ScHARFF — Some Rcmarlis on the AlhntU Problem. 269 



theories, and argued (p. 183)^ that the prominent European character 

 of the Atlantic Islands, as shown by their plants and insects, proved 

 that they were formerly connected by land with the continent of 

 Europe. Eut besides these forms, he noticed that certain American 

 types occurred in all the islands, and that the flora of the latter, in 

 some respects, resembled tlie tertiary flora of Europe, which, again, 

 was allied to that of America. These remarkable features were 

 explained by Heer by the supposition that, during the tertiary era, the 

 continents of Europe and America were joined across the Atlantic, 

 and that the plants trarelled on this old land-connection from the one 

 to the other. The plants of the Atlantic Islands, he thought, were 

 more European in character than' American, because the islands had been 

 united with the Old "W-^orld much longer than with the jS'ew (p. 185). 



Oliver denied altogether the necessity for what he called "the 

 Atlantis hypothesis," and insisted that the American element in the 

 flora of the Atlantic Islands played only a subordinate part, whereas 

 mediterranean, with a proportion of peculiar or macaronesian types, 

 greatly predominated (p. 163). He explained the relationship between 

 the flora of Europe and that of the Xew World — as has been done 

 more recently by Prof. Engier (p. 82) and Dr. v. Ihering (A. p, 43) — by 

 the supposition that the plants wandered across a land-bridge which 

 formerly joined Eastern Asia to jS'orth America. Christ, on the other 

 hand, attributes the American element in the flora of the Canary 

 Islands to tlie action of the Gulf stream (p. 515); and Trelease, in his 

 careful account on the Botany of the Azores, remarks that, so far as 

 the peculiar species were concerned, their ancestors seemed to have all 

 been introduced by such accidental means as drift or migratory birds 

 (p. 87). 



Edward Eorbes maintained that, at the close of the Miocene Epoch, 

 a vast continent extended far into the Atlantic from the coast of 

 Portugal, past the Azores, and bounded on the north by Ireland 

 (p. 14). While adopting Eorbes' s hypothesis, Murray enlarged the 

 area of this Atlantic continent as far as IS'ewfoundland, Greenland, 

 and Spitsbergen (A, p. 37). 



Imbued with the belief in the permanence of the great ocean 

 basins, Dr. A. R. Wallace vigorously attacked Heer, Eorbes, Murray, 

 and others in his Presidential Address to the Entomological Society of 

 London, delivered in January, 1871. I^either Murray nor later 



^ A list of the works and papers referred to in this Essay ■nill te found in the 

 Appendix. 



