102 Dr. Berger on the physical Structure 



containing a few laminse of calcareous spar, and some crystals of 

 quartz. This last rock forms the roof of the mine, the saalb'dnde * 

 consists of a calcareo-manganesian amygdaloid. As to the floor of the 

 mine, it is not known of what it consists, as the vein, which appears 

 to be of considerable magnitude, has not been cut through. Its di- 

 rection is from E. to W. dipping N. with an inclination of three feet 

 in six. Of the black oxide of manganese, several varieties are met 

 with, together with ferriferous carbonate of lime. The red argilla- 

 ceous sandstone occupies the surface of the country from Upton 

 Pyne to Thorverton. 



There are three or four quarries at Thorverton, and these not far 

 distant from each other. They are all in the same rock, viz. a calcare- 

 ous amygdaloid, the nature of which, however, varies considerably in 

 different places. In some places, the nodules are small, and very 

 closely united in clusters in the base, forming nearly a homogeneous 

 mass, with here and there nodules of a much larger size than the rest 

 imbedded in it. In other places the nodules are about the bigness of 

 a pea, all of the same size, and consist of rhomboidal sparry laminse. 

 There are other places where the base of the amygdaloid has the 

 appearance of a sand stone in which a small number of calcareous 

 nodules are imbedded, externally coloured green by the steatite, 

 and exactly resembling those which enter into the composition of 

 some of the amygdaloids of Derbyshire, and of the Pentland hills 

 near Edinburgh. 



The country between Exeter and Plymouth by Chudleigh, Ash- 

 burton, and Ivy-bridge, is quite hilly, the whole being a continual 



* The term saalb'dnde, for which we have no corresponding scientific expression, it 

 frequently denominated in some of the mining districts of this country, pasting or 

 stickinsc. Tr. 



