278 Proceedings of the Royal Irish Academy. 



upon tlie whole Atlantic Islands as summits of submerged mountain- 

 chains; w^hile i^eumayr (p. 547) and Guppy (p. 496), as I have already 

 had occasion to mention, saw in them the remnants of a great con- 

 tinent. 



Sir Charles Lyell maintained that Madeira originated in Upper 

 Miocene times, and that it was separated from the Continent by a 

 great depth. He did not consider it possible, therefore, that the 

 two could haye been ever connected (p. 411). However, I have 

 already shown that Lyell's supposition was not borne out by later 

 researches, and that Suess believed in some kind of coast-line having 

 stretched right across the Atlantic during part of Tertiary times. 

 Prof, de Lapparent expresses himself even more decisively on thia 

 subject. He favours the view of the existence of a coast-line, or at 

 least that of an island-chain, during the Miocene Period, connecting the 

 West Indies with southern Eiu'ope. The end of the Pliocene and the 

 whole of the Pleistocene Period, he beHeves, were distinguished by a 

 series of subsidences which resulted in finally opening up the northern 

 depression of the Atlantic Ocean (p. 1392). 



Prom a careful study of the structure and distribution of the 

 geosynclines, Mr.Haug has recently come to the conclusion that tlie 

 convex arch fonned by the Antilles, and the one found along the 

 western border of the Mediterranean, were connected, in the Tertiary 

 Era, by tangential chains of land. According to his view, a coast-line 

 stretched across the Atlantic from Yenezuelu to Marocco, and another 

 between the Lesser Antilles and Portugal, the intervening space being 

 covered by the sea (p. 635). 



The hypothesis of a North Atlantic continent and of an Africano- 

 Brazilian one, to some extent meets the views expressed by Murray on 

 zoological grounds. As already mentioned, Dr. Gregory lu'ged that 

 the intimate affinity between the Miocene marine species of the West 

 Indies and those of the Mediterranean Region could only be explained 

 by the assumption of the existence of a shallow-water connection 

 across the Central Atlantic in — at latest — [Miocene times (p. 306). 



pArXA OF ATLA^'TIC ISLA>'DS. 



Mammals. 



The historic reasons for the belief that the rabbit {Orydolayus 

 cnnicxdus) might be indigenous in some of the Atlantic Islands have 

 already been alluded to. If we supposed these islands to be the last 

 remnants of a former laud-connection between Europe and America, 

 the rabbit might be regarded as a relic form which reached u& 



