to have been yielded (or at any rate recorded) from the chalk of the county. There is however one very notable exception as regards the fossils of the chalk. This is an imperfect tooth of an iguanodont reptile from the Totternhoe stone near Hitchin described by Mr. E. T. Newton1 under the provisional designation of Iguanodon hilli. The iguanodons, it may be observed, form a group of gigantic extinct reptiles which walked exclusively on their three-toed hind limbs, and are specially characterized by the peculiar structure of their teeth. These latter have serrated margins and a sculptured external surface, and were adapted for a veget- able diet, wearing down by use after the manner of those of herbivorous mammals. The Hitchin specimen differs somewhat from the teeth of Iguanodon mantelli from the Sussex Wealden in the sculpture of the outer surface, and may possibly indicate a distinct generic type. It is of especial interest as being the most modern iguanodont fossil hitherto found in England ; while it has a local interest on account of being the only vertebrate fossil hitherto described as peculiar to Hertfordshire. If careful collecting of the fossils in the Hertfordshire chalk were undertaken it is probable that examples of many of the commoner kinds of Cretaceous fishes might be obtained. From the chalk of Tring the British Museum possesses seven teeth of the Cretaceous ray, scientifically known as Ptycbodus decurrens ; while the same collection likewise contains a lower median tooth of the allied species, Pt. iatitsimus, from the chalk of Hertford. Ptychodus teeth may be recognized by their quadrangular form and ridged centre ; the margins of each tooth being minutely pustulated. They were arranged so as to form a pavement in the mouth, and were adapted to crush shellfish and crustaceans, like those of modern skates and rays. Four teeth from the London Clay of Hertford preserved in the British Museum belong to a common Cretaceous shark, Odontaspis elegans. A fragmentary bone from the London Clay of Watford has 1 Geo/ogical Magazine, decade iii. vol. viii. p. 49 (1892). 41 A HISTORY OF HERTFORDSHIRE been assigned by Sir Richard Owen1 to the Ungulate genus Hyraco- therium, but the specimen has unfortunately been lost, so that the de- termination cannot be verified. As already mentioned, mammalian remains appear to be very scarce in the gravels of the county. In 1858 however the late Sir J. Prest- wich 2 recorded the occurrence of a molar and tusk of an elephant (probably the mammoth) at Bricket Wood near Watford. And the present writer has been shown antlers of the red deer (Cervus elaphus) from a gravel bed at Haileybury, where other mammalian remains are said to occur. As mentioned in the chapter on the geology of the county, bones of the reindeer (Rangifer tarandus), mammoth (Elepbas primigenius], and woolly rhinoceros (Rhinoceros antiquitatis) have been disinterred from beneath a bed of brickearth at Camp's Hill. Mr. J. V. Elsden 3 also mentions that mammalian bones are occasionally met with in the gravels near Essendon, Hatfield and St. Albans, although it does not appear that the list of species met with has ever been worked out. From the Hitchin lake-bed (see chapter on Geology) the following mammals have been recorded by Mr. C. Reid,4 viz., brown bear (Ursus arctus),6 Pleistocene horse (Equus caballus fossilis), woolly rhinoceros (Rhinoceros antiquitatis} ,6 Pleistocene hippopotamus (Hippopotamus amphibius major], red deer (Cervus elaphus] and mammoth (Elepbas primigenius) . A few other existing species were subsequently added 8 to this list, which likewise includes several living kinds of fish, such as the perch, pike, roach and tench. It may be added that the coprolite-pits in the Cambridge Green- sand at Ashwell have doubtless yielded some of the vertebrate remains so common in those deposits in the adjacent counties, but it does not appear that any record of such has ever been compiled. 1 front. Watford Nat. Hist. Soc., vol. i. p. 170 (1877). 8 Geofogilt, vol. i. p. 241. * Trans. Herts Nat. Hist. Soc., vol. i. p. 106 (1881). * Proc. Royal Society, vol. Ixi. p. 44 (1897). 6 In these cases Mr. Reid did not determine the species, which are named on account of the associated forms. 6 See Reid, Trans. Herts Nat. Hist. Soc., vol. x. p. 14 (1898). HISTORY OF HERTFORDSHIRE BOTANIC* LIST OF BOTANICAL DISTRICTS Based on the River Basins. II. lael til. Thame IV. Colne V. Brent VI. Lea <;^iA, • *- A ir.?ij _ u . ' - • .• ^ .. , THE VI CTORIA HI STORY DISTRICTS. HE COUNTI ES OF ENGLAND BOTANY r~ ~^HE botany of Hertfordshire has been thoroughly investigated with the exception of a few groups of cryptogamic plants, our knowledge of the lichens and of some of the microscopic fungi being the least extensive. Two floras of the county have been published. The first, the Flora Hertfordiensis of Webb and Coleman, which appeared in 1849, with supplements in 1851 and 1859, is noteworthy as being the first flora in which a county was divided into districts based upon the natural divisions of river-basins, a method now almost universally adopted. It originated in a list of local plants drawn up by the Rev. W. H. Coleman when residing at Hertford in 1838, and most of the records are his, the Rev. R. H. Webb, rector of Essendon, being responsible for the arrangement and production of the work. On the death of Mr. Webb in 1879, the botanical correspondence, manuscripts, and herbaria of Webb and Cole- man, and Mr. Webb's botanical library, were presented by Mrs. Webb to the Hertfordshire Natural History Society. In 1874 Alfred Reginald Pryor commenced the preparation of a new flora of Hertfordshire, working assiduously at it in the field and in the study until his death in 1881, except when interrupted, as he frequently was, by illness. He bequeathed to the Hertfordshire Natural History Society his botanical library, manuscripts, and the sum of £100. The result was that the society undertook the publication of Mr. Pryor's unfinished flora, securing the services of Mr. B. Daydon Jackson, botani- cal secretary of the Linnean Society, as editor. This work 1 forms the basis of the present article. The classification and nomenclature, which are in accordance with Nyman's Conspectus Florae Europeeee (1878—85), have here been altered in order to conform as far as possible with Hooker's Student's Flora of the British Islands (3rd ed. 1884). This has proved to be a tedious operation, for Mr. Pryor worked with Babington's Manual, and with Nyman's Conspectus as the successive parts of that work appeared, and his views on nomenclature differed as widely as possible from those of Sir Joseph Hooker. The forms which he considered to be distinct species are here as a rule treated as such, but in the flowering plants Hooker's names are in all cases adopted, Pryor's, when better known or more generally used, being added within brackets. 