14< PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 



o, 



the fine lamination of its alternating laminae of diiFerent colours is a 

 striking character, when exposed in the vertical edges of the joints or 

 backs of the stone, whilst a transverse blow sometimes gives a con- 

 choidal fracture, in which no lamination is visible. Besides these 

 more compact beds, others which are more micaceous split into flag- 

 stones and expose ripple-marked surfaces. Now, whilst this rock can- 

 not be distinguished from the Old red sandstone of Great Britain and 

 Norway, and is here, as in the latter country, encased between masses 

 of porphyry, it is wholly unlike any member of the Silurian rocks of 

 Scandinavia, and is in every respect dissimilar, since the latter consist 

 of soft non-micaceous fucoid sandstone and arkose, which form, as I 

 have shown, the fundamental deposit of the protozoic series of Scan- 

 dinavia. My belief is, that whenever the north of Sweden shall be 

 correctly explored, this Old red sandstone will be found to have a very 

 considerable extension ; for I was informed that the rock extended 

 for many miles (forty to fifty miles English) northwards from Wenjan 

 into tracts where there are no roads, and where, in fact, owing to 

 impassable forests, the country can only be examined by ascending 

 the streams and lakes. 



How far the sandstones which exist in large expanses in the region 

 immediately to the north of Dalecarlia may be of this age I am not 

 prepared to say, but the Lower Silurian rocks, including vast sheets 

 of red Orthoceratite limestone, are largely expanded around Oster- 

 sund*, and as these are surrounded by vast breadths of red sand- 

 stone, also associated with porphyry, I am disposed to believe that 

 the relations must there be the same as those in Dalecarlia ; a sugges- 

 tion, it is right to state, which could not have been ventured upon 

 if I had not previously made myself acquainted with the precise 

 relations of the Silurian and Old red formations of Norway in their 

 normal positions. 



Before dismissing the consideration of the Old red sandstone 

 of the north of Sweden, I may allude to the red sandstone and con- 

 glomerate of Gefle, which we examined on our return from Dale- 

 carlia to Stockholm. Occurring on the south bank of the river at 

 Gefle, in a width of about one and a half English mile, this rock 

 ranges from the sea on the N.E. to the lake called Storsjon on the 

 S.W., or along a space of about twenty English miles. In that low 

 country, no part of which rises much above the sea, and which is 

 to a great extent either covered by detritus of rocks or by rich clay 



* A knowledge of this fact I owe to M. Henry Gahn, a young Swedish geologist, 

 with whom we fell in on his return from Ostersund, as we were proceeding from 

 Furadal by Dalfors and Alfta to Gefle. In respect to the region which lies to the 

 W. andN.W.of Dalecarha, I leai'ntfrom M. Erdmann, that red sandstone, associated 

 with porphyries, ranges along the mountains which form the banks of the Western 

 Dal Elf to Hormundsjon, and which in the hills between Tisjon and Arefors trend 

 from N.N.W. to S.S.E., and are consequently parallel to the band of Wenjan. Red 

 sanditone occurs also largely in the mountain of Stadjan, and much higher up 

 this drainage and 3904 feet above the sea, where it is said to alternate witli schist 

 or slaty clay, and is highly indurated near its contact with the greenstone of 

 Idresjon. The northern boundaries of this sandstone are unknown. 



