Geological Society of London. 333 



its present position, one stream of it going straight out througli tlie 

 Tees valley, and another down the vale of York and out by tlie 

 Humber, so as to overspread southern Holderness and the sea-board 

 of Lincolnshire. The fluviatile formation of this minor glaciation 

 is the gravel which overlies the C^)-e?2a-formation at Crayford and 

 Jlford (Uphallfield) up to the elevation of about 30 feet, and at 

 similar elevation lies up to the foot of that formation at Grays ; and 

 it is that which forms the 40-4o-foot terrace at Acton, where it has 

 yielded reindeer-remains. Owing to the rise from the depression 

 under which the C?/re»a -formation accumulated, which had taken 

 place when this gravel was formed, its level does not differ greatly 

 from that of the fossiliferous part of the (7j/re?ia-formation at Grays 

 and Crayford, so that in more inland districts, as at Oxford, the two, 

 though quite different in age, may be undistinguishable. This 

 gravel the author regarded as corresponding in position with the 

 beaches of the buried cliffs of Sangatte, Brighton, Isle of Wight, 

 Portland, and Sili Bay, these beaches and the gravel having originated 

 during a pause in the rise from the depression of the C?/rena-forma- 

 tion. The floe-ice of this glaciation driven on to these beaches left 

 blocks on them, which becoming mixed with loam from rills pouring 

 in summer over the cliffs, is covered by the atmospheric formation 

 which accumulated as, by renewal of emergence, the sea receded 

 from these beaches. At the same time floes grounding on the Pagham 

 and Selsea flats, which, in correspondence with the shingle of the 

 Isle-of- Wight beach, were then submerged about 30 or 40 feet 

 below their present level, left the great blocks found in the clay- 

 gi-avel of Pagham and Selsea which was then forming, and which 

 overlies the mud-bed with Lusitanian shells, and is itself overlain 

 by the atmospheric formation. He also showed by a line of section 

 that this gravel occupies a position several hundred feet below that 

 which the gravel of the great submergence and major glaciation 

 occupies in the adjoining parts of Hampshire. 



The atmospheric formation of the minor glaciation, he regarded as 

 the brick-earth with angular fragments of stone and splintered flints 

 overlying the buried cliffs and their beaches. This is the " formation 

 of great submergence " (with land shells and Mammalian remains) 

 of Prestwich, and identical with the "warp" of Trimmer and 

 " trail " of Fisher in other parts of England. The origin of this he 

 referred to an annual thawing of the upper layer of the permanently 

 frozen land-surface, such as takes place in arctic countries not occu- 

 pied by land-ice, such as Siberia. Owing to the subsoil being per- 

 manently frozen, no water can penetrate it, so that the thawing 

 surface-layer becomes sludge from the snow-melting and rainfall of 

 summer, and slowly slides from higher to lower places, thus exposing 

 on the higher a continually renewed superficial portion of the per- 

 manently frozen soil to this action, and accumulating it in the lower. 

 In sliding, this material has collected not only the bones of animals 

 such as the reindeer and mammoth which lived on this surface, but 

 also those of the hippopotamus, which did not, but had lived daring 

 the C?/re?ja-formation stage, from superficial deposits of that stage 

 (from which also they got by derivation into the gravel of this 



