DESCENT OF THE RIVER ISSETZ. 
361 
part of the town at various angles of inclination, that the observatory is built upon 
a boss of serpentine, whilst hummocks of that rock and greenstone protiu e ieie 
and there even in the streets. As to many of the rocks in the immediate pre- 
cincts, we should say with M. Rose, to whose admirable description we must 
refer that with the exception of unquestionable igneous rocks, such as granite, 
greenstone, porphyry and serpentine, they have often the undecided character of 
altered schists, preserving still some imperfect traces of their original structure, 
and not having assumed any specific form'. Numerous other varieties of rock, 
including varieties of aventurine, might be cited, and many beautiful and peculiar 
simple minerals. Of the latter, indeed, our associate Lieut. Koksharof has pre- 
pared for the use of English readers a list which will be given in the sequel 2 . 
Among the phenomena exhibited in or close to Ekaterinburg, it is however im- 
portant to remark, that crystals of magnetic iron are disseminated both in the ser- 
pentine and adjacent chlorite schist ; and that the granite which cuts through the 
serpentine in dykes, is the youngest intrusive rock of this neighbourhood. (See 
Rose, vol. i. p. 172 et seq.) 
Descent of the Issetz River to Kamensk and ICaltchedansk (Siberia) (continuation 
of Section, PI. II. fig. 1.).— In the great flat regions of Russia, whether in Europe 
or in Siberia, the truest method of ascertaining the nature of the subjacent rocks 
and their relations is to descend the rivers, or frequently to examine their banks. In 
Russia— even on the noble Volga— whenever we put this in practice, our patience, 
indeed, was sorely tested, so uniform and wide-spread is one formation only, over 
such vast countries do the very same beds extend, and so hidden are they in 
numberless places by vast mounds of superficial detritus. Very different is a river 
section on the Siberian flanks of the Ural. There, though the country ts equally 
flat the surface is never more than slightly encumbered with clay, sand or local 
debris and never obscured b, far-transported numerous blocks or boulders 
its subsoil, composed of hard and crystalline rocks, 
step. Such, at all events, we found to be the case m boating down the Issetz. 
- , v- , vi, M Rose describes in the neighbourhood of Ekaterinburg, near the polishing 
’ A Stratlfi6 f d J with crystals of hornblende, and other parts have the characters of an 
* *“<■” *“ ** “ 
schaalstein. See on pp. 363 et seq. chief author ities, General Glinka and Colonel 
- **■ t -- - — - 
must specially mention M Borisdin, M. Arsenieff, and their agreeable fam ics. 