1 A Flora of Hertfordshire, by the late Alfred Reginald Pryor, edited for the Hertfordshire Natural History Society by Benjamin Daydon Jackson, with an Introduction on the Geology, Climate, Botanical History, etc., of the County, by John Hopkinson and the Editor, pp. Iviii. 588 (London and Hertford, 1887). 43 A HISTORY OF HERTFORDSHIRE PHANEROGAMIA The most interesting questions to determine with regard to the flowering plants of our county are how and when they were introduced, and what changes have taken place, or are doing so, in the character of the flora. It is essentially of a southern type, possessing but few northern species, and these are ' mostly rarities and numerically quite insufficient to modify the aspect of vegetation.' 1 To show what is meant by this it is necessary to state that the flora of Britain is a derived one, having originally been introduced from the continent of Europe somewhere about the Glacial period, with many subsequent accessions. Most of our commoner species have come from central Europe, whence they have spread over the whole of the British Isles, some northern species having a Scandinavian origin and some southern species having migrated from France and Spain. It is these which greatly predominate over the northern species in Hertfordshire. The introduction of some of our existing species may date from before the Glacial period, part of our small arctic flora may have been introduced from the Scandinavian peninsula during this period, but by far the greater number of our widely diffused plants appear to have followed the retreat of the ice towards the close of the Glacial period, migrating into this country from the great Germanic plain. Although at that time the present main features of the surface of the county had been impressed upon it, sub-aerial denudation has been actively going on for the countless ages during which man has been upon the scene, and a vast amount of material has been removed. But this erosion has been effected by our existing rivers flowing in the same general direction as they do now, though at higher and higher levels as we trace them back in time. The flora of the county would not necessarily be thereby affected, but it has doubtless been modified to some extent by the clearing of forests and the draining of land. Hertfordshire was undoubtedly much more densely wooded in past times, even within the historic period, than it is now ; the sources of our rivers were much higher ; streams ran down many valleys which are now dry ; and early man had to seek the higher ground away from the morasses which have left evidence of their former existence in beds of peat, or perhaps as elsewhere to seek safety from the wild beasts which prowled over the country by erecting his dwellings over lakes which have long ceased to exist. That the flora of Hertfordshire between the close of the Glacial period and the advent of man was not widely different from what it is at the present day may be gathered from the following list of flowering plants determined by Mr. Clement Reid from the ancient lake-bed at Hitchin : 2 Ranunculus aquatilis (aggregate), R. sceleratus, R. repens, Montia 1 Flora of Hertfordshire, p. 558. » 'The Palaeolithic Deposits at Hitchin,' Trans. Herts Nat. Hist. Sac. vol. x. pp. 18, 19 (1898). 44 BOTANY fontana, Prunus spinosa, Poterium officinale, Pyrus torminalis (?), Hippuris "vulgaris, Myriophyllum, Cornus sanguinea, Sambucus nigra, Eupatorium cannabinum, Fraxinus excelsior, Menyantbes trifoliata, Lycopus europeeus, Ajuga reptans, Alnus glutinosa, Quercus robur, Ceratopbyllum demersum, Sparganium, Potamogeton crispus (and two other species of the genus), Naias marina, Scirpus lacustris (and one other species), Carex. Several species of Chara also occur. Mr. Reid remarks : ' Such trees as the oak, ash, sloe, cornel, elder, and alder point unmistakably to a temperate climate, and the fauna and flora as a whole suggest climatic conditions not differing greatly from those we now enjoy. . . . The occurrence of Naias marina, now only found in Britain in two of the Norfolk Broads, is singular, though the plant was evidently more common in former times than it is at the present day.' This is the only plant on the list which is not now found in the county, and with this exception the whole of the plants are common or fairly common with us ; more than half the number are of the generally diffused or British type, two (Pyrus torminalis and Naias marina) are exclusively English, one (Cornus sanguinea) is nearly so, and the rest are mainly British but more frequent in England than in the rest of the British Isles. By ' exclusively English ' is meant confined to England in Britain, for all are continental, and all but Naias marina, which is a French and south German plant only, are widely diffused over the continent. There is one point of great interest in this assemblage of plants, corroborating other evidence of the change which has taken place in our climate. All the herbaceous species are hygrophilous or moisture- loving, or actually water-plants, while one at least of the trees, the alder (Alnus glutinosa} , grows only in wet places (on river-banks or in marshes). Here we have an indication of very different conditions from those which now prevail in the neighbourhood of Hitchin ; the lake, the swamp, and the moist woods of this bygone period having given place to the dry gravelly hills and open chalk downs which are so characteristic of the north of Hertfordshire. While climate has by far the greatest influence upon the distribu- tion of plants, that