Correspondence — Mr. Frank Ridley. 527 



ing or naining, and that there was sure to be exaggeration. Mr. 

 Smyth quoted likewise a report on the tin-stream district of 

 Tenasserim, wliich was not likely to increase its production in any 

 material degree. After referring to the Laurium mines, the President 

 concluded by remarking upon the issue of a fourth edition of Lyell's 

 "Antiquity of Man," and to Mr. Borlase's "Nasnia Cornubise," a 

 work in which the metalithic element was so strong as almost to 

 stamp it as a work of applied geolog}^ whilst the scientific treat- 

 ment of the details of the sepulchral relics of the county entitled 

 the author to the thanks of all who were not blind to the interest 

 of the early history of the British race. 



coI^I^Es:FOIs^XD:EI^^o:E]. 



THE " SUB-WEALDEN " EXPLORATION— IMPORTANT DISCOVERT. 

 Sir, — I am able to announce to you an important fact in relation 

 to our great " Sub-wealden " exploration. The specimens from the 

 lowest 23art of the boring are marine deposits ; they contain shells ; 

 among these are distinct small Lingulce, which are identical with 

 examples of Lingula ovalis from our Kimraeridge Clay in Shotover 

 Hill. Mr. Pej'ton, to whose care in examining the shale from the 

 boring, I am indebted for the specimens which, with the consent of 

 Mr. Willett, have been placed in my hands for scrutin}^ and the 

 result is quite certain. There are other shells, but not sufficiently 

 exhibited in these specimens (Ostrea, Avicula ? Spine of Acrosalenia ?). 

 It appears, then, that we have touched the great upper clays of 

 the Oolites, without encountering shore sands or shelly Oolites — no 

 I'ortlandian rocks have appeared. It is the open sea-bed which we 

 have reached, and mny not find other than clay deposits for a con- 

 siderable depth. There may be no Triassic limestones or sandstones ; 

 and we may come on Palaeozoic rocks at no enormous depth, and 

 with no unusual difQculty. John Phillips. 



Oxford, 26<A Se2}t. 1873. 



ON A NEW METHOD OF WRITING CRYSTALLOGRAPHIC FORMULA. 



Sir, — In the September Number of this Magazine (p. 428), Mr. 

 Danby does me the honour to criticize my paper on Cry stall ographie 

 Formulae (p. 299). 



His objections to my proposed sj^stem of writing formulae appear 

 to. me to be just ; and with regard to the application of the system to 

 the more advanced requirements of the crystallogrnpher, they seem 

 not merely just, but important, and it was from antici[)ation of such 

 objections that I refrained from making any mention of Professor 

 Miller's system. Upon one point, however, Mr. Danby appears to 

 have put a wrong construction, namely, in crediting me with the 

 presumptuous notion that my method of writing these formulte 

 should be able '■ to sweep all others from the field." 



I intended my little paper merely as a suggestion, capable of 

 modification and improvement, but, nevertheless — a suggestion which 



