6 The Hon. Mr. Strang ways on the Geologi/ of Russia. 



These slaty kinds of primitive rock, which may all be comprehended under 

 the term granitic slate, seem to be continued in a north-easterly direction 

 across the country to the neighbourhood of Wilmanstrand, not far from which, 

 the river Voxa, flowing between banks of this substance, forms the rapids of 

 Imatra, one of the grandest spectacles of the Northland which merit a particular 

 description. I have, therefore, made it the subject of a separate paper*. 



Still further to the eastward, is a finer slate, which is quarried in the hills 

 which extend at a short distance from the north-west shore of the Lake Ladoga. 

 Its colour is a deep black, and its texture is of the very finest quality. Although 

 not yet in the general use which it merits, it is sometimes carried to Peters- 

 burg in large slabs for writing-tables. 



In the same neighbourhood is also a garnet rock, said to resemble that of 

 which boulders are found at Strelna. Higher up the country, near Cuopio, is 

 found a species of potstone Avhich is turned for bowls of pipes and other pur- 

 poses ; and also a black mica slate containing staurolite, boulders of which are 

 found near Petersburg. At Nyslot is found rose quartz. 



South of the tract above described, the primitive rocks lose entirely their, 

 schistose structure, and a true granite, perfectly free from any symptom of la- 

 mellar arrangement, prevails. Their general character may be described as 

 glandular, better than by any other name, and is most conspicuous in the rocks 

 around Wyborg f . 



On a hill situated on the right bank of the river which runs by Borgo, and 

 nearly opposite the town, is a tor of granite, in which red felspar predomi- 

 nates, spotted with small crystals of hornblende and black mica. Rolled masses 

 of this rock are by no means uncommon in the neighbourhood of Petersburg. 

 Between Borgo and Louisa are found boulders of jet black mica slate, both with 

 and without garnets ; the former variety is by far the hardest : also fragments 



* Imatra is not the only remarkable waterfall on the Voxa : Turns or Turu Nemy is cele. 

 hrated for the fall of Turoun kosky, immediately below which is the passage of the river. It is 

 only fifteen versts from the post station of Kevy nemy, on the great road from Petersburg to 

 Kexholm; and is close to the spot where the Voxa is crossed on the road from Kevy nemy to 

 Raizela. Many other parts of this river, or chain of lakes, present interesting and picturesque 

 scenery, especially in the neighbourhood of St. Peter and St. Andrus ; the road by which vil- 

 lages, though only a cross road, is far superior to the best of the great roads of Russia. 



There are two rapids at Imatra : the upper, where the Voxa issues from the Lake Saima; the 

 lower, which is the most remarkable, a few versts further down the river. The latter I have de- 

 scribed in another place. — Geological Transactions, vol. v. page 340. 



+ This granite may be well examined in the quarries belonging to Baron Nicolai, in an island 

 in the Gulf of Wyborg, which furnished the great columns now seen in the Cazan Church at 

 Petersburg. 



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