114 ; -/■ of the Geological Society. 



mountain, and primltivi sides. Tlie contacts 



tie, without the least of One rock graduating 



into the other, and in all case-* the granite i> continued from the 



in M '. through the slate, but never the contrary." 



I ite often occur, like islands floating in, and surrounded 



l>v the granite of the vein.. Mr. Playfair, who was with Dr. 



D Mtinell, remarked that the schist, which lies upon and near 



inite, has a mui number of fissures than that which 



U a mile distant. The granite veins generally terminate in fine 



thrc.i 



1811, November I. 



A letter from George Cumberland, Ksq. of Bristol, was read, 

 giving an account of a trap rock that had been discovered at Mickle- 

 wood, in Gloucestershire. It occurs to the east of the road 

 from Bristol, within two miles ofFrampton, on an estate be* 

 to Lord Berkeley, and is known by the name of tin 

 1 he mas-> rises perpendicularly to the height of about 30 feet, 

 i^k.ss than 300 yards wide, and extends in the other direction 

 i quarter of a mile. The same rock is found again to the 

 north-east of the first mentioned place, dipping to the east b< 



Micklewood n n amygdaloidal character, contain- 



in or sniped chalcedonies, .\nd numerous fungiform or ir- 

 regularly cylindrical nposed of iron spar. 1 hose masses 

 .tre often found two feet in length; the chalcedonies van 



-\ r, and are nearly all of the 

 convex a!>u\ e, ave beneath. 



