112 Proceedings of the Royal Irish Academy. 



■^Mch. had for result the present general coast outline of these 

 countries. 



It may he asked Tvould the 100 fathoms line as supposed hy Boyd 

 D^wtins truly or approximatively represent this Atlantic coast line 

 at the end of the Pleistocene time ? and are there not grounds for 

 admitting the existence of a more extended "western land and of 

 adjacent islands, Trhich could have afforded the shelter necessary for 

 the forests -ffhich covered these countries prior to the gi'o-^h of the 

 hogs. 



This query is in some degi'ee met by the results pointed out in 

 an article hy Dr. Reusch in "Xaturen," cited ia Nature, vol. 63 

 (Dec. 13th, 1900), p. 160, in vhich he calls attention "to the 

 changes of level that have taken place in Iceland in recent 

 geological times viz. siace the Ice Age." He says: "In 1896 the 

 Danish Ingolf Expedition investigated the sea bottom between Jan 

 Mayen and Iceland. In examining the dredged material Herr A. 

 S. Jansen made the observation that almost everywhere on the bottom 

 of the deep ocean lie shells of dead Molluscs of well-known shallow- 

 water forms, side by side with deep-water forms. It was veiy remai'k- 

 able to dredge up from depths of 500 fathoms to 1300 fathoms 

 Toldia Arctica which now lives at Spitzbergen, and in the Kara Sea 

 at depths from 5 to 100 fathoms. Dr. Eeusch suggests that these 

 remains of Arctic life forms cannot have been carried there by drift- 

 ing ice, but that the sea bottom, in comparatively recent times during 

 the Ice Age, must have been much nearer the sea level than now. At 

 that time the Arctic shallow- water forms must have lived there ' in 

 situ ' ; then a sinking of the sea bottom has taken place which can be 

 estimated at not less than about 2500 metres (about 1355 fathoms). 

 It is easy to see that these results of the Danish natui'alist have an 

 important bearing upon the phenomena of the Ice Age." It is evident 

 that from these results, there may be presumed a much greater exten- 

 sion of the "Western European plateau and of its resulting islands 

 than Boyd Dawkins was prepared to admit. "Wliatever the chain of 

 events was that gave rise to the depression of the land, it is reasonable 

 to assume that the causes thereof were more active on the Atlantic 

 side of Ireland than on the eastern coast, and that the surface of land 

 affected thereby was more extensive. The breaking up of the land and 

 accompanyiag island groups during the Pre-Historic Period necessarily 

 occupied a considerable time, and allows us to admit that fi'om the 

 coast of Spain, northwards to Ireland, and even farther, a great 

 number of islands, more or less inhabited, and of greater or less extent, 



