1846.] MURCIIISON ON THE GEOLOGY OF DALECARLIA, ETC. 9 



In travelling from Skatunge to Ore we crossed a tract marked 

 as limestone by Hisinger, but that rock is no way visible from be- 

 neath coarse detritus (as far as we could observe), except in the bed 

 of the stream, which at about three English miles east of Skatunge 

 flows from the porphyry dome or plateau into the lake of Skatunge. 

 The bridge by which the road crosses this stream at a spot called 

 Lada-Oken, is arched over upon ledges of red Orthoceratite lime- 

 stone, which there dip to the N.N.W. at 15°, but on ascending the 

 bed of the rivulet amongst a chaos of fallen trees and rank vegeta- 

 tion, the same beds were found to be completely wrenched round 

 even in a hundred paces, dipping first to the east and afterwards to 

 the E.S.E. 



These strata doubtless owe their contortion to the influence of the 

 contiguous porphyry, which a little further east (in the tract called 

 Ruttberge) rises and occupies the surface of the higher grounds in a 

 multitude of small spherical domes. No sooner were we on these 

 hard knolls than we observed their surface to be striated in the 

 manner described in my last communication, and here most unques- 

 tionably the direction of the striea was from N.N.W. to S S.E., the 

 direction which the great mass of the drift has taken in this part of 

 Sweden. 



These rounded porphyry knolls are miniature representations of 

 the entire dome, around which the fragmentary masses of the 

 Lower Silurian rocks can be traced. In one spot we observed (al- 

 most in contact with the porphyry) a compact, finely-laminated 

 ironstone, which the peasants had begun to break into, in hopes that 

 it might prove of value ; and this rock, in almost horizontal strata, 

 graduated into a hard, flag-like, red, micaceous sandstone*, evidently 

 a portion of the same rock to which I have previously adverted, and 

 which here (as in Norway) seems to be intimately associated with 

 the porphyry, the elevation and outburst of which have also broken 

 up the symmetry of the Silurian deposits. 



Leaving the porphyritic dome or plateau with its red sandstone 

 and passing southwards, we found ourselves in an undulating tract, 

 which, extending along the western shores of the lake of Ore (Ore- 

 Sjon) from Furadal by Ore to Dalby, and thence by Osmundsberg 

 to Boda and Kattvik, is usually void of crystalline rocks in situ. 

 Wherever the fundamental rock can be discovered beneath the 

 detritus, it consists of Lower Silurian strata, similar, or nearly so, 

 to those on the other sides of the crystalline dome. In these frag- 

 mentary masses, however, other links in the chain of a Lower 

 Silurian group are detected, which we had not yet observed in this 

 tract. Thus, at Furadal, at the northern end of the Ore Sjon, 



* In the wild forests north of Skatunge inhabited only in summer by shepherds 

 &c., and into which we did not penetrate, we were informed that there was much 

 sandstone as well as limestone. Having cross-questioned the peasants, we clearly 

 ascertained that they perfectly distinguished what they called sandstone (undi- 

 stinguishable from our Old red) from the " Slepsten " or whetstone which is a 

 Lower Sihirian rock ; and it is therefore probable that the Old red occupies a 

 large tract to the N.E. of the great porphyry region of Elf Dal, as I shall presently 

 show it does to the west thereof. 



