^54 PRIMITIVE GYP8USI. 



Cf its length, thickness, or th^ circumstances of its super- 

 position. However at move than 50 met. beyond the place 

 'Vfrhere it has been laid open for working 1 have seen indi- 

 cations of its existence. It^ thickness cannot be great, 

 for the rock appears in its natural position a few yards 

 jptlow the place where it is worked. The rock at this place, 

 9s well as above the straiuno, is a micaceous and calcareous 

 jchist, of a deep gray, with plane laininse, traversed by nu- 

 merous filanients of calcareous spar, and including some 

 veins and nodules of quartz. In getting out the gypsum 

 the workmen have advanced about two yards under the 

 $chist, so that this rock forms a projecting rooT, under which 

 they work. In this place we see in the most distinct man- 

 ner, that the schist overlies the gypsum : both are strati^, 

 fied : their strata are perfectly parallel, and dip only a few 

 degrees to tlie south-east. The strata of gypsum are a few 

 centim. [the cent, is ne:ir 4 lines] thick, and frequently se- 

 parated from each other by u greenish talcy coal. 



Tbegypsuoj fj^Js gypsum is of a fine white colour, with sometimes a 



described, .,""'• , n n • -i 



1^1 1 ght rosy tinge, its grain is very hne crystalline, smiuar 



io that of the beautiful Carrara mai'ble. It is very trans- 

 Uicid, and very soft. If pieces of any size, and exempt 

 from fissures, could be got from the quarry, it would form 

 ^ very tine alabaster. It is uspd however for building, and 

 ipakes good plaster. 

 Talc contained It contains a great deal of talc in detached particles, ge- 

 ^^ ^^* neially lenticular, and varying in size from that of a lentil 



to that of a walnut* These almost always lie flat, and ar- 

 ranged in lines parallel to each other, and to the stratifi- 

 cation. Their colour is a very pleasing green. Sometimes 

 the laming of talc are so close together as to produce a 

 kind of steatite ; i^ometimes they are very narrow, resem- 

 bling fibres, and forming together littje masses, ^'?ihibiiing 

 .8 pleasing variety of fibrous talc^ , Pretty frequently these 

 isbies are disseminated in small groupes through the gyp- 

 sum, are of a delicate light green, and might be taken at 

 first sight for amianthus, of which they have all the apr 

 pearance. Martial pyrites also is seen in the gypsum, and 

 particularly in the small masses of talc. It is sometimes iq 

 founded grains, sometimes in little striated cubes. 



What 



