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421 



THURSDAY, AUGUST 30, 1894. 



A THEORY OF THE GLACIAL DEPOSITS. 



Papers and Notes on the Glacial Geology of Great 

 Britain and Ireland. By the late Henry Carvill 

 Lewis, ^!.A., F.G.S. (London: Longmans, Green, and 

 Co., 1894.) 



THEY are wrong who think that little is left in Eng- 

 land for a geologist to discover or do. Not only 

 are there gaps to be filled up, and doubtful points to be 

 made certain, but even whole fields remain where if 

 labourers have been at work they have as yet reaped 

 little fruit. Especially may an Alexander, sighing for a 

 fresh world, be invited to turn his attention to what are 

 called the glacial deposits. In area they extend over the 

 greater part of the British Isles ; in variety they far ex- 

 ceed the Archseans ; in difference of opinion about them 

 they would also exceed Archsans, if such an excess be 

 possible. They have difficulties peculiarly their own. It 

 is well said by the editor of this volume that in glacial 

 geology not merely the interpretation of facts is debated, 

 but there is dispute as to what the facts are themselves. 

 Geologists of repute go to the same section, see the same 

 phenomena, and describe them in contradictory terms. 

 Mr. Clement Reid surveys the Cromer cliffs, and figures 

 chalk masses ploughed up by glaciers. Mr. Mellard 

 Reade examines the same cliffs, and sketches chalk 

 masses dropped down by ice-floes. The questions con- 

 nected with these deposits have been raised on the hills of 

 Nicaragua and the banks of the Amazon. As their range 

 of space, so their range of time : glacial phenomena have 

 been described from the Permian epoch, and the Car- 

 boniferous. They seem to claim all time and all space 

 as their province. 



To conquer such a world is needed an Alexander in 

 truth. Such an one some friends hoped they saw risen 

 in the student whose remains are now given to the world. 

 Those who knew Carvill Lewis, who knew his ability, 

 energy, enthusiasm, perseverance, with his equipment of 

 knowledge, travel, and means, when they saw him devote 

 all these to his study of glacial deposits, thought that 

 nov,r :U last order would emerge out of chaos ; that what 

 Sedgwick and Murchison did for the Grauwacke he might 

 ilo for the Drift. His early death destroyed these hopes, 

 quenching a kindled light. We' have, however, in this 

 volume a not unworthy memorial ; no mean contribution 

 to science. It is a record of the ideas he had formed or 

 was forming, in some respects more valuable than a 

 completed treatise would have been. For here we discover 

 his plans, ideas, observations ; his opinions, formed, 

 corrected, abandoned ; together with an immense mass 

 of materials, collected out of previous writers, abstracted, 

 arranged, and criticised. Dr. Crosskey has performed his 

 most difficult task of editing with extreme tact and judg- 

 ment. " I venture," he says in his introduction, " to set 

 aside the injunction laid upon me to ' criticise ' as well 

 as to arrange and edit." .V high proof this of fitness 

 for such a task ; it makes of correspondingly high value 

 the two or three criticisms which he does pronounce. 

 Sad that we should be presented with a volume doubly 

 NO. 1296, VOL. 50] 



posthumous ; that science must mourn the loss of editor 

 as well as of author. But science should be grateful 

 for what she has gained. The gain is great. Here we 

 have presented a theory of the glacial deposits which, 

 whether the truth or no, is certainly clear, consistent, 

 rational, and moderate in its demands. Probably 

 it will not ultimately be accepted as complete ; assuredly 

 it will not at once convince every sceptic, or even create 

 an orthodox belief; but it may do much to destroy some 

 current absurdities, it does bring out clearly some 

 neglected truths, and it should form a very convenient 

 working hypothesis to direct our reflection and research. 



The volume consists of introductions by Dr. Crosskey 

 and Mrs. Lewis, five entire papers, a mass of extracts 

 from note-books, some memoranda and brief essays, with 

 two appendices. One of these might, perhaps, be spared. 

 We are keen to know what Carvill Lewis thought, but 

 not so much what another thinks he would have thought 

 on sections which he did not see. The other appendix, 

 " Field Notes from Switzerland," though introduced with 

 an apology, is inseparably connected with the rest of 

 the notes, an essential part of the book. If dates could 

 have been added to the extracts from note-books, it 

 would have helped a reader to perceive which of the 

 writer's varying views was his latest. 



Prof. Lewis concerned himself little with the causes of 

 the glacial epoch, though one or two shrewd remarks will 

 be found. He devoted his research and thought to the in- 

 terpretation of the effects which that epoch produced, of 

 what occurred during the period, of what its phenomena 

 represent. His fundamental idea pictures many separate 

 glaciers originating from separate centres of high ground, 

 spreading from these centres till they meet, then still 

 retaining their separate individualities in the motions of 

 the continuous ice-cap into which they have joined. 

 His guiding principles are that such separate indi- 

 vidualities can be traced by the peculiarities of the stones 

 transported ; still more, that the furthest advance of 

 such glaciers must be marked by a moraine, or by some 

 visible boundary of like nature. The tracing of these 

 boundaries he made an especial work, and he believed 

 himself to have followed them across England, through 

 Yorkshire wolds and Welsh mountains, from the Humber 

 to the Bristol Channel. As a consequence of prime im- 

 portance, he lays down that such advancing glaciers 

 would frequently dam the courses of rivers, and that the 

 lakes formed by the ponded-up waters would produce 

 deposits of their own. Such deposits he continually 

 recognises and describes. Especially he maintains that 

 the Scandinavian ice met the British, and damming 

 the waters of the Humber and the Wash, created an 

 enormous lake, which drowned all England east of the 

 Pennines and north of the Thames. This vast sheet of 

 fresh water he regards as the manufactory and manu- 

 facturer of all those deposits in East Anglia and the 

 Midlands which are commonly called by us glacial 

 And whatever difficulties may lie in the way of this 

 hypothesis, it is certainly remarkable that the highest 

 level of such deposits at Flamborough Head (according 

 to Lamplugh), on the Lincolnshire Wolds (according to 

 Jukes-Browne), in East Anglia (according to Survey 

 Memoirs), together with the lowest level of passes 

 across the central watershed (as I infer from a map of 



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