446 Analyses of Books. [Junjs, 



chains, separated from each other by high table lands. Three 

 very narrow openings cross the group from east to west. The 

 furthest north of which lies between Douglas Town and Peel 

 Town ; and the furthest south is the narrow channel between the 

 island and Calf of Man. The first of these is highest, and the last 

 lowest, being under the level of the sea. The highest mountain 

 in Man is Snowfield, i^hich is 2000 feet above the level of the sea. 

 Dr. Berger has given the elevation of 89 mountains and spots of 

 this island, which has enabled him to give interesting sections of 

 the island in various directions. The Calf of Man is 206 feet high. 

 The mean annual temperature he reckons from the heat of 31 

 springs, at 49-99°, or .50°, Fahrenheit,^ 



Very little granite has been observed in Man. It occurs, how- 

 ever, in two or three spots ; but most likely only forming beds in 

 the clay-slate, which constitutes the central and highest part of 

 the island. Grey-wacke covers tlie lower parts of this clay-slate, 

 almost surrounds it, and constitutes the sea-coast both on the east 

 and west side of Man. This grey-wacke sometimes contains beds 

 of grey-wacke slate and flinty slate. It has not been observed to 

 contain any animal remains. A floctz lime-stone containing ma- 

 dreporites, and some univalve shells, occupies the south-east coast; 

 except a peninsula of old red sand-stone, which occurs likewise at 

 Peel Town. The Calf of Man is grey-wacke. Veins containing 

 galena occur in three different parts of the island, and always in 

 the grey-wacke. Sulphuret of copper likewise occurs. These 

 veins have been wrought more than once, but are at present 

 abandoned. Dr. Berger thinks that the southern part of the island 

 has at some former period subsided. Hence he accounts for the 

 gradual declivity, the dip, and the narrow valleys. The population 

 is reckoned at 28,000 ; but Mr. Curwen thinks it does not exceed 



23,000. 



III. On the Granite Tors of Cornwall. By Dr. Macculloch. — 

 The Logging Rock, and Cheese Wring in Cornwall, and the Vixen 

 Tor in Dartmoor, exhibiting curious configurations of granite 

 rocks, are described and figured ; and Dr. Macculloch shows very 

 clearly that they have resulted from the natural effects of the dis- 

 integration of the rock, and that they have not, as some sup- 

 posed, been formed artificially. He terminates the paper with 

 some speculations on the origin of granite, and rather inclines to 

 its igneous origin. Into these speculations I think it unnecessary 

 to enter ; because I conceive them to be entirely beyond the reach 

 of the human faculties. Supposing a man to spend his life in 

 guessing how the Almighty brought the earth into its present 

 state, and supposing him even to guess right, (no very probable 

 supposition) I ask by what means he could prove iiis conjecture ? 

 The only conclusive evidence in such a case is historical evidence, 

 and wliere could it be found? Geology does not consist in specu- 

 latino- about the origin or creation of the earth, it consists simply 

 in determining the number ^ nature, and position of all the rocks 



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