10 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [ Juiie 3, 



which we reached by passing through deep sands (similar to those 

 of the Ore Elf, and probably like them derived from the decom- 

 position of the bottom sandstone or " Slepsten"), we obtained from 

 M. Classen* some specimens of Trinucleus in black schist (one 

 approaching very near to Trinucleus Caractaci), as well as other 

 Lower Silurian fossils ; but here as elsewhere no connexion between 

 the beds could be detected ; the limestones and black schists with 

 Trinucleus being only discernible in fragments which have either 

 been rent asunder by eruptions or buried under superficial detritus. 



Further southward, Osmundsberg is an insulated, tabular-crowned 

 hill, rising to the height of 498 feet above the adjacent lake of Ore, 

 or 1272 Swedish feet above the sea, and lies about two or three 

 English miles to the north of Bodaf . 



When I first cast my eye over this hill (the summit of which is 

 about an English mile in its longest diameter) I thought it must 

 afford some explanation of the relation of the limestone, of which 

 its upper part is composed, to the surrounding lower tract ; but even 

 here no clear sections could be obtained, OMnng to the slopes being 

 covered with detritus. To the west, as well as on the eastern and 

 southern sides of the hill, the limestone presents bold cliffs in which 

 no clear stratification is visible ; the hard and crystalline rock con- 

 veying the idea that it had been partially affected by heat. 



But to whatever extent it has been altered, the limestone is here 

 and there charged with fossils, which when examined left no doubt 

 of its age. Without such search, and judging from its grey colour 

 and resemblance to some of our English mountain limestone, as well 

 as from its profusion of imbedded Encrinites, a field geologist, if 

 brought suddenly to the spot, might well have pronounced it to be of 

 carboniferous age. 



The fossils however that we collected at Osmundsberg were all 

 Lower Silurian forms, viz. Illcenus crassicauda, Asaphus expansus, 

 Orthis parva, O. moneta, O. n. sp., Leptcena sericea and L, imbrex^ 

 with some undescribed species, a few corals, and many Encrinites. 

 As the rock in which these fossils occur occupies the summit of a 

 nearly horizontal plateau (see PI. L fig. 5), and as the sandstone or 

 wdietstone (a) is seen, though in fragments only, in the surrounding 

 low country, the inference would clearly be, that if the rolled debris 

 on the slopes of the hill did not obscure a junction, the limestone (c) 

 would be seen to repose, as in other parts of Sweden, on black 

 schist with some limestone, and the latter on the light-coloured 

 sandy rock as a base. 



That this is the true succession in this region was sustained by 

 the evidences which are afforded in the picturesque gorge of Stygg- 

 fors near Boda, two or three English miles to the south of Os- 

 mundsberg (PI. L fig. 6). There, one of the branches of a stream 

 which works several small mills, issues from the edge of the plateau 



* The director of the iron-works at Furadal. 



t The slight descent of the waters from this rocky region of Dalecarha to the 

 Baltic lias been noticed in the memoir previously read upon the superficial ac- 

 cumulations of Sweden (see Quart. Geol. Journ., vol. ii. p. 374). 



