Tol. 68.] A LATE GLACIAL STAGE IN THE LEA VALLEY. 2.51 



i^Torth Sea and Irish Sea were melted out. In Britain, as in 

 Scandinavia, there appeared to have been some considerable varia- 

 tions of climate during the slow and oscillatory recession of the 

 ice-sheets ; but the speaker had as yet failed to find evidence that 

 the changes were ever sufficient to initiate a new and independent 

 system of ice-sheets or glaciers anywhere in England. It was a 

 characteristic feature of the late-Glacial erosion that, while the 

 high-graded upper parts of the valleys were sharply deepened, 

 great sheets of flood-washed detritus were deposited simultaneously 

 in the lower and broader parts of the valleys. Consequently, the 

 gradient of the late-Glacial terraces was generally steeper than that 

 of the present valley-bottom, and deposits on the floor of the open 

 lower valley were often equivalent in age to high terraces of the 

 upper reaches. This condition was observable in the upper part of 

 the Lea Valley, and the speaker seconded Mr. Reid in asking the 

 Author to consider the possibility of the ' Arctic Bed ' in question 

 being older than its position would seem to imply. 



Mr. Whitaker explained that he had not compared terraces at 

 distant parts of a valley, as Mr. Lamplugh had done, but terraces 

 at one and the same part, which was a very difl'erent matter. 



The Rev. E. C. Spicee, in the hope that the paper would throw 

 light upon the gravel--^ ounds around Buckingham, drew attention 

 to the occurrence of a lenticular patch of loose dark peat in a 

 gravel-pit near Woodford and Hinton railway-station, which was 

 unfortunately destroyed before it could be investigated. The patch 

 of peat was intercalated among contorted gravels containing very 

 large pebbles and big fragments of Jurassic rock, and must have 

 been a frozen flake originally. One shell, which was possibly 

 Pupa onuscorum, was obtained from a small handful of the peat^ 

 but this too was accidentally destroyed. 



The Author, in reply, thanked the Fellows for their reception 

 of his paper. With regard to the point raised by Mr. Reid, he 

 admitted that some valleys had been filled with drift and then 

 re-excavated, so that the higher terraces were the newer ; but this 

 explanation could hardly apply to the River-Drifts of the Thames 

 Basin. The fact that abraded implements derived from the higher 

 terraces were found in the lower, was a confirmation of the 

 reading of the drifts as given in the paper. He had also to thank 

 Mr. W'hitaker for answering this point. In reply to Mr, Reginald 

 Smith, the photographs of implements shown on the screen were 

 not copied from Mr. Worthington Smith's book, but were all of 

 specimens in the speaker's own collection : they had been given in 

 their correct sequence of relative age. He so far agreed with 

 Mr. Lamplugh that the Arctic conditions claimed in the paper 

 would not compare with those of the epoch of maximum glaciation. 

 The evidence, so far as it went, suggested snow and river-ice for 

 the lowlands, probabl}" with glaciers in the more mountainous 

 districts : but not a general ice- sheet of such magnitude as to 

 displace the water of the sea-basins adjacent to our shores. 



In reply to a question put by Mr. J. F. jST. Green, the Author 

 was certainly of opinion that the Ponder's-End deposit was a true 

 Lea river-gravel. 



a J. G. S. iSTo, 270. T 