exercised by geological formations is next in import- ance, and it should not be overlooked that geological formations have an influence upon climate. On a damp soil, especially in a well-wooded district, more rain will fall than on a dry soil, which will naturally tend to be a barren one. When the Reading Beds and London Clay extended over the whole of Hertfordshire and perhaps the greater part of the county was forest or swamp, the rainfall would be heavier and the temperature would probably be lower than at a later time, when the greater part of the clays and sands of these formations had been carried away, exposing the chalk beneath them, and when beds of permeable gravel were deposited upon both clay and chalk. The subsoil, originally eugeogenous, that is abrading easily and yielding much detritus, would give place to a subsoil of a dysgeogenous nature, that is disintegrating 45 A HISTORY OF HERTFORDSHIRE with difficulty and yielding but a small detritus. The result would be that hygrophiles or moisture-loving plants would be supplanted in the struggle for existence by xerophiles or heat-loving plants which thrive with a smaller amount of moisture. That is the principal change which has taken place in our flora since the epoch of the Hitchin lake-bed which immediately preceded the arrival of man in that district, and this change is still going on, every bit of land which is drained and brought under cultivation, and every drop of water abstracted from our under- ground Chalk reservoir in excess of that which percolates into it, hastening it on. We have now scarcely any purely eugeogenous soils. Of the eighteen botanical provinces into which Hewett Cottrell Watson, in his Cybele Brifannica, divided Britain, Hertfordshire is in two, the Thames and the Ouse, and each of these provinces comprises two geognostic types, dysgeogenous and subeugeogenous. Much the greater part of the county is in province 3, Thames; only a small portion in the north being in province 4, Ouse. In the Thames province it is only a small portion of the county, the London Clay area in the south, which is subeugeogenous ; and in the Ouse province the very small area of the Gault Clay in the extreme west which is subeugeogenous may be disregarded for any practical purpose. Very much the greater portion of the county, in both the Thames and the Ouse provinces, therefore partakes of the dysgeogenous type of each of those provinces. A list of 89 ' dysgeogenous species ' (xerophiles) of British flowering plants and of 138 'eugeogenous species ' (hygrophiles) has been given by John Gilbert Baker in a paper read before the British Association in 1855.* Of these we have in Hertfordshire 30 xerophiles, being about 33 per cent, of those enumerated by Mr. Baker, and only 10 hygrophiles, or about 7 per cent, of the species which he enumerates. But this is not all : our 30 xerophiles are comparatively common — their relative frequency in our six botanical districts may be expressed by the number 104 ; on the other hand our to hygrophiles are comparatively rare — their relative frequency in our botanical districts being represented by the number 17. What is meant by this will be seen from the following tables, which give the occurrence of each species in each of the six botanical districts to be described presently. These lists might easily be extended, but it is thought better only to include those species which are enumerated by Mr. Baker. In these and all other tables of flowering plants the sequence of species is the same as in Sir J. D. Hooker's Students F/ora, and the names adopted by him are used. In some cases the names used in Pryor's Flora are added as synonyms. 1 ' The Flowering Plants and Ferns of Great Britain : an attempt to classify them according to their geognostic relations' (1855). This paper, which was printed as a separate pamphlet, is mainly based upon J. Thurmann's Essai de phytostatiyue . . . Jura . . . (Berne, 1849). 46 BOTANY DYSGEOGENOUS SPECIES (XtropbUts) g «j o "ftj > I—I u § « I o a "3 U +J a u m rt u h-1 is S tt £, T-, _ _ 6 7 _ _ 5 _ == 3 _ 4 I 2 _ 4 4 _ 4 4 _ 5 _ 5 Cnicus (Cirsium) eriophorus, HofFm. . - - - 3 5 5 = 2 Calamintha nepeta, Savi (sub-sp. Hooker) . . Thesium linophyllum, L. (humifusum, DC.) . - — — 3 2 4 I 2 _ 5 Aceras anthropophora, R. Br - i 5 _ 5 Herminium monorchis, R. Br ? _ 7 _ 7 Brachypodium pinnaturti, Beauv 2 »7 23 T3 26 2 23 104 EUGEOGENOUS SPECIES (Hygrophilei) 8 O 0) > t-H u h u c 3 c a m H 3 U-t S O U li •^i 13 Ranunculus circinatus, Sibth 4 Silene conica, L Medicago falcata, L Galium anglicum, Huds Arnoseris pusilla, Gasrtn. Chenopodium glaucum, L Ceratophyllum demersum, L 4 Stratiotes aloides, L 2 Potamogeton acutifolius, Link I Carex paradoxa, \Villd I o 4 2 5 i 5 »7 47 A HISTORY OF HERTFORDSHIRE Although the best division of a county for botanical purposes is into river-basins, there are some characteristics of our flora which are more prominently brought out by a lithological division. The Upper Chalk occupies very much the greater part of Hertfordshire, with much boulder-clay upon it in the east, and with clay-with-flints and gravel, chiefly Glacial, in the west. These divisions coincide so nearly with the Lea river-basin on the east and the Colne river-basin on the west that they need not here be further alluded to. The Upper Chalk ends off and the Middle Chalk crops out along the Chiltern Hills on the north-west, and this portion of the county, being chiefly chalk downs, has a peculiar flora, essentially xerophilous. The pasque-flower (Anemone pulsatilla] occurs in Hertfordshire only on the Middle Chalk, growing abundantly, though very locally, in some of the chalk combes, chiefly on slopes facing south-west. The combe south of Barton, just outside our boundary, is known as the ' Pulsatilla Banks,' and this name might well be given to the westerly slopes of Aldbury Owers near Tring. The Middle Chalk is also with us peculiarly the home of the orchids. The dwarf orchis (Orchis ustulata), the man orchis (Acer as anthropophord)^ and the butterfly orchis (Habenaria bifolia) seem to be restricted to it, but this is probably due merely to the bareness of this division of the Chalk, some orchids only thriving on a calcareous soil. Carum