IS^e.] MURCHISON ON THE SILURIAN ROCKS OF SWEDEN. 4-7 



DESCRIPTION OF PLATE I. 



1. Dalecarlian Sections. 



Fig. 1. Section near the eastern end of the Lake Siljan in Dalecarlia, between Lek- 

 sand and Rattvik, showing how the Lower Silurian Hmestone (c) is tlirowu 

 off by the " granitello " (g) at Alsarby. The slope below the limestone is 

 covered by detritus. 



2. Relations in the Isle of Soller of the Lower Silurian rocks.— (a) inferior 



sandstone, (b) schist obscured by morass, and (c & c*) beds of limestone 

 with Orthoceratites and Cystidea in irregular contact with the granitello 

 (g). The limestones are broken by transverse faults, and in one part 

 (not represented in this drawing), mantle in an altered condition around 

 bosses of granite. 



3. Section at Watnaes near Mora. — The same Lower Silurian limestone (e) 



as that of the preceding diagrams, appears at intervals in highly-inclined 

 strata, but is here separated from the eruptive rocks (jo*), which form the 

 western part of a great porphyritic dome, by quartzose rocks, siliceous 

 sandstone and fine conglomerate (<r), which seem to have been altered 

 by igneous agency. 



4. Section at Skatunge on the north side of the great dome of porphyry and 



granitello, exhibiting regularly stratified and jointed, earthy, red porphyry 

 (p). — A slope obscured and the Lower Silurian limestone and shale (e*) 

 with Cystidea in highly-inclined positions. 



5. Section across the insulated hill called Osmundsberg, which is composed 



of Lower Silurian limestone (e), the inferior schist (lerskiffer) (b) and 

 sandstone (a), being for the most part covered by detritus. 



6. Relations at the waterfall of Styg-fors near Bbda on the eastern flank of 



the eruptive dome. The subjacent or eruptive rock is here a granitello 

 (g), and the sandstone (a*) in contact with it is a highly-indurated quartz 

 rock, which is surmounted by peculiar nodular shale (**). 



2. Sections and Drawings in Oland and Gothland. 



7. A general transverse section showing how the Lower Silurian sandstone 



(a) reposes (though chiefly in dismembered lumps) on the azoic or ante- 

 cedent crystalHne rocks of the province of Smoland (az) ; and also, how the 

 same sandstone (fucoid grit of ray former memoir) is seen on the western 

 shore of Oland to be surmounted first by the alum schist (b), and finally 

 by the Lower Silurian limestone (e), which occupies the great surface of 

 the island of Oland in very slightly-inclined strata. The surface of the 

 mainland is obscured by erratic blocks (bl). 



8. Geological view, looking from Hog Klint, the highest point of the cliffs of 



Gothland, and representing Upper Silurian rocks, consisting of the nodu- 

 lar Wenlock shale (e) surmounted by the Wenlock limestone (/"), both 

 to the S. and N. of the city of Wisby. 



9. View of " Hog Klint," or High Cliff, as seen from its northern base, and 



showing the detailed order of the Wenlock limestone (/&/*), in rela- 

 tion to the subjacent nodular shale (e). Two or three erratic blocks {bl) 

 are seen on the summit. 



10. Grotesque forms of the Upper Silurian coralline limestone (Wenlock) at 



Lanna, in the fine bay and anchoring-ground of Slite on the east coast 

 of Gothland. 



11. General Section from N. by W. to S. by E., showing an ascending order 



in the Upper Silurian strata of Gothland from the Wenlock shale and 

 limestone of the environs of Wisby, through other strata near Klinte, 

 which represent the Lower Ludlow rock and Aymestry limestone (ff, h) 

 into overlying oolite, calc grit, and sandstone at GrotHngbo, which are 

 true equivalents of the Upper Ludlow rocks {i, j). The coralline lime- 

 stone of Mount Hoburg {k) may represent a passage into strata of the 

 Devonian age (see memoir). 



12. Detailed order of the strata at Mount Hoburg, the isoutherniuost proiaon- 



