576 Correspondence. 



ounces to the ton of ore, but the ferruginous gossan at that time con- 

 tained much silver also, in what form I know not ; and I cannot 

 ascertain whether the gossans were assayed only, or the compact 

 silver-fahlerz likewise. In one instance the proportion of silver to 

 the ton of ore was 214 ounces ! The last sample sold contained 

 36^ ounces to the ton. Unlike the position of this mineral in the 

 Fox-dale mine, there is no granite within a distance of two or three 

 miles. This mine affords the only known instance in this country 

 of a continuous lode of silver-fahlerz, and, as I have before stated, 

 no other ore is found in sufficient quantity to be of any commercial 

 value. The associated minerals are quai-tz (which in some parts of 

 the lode is much mixed up with the tetrahedrite) chalybite, and iron- 

 pyrites. Under the name of Wheal Fortescue, Silver-vein was 

 formerly worked for the rich deposits of silver it contained ; I sup- 

 pose in the state of sulphide, but was abandoned for want of capital. 

 If Mr. Forbes should be sufficiently interested in the fact as well as 

 in the mode of occurrence of silver-fahlerz in this locality as to visit 

 it, I can assure him that he will meet with very willing assistance 

 from my friend, Mr. Tailing, of Lostwithiel, who knows every part 

 of the mine well, and who I have to thank for many of the above 

 particulars which I had nearly forgotten, as it is now three years 

 since I descended it in his company. 



I am, Sir, yours very truly, 

 British Museum. Thos. Davies. 



THE BELGIAN TERTIARIES. 

 To the Editor of the Geological Magazine. 

 Sir, — I am desirous to correct a mistake which I unintentionally 

 made in my paper on the Belgian Tertiaries, contained in the 

 Geological Magazine of November 1st. I have there stated 

 (p. 504) that Mr. Searles Wood had remonstrated against certain 

 views explained by Mr. Godwin -Austen in his paper, " On the 

 Kainozoic Formations of Belgium." I now learn from Mr. Searles 

 Wood that he has not published any paper relating to this subject, 

 but that the opinions which he had expressed with regard to certain 

 of Mr. Godwin- Austen's views were communicated to me in letters 

 which we exchanged on that subject. I trust to be excused for this 

 error on the ground that my paper was written at a time when I 

 had none of my books at hand to refer to, as already stated (p. 506). 

 — Yours truly, A. von Koenen. 



TTniverstty of Marburg, 

 iioveinber 18th, 1867. 



We are informed that the collection of M. Deshayes' Eocene Shells, 

 from the Paris Basin, forming the types of his great work, "De- 

 scription des Coquilles Fossiles des Environs de Paris," which has 

 occupied so many years in publication, has just been purchased by 

 the French Government, for the Museum of the Jai'din des Plantes, 

 Paris, for the sum of 100,000 florins. 