bulbocastanum is almost entirely restricted to the chalk hills on the north ; and Fumaria paruiflora^ Astra- galus hypoglottis, Senecio campestris, Tbesium linophyllum, and Bracbypodium pinnatum are absolutely restricted to them, with the exception of one record of the last-named species which is open to question. In the south-east, overlying the Chalk, are Eocene beds, the London Clay ending ofF and the Reading Beds cropping out from underneath it in a range of hills which form the north-western edge of the London Tertiary Basin. This is our subeugeogenous district, and it presents a marked contrast to the dysgeogenous Cretaceous area. As stated in the article on the geology of Hertfordshire, ' its soils, its agriculture, and its flora are of an essentially Middlesex type. In the Colne and Brent dis- tricts it forms grass lands devoted to hay-farming and grazing, interspersed with woods chiefly of oak, ash, elm, and fir trees ; in the Lea district, on the south, owing to the rich alluvial soil, market gardens and nurseries predominate ; while on the east, owing to the covering of boulder-clay, the land is chiefly under arable culture, partaking of the character of the corn-growing districts of the adjoining county cf Essex.' The hygrophiles Medicago falcata, Arnosera pusilla, Cbenopodium glaucum, Potamogeton acuti- fohus, and Carex paradoxa are restricted to this Eocene area. The counties by which Hertfordshire is surrounded are Cambridge- shire, Bedfordshire, Buckinghamshire, Middlesex, and Essex. There are no species of flowering plants in these counties which are not recorded for Herts. Three of these, Ranunculus Jiuitans, Salix rubra, and Potamoge- ton zosterifo/ius, occur in all the adjoining counties. The following Herts species are not recorded from any one of them : Ranunculus jloribundus, Silene conica, S. nutans, Rosa sihestris, Pyrola rotundifolia, Cuscuta epilinum, 48 ' BOTANY Verbascum lychnitis, Orobancbe ccerulea, Cephalanthera ensifolia, Gagea /utea, Carex bosnninghausiana (hybrid), C. xanthocampa (? hybrid) and Phleum pracox. Eight Rubi are not included in this enumeration, not being considered distinct species by Sir Joseph Hooker. They are Rubus affinis, R. tbyrsoideus, R. fusco-ater, R. Sprengelii, R. glandulosus^ R. birtus, R. Bellardi, and R. pseudo-idceus. Of the 893 species of indigenous Hertfordshire flowering plants there are about 1 1 o not recorded as native plants in Cambridgeshire, about 1 20 are wanting in Bedfordshire, 170 in Buckinghamshire, 140 in Middlesex, and 100 in Essex. On the other hand, Cambridgeshire has 55 indigenous species which are wanting in Herts, Beds has 30, Bucks 22, Middlesex 34, and Essex 56 (exclusive of its coast plants). Doubtful records are in all cases excluded. These figures might be very much modified if the botany of each of the counties were equally worked up. Taking the number of species in any adjoining county which are absent from Hertfordshire as the best index of the degree of relationship, it would appear that the flora of Bucks is the most nearly allied to that of Herts, and that those of Cambridge and Essex are the most divergent from that of Herts. This is just what might be expected from the physical features and geological structure of these counties. The floras of Cambridge and Essex have also a more northern or north-eastern facies than that of Hertfordshire, which, as previously stated, is of a decidedly southern type. The large number of Hertfordshire species which have not been recorded from Buckinghamshire is probably due to the flora of that county not having been so thoroughly investigated as ours has been. The following table gives a list of the Natural Orders of Phanero- gamia which are represented in the county, with the number of genera and species in each Order, and also the number of species which have been reported but are excluded either because they cannot be considered to be indigenous or because the evidence of their occurrence is open to doubt. The general classification is that of Sir J. D. Hooker, but the numbers indicate the genera and species enumerated in Pryor's Flora of Hertfordshire, The number of species given in the table does not exactly tally with the number on page 557 of that work. The total number of flowering plants and ferns is there stated to be 1,1 16, of which 26 are ferns, leaving 1,090 flowering plants, of which 898 are considered to be indigenous. Two species have since been added — the oxlip (Primula elatior), a native plant, and the alkanet (Ancbusa officinalis)^ an alien.1 The soapwort (Saponaria officinalis) being a denizen, and the water-thyme (Anacbaris alsinastrum) being an introduced species, have been relegated to the excluded species, and so also have Wallenbergia bederacea, Pyrola media, Euphorbia stricta, and Carex canescens as having been included in our flora on insufficient evidence. The 898 numbered species in Pryor's Flora are thus reduced to 893, and the 192 excluded species are increased to 199, giving a total of 1,092. 1 See Tram. Herts Nat. Hist. Soc. vol. x. p. ix. (1901). I 49 E A HISTORY OF HERTFORDSHIRE SUMMARY OF ORDERS, GENERA, AND SPECIES Number of Genera S'umber of Specio Ex- cluded Specie* Number of Genera Number of Specie! Ex- cluded Speciei CLASS I 42. Oleaceae .... 2 2 _ DlCOTYLEDONES OR EXOGEN.S 43. Apocynaceae 44. Gentianeae . Polemoniacete . I 4 I 7 I I I Div. I. Thalamiflorte 45. Boragineae . 6 i5 8 I. Ranunculaceae . II 29 6 46. Convolvulaceas . . 3 6 i 2. Berberideae . I I — 47. Solanaceae 3 4 2 3. Nymphaeaceae . 4. Papaveraceae 5. Fumariaceae. 2 2 I 2 6 5 i 2 48. Plantagineae . 49. Scrophularineas . 50. Orobanchaceas . . 2 13 2 38 4 4 6. Cruciferae . *9 34 21 51. Lentibularineae . 2 2 — 7. Resedacez . . . i 2 I 52. Verbenaceae. I I — / 8. Cistineae .... i I 53. Labiatas .... 20 38 5 9. Violaceae. 10. Polygaleae . i i 6 3 Div. IV. Incomplete 1 1 . Caryophylleae . i5 33 9 Amaranthacete . — i 12. Portulaceae . i i 2 54. Illecebraceae . I I — 13. Hypericineae 2 7 3 55- Chenopodiaceas . 2 13 2 14. Malvaceae . I 3 2 56. Polygonaceae 2 20 3 Tiliaceet .... — 2 Ariitolachlacete . 2 15. Lineae .... 2 2 I 57. Thymelaeaceae . I I I 1 6. Geraniaceae . 