338 Mr. William Phillips on the OxydofTin, 



The above quotations from Dr. Berger's valuable paper are 

 given solely with a view of shewing it to be his opinion that at 

 least one district of Cornwall, producing tin, is not primitive. 

 This has long been my opinion of that district, as well as of other 

 parts of that county in which tin is found : and I cannot doubt 

 but some specimens of granite in my collection from different 

 places, enclosing tin, tend to confirm that opinion. But it may 

 be well to await tlie developement of many facts, which yet 

 remain requisite to the better understanding of the geology of the 

 county, as well as the light that might be thrown on the subject 

 by a more perfect agreement in the use of geological language. 



The existence of tin in the native or pure state is no longer 

 believed. It was admitted by Rome de Lisle to have been so found, 

 from the examination of a specimen from Cornwall under that name, 

 which, by the description he has given of it, seemed to partake of 

 the exterior appearance of molybdena. I possess a specimen of 

 tin, found in the neighbourhood of St. Austle in that county, which 

 with two or three others was arranged in the collection of my late 

 uncle, now in my possession, under the name of native tin. It is 

 almost coated by a ferruginous rust, and on one of its larger sides 

 there are numerous portions of a very hard substance resembling 

 iron, in which are embedded minute pieces of quartz ; on this side 

 I presume it to have been deposited. The fracture in some places 

 is that of the finest steel-grained sulphuret of lead. The more 

 pure parts of it easily flatten under the hammer, and fall off in small 

 scales, which crackle between the teeth and easily yield to the 

 knife. This specimen seems very much to agree with some found 

 in France by Schreiber, an account of which he has given in the 

 Journal des Mines, except that those were accompanied by a 

 white substance, which proved to be the white muriate of tin. 



