ii SUPPLEMENT TO THE CRAG MOLLUSCA. 



regarding as separate formations, beds that differ only from local peculiarities, but are in 

 fact identical in age and continuity. 



From the map so constructed by them, the lithographic map which accompanies this 

 Supplement, and which, although it embraces the entire Crag area, comprises only a 

 portion of that embraced by the original, has been taken by reduction to the scale of one 

 fourth (linear) of the original ; and the sections which accompany it (and without which 

 it would be difficult to understand either the structure of the country or the sequence of 

 the deposits) have been carefully prepared by them for its illustration. All the 

 formations quoted for Mollusca in my work will be found in this map, with the following 

 exceptions ; viz. the Bridlington bed, which is on the Yorkshire coast ; the Kelsea Hill 

 gravel, which is near the same coast ; the gravel of Hunstanton, which is at the north- 

 western extremity of the Norfolk Coast ; the Brick-earth of the Nar, which is in the same 

 neighbourhood ; and the gravel of March, which is in the midst of the great fen district 

 of Cambridgeshire. 



The geological position of the beds thus beyond the limit of the map will, however, 

 be explained in the following outline of the geology of the Upper Tertiaries of East 

 Anglia, which has been written by my son and Mr. Harmer as embodying their views of 

 the subject. The actual area from which the Mollusca described or referred to in my 

 Supplement were obtained, is that which lies east of a line drawn from London to 

 Bridlington, and including the latter place. 



I defer some remarks which I propose to make on the fauna of the several Upper 

 Tertiaries embraced in this Supplement, until the remaining part of it, which will contain 

 the Bivalvia ; and I propose then to give a tabular list of the species. 



S. V. Wood. 



AN OUTLINE OF THE GEOLOGY OF THE UPPER TERTIARIES OF 



EAST ANGLIA. 



By S. V. Wood, junior, F.G.S, and F. W. Harmer, F.G.S. 



The Coralline Crag. . 



The oldest of the Upper Tertiaries of East Anglia — the Coralline Crag — is 

 but a fragment of the once continuous deposit that must have spread at least 

 from Tattingstone on the south-west, to Aldborough on the north, nearly the whole 

 of the formation having undergone destruction prior to the accumulation of the 

 Red Crag. It is not improbable that under the highlands formed of Glacial beds other 

 isolated masses of the Coralline Crag may be concealed, but the only fragments which offer 

 themselves to our investigation are a very small one at Tattingstone (see the south-western 



