5 
Several Fossil shells of this and the Stratum preceding, greatly resemble some which are 
recent. In the Clay they are generally white, but some in the Crag, as Turbo littoreus, often 
retain their natural colour. 
Oysters, of various sorts, found plentifully in the Strata over Chalk, seem to define the 
course of Crag at the following places :• — Headley, Reading, Woolwich, Blackheath, and in 
stone at Stifford, in a valley one mile south of Hertford, at Beckingham and Damerham, and 
in stone at New Cross, and Addington Hills, near Croydon. 
Crabs and Lobsters are more numerous in these than in any of the inferior Strata. 
Horns of very large animals are also found in low places, where these Strata approach the 
Marshes, which are considered to be alluvial. 
Ivory has been collected from the sandy Crag ; teeth, vertebrae, and other bones are numerous 
in it, some of these, and the shells being rounded and mixed with fragments of numerous imper- 
fect shells, lead to an opinion that this part of the Crag may be alluvial. It is, however, traced 
through the same course of country, and if not connected with the stoney Crag, is so very conti- 
guous thereto, as not to be separated in a general account. 
The stoney calcareous Crag is in more regular layers than the sandy. In some places it 
appears to be covered with Brickearth. Shells are found perfect in this sort, which are probably 
only fragments in the other, aud some perfect in that, are only casts in this, as the murex 
striatus of Sowerby. 
