THE ANNALS 
AND 
MAGAZINE OF NATURAL’ HISTORY. 
[THIRD SERIES. | 
No. 75. MARCH 1864. 
XX.—On the Red Crag and its Relation to the Fluvio-marine 
Crag, and on the Drift of the Eastern Counties. By 8S. V. 
Woop, Jun. 
| With a Map, Plate XVII. ] 
Some observations made during a visit to the Red-Crag beds 
disclosed such peculiar conditions of structure that I was induced 
to enter upon a careful and minute survey of the whole Red-Crag 
area. The result of that survey, with the observations that I 
have been enabled to make upon the Drift-beds of the counties 
of Essex and Suffolk, form the subject of this paper; and they 
have led me to the conclusion that in the Red Crag (once re- 
garded as of Miocene age) we have the initiatory stage, in Eng- 
land at least, of that series of events which, chiefly studied under 
the term drift, began by the encroachment upon the land of 
England of a bay of the Northern Ocean, progressed by the ex- 
tension of that bay into what now forms the Eastern Counties, 
and eventually involved a far more extensive area in a submer- 
gence beneath the sea that furnished the ice-borne sediment and 
detritus known as the northern Clay-Drift. 
I have thought it more convenient to embody in an appendix 
a list of the various sections of Red Crag examined by me. 
They are taken from every part of the Red-Crag area, and 
comprise, with the exception only of Felixstowe, almost every 
Red-Crag exposure between the Alde and the Orwell, as well as 
several south of that river. 
It will be perceived, from the diverse shading upon the map 
(Pl. XVIT.)accompanying this paper*, that the Red Crag isdivided 
* This map, in so far as concerns the division between the fifth-stage 
Crag and the beach stages, must be taken as a very imperfect approxima- 
tion, the chief part of the Crag area being hidden under the great heaths 
formed of the lower-Drift beds ; the object is to show the features presented 
by the two Crags in their mode of deposit. The district on the east of the 
Deben, between Woodbridge and Ramsholt, may be taken as a tolerable 
approximation to exactness. 
Ann. & Mag. N. Hist. Ser. 3. Vol. xiii. 13 
