CELESTINE AND BARYTO-CELESTINE OF CLIFTON. 293 



of a beautiful faint blue owing to small quantities of ferroso-ferric 

 phosphate, but this has been questioned by Mr. Stoddart, who 

 could hnd no ferroso-ferric phosphate in the blue specimens wdiich 

 he examined. Some singularly perfect and beautiful crystals were 

 found whilst excavating the tunnel under the Downs near the 

 Black Rock Gully, some of these specimens are preserved both in 

 the British and Bristol Museums, and are (Mr. Grenfell tells me) 

 amongst the most perfect as regards size and development of 

 crystals ever obtained. The massive variety is found in this neigh- 

 bourhood in large oval or round masses at the bottom of the new 

 red marl. 



An analysis of some of the celestine found in Clifton, gave : — 

 Strontium Sulphate .. ... 99.13 



Barium Sulphate ... ... .46 



Calcium Sulphate ... ... .25 



Ferric Oxide ... ... ... .02 



Manganese ... ... ... trace 



Silica, Alumina, and loss .. .14 



100. GO 



An old mineralogical work of 181 1, mentions some celestine 

 found at Bristol having the composition : — 



Strontium Sulphate ... ... 97.208 



Barium Sulphate 

 Silica 



Ferric Oxide 

 Moisture and loss 



1.222 



.254 

 .116 



.200 



100.000 



Knowing that celestine occurred in Clifton, I was anxious to 

 obtain some specimens, and one day while walking along a turning 

 leading out of Oakfield Road, I saw some heaps of spar which had 

 been excavated from the foundations of new houses. From their 



