S. V. Wood,ji(ii. — American and British Surface- Geology. 23 



Geologists have so long been cognizant that a minor glaciation oc- 

 curred in Switzerland subsequently to the first and great extension 

 of the Alpine glaciers, that it is unnecessary for me to do more than 

 cite it in corroboration of the conclusions to which an analysis of the 

 evidences offered by Britain and Eastern North America seem to me 

 to point ; while according to the abstract of a paper by Mr. G. M. 

 Dawson on the Superficial Geology of British Columbia (read before 

 the Geol. Soc. of London on 20tli June, 1877), this gentleman dis- 

 covers on the north-west side of North America similar evidence 

 of two glaciations divided from each other by a warm period. 



The semifossiliferous condition of the Selsea shells coupled with 

 their recent and more southern facies is not the only indication of a 

 warmer marine climate having occurred in Northern Europe at a 

 very late date geologically speaking, for Torell and others found in 

 Spitzbergen some beds of what are called by them " post-Tertiary " 

 shells, containing Mytilus edulis, which is not known as now living 

 there ; and Nordenskiold (Journ. of the Geograph. Soc. 1869, p. 136) 

 speaks of these beds as containing plant- fragments and suhfossil 

 marine shells, of which some now first occur in living condition in 

 the northern part of Norway. This recent, more southern, and sub- 

 fossil condition of the Spitzbergen shells, is just that of the Selsea 

 ones, and is altogether in contrast with that of the shells of all East 

 Anglian Glacial (in the sense I use that word) deposits, which are 

 thoroughly fossilized, besides containing among them forms charac- 

 teristic of their superior age. Indeed, some of my Bridlington shells 

 imbedded in indurated sand are in the condition of Oolitic fossils ; 

 for which but for their species they might be mistaken. 



Mr. Geikie in the second edition of his work having made copious 

 reference to the Hessle beds as described by myself and Mr. Eome, 

 and (though making some confiision between our views and those of 

 the late Prof. Phillips ^) having also adopted the view of their 

 position in the general sequence of deposits for which we pontended, 

 as well as their correlation with the upper clay and (so-called) 

 middle sand of the North-west of England, which I have for several 

 years past suggested,^ the only difference that • seems to remain 

 between us in reference to them concerns the mode in which the 

 clay originated. This clay Mr. Geikie insists is not only tei'restrial 

 in its origin, but is a morainic accumulation over a land-surface, 

 beneath an ice-sheet, and left where engendered. I on the contrary 

 have contended, and still maintain, that it is a submarine accumula- 



^ Professor Phillips not only never recognized what we contended was the true 

 position of the Hessle beds relatively to other Glacial or post-Glacial deposits, but 

 he had not up to the time of our paper even recognized that the Hessle beds were 

 distinct firom the mass of the Glacial clay of Holderness, Avhich latter he then regarded, 

 not only as identical with the ordinary Glacial clay of East Anglia (Upper Glacial or 

 great chalky clay), but as identical also with the (Lower Glacial) beds of Cromer 

 Cliff. 



2 Eeport of Brit. Assoc, for 1870, Geol. Mag. April, 1872, p. 176, and Sept. 

 1876, p. 396 (footnote). In a paper also "On the Climate of the Post-Glacial 

 Period" in the same Mag. for April, 1872, p. 153, 1 drew attention to what appeared 

 to me to be evidences of the recurrence of a glaciation of minor extent during that 

 period. 



