8 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 3, 



proceeding a few miles and ascending to Skatunge, we reached 

 quarries of tiie whetstone, in one of which the reddish or pinkish 

 variety is obtained, and in the other the usual fine white sandstone. 

 This rock is very irregularly bedded, traversed by innumerable de- 

 vious joints and affected by slickensides. Though of pinkish and 

 reddish colours, the fine-grained, soft, non-micaceous character of 

 the rock was quite the same as that which characterizes the Lower 

 Silurian sandstone in many parts of Sweden where that rock (as 

 previously shown*) forms the base of the fossiliferous series, like 

 which it is here charged with flakes and spots of whitish and green- 

 ish clay, and is occasionally irregularly laminated with white and 

 greenish-white lines. 



At Skatunge, or a mile only in advance of those quarries, but at 

 a higher level, the " Slepsten " or fine sandstone is no longer visible, 

 and its place is apparently occupied (see PI. I. fig. 4) by a red felspathic 

 porphyry (/?), regularly bedded and jointed, striking east and west 

 (in conformity with the outline of this portion of the porphyritic 

 dome), and dipping 60° to the north. The succession on the dip is 

 obscured for a short distance ; but on the grassy slopes and fields 

 below the village calcareous and sandy beds with Orthoceratites and 

 other fossils (c) are overlaid by black shale, the whole dipping 

 north and being conformable to the porphyry (jo), by which they 

 have unquestionably been thrown off. 



As if to add to the confusion within the area of dislocation, we 

 observed on the road hard micaceous flagstones, perfectly unlike the 

 soft whetstones described, which the peasants had extracted from the 

 adjacent low hills, where, as in Norway, they are associated with 

 porphyry ; and as these rocks were wholly unlike anything seen in 

 the Silurian series of other parts of Scandinavia where the relations 

 are clear, and were undistinguishable from well-known specimens of 

 Old red sandstone in Norway where its position is distinct, we began 

 to infer that these as well as the highly inclined beds of red sand- 

 stone and conglomerate seen near Wattnas (PI. I. fig. 3) might belong 

 to that formation, to the abundant presence of which in another part 

 of this country I shall presently allude. 



But although most of the porphyry of this tract, like the " rhombic 

 porphyry " of Norway, has evidently been protruded after the de- 

 posit of the Old red sandstone, it must be observed that near Mora 

 we found a very large rolled block of a hard coarse red conglome- 

 rate containing fragments of porphyry, thus showing that there 

 must also have existed a rock of that character which had been 

 consolidated anterior to the accumulation of the Old red sandstone. 

 Some of these porphyries, as in PI. I. fig. 4, may, therefore, have been 

 formed contemporaneously with the Lower Silurian or protozoic 

 strata f. 



* See Quarterly Journal of the Geological Society, vol. i. p. 15 ; and Russia and 

 the Ural Mountains, vol. i. p. 15 et seq. 



t According to M. Erdmann of Stockholm, who kindly explained his views to 

 me, there are three chief varieties of porphyry only in Sweden ; viz. felspar, 

 hornstone, and jasper porphyry, each of which has heen erupted posterior to the 

 primary or azoic rocks. 



