RED CRAG. 
81 
In 1880 S. V. Wood, jun.,* * * § remarked that the formations from 
the Red Crag upwards—except the recent deposits-— should be 
studied as one group, for they were all accumulated, he thought, 
* during one continuous movement of depression and re-elevation. 
The whole of the strata included in this group he classed as 
Newer Pliocene. The mode of formation of the different deposits 
was fully treated of by this author, who traced step by step the 
physical changes which he considered to have caused the varia¬ 
tions in the character of the strata and in their included fauna. 
In 1882 appeared the last contribution from the pen of S. V. 
Wood, I which gave a list of the Mollusca from the Red Crag at 
Felixstow, distinguishing the species that have been derived,firstly, 
from beds older than the Red Crag, secondly, from earlier Red 
Crag beds; also a supplementary list for Walton Naze, by R. Gr. 
Bell. He referred to the contrast between the Crag of Walton 
and that of Felixstow and stated that the fragmentary condition of 
many shells at Felixstow, which are abundant in a perfect state at 
Walton, must be owing to derivation. Between the deposit of 
these two divisions of the Red Crag certain species, he thought, 
had ceased to exist in the Crag sea, and others had been brought 
in, whilst in the Butley Crag this change is further marked. He 
traced the sequence of events during the Pliocene period in 
England, and re-stated the conclusion that all but the top part of 
the Red Crag was formed between high and low-water mark as 
banks which were continuously undergoing destruction and re¬ 
accumulation. 
S. Y. Wood, jun., added to this communication some remarks 
in correction of the map and section in the First Supplement 
(1872) ; and whilst classing much of the sand over the Red Crag 
as Lower Glacial, allowed that some is merely Crag from which 
the calcareous matter has been dissolved. 
In 1884 R. G. BellJ remarked that few traces of land and fresh¬ 
water shells have been found in the Red Crag, which is the more 
notable as the deposit must have been formed at no great distance 
from shore. All the specimens are of living British species of 
wide range, and are first found in this bed. This author noted 
the finding of three additional species in the lower part of the 
Crag at Walton Naze, and remarked that their present geogra¬ 
phical range, compared with that of the land-shells from the 
Butley Crag, leads to the same conclusion as that deduced from 
the marine species, the shells of Walton being mainly southern, 
whilst at Butley there are more of northern kinds. 
In 1885 Messrs. Whitaker and Daltom§ described in detail 
the greater part of the Red Crag area; and during the years 
* Quart. Journ. Geol. Soc., vol. xxxvi. pp. 457-459. 
t In the posthumous Third Supjdement to the Crag Mollusca, edited h}^ his son, 
S. V. Wood, Jun., pp. 13-24. 
t Geol. Mag.., dec. iii. vol. i., pp. 262-264. 
§ The Geology of the country around Ipswich, Hadleigh, and Felixstow. 
(^Memoirs of the Geological Survey), pp. 29-71. 
E 60798. 
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