[ M7 ] 



13th. It would be neceffary to examine whether that pure 

 calcareous ftone be fixed on the flate, as the calcareous fhelly ftone 

 is j or whether it be interpofed in beds, or in veins among the 

 flate, as it feems to be at Glan; or whether it forms a particular 

 fyftem like the granite. 



14th. Above the granite to the weft, at about two miles 

 diftance from Oughterard, at a place called Lettercraft, there is 

 a flate very like that at Glan, in which it was pretended a vein 

 of lead was difcovered. We have in truth obferved fome quartz 

 and argillaceous veins expofed by the current of the river ; but it 

 is impoflible to fay any thing more of it at prefent. The pieces 

 of lead which we carried from that fpot, came from the trials 

 that have formerly been made there. 



15th. On the banks of the river of Oughterard, both in the 

 granite and calcareous parts, one may obferve an ochreous fediment 

 or depofite, often very hard and thick ; which made people imagine 

 that it was contiguous to fome iron mine : the ferruginous tafte 

 of the little fountain which runs above the grotto of Calypfo 

 ftrengthens this opinion ; but as the entire valley traverfed by the 

 river of Oughterard is covered with turf to a very great depth, 

 and as this bog or turf, being decompofed in the bofom of the 

 marflies, muft communicate to the waters which traverfe it per- 



T 2 petually 



