OBSEHVATIONS ON A CALCAREOUS MOUNTAIN. g3 



a mine,, a quarry, an earthslip, are so many pictures, in 

 which geologists may discern this history. 



From tiie same considerations I am induced to think, that 

 they will be gratified by the account and sketch I here pre- 

 sent theiUs which appear to me to exhibit something singular, 

 if not problematic, which it is for them to solve. See PI. II, 

 fig. 1. 



The schistose vale, in which the village of Chessy, near Vale near 

 Lyons, is built, is bounded on the north-east by a chain of Lyons, 

 mountains of no great height, which appears to run south- 

 east and north-west, and in which a well known mine of 

 yellow sulphuret of copper is wrought. On the opposite 

 side of the vale is a chain of mountains of two or three 

 hundred yards high, nearly parallel to the former chain, but 

 not stretching so far to the north-west, and cut about three 

 quarters of a mile from Chessy by another vale, meeting the 

 first almost at a right angle. 



The last mentioned chain is calcareous from its summit ^ , 

 about two thirds of its height. Its base appeared to me to mountains on 

 be composed of a schistose rock, similar to that which com- ^ baseof schist. 

 poses probably the first chain and the whole of the interme- 

 diate valley, since the vein of copper, which has been "^PP""^^"*' 

 wrought to the depth of upward of a hundred and sixty 

 yards, is enchased in this rock. 



The extremity of the high calcareous chain, at the kind quTrr*'a"!be 

 of promontory it forms where the two vales meet in an angle, top- 

 exhibits at its summit a large quarry of palcareous stone, 

 which is used for Lailding in the adjoining country. A per- 

 pendicular section eighty or ninety feet high, made in a di»- 

 rection nearly east and west, exhibits a series of strata from 

 eight to fifteen inches thick, not arranged horizontally, but Strata varlou*. 

 with different deijrefts of inclination to the horizon, and ' 

 crossing one another in various directions, as seen in PI. II, 

 fig. 1, which is from a drawing taken on the spot. The 

 value of the angle I have inserted at the different arrange- 

 ments of the strata is only estimated by sight, as I was un- 

 able to measure it, on account of the steepness of the place. 

 It is according to the decimal division. All the strata in 

 each arrangement are parallel, except those marked A & B, ^iden in th'-ir 

 which grow wider, the first as it descends, the second as it cou^e 



follows 



