482 
THE GEOLOGIST. 
with layers of rag, and are called by the quarryraen, the " Cock-beds." 
The orgaaic remains consist of sponges, zoopliytes, Pecten qicinque- 
costatus, and a large Terebratula, but these are sparingly found. The 
beds are twenty-four in number. 
5th. "We now come to a succession of beds of chert and sandstone. 
One bed, about nine inches or a foot thick, is called by the masons the 
Firestone, and is most probably the equivalent of the rock so-called in 
Sussex, and described by Dr. Mantell, who denominated the whole of 
the series as " Firestone," but which appears from his description to have 
thinned out considerably in that locality, and to have become amalga- 
mated with the chalk-marl. Still, the fossils he describes as belonging 
to the Firestone at Southbourne are never met with in the Isle of Wight 
below the Phosphatic Greensand, nor does the chalk-marl ever appear 
in the whole section of the Uudercliff, a distance of nine miles from 
Shanklin to Blackgary, below the Firestone, or Upper Greensand, as 
exhibited in his section of the beds near Southbourne.* 
Again, at page 164, he says the "Firestone contains the same fossils 
as the Grey marl ; " but one, at least, which he enumerates, the Ostreea 
oarinata, is a characteristic fossil of the two beds, the phosphatic and 
chloritic greensands, capping the firestone in this locality, and is very 
rarely found below them. Ammonites planulatus also occurs higher up in 
the same bed, but I have never met with it in those below. I have 
merely mentioned these discrepancies with the view of calling attention 
to the fact, namely, that all the fossils which Dr. Mantell has described 
and figured in his work on the " Geology of the South-east of 
England," as belonging to the " Upper Greensand," or " Firestone," 
belong to the two upper beds of the "Phosphatic Greensand," and to 
the " Chalk Marl '' in this district; whilst neither in the list there 
appended, nor elsewhere, has he described or enumerated any of the 
characteristic fossils of these deposits which occur in the Undercliff- 
series of the Upper Greensand, namely, the Pecten quinque-costatus, the 
large Ammonites, Ancyloceras (or Hamites), &c. 
" The Fire-stone group" of Dr. Mantell includes those twenty-four 
beds above described, but the term is restricted in this locality to an 
upper bed, about eight inches thick, superimposed on a stratum of rag 
of a pale blue colour, tinted with red, very hard, about nine inches in 
thickness, and succeeded by another bed of fire-stone of the same thick- 
• Vide, Manteli's " Geology of the South-east of England," pp. 161—164. 
