58 REPORT—1846. 
In a note in the last number of the ‘ Journal of the Geological Society,’ I alluded 
to the discovery by Mr. Pratt of impressions of plants ina stratum which I believed 
to correspond with No. 17 in the Alum Bay section. This I can now cunfirm, and 
testify to their great abundance and beautiful state of preservation, but from their 
light colour (being nearly that of the clay) they were long overlooked. 
With regard to Headon Hill, I regretted to find its cliffs so fallen down and its 
fine sections comparatively so obscure ; still the interpolated marine beds, Nos. 56 to 
60, can easily be traced at intervals. The fossils of these beds can now be best pro- 
cured at the eastern extremity of the hill. At Colwell Bay however the section 
continues extremely well exposed and full of interest. 
On the Arrangement and Nomenclature of some of the Subcretaceous Strata. 
By W. H. Firron, M.D., F.R.S. 
This communication included a summary of the latest inquiries on the strata im- 
mediately beneath the chalk in England; with a table of the fossils (connected with 
a paper previously read before the Geological Society of London), from a new col- 
lection made by the author in the cliffs near Atherfield, in the Isle of Wight, from 
the gault down to the Weald clay. The specimens were named by Mr. Morris, and 
compared with the series in the Geological Society’s Museum catalogued by Professor 
Edward Forbes. This tabulated arrangement exhibits about 150 species, in their 
true places; so that numerous results can be obtained from it, respecting their re- 
lative positions and distribution in the series of strata. 1. The accumulation of 
species in the lower part of the section is very remarkable ; about 130 of the total 
number originating within 150 feet from the bottom, while not more than twenty 
other species originate in the remaining portion; the thickness of the entire section 
being 800 feet. The absolute numbers also of shells diminishes rapidly upwards, and 
in the strata near the top of the section in this part of the Isle of Wight, even in- 
dications of fossils are rare ; though near Shanklin, and near Folkstone in Kent, the 
fossils of the corresponding beds are more numerous and distinct. 2. These and 
other facts indicate the existence of only one series of fossils, throughout a period of 
continuous but unequal deposition,—the gault, with its peculiar and characteristic 
fossils, being immediately above,—a result which perfectly accords with the view 
taken by Professor Forbes, in a paper published by himself and Captain Ibbetson, 
in the ‘Geological Journal’ (vol. i.). 3. The upper and less fossiliferous portion of 
the section here, is distinguished, if not separated, from the lower beds by the pre- 
sence of a very remarkable group of ferruginous concretional bands, which occurs in 
a corresponding place, at Horse-ledge, west of Shanklin Chine; at Parham Park, in 
Sussex ; and at Sandgate, in Kent: including in all those places the same fossils, 
Thetis, Gervillia, Trigonia, Rostellaria, &c. 4. From the general mode of distribution 
of the species, as above described, and the great variation in the components and 
proportion of the beds which form the sections of the lower greensand in different 
places, it may be inferred that subdivisions, founded on the occurrence, or grouping 
of the species, cannot be expected to be either generally prevalent or very precise. 
5. The remarkable deposit of Neufchatel (Terrain Néocomien) appears to be the 
equivalent of the lower part only of the section near Atherfield, the upper divisions 
being wanting at the former place. In most of the published sections of the sub- 
cretaceous groups in France and other places, an upper division or series of strata, 
like this of the English coast, is likewise found, under the names of sables verts, sable 
Serrugineux, jaune, &c. The Atherfield section, therefore, includes the Terrain Néo- 
comien, with the addition of the group last mentioned, which at Blackgang Chine is 
not less than 250 feet in thickness. 
Captain Ibbetson and Prof. Forbes exhibited models and sections of various parts 
of the Isle of Wight, and pointed out the localities and geological features most in- 
teresting to visitors. 
Sir R. I. Murchison presented, on the part of Dr. Mantell, a Geological Map of 
the Isle of Wight, and the preliminary pages of a work devoted to the description of 
the island. 