3 II 8 58. Loranthaceae I I 17. Ilicineae .... I I — 59. Santalaceae . . . I I Div. II. Calyclflorte 1 8. Celastrinez . . . 19. Rhamneae . 2O. Sapindaceae . 21. Leguminosae I I I 18 I 2 I 47 i 12 60. Euphorbiaceas . . 61. Urticaceae . 62. Cupuliferae . 63. Salicineae 64. Ceratophylleas . . 2 4 6 2 I 7 6 8 H i 3 i i 4 22. Rosaceae .... 23. Saxifrageae . . . 24. Crassulaceae . 15 3 i 76 4 3 8 3 5 Div. V. Gymnospernue 65. Coniferae. . . . I i — 25. Droseraceae . i i 26. Halorageae . . . 3 8 — CLASS II 27. Lythraceae . . . 28. Onagrarieae . 29. Cucurbitaceae . 2 3 i 3 9 i i MONOCOTYLEDONES OR ENDOGEN^E 30. Umbelliferae. . . 28 36 8 66. Hydrocharideae . 2 2 i 31. Araliaceae . . . i i — 67. Orchideae . . . H 24 2 32. Cornaceas i i — 68. Iridez .... I 2 I Div. III. Monopetala 69. Amaryllideae 70. Dioscoreae ... I I I I 4 33. Caprifoliacez . 4 6 3 71. Liliaceae .... 8 10 5 34. Rubiaceae 35. Valerianeae . . . 36. Dipsaceae . . . 3 2 4 15 6 5 i 2 I / 72. Junceas .... 73. Typhaceae . 74. Aroideae .... 2 2 2 15 5 2 37. Compositae . . . 38. Campanulacea? . 44 3 83 7 20 3 75. Lemnaceae . . 76. Alismaceae . 2 4 4 6 — 39. Ericaceae . . . 40. Monotropeae 41. Primulaceae . . 4 i 6 6 i 12 i i 77. Naiadaceae . 78. Cyperaceae . . . 79. Gramme* . 3 8 35 17 49 76 i 16 Total . 384 893 199 BOTANY NOTES ON THE BOTANICAL DISTRICTS, WITH LISTS OF THE RARER PLANTS OF EACH DISTRICT In the Flora Hertfordiensis of Webb and Coleman (1849) Hertfordshire was divided into botanical districts founded on the river-basins. The three main districts were the Lea, the Colne, and the Ouse, each of these being divided into sub-districts representing the tributaries of these rivers, and the number of such sub-districts were twelve. In a paper read before the Watford (now Hertfordshire) Natural History Society in 1875 * the late Alfred Reginald Pryor recognized the primary separation of the county into the catch- ment-basin of the Ouse on the north and that of the Thames on the south, ' districts which,' he said, ' in the floras of the future, will probably be entirely dissociated from each other and united respectively to those portions of the same river-system with which they are naturally connected, but which are now scattered among the southern and eastern shires.' He then divided the Ouse district into the Ivel and Cam ; and the Thames into the Thame, the Colne with five sub-districts, the Brent, and the Lea with six sub-districts, making sixteen districts in all. He afterwards found this subdivision to be impracticable from the impossibility of assign- ing many of the old records to these districts, and he therefore abandoned the sub-districts of the Colne and Lea and finally left the scheme thus — T T-U r\ ( !• The Cam I. The Ouse . ™, T . 2. The Ivel II. The Thames • 3. The Thame 4. The Colne 5. The Brent 6. The Lea This is the division of the county which was adopted in his Flora of Hertfordshire published in 1887, a few years after his death. As this work is the basis of the present article on the botany of Hertfordshire, the above division is necessarily followed.8 DISTRICT I. — THE CAM This is the most northern district. It is bounded on the east by Essex, on the north by Cambridgeshire which divides it into two, on the west by Bedfordshire, and on the south by the Ivel and Lea districts. A stream called the Wadrington Brook, which while in Herts is little more than a ditch, flows through the eastern division of the district, and through the western division flows the Rhee, which rises from copious springs in the Totternhoe Stone at Ashwell, is joined at the extreme north of the county by the Ruddry Brook, and joins the Cam a little south of Cam- bridge. The district is almost entirely on the Chalk, a small portion on the north-east being on the Gault. It is very bare of trees and is marked by the absence of hygrophiles (see p. 39). In the eastern division are the Royston Downs, rising to about 500 feet above sea-level. The few species which are restricted to this district are very rare. Thalictrum jacquini- anum and Antennaria dioica occur only on Royston and Therfield Heaths in the eastern division ; ARsma ranunculoides and Potamogeton cokratut only on Ashwell Common in the western division ; and of Poterium officinale the only record is that of a plant in Coleman's herbarium gathered in the neighbourhood of Ashwell in 1840. The rarer plants of the district are — RANUNCULACE* FUMARIACR* TbaRetnm Jacqmnianum, Koch Fumaria parviflora, Lami. Anemone pulsatilla, L. _ Vaillantii, LnuL Helleborus foetidus, L. PATAVERACE* Papaver hvbndum, L. Iberis amara, L. \ l?n the Botanical Work of the Past Season,' 'Trans. Watford Nat. Hist. Sot. vol. i. pp. 65-77. The names of the plants which only occur in one .listrict are printed in italics. 51 A HISTORY OF HERTFORDSHIRE CARYOPHYLLE.* Silene noctiflora, L. Arenaria (Alsine) tenuifolia, L. LEGUMINOS/E Trifolium ochroleucum, L. Astragalus hypoglottis, L. Hippocrepis comosa, L. ROSACE.S Poterium officinale, Hook. f. UMBELLIFER.* Bupleurum rotundifolium, L. Apium graveolens, L. Carum (Bunium) bulbocastanum, Koch Sesseli libanotis, Koch (Libanotis montana, CEnanthe Lachenalii, Gmel. Caucalis daucoides, L. VALERIANS* Valeriana ofHcinalis, L. COMPOSITE Antemaria dtoica, Br. Senecio (Cineraria) campestris, DC. Arctium majus, Schk. Cnicus eriophorum, Hoffin. SCROPHULARINE.S Linaria spuria, Miller Melampyrum cristatum, L. OROBANCHE^ Orobanche major, L. LABIATVE Ajuga chamxpitys, Sckreb. LORANTHACEJE Thesium linophyllum, L. (humifusum, DC.) ORCHIDEJE Orchis ustulata, L. AunucEB Aftsma ranunculoides, L. NAIADACUI Potamogeton coloratut, Hornem GRAMINEJE Bromus racemosus, L. Brachypodium pinnatum, Beauv. DISTRICT II. — THE IVEL This district is south-west of that of the Cam, and is bounded on the north-west by Bedfordshire and on the south by the Lea district. The Ivel rises near Baldock, leaves our county for Bedfordshire after a run of a mile and a half, and is then soon joined by a longer stream rising near Wallington. Its next tributary is the Hiz, which rises at Wellhead, a mile south of Hitchin (Hiz-chine), through which it flows. A mile below Hitchin the Hiz receives the Purwell or Pirrall, a stream having a much longer run than itself, and rising between Weston and Graveley ; and in another mile, at Ickle- ford, it