UNDULATIONS AND DISLOCATIONS SOUTH OF ST. PETERSBURGH. 31 * 
That such rapid undulations and breaks (though partial exceptions when such 
a large surface as Russia is considered) are due to disturbances of the strata by 
elevations from beneath, we have further satisfied ourselves by an examination of 
the banks of the Popovka rivulet to the south of Pavlosk. This stream, which falls 
into the Slavenka, occupies a longitudinal chasm, which as nearly as possible coin- 
cides with the general direction of the strata in the environs of St. Petersburgh, or 
from west-south- west to east-north-east. Near the plateau from which the water 
descends, the pleta limestone lies in great horizontal masses, and is thus observed 
to fold over in gentle undulations, which so increase in measure as they approach 
the village of Popovka as to form a complete arch, as represented in the following 
woodcut. By this curvature the Ungulite sandstone (b), with the bituminous schist 
(c) over it, is thrown up in an arch, over which the pleta limestone (d) folds rapidly 
over to the east, and is seen in highly inclined beds at the little bridge. After 
several minor flexures a decided transverse fault is exposed in a low hill, and 
winding along another denudation, the cliff on the right bank is a marked and 
decided elevation, called the Pastor Hill, from sixty to seventy feet above the 
water. Here the great mass of the “pleta” limestone, rising gradually to the 
west, is again regularly succeeded, first by the bituminous schist (c) and Ungulite 
sand ( b ) , and finally, near the village of Poselevo or Peselova, by the lower shale (a) , 
which there is of a greenish tint. 
6 . 
E.N.E. Pastor Hill, Popovka, W.S.W. 
No geologist can view these sections without admitting, that they exhibit clear 
evidences of dislocation. When, indeed, it is seen that the brooks of Pulcovka and 
Popovka both run in rents nearly parallel to the general strike of the formation, and 
that, though separated from each other by a space of twelve or fifteen versts, they so 
exhibit the same violent transverse flexures and even fractures, that those of Pul- 
covka, when prolonged, coincide with those of Popovka, no doubt can be enter- 
tained that they have resulted from the same operation. In truth, the axis of 
these arches and the direction of the faults are from north-north-west to south-south- 
east, or directly at right angles to the general bearing of the formations, and we 
therefore feel confident, that such dislocations athwart the prevailing line of eleva- 
