DEVONIAN ROCKS UPON THE DON — VORONEJE — LEBEDIAN. 
61 
At Jendovistie, on the stream Veduga, another feeder of the Don, sandy, cal- 
careous flagstones of greenish colours, are interlaced with spotted red marl and 
clay, containing Devonian fossils, and similarly covered by sands and ferruginous 
concretions. In ascending the Don we traced Devonian rocks in the hillocks ot 
Sadonsk, and in them we no longer found the same fossils as those collected in the 
neighbourhood of Voroneje : others, however, became dominant, such as the Spi- 
rifer Archiaci, with its elevated area, and a plicated Terebratula resembling T. venti- 
labrum. 
At Lebedian, on the Don, the sloping banks of the river give a section, where 
upwards of seventy feet of strata are exposed in the following order : — 
Feet. 
Black earth and detritus 
Ferruginous grit (greensand?) 3 
Devonian Rocks. 
Marly limestone 4 
Impure, compact, finely laminated, light grey limestone, containing remains of the 
same species ? of fishes as at Orel 10 
Flagstones : in parts magnesian and cavernous, with Lep>tana caperata 8 
Finely laminated and striated siliceous limestone 12 
Beds filled with the same minute fossil as at Ottrada (see p. 57 ) 4 
Sandy beds, with breccia-like (concretionary ?), marly limestone 4 
Thick flags of compact, hard limestone, in part concretionary, with cavernous sur- 
faces, and filled with Spirifer Archiaci and Leptana caperata 12 
White, marly fragmentary limestone, with broken concretions 15 
Concretionary, siliceous limestone, consisting of large, spherical concretions, com- 
posed of concentric laminae, forms the base of the cliffs 
Beds of the same lithological structure as those previously mentioned, viz. 
yellow, sandy, magnesian limestones and marls, extend to Donkof, a little to the 
north of which, we place the upper limit of the Devonian system, in this parallel. 
The peculiar type of the system which has just been described, being so veiy 
calcareous and so equably bedded, is, as might be expected, more highly charged 
with the remains of fossils, than the red and green marls, impure limestone and 
red sand, which lie to the north of the Moscow basin (see Map and section below 
it). Organic remains are, it is true, much more abundant in some parts than 
others. Thus, as above stated, the strata which have afforded us the greatest num- 
ber of species of shells are the flag-like limestones near Voroneje. These are 
probably among the inferior beds of the central region ; and we form this opinion, 
not simply because Voroneje is situated at a lower level than Orel, a point of 
some little value in a country where the strata are so nearly horizontal, but chiefly 
K 
