MODE XII. SLATE. 



in his Natural History of Spain, indicate that 

 he has observed any in that kingdom*." 



To these accounts may be subjoined a short 

 description of a remarkable quarry in Cornwall, 

 unknown to Patrin. 



" Between Liskeard and the Tamar, on the 

 south-west, are some quarries of slate, which 

 supply the inhabitants of Plymouth with cover- 

 ing for their houses, and for the purpose of 

 exportation. Several quarries have also been 

 opened at other places ; but the best covering- 

 slate in Cornwall, or perhaps in England, is pro- 

 cured at Denyball, nearly two miles south of 

 Tintagel, in the north part of the county. The 

 whole quarry is about 300 yards long, 100 

 broad, and almost 40 fathoms in depth. The 

 slate-rock is disposed in strata, dipping to the 

 south-west, and preserving that inclination from 

 top to bottom. It is first met with at about 

 three feet below the surface of the ground, in a 

 loose, shattery state, with short and frequent 

 fissures ; the laminae of unequal thickness, but 

 not horizontal. Thus it continues to the depth 

 often or twelve fathoms, when a more firm and 

 useful stone is procured, the largest pieces of 

 which are used for flat pavements. This is called 



* Patrin Min. iii, 307. / 



