Ch. XIV.] COMPARISON" OF THE CRAG AND FALUNS. 177 



luscous fauna of the " faluns" is on the whole much more littoral than 

 that of the Ked and Coralline Crag of Suffolk, and implies a shallower 

 sea. It is, moreover, contrasted with the Suffolk Crag by the indications 

 it affords of an extra-European climate. Thus it contains seven species of 

 Cyprcea, some larger than any existing cowry of the Mediterranean, sev- 

 eral species of Oliva, Ancillaria, Mitra, Terebra, Pyrula, Fasciolaria, 

 and Conus. Of the cones there are no less than eight species, some very 

 large, whereas the only European cone is of diminutive size. The genus 

 Nerita, and many others, are also represented by individuals of a type now 

 characteristic of equatorial seas, and wholly unlike any Mediterranean 

 forms. These proofs of a more elevated temperature seem to imply the 

 higher antiquity of the faluns as compared with the Suffolk Crag, and 

 are in perfect accordance with the fact of the smaller proportion of testacea 

 of recent species found in the faluns. 



Out of 290 species of shells, collected by myself in 1840 at Pontlevoy, 

 Louans, Bossee, and other villages twenty miles south of Tours ; and at 

 Savigne, about fifteen miles northwest of that place, seventy-two only 

 could be identified with recent species, which is in the proportion of 

 twenty-five per cent. A large number of the 290 species are common to 

 all the localities, those peculiar to each not being more numerous than we 

 might expect to find in different bays of the same sea. 



The total number of testaceous mollusca from the faluns, in my pos- 

 session, is 302 ; of which forty-five only were found by Mr. Wood to be 

 common to the Suffolk Crag. The number of corals, including bryozoa 

 and zoantharia, obtained by me at Doue, and other localities before ad- 

 verted to, amounts to forty-three, as determined by Mr. Lonsdale, of which 

 seven (one of them a zoantharian) agree specifically with those of the Suf- 

 folk Crag. Only one has, as yet, been identified with a living species. 

 But it is difficult, notwithstanding the advances recently made by MM. 

 Dana, Milne Edwards, Haime, and Lonsdale, to institute a satisfactory 

 comparison between recent and fossil zoantharia and bryozoa. Some of the 

 genera occurring fossil in Touraine, as the Asirea, Dendwpliyllia, Lunu- 

 lites, have not been found in European seas north of the Mediterranean ; 

 nevertheless the zoantharia of the faluns do not seem to indicate on the 

 whole so warm a climate as would be inferred from the shells. 



It was stated that, on comparing about 300 species of Touraine shells 

 with about 450 from the Suffolk Crag, forty-five only were found to be 

 common to both, which is in the proportion of only fifteen per cent. 

 The same small amount of agreement is found in the corals also. I for- 

 merly endeavored to reconcile this marked difference in species with the 

 supposed coexistence of the two faunas, by imagining them to have sever- 

 ally belonged to distinct zoological provinces or two seas, the one opening 

 to the north, and the other to the south, with a barrier of land between 

 them, like the Isthmus of Suez, separating the Red Sea and the Medi- 

 terranean. But I now abandon that idea for several reasons ; among 

 others, because I succeeded in 1841 in tracing the Crag fauna southwards 

 in Normandy to within seventy miles of the Falunian type, near Dinan, 



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