144 Geological Society : — 



shingly sand and gravel of Avisford and Bourne Common in Sussex — 

 the Selsea mud-bed with Lusitanian shells, near the present sea- 

 level, representing the first part of the formation, which the depres- 

 sion carried transgressively to Avisford. In the Thames and lower 

 Lea valleys he described, and showed, by many lines of section, how 

 considerable a denudation accompanied the rise from this depression, 

 so that not only most of the formation but also much of the gravel 

 /, of glacial age, on which the uppermost bed of this formation 

 rested, was washed away, the latter having for a great distance been 

 left on an escarpment facing the valley-sides. This denudation, he 

 showed, was in the same places repeated after the formation of the 

 gravel of the minor glaciation. 



He then, under another division of the period (which he distin- 

 guished as that of the minor glaciation or reindeer age), described 

 the various formations, morainic, atmospheric, fluviatile, and marine, 

 due to a return of glaciation after England had, except in the 

 north-west, become all land. The morainic part in the north-west 

 (which was the Upper Clay of Lancashire and adjoining counties) he 

 regarded as extruded beneath the sea up to that level at which it 

 contains shells, these having been dropped from floe-ice detached 

 from the shores, which drifted over it while thus undergoing extru- 

 sion ; but in the north-east it was terrestrial, owing to this part 

 having emerged from the depression of the Cyrena formation before 

 the moraine reached Holderness, and therefore it contained no shells. 

 The ice giving rise to this moraine was of far less volume than that 

 of the Chalky Clay, and instead of seeking the sea as that did, when 

 the sea lay over the centre and south of England it passed to it in 

 its present position, one stream of it going straight out through the 

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

 H umber, 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 Cyrena formation at Crayford and 

 Ilford (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 40-45-foot terrace at Acton, where it 

 has yielded reindeer-remains. Owing to the rise from the depres- 

 sion under which the Ctyrma-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 Cyrena 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 Cyrena forma- 

 tion. The floe-ice of this glaciation, driven onto 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 



