490 Dr. H. Trautschold—Periodical Movement of the Ocean. 
height of the Russian plain and again overflowed a large part of it. 
The rising waters found here indeed an almost thoroughly flat 
plain, the deposits of the former Paleozoic sea having filled up 
every depression of that part of the earth’s crust. Only a com- 
paratively narrow depression remained in the northern part of 
Russia, parallel with the Urals, and in their neighbourhood ; 
Southern Russia being inclined to the south and separated. 
If we take into consideration the low position of mount Bogdo 
of Triassic age, it isnot probable that there are under the Cretaceous 
and ‘Tertiary deposits in Southern Russia still sediments of Lias or 
Inferior Oolite ; at least there is nothing visible, and what there is to 
be seen belongs to the Upper Oolitic strata, as e.g., the Coral-rag 
of the Donetz (Isium) forming a kind of isle, partly covered with 
Cretaceous sediments. In middle and northern Russia only Upper 
Oolitic strata exist, the fauna of which is comparatively uniform, the 
typical forms being nearly the same at Sysnau, Moscow, Yaroslav, on 
the Petshora and on the isles of the Arctic Sea. This uniformity is 
explicable, because the rising waters must have spread with great 
tranquillity over the almost absolutely horizontal plain. 
But these waters did not cover the Russian plain to any great 
height, and the sediments they deposited are to be estimated by 
hundreds, but not by thousands of feet; likewise these sediments 
evidently do not belong entirely to the sea-water of that epoch, 
neither were they brought by currents from far; but the advancing 
sea found them at the spot itself, stirred them up, mixed the diverse 
material, and deposited them again, burying at the same time in the 
mud the remains of the marine animals of the Bath, Kelloway, etc., 
periods. 
The strata of the Moscow Oolitic system offer a good illustration 
of this process. As it is known, the plastic black Oolite clay 
(Kelloway and Oxford) rests in the government of Moscow imme- 
diately on the Upper Mountain Limestone. But here and there 
between the latter and the Oolitic clay, is intercalated a red or 
variegated clay, which has been deposited during the Permian period 
aud is not fossiliferous. The rising waters of the ocean met with 
these clays, but at the same time also with the remainder of the 
vegetation of the Carboniferous and Permian systems, originated in 
the shallow basins of the Carboniferous Limestone. The depth of 
the new sea not being considerable, every storm must have stirred 
up the shallow water and caused the mixture of the Carboniferous 
substance with the underlying clay. In this manner a clayey 
sediment of the quality of the Moscow Oolite clays was produced, 
without the sea-water furnishing the material, which, considering 
the shallowness of the Russian sea of that time, was impos- 
sible. But not only was the clay coloured black, but also the 
glauconitie sand, of which the upper half of the Moscow Oolite 
beds consists, as the stratum with Amm. virgatus, and not un- 
frequently the stratum with Amm. fulgens. Even near Moscow in the 
stratum with A. virgatus are often to be found pieces of petrified 
wood of Coniferze, which possibly can be explained by the formation 
