242 J. S. Gardner — Britisli Eocene Land-Mollusca. 



nient of land and water can be made to suffice for the distribution of 

 sucli recently developed things as the existing species of mammals, 

 birds, and butterflies ; but the far more ancient families of land- 

 mollusca, at least, seem to have been in possession of their pi'esent 

 habitats from the most remote times. I find in " Island Life " that 

 the Azores are stated to possess 69 species, 32 being peculiar, though 

 with a general European facies. A fourth of the land-shells of 

 Bermuda are peculiar, including one genus, while most of the 

 remainder are found in the West Indies and American mainland. 

 The Galapagos Isles possess about 20 species, most of them peculiar. 

 St. Helena has 29, 20 of which are truly indigenous, two of them, 

 Bulimi, resembling Brazilian types. The land-shells of the Sand- 

 wich Islands number between 300 and 400 species, and 30 genera, 

 three-fourths peculiar ; the large sub-family Achatinellinse, with 14 

 genera, being entirely confined to the Sandwich Isles, and the genera 

 of Auriculidae only met with there and in Australia, China, Bourbon, 

 Cuba, and the West Indies. About two-thirds of the land-shells of 

 the Seychelles are peculiar, most being Indian forms, and some like 

 those of Madagascar. 



Such examples may be multiplied if we look into Woodward's 

 Manual of the Mollusca. The author of this work is profoundly 

 impressed with the belief that many of the Oceanic Islands are 

 relics of lands that have disappeared. The mollusca of St. Helena 

 especially indicate a closer geographical alliance between the east of 

 South America, than now holds. The presence of several species of 

 old-world genera in the Columbian region, which are wanting in 

 North America, implies a land connection at some very remote period 

 across the Atlantic in temperate latitudes. Two genera, Anastoma 

 and Megaspira, now peculiar to Brazil, inhabited France during the 

 Eocene. There is nothing in these facts to support the extreme views 

 of the Permanence of Continents, advocated by Wallace ; and taken 

 in connection with the observations of such writers as Sir Joseph 

 Hooker and many other botanists, there is such an array of at least 

 prima facie evidence against them, which has not been explained 

 away, that they must be held as far indeed from generally acceptable 

 to geologists. 



The re-examination ' of the Eocene land and freshwater fossil 

 shells, which I propose to undertake, will I am convinced present 

 some very curious problems in connection with this subject. The 

 jDrogress of science has moreover rendered some revision neces- 

 sary, and though Professor Sandberger has to a great extent already 

 effected this, his work is in German, and the British species are 

 mixed up in it with a large number of others. 



As the first instalment, I have selected the group of land-shells 

 of the Bembridge and Headon limestones of the Isle of Wight, 

 which, from their size, number, and splendid preservation, probably 

 form the most important assemblage of the kind from any rocks of 

 similar age. 



1 Nearly all the species have been described for the Paloeoutographical Society by 

 Mr. F. Edwards, 1862. 



