480 Correspondence — R. M. Brydone. 



Ave were the first to record Anthracomya Phillipsi from this bed, and 

 are sorry if Mr. Stobbs thinks we have done him an injustice by 

 omitting to refer to the papers he mentions. 



David Woolacott. 

 August, 1919. 



GAPS IN THE MUCRONATA CHALK OF THE ISLE OF WIGHT. 



Sir, — Last autumn I happened to be in the neighbourhood of Ryde 

 Waterworks and paid a visit to the " pit " there (No. 45 of Dr. Rowe). 

 I found on the talus two fossils, which, owing to a long illness which 

 has left me crippled, I was only recently able to examine thoroughly. 

 They proved to be unmistakable specimens of Echinocorys scutatus 

 var. subconicus, a typical and exclusive fossil of the zone of 

 Bel. mucronata. They were found at the extreme south end of the 

 talus and presumably came from the south end of the exposure. 

 This end of the exposure is at least 150 feet from the Chalk boundary 

 as mapped, and though the dip at this point appears to be unusually 

 low for the central ridge it should be safe to take it as at least 

 60°, which would give a minimum of 100 feet of mucronata Chalk at 

 this point. 



This makes the third of the five alleged instances of a breach 

 completely through the mucronata zone to be definitely discredited. 

 The other two instances, near Freshwater, remain subject to the 

 criticism which I passed on them in the Geological Magazine for 

 August, 1918, reinforced by the fact that in the northern part of the 

 pit, west of Freshwater, I have found Membraniporella manonia, 

 which in my experience is rigidly confined to the lower part of the 

 mucronata zone, and Herpetopora, a genus which is extremely rare in 

 the quadratus zone, but in the Isle of Wight is almost abundant 

 in the mucronata zone. 



May I take the opportunity of recording that I have found 

 brachials, presumably of Uintacrinus, in the upper part of pit 36 of 

 Rowe, who does not record Uintacrinus there, although he maps it, 

 and at the head of Freshwater Bay on the west side, which involves 

 some shifting of the mapped boundary, and that the Isle of Wight 

 has had scant justice done to it as a locality for Stephanophyllia. 

 I have examined the T. lata Chalk of Compton Bay on three 

 occasions for periods ranging up to three-quarters of an hour, and my 

 smallest bag was ten specimens. I found two specimens in my only 

 search of the same zone at Culver Cliff, and five in a short search of 

 the H. subglobosus zone of Compton Bay. With specimens from the 

 Chalk Marl and Chloritic Marl of the Isle of Wight, and of course 

 elsewhere, and a specimen from the quadratus zone of Sussex to 

 bridge the gap between the well-known cor-anguinum occurrences 

 of Kent and the abundance of Studland (where, after Dr. Rowe's 

 party had swept the section, I once found sixteen specimens in a day) 

 and Weybourne, Stephanophyllia is much more freely distributed in 

 the Chalk than is likely to be generally realized. 



R. M. Brydone. 

 27 Maybury Mansions, 



Marylebone Street, W. 

 September 20, 1919. 