receives a small stream called the Oughton. Half-way between Bedford and St. Neots the Ivel joins the Ouse, which pursues its course for some forty miles before it receives the Cam near Ely. The Chalk downs of the eastern division of the Cam district are continued in a south- westerly direction through the Ivel district, of which they form the north-western half. Highest on the south-east, they slope downwards to the Gault plain on the north-west. Here there are numerous combes in the Lower Chalk which have been formed by water issuing from springs in the Totternhoe Stone. In most of them there is now no water and the soil is particularly dry owing to the sinking of the plane of saturation of the Chalk, this portion of the district consequently having an essentially xerophilous flora. Although this is a much larger district than that of the Cam, and its botany has been more thoroughly investigated than that of any other, only half a dozen species are restricted to it. Melampyrum arvense occurs only in one spot south of Ashwell ; Smyrnium olusatrum has been found in one or two places north of Baldock and near Pirton, and there is also a record of its occurrence at St. Albans in the Colne district, but its site has long been built over ; and the other four species are confined to the neighbourhood of Hitchin. Of these Silene conica is the rarest. The only record of its occurrence is near High Down, Hitchin, in 1875. The rarer plants of the district are — RANUNCULACEJE Anemone pulsatilla, L. Ranunculus diversifolius, H. Wats. Helleborus fcetidus, L. — viridis, L. PAPAVERACEJK Papaver hybridum, L. — Lecocjii, Lamotte FUMARIACEJK Fumaria Boraei, Jord. — parviflora, Lamk. — Vaillantii, Lotsel. CRUCIFER.S Senebiera (Coronopus) didyma, Pennon Iberis amara, L, BOTANY PoLYGALEJE Polygala oxyptera, Reichb. CARYOPHYLLE.K Silene conlca, L. — noctiflora, L. Arenaria (Alsine) tenuifolia, L. LEGUMINOSJE Trifolium ochroleucum, L. Astragalus hypoglottis, L. Hippocrepis comosa, L. Vicia (Ervum) gracilis, Lo'ucl. — lilvatica, L. Lathyrus aphaca, L. — silvestris, L. ROUCES Prunus cerasus, L. CRASSULACEJE Sedum fabaria, Koch ONAGRARIE./E Epilobium roseum, Schreb. UMBELLIFERJE Smymlum olusatrum, L. Bupleurum rotundifolium, L. Apium graveolens, L. Carum segetum, Benth. — (Bunium) bulbocastanum, Koch Sesseli libanotis, Koch (Enanthe Lachenalii, Gmel. Caucalis daucoides, L. RUBIACE.E Galium Witheringii, Sm. — erectum, Huiis. VALERIANEJE Valeriana officinalis, L. Valerianella auricula, DC. (rimosa, Bast.) COMPOSITE Filago spathulata, Presl Senecio (Cineraria) campestris, DC. Centaurea calcitrapa, L. Crepis biennis, L. — taraxacifolia, Thutll. MONOTROPEJE Hypopithys multiflora, Scop. PRIMULACE^ Anagallis cxrulea, Schreb. CONVOLVULACEJE Cuscuta europaea, L. SCROPHULARINE.« Verbascum blattaria, L. Antirrhinum orontium, L. Linaria spuria, Miller Melampyrum arvense, L. — cristatum, L. OROBANCHEJE Orobanche major, L. — minor, Suit. LABIATE Mentha pulegium, L. Ajuga chamaepitys, Schreb. CHENOPODIACEJE Chenopodium vulvaria, L. — ficifolium, Sm. — hybridum, L. POLYGON AC EJE Polygonum maculatum, Dyer et Trimen SANTALACEJE Thesium linophyllum, L. (humifusum, DC.) EUPHORBIACE.S Euphorbia platyphyllos, L. ORCHIDEJE Cephalanthera pallens, Rich. Orchis ustulata, L. Herminium monorchis, Br. IRIDE/E Iris foetidissima, L. CYPBRACE.® Carex Jioica, L. — stricta, Good. — xanthocarpa, Degl. (1 hybrid) GUMMBJI Phleum phalaroides, Koel. Bromus racemosus, L, Brachypodium pinnatum, Beauv. Hordeum silvaticum, Huds. (Elymus europxus, L.) DISTRICT III. — THE THAME The very small portion of the extreme west of the county which is in this district forms a tongue-like protrusion into Buckinghamshire, being bounded by that county on all sides but the east, where the Colne district forms the boundary. The small tributary streams of the Thame, rising near Tring, are intercepted by the reservoirs which supply the Grand Junction Canal, all of which are in this district. The Thame soon leaves our county, and, flowing westward north of Aylesbury to below Dorchester in Oxfordshire, there unites with the Thames ; or, as Chauncy says (Hist. Antiq. Herts), ' then congratulates the Isis ; but both emulating each other for the name, and neither yielding, they are complicated by that of Thamisis.' The district lies high : a mile north of Tring is the summit-level of a system of canals which radiate to the north, west, south-west, and south-east. The Chalk terminates near the 53 A HISTORY OF HERTFORDSHIRE centre of the district, and beyond it on the north-west is the only considerable are* of the Gawk » Hertfordshire. Tire accounts for the prexiKe of a few hy$rof4tiks. to the district (fjnwa i if i l/ifmad .Pilini^ili i frWsa) are muit photi which occur only in the Tring Reservoirs or the canak which they supply. £ntoaw ttMOMB grows If the Wiktone Reservoir, and Jam «uatr«t«id«r» on terraces cut in the chafe near Tria* The fallowing; are the rarer plants recorded from dm district— RMMHCUIACU t£*MftlwWM* fi^w^Mt t Ceffcihathen DC . L~ M5>|.-^» ntavflfBtBn oattMMM^ tttrt. — ««. Rajx. GUUBUM ^^ *— «f nceascsms. L. fla DBTUCT IV.— ^THI COLXS Tas K a large d&tnct, coaaprtsutg ahnost the whole of the western nutiiun of the county. The L?- - . - -:- I -:-:; ReXT : - r, the river is i TCTT Arr aasoa»» by the ijiaifci of O=«ggaoL Afier pn«an$ Watford the Gade above andi the Che* at Kidbawmonh. The G^de rises near Great •i poolnui af > aunm •jnuj :-.-:-: eon awi at Two Waves at iiniin iht BUU-U-, ll f _L1 -".--:-.- -:;:•;;; CM^amd . - .- -,- :: J :---:.