The Hon, Mr, Strangways on the Geology of Russia. 15 



plain, and, meeting the river opposite the upper end of the long* cliff on the 

 left bank^ form a sort of gorge ; which being much filled up with ledges of 

 stmta that cross from side to side, together with great accumulations of primi- 

 tive boulders and fragments of the surrounding rocks, constitutes what is 

 called the lower fall*. 



The sand here appears in horizontal strata, containing thick and regular 

 beds of an argillaceous ironstone, which is an agglomerate of charred wood 

 and every sort of geode ; it is mammillated on the surface, in which character 

 and in colour it resembles the sandstone of the Popovca, and other streams 

 near Petersburg, and in its whole appearance is like that near Helsingborg 

 in Sweden ; which, it is remarkable, is in a true coal country. Some of its 

 concretions are coloured much like Egyptian pebbles, and appear to be sili- 

 ceous. Above this is a reddish sand, which forms the most projecting point 

 of the rock ; below it a yellow sand, presenting a pseudo-stratified structure 

 or cleavage, which forms a considerable angle with the true lines of its beds, 

 when viewed in the mass. The next beds are a blue limestone, which con- 

 tinues to near the water's edge, containing madrepores like those of the 

 mountain-lime in Northumberland. Still more abundant is a very peculiar 

 sort of Briarean Pentacrinite, the joints of which are very minute, and at 

 first scarcely perceptible to the eye of one who does not suspect their exist- 

 ence. Its manner of growth seems to have been panicled, not unlike that of 

 millet, with an inclination to droop on one side. Impressions of large tufts 

 of this pentacrinite cover the greatest part of the surface of these limestone 

 strata, bending sometimes in one direction, sometimes in another. In the 

 bed of the river, the ledges of rock show a yellower and more sandy variety 

 of this limestone, in which I could not discover the madrepores, though the 

 pentacrinites were as abundant as in the blue beds. The latter contain also 

 quantities of fragments of large encrini, minute corallines, and other marine 

 fossils, in which it resembles the limestones of Dudley in England and some 

 of the varieties of the Pleta formation in Russia, before described. This 

 blue limestone also contains those large terebratulites with very thick shells, 

 so common in certain limestones of the neighbourhood of Moscow, but 

 which I have never yet seen in the northern limestone district. Although 

 the bituminous and pyritical clays do not appear in this place, yet I suspect 

 this dark limestone to be very near them. 



* Most of wliatare called Fallsin the rivers of the north of Russia, are merely rapids, owing to 

 a combination of obstacles such as are here described. In Russian, the word paroghee is applied 

 to waterfalls of every description. 



