RED ROCKS ABOVE THE ZECIISTEIN. 
175 
great band of carboniferous limestone, we had been passing over strata dissimilar, 
both in mineral characters and zoological contents, from that well-known rock and 
all the inferior deposits. 
A parallel transverse section across the calcareous zone to Kirilof, north of Vo- 
logda, establishes the same succession, to strata equally unlike the carboniferous 
types as those we have just described ; for a little to the north of the former 
town, the Baron von Meyendorf and Professor Blasius, in a traverse from Vitegra 
to Ustiug 1 , detected white marls and limestones charged with fossils, some of which 
are identical with those of Ust-Vaga, such as the well-characterized Productus hor- 
rescens ; whilst others are peculiar to this locality, viz. Pentcimerus superstcs (nob.), 
Spirifer Blasii (nob.), and a Terebratula closely resembling T. Royssii (L’Eveille). 
We were unable to trace distinctly the steps of a further ascending series into 
deposits clearly chai'acterized by fossils. 
Red Series above the Fossiliferous Limestones. — In travelling up the Dwina, for 
300 versts, we had been led, step by step, as above stated, through deposits unlike 
any of the inferior rocks of Russia, both in zoological contents and mineral struc- 
ture, and on further ascending the stream, it became evident, so horizontal were the 
strata, that the red and green marls and sands which occupied its banks, must 
belong to still younger deposits. After long and fruitless journeys to detect any 
further order of superposition, or any new fossils between the Permian limestones 
and certain Jurassic strata, to be described in the next chapter, it is with great 
hesitation that we place (even provisionally) any portion of the strata in the inte- 
rior of the province of Vologda and the adjacent governments of Kostroma, Nijni 
Novogorod, &c. in a newer system than the Permian, strictly so called (see lighter 
tint of Permian colour on the Map and Table marked No. 5.). 
To enable our readers to judge of the amount of evidence we possess, we will 
now successively describe the natural appearances seen in the ascent of the Dwina 
to Ustiug-Veliki, in a traverse to Vologda by the Suchona and Strelna rivers, in 
an exploration of the northern and western limits of these deposits, and in a descent 
of the Volga, from Kostroma, to Nijni Novogorod. Lastly, we will show that all 
the masses near the last-mentioned city are continuous with the red strata which 
overlie the Permian limestones on the Volga, and extend to the Kliasma on the 
west. 
1 Whilst we were ascending the Dwina in 1840, from Archangel to Ustiug, Baron A. von Meyendorf, 
Professor Blasius and M. Zinovief passed direct from Vitegra to Ustiug, where we met them. 
2 A 2 
