452 Froceedings of the Royal Iri^h Academy. 



from the numerous lacustrine and fluviatile deposits in the low grounds, 

 Vae, country seems to have been studded with numerous lakes. 

 Prof. J. Geikie informs us (35 «, p. 699) that the Hain-Hai or great Dry- 

 Sea in Central Asia was, during Glacial times, a much better watered 

 region than it is now. We have also strong evidence that the Caspian, 

 towards the commencement of the Pleistocene Epoch, extended not 

 ■only considerably further north, but also further to tlie east, and was 

 indeed joined to the Sea of Aral. The slight extension of local 

 .glaciers in tlie Sibei'ian mountains, during those times, does not, 

 therefore, indicate a cold climate, but is the natural result of the 

 more humid conditions which prevailed in Siberia. Tcherski thinks 

 "that there is no evidence to show that the Siberian rivers formerly 

 flowed in a different direction from that at present, as has been 

 supposed by Sir Henry Howorth (40 V) to have been the case. 



Eastern Siberia seems to have been more elevated than it is at 

 present, for the J^ew Siberian Islands must have been joined to the 

 •continent. A considerable area in the Behring Straits was also 

 raised above sea-level, so as to unite Asia and North America. By 

 means of this land-connexion, the red-deer, mammoth, grisly bear, 

 and other large Mammals migrated across to the J^ew World ; and, on 

 the other hand, Asia received the woodland caribou, and possibly also 

 the horse, in excliange. An enormous extension of the Siberian fauna 

 evidently occurred in later Pliocene times ; but, nevertheless, there 

 is strong evidence for the assumption that no direct emigration to 

 Central Europe took place then. An indirect emigration, which will 

 be referred to more fully later on, did, however, occur to some extent. 



A southern variety, Lepus europotus mediterr emeus, of the common 

 European hare inhabits the Mediterranean region ; and since it reached 

 the islands of Corsica and Sardinia and also Northern Africa, which 

 ■can be clearly demonstrated to have been separated from the mainland 

 -of Europe at a comparatively early geological period, it must have 

 migrated from Asia much before its more northern relative. We 

 have a similar case in the bullfinch {Pyrrlnda europmC), with the 

 difference that it wandered a good deal further than the Mediterranean 

 hare. On its arrival, in the extreme western limit of the Mediterra- 

 nean, it turned north and invaded even the British Islands, and 

 •spread also into Western Germany from France. But a larger form, 

 known as the Russian bulMnch {Pyrrhda major), emigrated from 

 Siberia at a later period, and occupied the greater part of Central and 

 Eastern Europe. 



I mentioned already, on a previous occasion (76c, p. •436-474), 



