180 BR G. W. LEE ON 



unmodified descendants of the forms originally described from lower horizons. Through 

 the kindness of Professor Th. Tschernyschew, I am enabled to mention a striking 

 instance of persistence in the most familiar of Lower Carboniferous fossils : he found a 

 specimen of Productus giganteus in the Spirifer mosquensis limestone of the Timan, a 

 region where the Lower Carboniferous is absent and the Mosquensis zone transgresses 

 on the Devonian. Vice versa, Upper Carboniferous species may have appeared earlier 

 than usually supposed, and, to mention an example taken from this country, Dr 

 Vaughan cites Derby a grandis Waagen, from the top of the Carboniferous limestone 

 at Loughshinny, Ireland.* 



Bearing these facts in mind, one might hesitate to assign a definite age to a limited 

 collection of Carboniferous fossils ; but in the present case the evidence is very strongly 

 in favour of a correlation with the Giganteus zone, since the number of species typical 

 of this zone is as large as that from any bed in a typical Visean locality, not to mention 

 the complete absence of typical Upper Carboniferous forms. 



In the following table I give a list of the species found in the Cape Cherney lime- 

 stone, with an indication of their occurrence in the Lower Carboniferous beds of Russia 

 and Western Europe. Their occurrence in higher horizons is also indicated, but these 

 data have been compiled from various sources, and needless to say no Upper Carboni- 

 ferous locality is known where so many Lower Carboniferous forms would occur together. 

 It must also be understood that many of the species quoted from Upper Carboniferous 

 beds are probably not strictly identical with the Lower Carboniferous forms the names 

 of which they bear, for the reason stated above. Had they all been described instead of 

 being simply cited in lists, I should perhaps have been justified in dispensing with many 

 of these comparisons. 



As regards the relation of the fauna to its distribution in space, it seems to be very 

 closely allied to that of the Giganteus zone of the Urals and Central Russia, which is 

 practically the same as that of Western Europe. The list of fossils described in this 

 paper has many points in common with those given respectively by Messrs Tscherny- 

 schew, Krotow, Krasnopolsky, etc., in various monographs treating of the Carboni- 

 ferous of the Urals. t 



It is true that, of the districts surveyed by these authors, the most septentrional one, 

 viz. the district of Tscherdyn and Ssolikamsk described by M. Krotow, lies some ten 

 degrees south of Cape Cherney ; but Professor Tschernyschew kindly informs me that 

 I ' roductus giganteus has been found much farther north, in the basin of the river Adzva, 

 a branch of the Oussa. Thus, although marine Lower Carboniferous beds' have not yet 

 been proved to exist in the extreme north of the Ural range (Pai-Khoi), it appears 

 probable that the Cape Cherney limestone was deposited in a sea situated in the con- 

 tinuation of the Uralian geosyncline. At all events, the Lower Carboniferous sea did 

 not apparently extend farther west — over the Timan — and the Cape Cherney fauna 



* Quart. Jour. Geol. Soc, 1908, p. 446. 



t M6n. Com. Geol. Russie, t. iii., 1889, t. vi., 1888, and t. xi., 1889. 



