FUSULINA, OR UPPERMOST CARBONIFEROUS LIMESTONE. 
85 
tertiary rocks (see Map) and vast tracts of sand, it is evident that the regular 
ascending section has here been interrupted throughout this region as in the neigh- 
bourhood of Moscow (see woodcut, p. 80). 
Fusulina Limestone . — Upper Division of Carboniferous Limestone. — Our most 
recent researches have convinced us, that the limestone charged with Fusulina, 
which during our first journey we had seen in the government of Archangel 
only, but which we then could not separate from the other masses, is, in truth, 
a superior member of the great deposit of carboniferous limestone. In a flat 
region like Russia, where the same beds range over such very wide spaces, the 
order of superposition of the different members of a system can seldom be 
seen in any one section. In the southern carboniferous tracts, where the strata are 
highly inclined, better proofs of this order are naturally obtained, in sections which 
will presently be described. In the mean time we may remark, that from the 
great extension of the strata on the eastern limits of the large area of carboniferous 
limestone, of which Moscow is the centre, it is impracticable there to trace 
so clear a sequence. In one district only were we enabled to see what may 
be considered a passage into beds of nearly this age, in the white limestone 
which is worked along a low ridge extending from Kosrot to Yelicovo on the 
right bank of the Nerecta, a tributary of the Kliasma. The sand and clay (drift) 
having been removed, and the beds laid hare by the workmen, the best or white 
courses of the rock are extracted (above Velicovo) from beneath coarse roof-stones, 
and though almost horizontal, these strata incline slightly to the east-north-east, 
so as to pass under the red deposits of the great basin of Nijni Novogorod. In 
these bands, in which chert is no longer so abundant as in the central limestone, 
we did not perceive any Producti, the fossils being Euomphalus pentangulatus, Spi- 
rifer Mosquensis, with an occasional Fusulina. 
As this limestone of Velicovo differs, somewhat, from all the bands we have 
hitherto described, lies upon the exterior of the great carboniferous masses, and is 
followed on the east by newer deposits, we had no hesitation in considering it to be 
the superior member of the carboniferous limestone. We have already adverted to 
Fusulina limestone in the north (p. 76), and in pursuing our journey from Moscow 
to the east upon two lines of research, we met with this rock at one other locality 
only, viz. at the village of Schwetzi, north-west of Murom. Beyond this boundary, 
all the vast region extending to the foot of the Ural Mountains is composed of the 
overlying deposits which we have called Permian. To the south, however, after 
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