70 



NOTES ON THE MINERALS FOUND NEAR BRISTOL. 



from the surface of a limestone bed just below a clay parting 

 gave^ on analysis : — 



Ferrous Carbonate 

 Ferric oxide 

 Calcic Carbonate 

 Clay ... 

 Fine Sand 

 Moisture, &c. 



Iron 



55-81 



4.14 



31.65 



^33 

 i.oi 



5.06 



lOO.OO 



30.32 7o 



The ores that are more immediately connected with our 

 commerial interests are the Hsematitesor ferric oxide. Frequently 

 we get it in the hydrated form (Fez O^s H2 O,) and is then termed 

 Gothite. It is often embedded in quartz crystals, forming 

 beautiful objects for the cabinet. They must have become 

 enclosed while the silicic acid was crystallizing, forming a tolerably 

 good bit of evidence that quartz crystals are formed by very slow 

 dialytic action. 



A sample of Gothite taken from Sion Hill, contained. 



Ferric oxide 



Manganic oxide ... 



Silica 



Combined Water, &c. 



Iron 



59-^4 7o 



The Haematites are, however, the most important Iron ores of 

 our district. The great bulk of the ore is obtained from a bed of 

 conglomerate resting on the upper limestone shales, where it 

 occurs as a red earthy powder, or crystalline nodules. The purest 



