440 
CARBONIFEROUS FOSSILS OF COSSATCHI-DATCHI. 
The geological observer, who casts his eye around and sees that the limestone 
is surrounded by eruptive rocks, would have little hesitation in supposing, that 
these included masses also owed their peculiar form to some plutonic influence ; 
so completely do the calcareous protuberances resemble in outline the igneous 
“hornitos” of Jorullo in Mexico, described by Humboldt. Though all composed 
of limestone of a greyish-white colour, these calcareous hummocks, when ex- 
amined, convince the geologist that they have been thrown into their present 
outline, by heat and gaseous vapours which formerly struggled for expansion; since 
not only are nearly all traces of bedding obliterated, but the rock is rendered 
highly fetid and sub-saccharoid, and breaks for the most part upon the slightest 
application of the hammer. We believe that, in this case, the metamorphic action 
has been exactly of that degree of intensity, which in rendering the limestone as 
pulverulent as sugar, has left the fossilized organic remains comparatively so un- 
injured, that they easily drop out from the ambient matter. 
On referring to the Third Part of this work it will be seen, to how great an ex- 
tent our palaeozoic collection of the Ural has been enriched from this locality, 
which afforded us not only some new forms, but also many of the most charac- 
teristic species of the carboniferous limestone of the Valdai hills, Belgium, France 
and the British Isles. Among these we may specially enumerate — 
'1 erebratula sacculus (var. hastata ) (Sow.), T. pugnus (Sow.), T. pleuroclon, T. rhomboidea (Pliill.), T.fusi- 
formis (nob.), Spirifcr striatus (Sow.), S. ylaber (Sow.), S, crassus (De Kon.), Orthis Michelini (Ter. 
Lev.), Product m Vuldakus (nob.), or P. striatus (Fisch.), P. Martini (Sow.), P. semireticulatus (an- 
tiquatus), P. Scoticus (Sow.), P.punctatus (Sow.), P.fimbriatus (Sow.), Cardium Uralicum (nob.). 
Area arguta (Phill.), A, Lacordairiam (DeKon.), Cypricardia rlinmbea (Phil!.), Edmondia Uuioniformu 
( Isocardia , Phill.), Cardiomorpha sulcata (De Kon.), Peeten cllipticus (Phill.), Pleurotomaria striata 
(Sow.), P. Yvanii ( Trochus , Lev.), Buccinum acutum (Sow.), Euomphalus cequalis (Planorbis, Sow.), 
E. labulatus, Bdlerophon hiulcus (Mart.), B. dccussatus (Flem.), Nautilus bicarinatus (De Kon.), N. 
cyclostomus (Phill.), N. clitellarius (Sow.), N. Tcheffkini (nob.), Cyrtoceratites novm-angulatus (nob.), 
Orthoceratites calamus (De Kon.), Gonia/ites diadema (Goldf.), G. vyclulobus (Phill.), G. Barbottanus 
(nob.), G. Marianus (nob.), Asaphus gcmmiliferus (Phill.). 
Even in this convulsed region, we fancied we could distinguish the portion of these 
limestones which was the oldest, from that which succeeded it ; for near the junc- 
tion with the bedded schaalstein, evidently of high antiquity, we found at the point 
marked p in the preceding woodcut, the large form of Productus Valdaicus or P. 
striatus (Fisch.), which, as before shown, characterizes the lowest band of the for- 
mation in Russia ; whilst at the point q we collected many Goniatites and other 
species which pertain to higher members. 
