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A MEMOIR of the MINES of GLAN, the ROYALTY of 

 RICHARD MARTIN, Efq. By Monfieur SUBRINE, Engineer 

 to the King of France. 



X H E territory of Oughterard is covered to the eaft by a cal- Read, Ju 

 careous ftone of a blueifh colour, Ihelly and foetid, difpofed 

 in layers parallel to the furface, and fufceptible of a very 

 beautiful polifh. To the weft it is covered by a rofe-coloured > 



granite, which however varies fometimes to a green, the layers 

 of which are moftly perpendicular to the horizon, and are 

 eafily decompofed by the air. To the fouth it is bounded by 

 the mountains of Mahiramore, the fummit of which is com- 

 pofed of many confiderable layers of quartz of a very white 

 colour : but the bafe of the mountains is formed of alternate 

 layers of very hard flate, and is a fort of quartz more or lefs 

 denfe. To the north it is bounded by the niountains of Glan, 

 which are entirely compofed of flate, and in which the 

 mines, that make the principal objed of thefe obfervations, are 

 found. 



The 



