HARDWICKE'S SCIENCE-GOSSIP. 



more) in the Cotteswolds ; to 1200 feet in Lancashire, 

 and to 1340 feet in North Wales. Eastwards, through 

 Kent towards France, their elevation falls, and in the 

 North of France appears to be about 130 feet ; from 

 whence the evidences of the submergence are furnished 

 northwards by the Campinian sands and the diluvium 

 of North Germany and Holland. 



In Stage III. the author traced the rise from this 

 depression, the increase of the ice from the greater 

 snow interception caused by it on the Pennine chain, 

 and the consequent advance of the glacier- or land- 

 ice. This advance gave rise to the Chalky Clay, 

 which was the morainic mud-bank which preceded 

 this glacier, and was pushed by it as it advanced, and 

 the land rose partly into the shallow sea (where it 

 covered and protected for a time the gravel which 

 was synchronously forming there), and partly on to 

 the land ; and by the aid of maps he showed the 

 islands that were overwhelmed by it. He then 

 showed, by a line on a map, the limit up to which 

 this ice, as it thickened, cut through and destroyed 

 this first deposited moraine and the gravel which it 

 had covered, as well as such beds of Stage II. as 

 were formed there, all this material being pushed on 

 to add to later deposited moraine. Outside this 

 line the gravel, for the most part, remains unde- 

 stroyed, its contents, particularly in the uppermost 

 layers, showing that it was fed by the approaching 

 moraine. By the level at which the junction of this 

 gravel with the moraine clay occurs he traces the 

 position of the sea-line at this time (towards the end 

 of the formation), and finds it to rise along the south- 

 eastern edge of the clay, from 40 feet in N.E. 

 Suffolk to 160 feet in South Essex, and from that 

 along the south-western edge to upwards of 350 feet 

 in North Warwickshire and the parts of Northamp- 

 tonshire adjoining, all this agreeing with the original 

 increment of submergence in Stage II. He then 

 showed, from evidence afforded by the Yare and 

 Gipping valleys, that this ice, ceasing to advance in 

 East Anglia, shrank into the valleys of that district, 

 exposing the moraine it had previously laid down to 

 the growth of vegetation, and issued only through 

 these valleys to the sea. The Hoxne palaeolithic 

 brickearth he regards as the deposit of a lagoon 

 produced from the interception of the drainage of 

 this surface by the glacier-tongue thus passing through 

 the Waveney valley. The Brandon palaeolithic brick- 

 earth he regards as connected with the same state of 

 things. 



In Stage IV, he described the plateau and cannon- 

 shot gravels of Norfolk as resulting from the washing 

 out of the morainic clay by the melting of this ice, 

 which, though shrunken into the valleys of the East 

 of Norfolk, still lay high and in mass in West 

 Norfolk ; and showed that, by having regard to the 

 different inclination of the land thus traced, the 

 position of this gravel is reconcilable in no other 

 way. The cannon-shot part of it he attributed to 



the torrents pouring from this high-lying ice over 

 the west side of the Wensum valley ; and the plateau 

 gravels to the deposition of other parts of the same 

 spoil carried into East Norfolk at the commencement 

 of the process and while the ice had not thawed out 

 of the valleys, this gravel afterwards, as the valley- 

 ice thawed being deposited in them. He also traced 

 the exvacation of the trough occupied by the Bain 

 and Steeping rivers in Lincolnshire to the same cause. 

 The finer or sandy part of this material has an exten- 

 sive spread in South-west Norfolk, forming thick 

 beds ; and in a thinner form spreads over North-west 

 Suffolk, where it wraps the denuded edges of the 

 Hoxne and Brendon palseolithic brickearths. 



In Stage V. he traced the line of gravels that over- 

 lie that Chalky Clay where this clay entered the sea. 

 This entry to the sea over the Severn drainage- 

 system took place by way of the watershed between 

 the Welland and Avon, and by the valley of the 

 latter. Its entry into the sea over the Thames 

 system was by way of the watershed between this 

 system and that of the Great Ouse in South Bucks, 

 as well as by the valley of the Colne, Lea and 

 Roding, and over the lower part of the watershed in 

 South-east Essex. Its entry into the North Sea was 

 by the valleys of the Blackwater, Gipping, and other 

 Essex and Suffolk valleys, the entry of the Yare and 

 Waveney being far out beyond the present coast-line. 

 He also traced, by similar evidence, the extent to 

 which the sea entered the Trent System after the ice 

 vacated it. This line of gravel (after allowing for the 

 case that the elevation of the junction of the gravel 

 beneath the clay represents that of the sea-bottom, 

 while that over the clay more nearly represents that 

 of the sea-top), he showed to correspond with that of 

 the junction of the gravel beneath the clay so far as 

 this is not destroyed in the parts where the ice did 

 not shrink into the valleys ; and it also agrees with 

 this line, supplemented by the amount of rise in 

 the interval where the ice did so shrink. Along 

 the south-western edge of the clay this line of gravel, 

 subsequent to the clay, falls from near 400 feet in 

 Bucks to 150 feet in South Essex ; from whence 

 northwards along the south-eastern edge it falls 

 uniformly to Ordnance datum in central East Suffolk, 

 and probably continued to fall to 1 00 feet or so 

 further to the extreme point where the ice from the 

 Yare valley entered the North Sea far beyond the 

 present coast. Along the north-western edge of the 

 formation this line falls northwards in a corresponding 

 way to that on the south-eastern edge, save that, 

 starting there from near 350 feet, it does not fall 

 below, if even quite down to Ordnance datum near 

 the Wash. He then traced the extent to which the 

 sea on the west, deepening in that direction in 

 accordance with the original depression of Stage II., 

 entered the valleys of the area covered by the ice 

 of the Chalky Clay as this vacated it ; the carrying 

 out through the Welland and Avon valleys of the 



