192 Correspondence — S. G. Perceval. 



[Colonel Grreenwood is quite correct ia his criticism. The artist 

 has given such a twist to the prehensile fingers of the wing in Fig. 2 

 as to convey the idea that the expanded wing-membrane is supported 

 on the elongated thumb or first digit instead of its little finger, as 

 shown clearly enough in the skeleton, Fig. 1, Plate IV. — Edit.] 



DENUDATION OF THE LAEIE DISTRICT. 



SiK, — Mr. Mackintosh seems to have somewhat mis-read one part 

 of my article on " The Denudation of the Lake District," in the Geo- 

 logical Magazine for January, p. 14. I nowhere stated the proba- 

 bility " that the sea, during the Glacial submergence, was an im- 

 movable frozen mass." J. Clifton Wabd. 



Clapham Common, March 11, 1870. 



Buried Sea-cliffs versus Faults. — While this question is afloat, 

 Mr. D. Mackintosh would beg to re-direct the attention of Geologists 

 to a well-known spot in the railway-cutting near Uphill (Weston- 

 super-Mare), where the Upper Triassic and Ehsetic strata terminate 

 cleanly and abruptly against an overhanging wall of Carboniferous 

 limestone rock, without any sign of displacement except a slight dip 

 towards the limestone — so far as he can recollect. Some years ago 

 he felt a great difficulty in understanding how the phenomenon 

 could have resulted from a fault. 



Carlton Sill, Leeds. 



ON THE OCCUERENCE OF TOPAZES IN LTJNDY ISLAND. 



SiE, — I believe it is not generally known to Mineralogists that 

 Topazes occur in the Granite of Lundy Island. A small piece of 

 quartz, to which three topazes are attached, which was brought from 

 that locality, is in the collection of the late Dr. Alfred Day, at 

 Clifton : also a detached crystal, which was obtained by Mr. Eobert 

 Etheridge. The crystals are small and of a pale colour, not unlike 

 those found in the Mourne Mountains, Co. Down. S. G. Peeceval. 



February 24, 1870. 



The Geological Collection in the Prague Museum has much 

 increased of late, owing to the vigorous labours in the field by the 

 Committee of Exploration. Of chalk fossils the Museum contains 

 more than 6,000 specimens from 140 localities. Dr. Fritsch hopes 

 some English Geologists will visit and examine the collection. A 

 new entire Scoi"piou has been discovered in the Coal-measures at 

 Prahys, and a new Saurian in the Permian rocks near Pilsen, which 

 Dr. Fritsch hopes shortly to figure and describe. 



ERRATA. 



In the February number, 1870, page 79, line 9 from top, erase GraptoUtidce. 



„ ,, „ „ ,, ,, 12 ,, iov pusillus re&A putillus. 



In the March number, Glasgow Geological Society's Reports, page 139, line 20 from 



top, for inner read outer. 

 In the March number, in Mr. Scrope's article on Lavas, page 104, line 14 from foot 



of page, for silver read silica. 