---.: WtSCfcawPCBW &MO t>C OvbovnaC OCCnVtOofoMn' BOWS OfcC See axe 33 Lex dKcict (p. 57) at a» i •-- BOTANY Ulex nanus, Forst. Medicago falcata, L. Trifolium subterraneum, L. Hippocrepis comosa, L. Lathyrus aphaca, L. — (Orobus) tuberosus, L. — silvestris, L. ROSACE* Prunus cerasus, L. Geum intermedium, Ehrh. Rosa stylosa (v. systyla), Bast. Crataegus monogyna, jacq. mentioned (p. 28). The Bulbourne below Berkhamsted, the Gade below Two Waters, and the Colne below Rickmansworth, are frequently incorporated with the Grand Junction CanaL Leaving our county near Harefield, the Colne, flowing southwards, passes Uxbridge, where k begins to divide into numerous irregularly anastomosing channels which have several mil • It into the Thames at and above Staines. To the presence in the valley of the Ver of an old city, more interesting in its a tions than any other in the kingdom, is due the existence in Hertfordshire of Diplstaxis folia, Silent nutans, and Hieradum muranan, for they grow nowhere in the county but on old walls in St. Albans. Colney Heath, near the head of the Colne, is of much botanical interest, chiefly owing to its marshes and swampy meadows. It is our only habitat for the very rare Ljthrum bjfsopifiKa, and also for TtndaRa nudicauRs, while we nave only one other locality, a different one in each case, for four of its plants — Radiala hmda (Northaw), Ctsttmmcmha minimus (Moor Park), Cuscuta epitbjmum (No Man's Land, St. Albans), and Pttanugettn acmti- foKui (London Colney). The rarer plants of this district and those peculiar to it make a rather long list. They are — RAKUSCCUCEJE LTTHRJUUIM Anemone pnlsatilla, L. Lj&nm bjsufifiBa, L. Helleborus foetidus, L. — riridb, L. PAPAVZRACI* Papaver Lecoqii, Lamotte FITUARIACLS Fumaria Vaillantii, Loisel. CRUCIFIX* Nasturtium amphibium, Br. Dtntaria buttnfera, L. Dipbtaxis tenuifoRa, DC. Erophila praecox, DC. Lepidium ruderale, L. Iberis amara, L. TeesdaHa nudicauKs, Br. POLYGAUB Polygak oiyptera, Reicbb. CARYOPHYLLEJE Silene nutans, L. Cerastium quaternellum, Fenlz. Arenaria (Alsine) tenuifolia, L. LlNEJE Radiola Knaides, Gmel. GERANIACEA Geranium ntundifoKum, L. CRASSULACE* Sedum fabaria, Koch OXAGRAUEJE Epilobium roseum, Scbrtb. UMBELLJFEIJE Buplenrom rotundifolium, L. Carom (Buniom) bulbocastanum, Kxb Cicuu virosa, L. (Enantht enccata, L. Caucalis dancoides, L. RVBIACEJE Galium erectom, Huds. VALERIANLS Valeriana officinalis, L. Valerianella auricula, DC. COMPOSITE Pnlicaria vulgaris, Gtfrtn. Filago apicuku, G. E. Sm. — spathulata, Presl Senecio (Cineraria) campestris, DC. Arctinm intermedium, Lange — nemorosum, Lej. Centaurea calcitrapa, L. CarJutts tnuiflorus, Curt. Crepis uraxacifolia, Thrill. Hieraciitm muronun, L. CAUPANULAC&K Campanula rapunculus, L. ERICACEJE Vaccinium myrtyUus, L. Erica cinerea, L. Pyrola minor, Sto. — ntundifoRa, L. PRIMULACE* Ccntunculus minimus, L. GENTIANEJK Gentiana campestris, L. — germanica, Willd. BoRAGINEjE Cynoglossum montanum, Lamk. 55 A HISTORY OF HERTFORDSHIRE CONVOLVULACE.S Cuscuta europasa, L. — efithymum, Murr. PLANTAGINE.S Litorella lacustris, L. SCROPHULARINE.S Verbascum blattaria, L. — virgatum, With. Linaria spuria, Miller Limosella ajuatlca, L. OROBANCHE^: Orobanche minor, Suit. CHENOPODIACE/E Chenopodium vulvaria, L. — ficifolium, SOT. PoLYGONACE^ Polygonum minus, Huds. Rumex palustris, SOT. (limosus, Thuill.) EUPHORBIACE.S: Euphorbia platyphyllos, L. Mercurialis annua, L. SALICINEJE Salix russelliana, SOT. HYDROCHARIDEJE Hydrocharis morsus-ranae, L. ORCHIDEJE Malaxis paludosa, Sw. Cephalanthera pallens, Rich. — ensifolia, Rich. Orchis ustulata, L. — militaris, L. Herminium monorchis, Br. Habenaria bifolia, Br. LILIACETE Ruscus aculeatus, L. Polygonatum multiflorum, All. Fritillaria meleagris, L. JUNCE* Juncus diffusus, Hoppe — squarrosus, L. Luzula Forsteri, DC. NAIADACEJE Potamogeton rufescens, Schrad. — acutifolius, Link — obtusifolius, Mert. et Koch CYPERACEJE Ekochans acicularis, Br. (Hooker — Heleocharts) Scirpus caricis, Retz. (Blysmus compressus, Panz.) Carex paradoxa, Willd. — Icevigata, Sm. GRAMINEJS Setaria viridis, Beauv. Alopecurus fulvus, SOT. Calamagrostis lanceolata, Roth Gastridium lendigerum, Gaud. Bromus racemosus, L. Hordeum silvaticum, Huds. (Elymus europaeus, L.) DISTRICT V. — THE BRENT This is the smallest district, only four or five square miles of a tongue of the county somewhat similar to that of the Thame district being in the catchment-basin of the Brent. It is bounded on the east by a detached portion of the Lea district, on the north-west by the Colne district, and on the north and south by Middlesex. It is entirely on the London Clay. The Brent rises in Middlesex half a mile from Barnet Gate in Herts, and after a run of four miles leaves our county, flows past Finchley, through the Brent Reservoir, and, joining the Grand Junction Canal at Hanwell, enters the Thames at Brentford. This is an interesting district, chiefly owing to the presence of Totteridge Green and its ponds, in which grow Ranunculus lingua and Acorus calamus, the former however having been planted and therefore not being entitled to a place in the list of species. Totteridge Green is our only locality for Damasonium stellatum. It was first recorded there in 1805, by 1849 '* na<^ become very scarce, and it was last seen in 1855. Chenopodium glaucum has been seen much more recently in its only locality, Totteridge. Many common plants are not recorded for the district, perhaps partly from its small size, but chiefly from its flora not having been thoroughly investigated. The only indigenous plants in this district which are rare are the following — CARYOPHYLLEJE Dianthus deltoides, L. Cerastium quaternellum, Fenk,. ROSACEJE Prunus cerasus, L. ONAGRARIEJE Epilobium roseum, Scbreb. COMPOSITE Pulicaria vulgaris, Gtertn. Anthemis nobilis, L. Arctium nemorosum, Lej. BORAGINEA Symphytum tuberosum, L. BOTANY CHENOPODIACE/B LILIACE./E Chenopodium ficifolium, Sm. FritiUaria meleagris, L. — glaucum, L. AROIDE./E POLYGONACE^E Acorus calamus, L. Polygonum maculatum, Dyer et Trimen ALISMACE« Rumex palustris, Sm. (limosus, Thuill.') Damasonlum stellatum, Pers. DISTRICT VI. — THE LEA The Lea district is the largest, comprising the whole of the eastern portion of the county south of the Cam and Ivel districts. It is bounded on the south by Middlesex, on the east by Essex, on the north by the Cam and Ivel districts, and on the south-west by the Colne district. A small portion of the county on the north of the Colne district and having Bedfordshire for its northern boundary drains into the head of the Lea ; * and another small area on the east of the Brent district is drained by a tributary of the lower portion of the Lea, now however flowing into the New River. The Lea rises in Bedfordshire from springs in Leagrave Marsh three miles above Luton ; cuts through the Chalk escarpment before it enters Hertfordshire ; and flows past Hatfield, Hertford, Ware, and several