Correspondence — Mr. Joseph Prestwich. 539 



I am quite willing to extend the signification of Uniformitarian, in 

 geology, to any action, however varied in intensity, from the most 

 slow and steady to, at times, the most rapid or violent ; as long as 

 such catastrophes or paroxysms, as Mr. Scrope calls them, occur 

 (like the striking of a clock) at regular or equidistant intervals of 

 time, even if they do occur " but once in a century, or even in a 

 thousand years." Before, however, internal or volcanic action can 

 be brought under such a heading, it must first be proved that their 

 catastrophes or paroxysms do occur at regular intervals ; and until 

 this is shown — more especially as the bulk of evidence at hand at 

 present tends rather to the opposite conclusion — it does not appear 

 unreasonable to continue to call these agencies Cataclysmic, as long 

 as by the word Cataclysm in geology is understood some more than 

 ordinarily violent event in the earth's physical history occurring at 

 intervals altogether irregular and undeterminable. 



Davib Fobbes. 



11, York Place, Portman Square, London, "W. 



A FACT RELATING TO THE CEAG PIT AT THOEPE, NEAR 

 NORWICH. 



Sir, — In my paper on the Norwich Crag and associated beds, read 

 before the Geological Society last autumn, I mentioned a local feature 

 which I had noticed some fifteen years since, and which I had not 

 seen reproduced since that period, viz., the occurrence over the 

 shelly sand (Norwich Crag), overlying the Chalk, of a thin bed of 

 clay (which I suggested might be the Chillesford clay), succeeded 

 by an ironstone conglomerate containing impressions of shells. On 

 my visit there again last week, I found in a freshly cut part of the 

 section at the west end of the pit the same features exhibited, but on 

 a larger and better scale. A bed about 2 feet thick, at the lower 

 part of the gravel capping the section, is cemented into a ferruginous 

 conglomerate, which has been the means of preserving the casts and 

 impressions of numerous shells. Under this is a bed of light grey 

 clay, 1^ foot thick, and then 5 or 6 feet of white sand and fine 

 gravel, with an abundance of the usual Norwich Crag shells in the 

 lower part of it. 



The impressions in the ferruginous conglomerate are very abundant 

 and very well preserved. My visit was too short to make a proper 

 collection of them, and as the bed may, as the former one was, be 

 worked out before long, I would direct the attention of any geologists 

 visiting the pit to the interest of making a good collection of these 

 fossils, amongst which I noticed the following : — Pectunculus gly- 

 cimeris {?), Cardium eclule {?), My tilus, iprohahlj two STpecies, Paludina 

 lenta (f), Mactra, My a, etc. These are the beds which I placed in the 

 horizon of what I have termed the Westleton shingle, and which in 

 the neighbourhood of Southwold contain casts of Mytili and other 

 shells in abundance, and reposes in all that area on the Chillesford 

 clay. Joseph Pbestwich. 



