24 
CORALLINE CRAGe 
shells, with occasional oblique lamination, was spread over this 
deep-sea bed, indicating possibly a shallowing of the sea by a 
reverse movement of elevation, and the setting in of stronger 
currents with intervals of quiet deposition. Further elevation, 
exposing the sea-bed to the action of tides and currents, led to 
considerable wear and denudation of the lower beds and to the 
heaping up of the remains of Bryozoa and of MoUusca of beds 
and in banks over portions of the sea-bed. Under such 
conditions the upper division ^ g ’ of the Coralline Crag seems to 
have been generally formed; at a few places only do some of the 
beds seem to have been formed tranquilly.'" 
Bed ^ h ’ shows, in the finer state of comminution of the shells 
and Bryozoa, that the water probably continued to get shallower; 
and finally a continuance of the same movement of elevation 
gradually raised the Coralline Crag above the sea, and exposed 
it to the denuding action which has removed so large a portion of 
it. Then, or during the Bed-Crag period immediately following, 
the Coralline Crag was broken up into detached islands and reefs, 
amongst which the Bed Crag was deposited during a period of 
slow and small subsidence.” 
To this paper is added a full list of the Coralline Crag mollusca, 
with the determinations revised by Grwyn Jeffreys. Comparisons 
are also made between the Coralline Crag fossils and the fossils of 
various continental Pliocene deposits, and also with the living 
faunas of different seas. The conclusion come to is that a much 
larger proportion of the Coralline Crag mollusca belongs to recent 
species than was allowed by Searles Wood, and that the Coralline 
Crag contains a good many northern forms not recognised by 
that author. Thus the fauna is made to appear more like that 
now inhabiting the British seas, and less like that of the 
Mediterranean, than had generally been thought. 
Next year (1872) Messrs. S. Y, Wood, jun., and F. W. Harmer* 
gave a general description of the Coralline Crag, without entering 
into much detail of the sections. As the divisions adopted by 
them are somewhat diflferent from those suggested by Prof. 
Prestwich, it will be desirable to quote their account, especially 
as it is founded on the life-long work of S. Y. Wood, senr. After 
indicating the known extent of the deposit—which had scarcely 
been traced beyond the limits within which Mr, Charlesworth 
first described it in 1835—they mention a trace ‘‘at Trimley, 
where it was observed in the digging of a ditch by the late 
Mr, Acton,” If this note is accurate it carries the Coralline 
Crag 4 or 5 miles south of the furthest point to which it had 
previously been followed. 
Messrs. Wood and Harmer’s general description of the Coralline 
Crag is as follows: “ The Coralline Crag has long been known 
to consist of two main portions, and a third subordinate bed. 
The first and lowest of these consists of a series of calcareous 
* An Outline of the Geology of the Upper Tertiaries of East Anglia [with Map], 
in the Supplement to the Crag Mollusca. Palceontographical Society. (1872.) 
