The total number of species of testaceous mollusca from the faluns in my
possession is 302, of which forty-five only, or fourteen per cent, 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
adverted to, amounts to forty-three, as determined by Mr. Lonsdale, of which
seven (one of them a zoantharian) agree specifically with those of the Suffolk
Crag. Some of the genera occurring fossil in Touraine, as the corals Astrea and
Dendrophyllia, and the bryozoan Lunulites, 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 formerly endeavoured to reconcile this
marked difference in species with the supposed co-existence of the two faunas,
by imagining them to have severally 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, now separating the Red
Sea and the Mediterranean.
Pages:
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408