of the Neighbourhood of Bristol. 247 



countrv which has been the subject of my examination. I am 

 informed, however, that the chalk which hes above the great 

 ooHte begins to appear a short distance beyond Bath. 



I have now to treat of those minerals which are found partially 

 or in \'cins in tha several formations I have described above. 



Hor7islone or Petrosilex. This mineral I have foimd in 

 distinct beds on the top of a hill above Ashton, where it rests 

 upon the indurated sandstone, and is of a red colour from a deep 

 impregnation of iron, and possesses an uneven fracture. At Sod- 

 bury this rock is seen upon entering the town, where it lies in 

 distinct strata upon limestone. 



Quarlz crystals of great beauty and rich variety of colour oc- 

 cur in veins of clay ironstone travei^ing the limestone. The 

 crystal is commonly a six-sided pyramid, which is very freciuently 

 double. 



Celeitine or sulphat of stroniites is contained in veins in the 

 claystone at Aust Passage, and it is from hence that the finest 

 and best crystallized specimens are obtained. It has been found 

 in other situations massive and radiated. 



Hcematite. Good specimens are obtained from veins in lime- 

 stone and Pennant stone. 



Gypsiun, both massive and fibrous and in the state of selenite, 

 occurs at Aust Cliif, in thin seams in the red claystone lying be- 

 low tlie lyas. 



Sulphate oflarytes. I found crystallized specimens of this 

 fossil in masses of limestone tliat had been quarried near Harp- 

 tree. 



Calamine and Galerja. These minerals have been found in 

 thin seams in the limestone of Durdliam Down, and at Cleve- 

 don. Tlie brass v.-orks at Bristol are chiefly supplied with ca- 

 lamine from Shipham, a village among the Mendip Hills, where 

 it occurs in beds beneath tl'C limestone breccia. ■ 



Al/irh^ane^e iias been menlioued by Townsend, as being pro- 

 cured from the Mendips. 



Compact felspar, l Jpon visitiiig some time ago the Druidical 

 stones at Staunton Drew, I was very much surprised to find 

 them composed of rocks wliich I was perfectly unaware had anv 

 existence in tliis viciiiity — a siliceous breccia and compact fel- 

 spar. In returning a short time since from an excursion among 

 the Mendip Hills, I passed through the village of Harptree, 

 and I was very much struck by ol)serving about half a mile on 

 this side Harptree, masses of compact felspar exactly resembling 

 the blocks at btaunton Drew, which had been brought together 

 for the purpose of repairing the highway. All the information 

 I could learn respecting them, was, that they were taken from 

 Q4 tl.* 



