153 



IV. — Note on a Cornish Specimen of Wavellite. — By J. H. Collins, 

 F.G.S., Joint Son. Secretary. 



Read at the Annual Meeting, November 24:th, 1874. 



THE Mineral Wavellite, a hydrous phosphate of alumina, is 

 of considerable interest to the mineralogist, although it has 

 not hitherto occurred in such quantities as to be commercially 

 valuable as a source of phosphoric acid. It was originally dis- 

 covered by Mr. J. Hill of Tavistock, about the year 1785, by whom 

 it was found in rounded concretions resting upon clay-slate at 

 Filleigh, near Barnstaple. It was about thirty years later 

 analysed by Dr. Wavell, and named after him. It has also 

 occurred in Northumberland, Scotland, Ireland, and many 

 foreign locaKties — usually upon clay-slate or sand-stone. 



Its occiu'rence in Cornwall has been several times reported 

 and as often disputed. Thus in Greg and Lettsom* at page 80, 

 it is said to occur on a decomposing granite at Stenna Gwynn, 

 near St. Austell, often accompanied with fluor and the rare 

 mineral fluellite. 



I have now the pleasure of corroborating this statement, and 

 of presenting to the Royal Institution of Cornwall a small 

 specimen from that locaKty, which was lately placed in my hands 

 for analysis by Mr. Richard Tailing, of Lostwithiel, from whom 

 also Messrs. Greg and Lettsom had their information. I was not 

 able to use more than 1^ grains for this purpose, but, although 

 this was not enough to allow of a quantitative analysis, I was 

 able very well to determine the presence of all the essential 

 constituents of "Wavellite. It wiU be seen that the specimen is 

 really upon a granite rock, unlike the specimens from other 

 localities, but it is not, I regret to say, in this instance, associated 

 with the extremely rare Fluellite. 



* Manual of the Minei'alogy of Great Britain and Ireland. 



