72 
RED CRAG, 
adjacent seas. He also showed that the Crag overlies the London 
Clay—though subsequent observers overlooked his description and 
transposed the beds. 
Ill 1745 the llev. E. Pickering* * * § drew attention to the discovery 
of the value of Crag shells as manure, through the accidental 
upsetting of a load on cultivated land. 
In 1811 J. Parkinsonf pointed out that certain of the Eed 
Crag species seemed to belong to extinct forms ; and between 
1812 and 1819 SowerbyJ published figures of many of the shells. 
The several memoirs and maps, published between 1815 and 
1819, by William Smith, which form the foundation of strati- 
graphical geology, add nothing to our knowledge of the Crag, and 
through them all, owing to an unfortunate confusion of the 
Boulder Clay with the London Clay, the Crag is placed beneath 
the latter deposit. Smith used the term Crag,” but only in 
the local sense of shelly masses in the sands, not as the name 
of a stratigraphical division. 
In 1822, the Eev. W. D. Conybeare and W. Phillips§ con¬ 
cluded that the Ci'ag is probably the newest bed of the Upper 
Marine formation,” or in other words, newer than the Bagshot 
Beds and the Oligocene strata of the Isle of Wight. 
The next important addition to our knowledge of these strata 
was made in 1833 by Lyell,|| who bad devoted a good deal of 
time to the examination of the beds in the field during the year 
1829. Lyell gave a number of sections of the Ked Crag, and for 
the first time referred to the per-centage of living and extinct 
species.lT He classed the beds as older Pliocene and paralleled 
the Crag with the Subapennine deposits. 
In 1835 Mr. E. Charlesworth** separated the Eed Crag from the 
Coralline Crag; and gave the name Med Crag” to the Upper 
division, correlating it with the Crag of Norfolk. Two years 
later he considered! t that the Mammaliferous Crag of Norfolk is 
not an extension of the Eed Crag, but a newer deposit. In 
several of his papers between these dates he spoke of the mixture 
of shells of different ages in the Eed Crag. 
The Eev. W. B. Clarke in 1838 JJ criticised Lyelfs view of the 
impossibility of separating the Drift from the Crag, an opinion 
given up in later editions of Lyells works. 
* A Letter concerning the Manuring of Land with Fossil Shells [Woodbridge]. 
Phil. Trans., vol. xliii. no. 474, p. 191. 
f Organic Remains of a former World, vol. hi. 4to. London. 
X Mineral Conchology. 6 vols. 8vo. London. 
§ Outlines of the Geology of England and Wales, pp, 10-13. 
II Principles of Geology, vol. hi. pp. 19-21,'61, 171-177, 181, 182, 203-206. 
Appendix, pp. 47-49, 51. 
^ The determination of the shells was made by Deshayes, who compared the 
shells from Suffolk with those of Touraine and Piedmont. 
** Phil. Mag., ser. 3, vol. vh. pp. 81-94. 
If Pep. Brit. Assoc, for 1836, Sectio7is, pp. 84-86, and in Mag. Nat. Hist., 
n. ser., vol. ii., pp. 40-43. (1838.) 
Xt Letter on the Non-identity of Suffolk Diluvium and Crag. Mag. Nat. Hist., 
ser. 2, vol. ii. p. 285. 
