24 FOSSILS AND NON-MARINE MOLLUSKS 



marine fossils contained in it being now found living in the same region, at 

 moderate depths. The terrestrial forms have invaded the Islands since their 

 elevation above the sea level, and the aeolian rocks have also been formed since 

 that event. They contain the remains of the first forms which occupied the 

 recently elevated territory as well as those which by evolution and variation 

 have been developed since. Hence if we could form some estimate of the 

 definite time which has elapsed since the elevation of the Bahamas, we should 

 have a measure of the rate of variation and specific evolution of the landshells 

 referred to, under favorable conditions. 



It is hardly necessary to say that the data are yet quite insufficient to 

 do more than point the way toward the solution of this problem, but to the fact 

 that they do furnish some indications in this direction is due whatever inter- 

 est the fossils herein noticed may possess. 



The first evidence of the existence of extinct species of landshells in the 

 aeolian rocks of the Bahamas was given by the writer in the Bulletin of the 

 Museum of Comparative Zoology, Vol. XXV, No. 9, in 1894, in discussing 

 some collections made by Professor Alexander Agassiz during the voyage of 

 the yacht Wild Duck. 



The present collection adds considerably to our knowledge of these 

 forms, and it may be supposed that further exploration would reveal other 

 additions to the list. 



LIST OF STATIONS AND THE SPECIES COLLECTED AT EACH OF THEM. 



Station 1. — About two miles north of Governors Harbor, Eleuthera 

 Island, about six feet above the water, near the shore. 



Cerion {sp.). 



Phacoides {Here) pensylvanicus Linne. 



Station 2. — Fossils from the Mount Vernon estate, about four miles east 



of Nassau, N. P., in the walls of the sink-holes described in Note No. 8. 



Area iScapharca) transversa Say. 



Chama (sp.) fragment. 



Phacoides (Here) pensylvanicus Linne. 



Cerithium (sp.) fragment. 



Torinia canaUfera C. B. Adams. 



Fissurella listeri Orbigny. 



Station 3.— Hard limerock from basement of Eum Cay. 



CJiama {sp.). 



Phacoides {Here) pensylvanicus Linne. 



Livona pica Linne. 



Agaricia {sp.). 



