Ch. XIV.] 



VARIATION OF SPECIES. 



215 



with species not only still living, but which are now inhabitants of 

 neighboring seas, while the accompanying extinct species are of 

 genera such as characterize Europe. In the faluns, on the contrary, 

 the recent species are in a decided minority ; and most of them are 

 now inhabitants of the Mediterranean, the coast of Africa, and the 

 Indian Ocean ; in a word, less northern in character and pointing to 

 the prevalence of a warmer climate. They indicate a state of things 

 receding farther from the present condition of central Europe in 

 physical geography and climate, and doubtless, therefore, receding 

 farther from our era in time. 



Among the conspicuous shells which are common to the faluns of 

 the Loire and the Suffolk Crag is the Voluta Lamberti, before men- 

 tioned, page 204. All the specimens of this shell which I have my- 

 self collected in Touraine or have seen in museums are thicker and 

 heavier than British individuals of the same species, and shorter in 

 proportion to their width, and have the folds on the columella less 

 oblique, as represented in the annexed figures. 



Fia, 162 6. 



Fie. 163. 



Voluta Lamberti. 



Variety characteristic of Faluns 



of Touraine. Miocene. 



V. Lamberti. 

 Variety characteristic of Suffolk Crag. 

 Pliocene. 



Mr. Searles Wood has fully appreciated these constant differences, 

 but has, I think, with propriety regarded the two forms as mere 

 varieties, or races of one and the same species. It is remarkable, 

 however, that the late Alcide d'Orbigny,* who so often founded 

 species on very fine distinctions, should have coincided in this view. 

 It may, I think, be fairly assumed that be would not have done so 

 had he not imao-ined the Suffolk Crao; to be identical in age with the 



* A. d'Orbigny, Cours Elementaire de Paleontologie, vol, ii. pp. 793, 79V, 1852. 



