249 
UPPER JURA GROUP IN SOUTH RUSSIA. 
In fact, the Jurassic rocks of the Crimea, lying to the south of the granitic and 
porphyritic steppe, to which we have alluded, and much perforated by eruptive 
rocks, belong distinctly to another mineral region. They assume the Caucasian 
aspect of the strata of that epoch, and from their imbedded masses of hard and cry- 
stalline limestone, they might at first view seem to be referable to the same Jurassic 
limestone which is spread over Southern Germany, including the Alps and Car- 
pathians, and which bounds the shores of the Mediterranean Sea, a series which 
unquestionably includes in descending order all the strata, to the inferior oolite and 
lias inclusive’. 
On this point, although we do not yet pretend to have the means of forming a 
correct decision, we are bound to state, that, judging from the fossils which 
have been as yet submitted to him, M.D’Orbigny is of opinion, that even there, the 
lias does not form a part of the group as in the Alps and Carpathians ; but on the 
contrary, that, differing as it may in lithological character, the Jura of the Crnmea 
and the Caucasus represents, like that of Russia, the “ Terrain Oxfordien.” He 
has convinced himself, that the Ammonites of the Crimsea, when not identical, 
approach closely to forms which are common near Dignes in the Lower Alps 
and at the Mont du Chat ; whilst the northern species are evidently those of a 
separate basin, characterized by the distinct species to which we have before 
alluded. 
But to consider the tracts with which we are personally acquainted : the only 
deposit of the Jurassic or oolitic age hitherto observed between the Devonian axis 
of Voroneje and Orel and the Sea of Azof and the Black Sea, was first discovered 
by Major Blode on the banks of the Donetz near Izium. Accompanied by 
that persevering geologist, we were enabled to satisfy ourselves of the accuracy o 
his observations ; and although we slightly extend the limits of the group, we 
admit with him, that it occupies a tract of very limited dimensions It is, in 
truth, a minute patch upon the great surface of Russia ; for to the sout i i is en- 
tirely cut out near Bachmuth and Lugan, where the chalk reposes on Permian 
and carboniferous strata, without the intervention of a single bed to represent any 
member of the Jurassic series. Still the deposit is geologically important, both 
from its peculiar character and as marking a higher stage m the series than any 
other beds of this epoch in Russia. 
,. a „„„ ,, ptwPPn the synchronous rocks of the north and south of Europe, 
1 To mark the exceeding difference between > r| , „ 
. . „ ,• ,■ • i„,/i tb P latter by the term “ Mediterranean lype. 
M. Von Buch has graphically distinguished the latte ) 
