Interglacial Submergence in England. 5 



were several feet of till overlying the sand, and a thin stratum 

 of gravel at the junction of the two. In this gravel Mr. 

 Baldwin discovered several slightly worn shells and on further 

 examination forty or fifty well-preserved specimens were 

 brought out. All these were identified by Dr. Crosskey as 

 belonging to species now common on the English coast. The 

 elevation above the sea would vary only a little from 500 feet. 

 A few miles from the same locality, at an elevation above the 

 sea of about 700 feet, Dr. Crosskey had previously discovered 

 in the glacial deposits other shells which were of a decidedly 

 arctic type. It is extremely improbable that both could have 

 lived in that locality amid the conditions involved in the in- 

 terglacial hypothesis, as the temperature which would be 

 favorable to one would be destructive to the other. But on 

 the supposition that both had lived and died in succession 

 upon the bottom of the Irish Sea, and then had been trans- 

 ported by the moving ice to near their present position, where 

 the till was subjected to temporary water action sufficient to 

 sort out a portion of its material, everything is intelligible and 

 consistent. 



Various reports have also come from Scotland of arctic shells 

 in glacial deposits at some distance above sea-level. Those 

 found near Airdrie have been most written about, and were 

 the highest reported, being 510 feet above the sea. But closer 

 examination shows that they also may be explained in accord- 

 ance with the theory of Professor Lewis. This Sir Archibald 

 Geikie practically admits in the second edition of his " Text- 

 book of Geology," saying that "the layer containing them may 

 have been transported by an ice-sheet" (pp. 897,902). Mr. 

 Dugald Bell informs me that after carefully examining all the 

 alleged instances of elevated shell-beds in the glacial deposits 

 of Scotland, there is no clear proof of any glacial submergence 

 of more than 200 or 800 feet, and the evidence for even that 

 amount is questionable. 



As to the conceivability of the transportation of shells in 

 the till, many significant facts have recently been brought to 

 light. The till in the vicinity of the shell -beds mentioned, and 

 in other places where the ice has moved inland from the sea- 

 bottom, contains a great number of shell fragments indiscrimi- 

 nately mixed with the mass. I have even seen in a mass of 

 boulder clay the half of a bivalve, with its cavity filled with 

 sand, which had kept its place under the shell as it was shoved 

 along ; thus serving to protect it from being crushed. As 

 long ago as 1884, Mr. Lamplugh, in examining the dry dock 

 which was then being excavated in Esquimault Harbor, Van- 

 couver, discovered evidence that most of the glacial shells 

 which were found in the drift there had " been pushed up into 