towns in the south-east corner of the county. After receiving on its left bank several streamlets whose waters are lost in the Chalk in dry weather, it flows to Hertford, where the Mimram and then the Beane join it, and from this point downwards it is navigable for barges ; the Rib adds its tribute between Hertford and Ware, the Ash below Ware, and finally the Stort a little above Hoddesdon. All these rivers flow into the Lea on its north or left bank. The Mimram, or Maran, rises in Lilley Bottom near King's Walden and flows past Welwyn and through many beautiful parks. The Beane, or Bene, formerly called the Benefician, is formed by numerous small streams rising between Sandon and Weston, and is augmented at Walkern from springs in the Chalk, at Frogmore above Watton by a brook from Stevenage and Knebworth, and in Woodhall Park below Watton by the Munden Brook, dry in summer. The Rib rises in Kelshall Woods near Therfield, or in very dry years some miles lower down its valley, passes Buntingford, and a few miles below it receives the Quin, which rises at Rushing Well near Nuthamstead, and is often dry in summer as far as Braughing. The Ash rises in the winter near Brent Pelham on the borders of Essex, but for five miles down its valley it and its tributary streams are merely bournes, being dry in the summer and autumn, and its source is then a mile below Albury, where there is a spring in its bed, below which it is seldom dry. The Stort is the only affluent of the Lea, except a few small brooks below Hoddesdon, which does not entirely flow through Hertfordshire. Rising near Clavering in Essex, but having one of its tributary streams flowing from Scales Park Wood in Herts near the source of one of the feeders of the Quin, it comes into our county for a run of a quarter of a mile, then re-enters Essex, and enters Herts again at Pesterford Bridge, two miles above Bishop Stortford, from which point to its junction with the Lea it is navigable for barges and is called the ' Stort Navigation.' Here it serves as boundary between Herts and Essex. In addition to the supply from these tributary streams, the waters of the Lea are augmented on its left bank by the springs of Arkley Hole at Woolmers, and on its right bank by the Chadwell Spring between Hertford and Ware. This spring first dried up in 1898, and has done so in each succeeding year. Between Ware and Hoddesdon the Lea was formerly augmented by Amwell Spring (Emmewell or Emma's Well), but this seldom flows now, having been pumped dry by the New River Company. The Chadwell Spring is fast following in its footsteps, and Arkley Hole is also being affected. In course of time this lowering of the plane of saturation of the Chalk will affect the surface- soil and alter the character of the flora of this district. The Chadwell Spring for many years has formed the head of the New River, into which also the Amwell Spring was diverted when this water-channel was constructed. The Lea leaves the county at Waltham Cross for Middlesex, and flows into the Thames at Bow Creek below Blackwall. It is tidal as far as Lea Bridge. Below Ware the course of the Lea has been diverted for navigable purposes, and the ' Lea Navigation ' to its junction with the Stort, and ' Lea and Stort Navigation ' below this point, cross and re-cross the old bed of the Lea several times. 1 In the recent revision of the county boundary for administrative purposes this portion has been transferred to Bedfordshire. 57 A HISTORY OF HERTFORDSHIRE The district drained by the Lea and its tributaries is about 500 feet in height on the north, along the downs forming the water-parting between the catchment-basins of the Thames and Ouse, the surface gradually sloping towards the south, until along the river Lea below Hoddesdon the ground is much lower and flatter than in any other part of Hert- fordshire. Most of the district is on the Chalk, much covered by boulder-clay, but south- east of Furneaux Pelham, Much Hadham, Hertford, and Hatfield it is on the London Clay and its narrow margin of Reading Beds. The old towns of Hertford and Ware are the only localities in the county for the rare Sisymbrium irio, which sprang up in London after the great fire of 1666, whence its name of London rocket. The true oxlip (Primula elatior) occurs only near the head of the Stort on the borders of Essex ; the very rare Orobanche ceerulea only at Hoddesdon, where it is parasitic on the milfoil (Achillea millefolium) ; and an old wall of Brocket Park is the only habitat of the almost equally rare Galium anglicum. Trifolium gkmeratum is known only at Easneye near Ware ; the only locality for Stratiotes a/aides, except where it has evidently been planted, is Hatfield Park ; and the ponds on Hertford Heath lay exclusive claim to Carex bcenninghausiana. Two species usually of rare occurrence (Polygonum dumetorum and Apera spica-venti) are frequent in the district. The Lea district has the largest number of rare plants of any, and much the largest number peculiar to it. The list is as follows — RANUNCULACEJE Ranunculus diversifolius, H. Wats. — lingua, L. — hirsutus, Curtis (sardous, Crantz) Helleborus foetidus, L. — viridis, L. PAPAVERACE^ Papaver Lecoqii, Lamotte FUMARIACE.S Fumaria Boraei, Jord. — Vaillantii, Loisel. CRUCIFER^E Nasturtium silvestre, Br. — amphibium, Br. Sisymbrium irio, L. — Sophia, L. Erophila praecox, DC. Senebiera (Coronopus) didyma, Persoon Lepidium ruderale, L. Iberis amara, L. CARYOPHYLLEJE Silene anglica, L. — noctiflora, L. Cerastium quaternellum, Fenlz. Stellaria palustris, Ehrh. LEGUMINOSJE Trigonella ornlthopodioides, DC. Trifolium subterraneum, L. — ochroleucum, L. — glomeratum, L. Hippocrepis comosa, L. Vicia (Ervum) gracilis, Loisel. Lathyrus aphaca, L. — (Orobus) tuberosus, L. — silvestris, L. ROSACES Rosa silvestris, Woods — stylosa (v. systvla), Bait. Cratsegus monogyna, Jacy. CRASSULACE/E Sedum fabaria, Koch HALAGORE/E Callitriche obtusangula, Le Gall. OHAGRAKIEB Epilobium roseum, Schreb. UMBELLIFER^ Bupleurum rotundifolium, L. Carum segetum, Benth. — (Bunium) bulbocastanum, Koch Cicuta virosa, L. Sesseli libanotis, Koch RUBIACEA Galium Witheringii, Sm. — anglicum, Huds. VALERIANE./E Valerianella auricula, DC. COMPOSITE Pulicaria vulgaris, G