220 BULLETIN OF THE ZOOLOGICAL MUSEUM. 



Still more instructive is the supposition of a subsidence in Eastern North Amer- 

 ica which would leave above the level of the sea only two groups of islands formed 

 by the White Mountains of New Hampshire, and Mount Mitchell and Black Moun- 

 'tain of North Carolina. On the latter we may suppose would be preserved all the 

 species given in the lists on pp. 209, 210, 211. Of these species all would he pecu- 

 liar to the island, except such as are named in the list on p. 208, which would all 

 be found also in the White Mountains, where we should also find the following 

 species peculiar to the islands, Helix Sayii, dentifera, Vitrina limpida, Zonites milium, 

 Binneyanus, ferreus, exiguus, midtidentatus, Patula striatella, asteriscus, Pupa decora, 

 Vertigo Gouldi, Bollesiana, simplex, Succinea Totteniana. Of the former distribution 

 of these species nothing could be known, hut a former connection of the two groups 

 of islands would be surely indicated by the presence of so large a proportion of 

 species common to each. A former connection of the two groups of islands with 

 Europe and Asia would lie as surely indicated by the presence on each of Zoiiitcs 

 fulvus, nitidus, viridulus, Helix harpa, pulchella, Cionella subcylindrica, and Pupa mus- 

 corum. Nor could it escape the attention of conchologists that these and other small 

 species, Z. arboreus, &c. (see p. 204, note,) proved that a former connection must 

 have existed between these groups of islands and the far-off Central and Pacific 

 Provinces. 



