ORIGIN OF WARM FLORA AND FAUNA 211 



in Wales, Macclesfield in England, and various other places. In these 

 localities well preserved shells, snch as occur in the Irish Sea, were pushed 

 np by the glacial movement from the north to an elevation of more than 

 1,000 feet, where on the melting of the ice they were redeposited in tem- 

 porary lacustrian pools and preserved in strata of sand marked by every 

 characteristic of cross-bedding.^ While most of these specimens are 

 fragmentary they were by no means all of them so. Professor Kendall 

 reports finding five whole shells in the course of a few hours' search at 

 Moel Tryfaen alone, while Prof. McKenny Hughes reports that some 

 of the specimens are whole, and he personally assured me that he had 

 found in these deposits some shells with both sides held together by the 

 original ligaments. How these shells could have been brought up to 

 these positions without showing signs of abrasion may be explained on 

 the supposition that large compact masses of the sea-bottom were broken 

 up and pushed before the advancing ice, as great masses of chalk have 

 been pushed inland over the east shore of England and over the southern 

 end of Sweden. Professor Hoist took me to visit such a mass of chalk a 

 few miles east of Malmo, which was 3 miles long, 1,000 feet wide, and 

 100 to 200 feet thick, which had glacial deposits both under it and over 

 it. In the case of a frozen or compact mass of soil containing fossils the 

 process of melting would result in waterlaid deposits containing fossils 

 showing even less signs of abrasion than if carried along tumultuously 

 by a running stream for any considerable distance. 



All the older geologists interpreted these lacustrian shell beds at Moel 

 Tryfaen and Macclesfield as evidence that the shell-fish had lived and 

 died in that immediate locality, and supposed that to account for them 

 there must have been a subsidence of the British Isles to the extent of 

 more than 1,000 feet, permitting the shells to grow on the ocean bed at 

 the level where they are now found. Among the authorities maintaining 

 this view are to be numbered Darwin, Prestwich, Eamsay, and McKenney 

 Hughes; but at the present time the geologists of Great Britain almost 

 universally regard the deposits as having been formed in the manner de- 

 scribed. In the case of the deposits under consideration at Toronto, 

 where there has been scarcely any, if any, elevation of the fossils above 

 their original position to get them where they are now found, it would 



» The fullest statement of the evidence bearing on this subject will be found in a com- 

 munication of Prof. Percy F. Kendall, F. G. S., incorporated in Wright's "Man and the 

 Glacial Period," pp. 137-181 ; but see also a paper of T. McKenny Hughes, of Cambridge, 

 England, on "The evidences of the later movements of elevation and depression in the 

 British Isles," Victoria Inst, 1880. See especially, however, "Supposed interglacial 

 shell-beds in Shropshire," England, by G. Frederick Wright, in Bull. Geol. Soc. Am., 

 vol. 3, pp. 505-508 ; and, by the same, "Theory of interglacial submergence in England," 

 in American Journal of Science, vol. xliii, January, 1892, pp. 1-8. 



