WATjiON — ON MURCURY IN ALLUVIAL DEPOSITS. 



387 



became a subject of speculation. Accordingly, tbe drain near the 

 barracks of the gendarmerie was opened, but no traces were then 

 discovered of the precious metal, and the subject again became a matter 

 of tradition. In 1855 a company, having for its object the industrial 

 development of Corsica, was formed in Paris under the comprehensive 

 title of Compagnie Miniere, Industrielle et Agricole de la Corse," its 

 principle object, as set forth in the prospectus, being the search for a 

 mine of mercury. The operations of this company commenced in the 

 following year, and were followed out in a manner certainly novel, as 

 far as regards ordinary methods of mine-exploring, but. as far as getting 

 to see things geologically, on certainly the best plan that could have 

 been pursued. On my arrival at Ajaccio in the summer of 1856, I 

 found that M. Aqui, the gerant of the aforesaid company, had opened a 

 rude description of quarry in three floors near to the spot where the 

 mercury is stated to have been found in digging the foundation of the 

 houses in the Place Mourou. The quarry was placed by the side of a 

 low hill, and the uppermost floor consisted merely of the rock bared by 

 the removal of the soil ; the middle and lowermost floors were worked 

 in the rock itself, the latter being approached by a drift driven across 

 the rise of the hill from the level of the road from the barracks to the 

 sea : the direction of this drift was parallel with the drain before -men- 

 tioned. I found the shelf," thus exposed, to be a white granite, the 

 felspar (both orthoclase and albite) being rather in excess of the other 

 constituents. The rock was somewhat stained with oxide of iron, and 

 contained patches, or rather little nests, of chlorite in the horizontal 

 divisional planes, which inclined steadily towards the sea : the trans- 

 verse vertical joints ran north-east and south-west. To describe all the 

 points, lithological and petrological, in connection with this granite 

 would take up too much space and be beside my object, but the follow- 

 ing peculiarities may be enumerated : — 1st. The occurrence of little 

 lenticular patches of crystallized arsenical iron-pyrites, apparently in 

 the heart of the rock, but really placed on the sides of the vertical 

 divisional planes. 2nd. Kidney-shaped nodules, having a radiated struc" 

 ture (called by the workmen " rognons") of the same mineral, reposing 

 in little hollows in the horizontal joints, and on the surface of the rock 

 immediately below the soil. 3rd. Drusy cavities, lined with a black 

 meagre mineral, wliich greatly resembled carbonaceous matter, but 

 which I ascertained to be mica in very minute laminse, and 4th, Thin 



