298 MM. Wilson and Crick—The-Lias Maristone of Tilton. 
has converted this dense grey ferruginous limestone into a porous 
and friable rusty brown ironstone over such large areas, where it 
forms the surface rock, in Leicestershire and Rutland.! This soften- 
ing process has made it possible to extract a large number of fossils 
in a fairly complete state of preservation. 
The list of Tilton fossils here given is in large measure founded 
upon specimens thus obtained. It is therefore in many cases im-— 
possible to say with absolute certainty from what part of the Tilton 
section these fossils came; but as we find that the chief repository 
for the cephalous mollusea, at any rate, at Tilton, is the top or 
“Transition Bed,” we shall probably be pretty safe in assuming that 
most if not all of the similar organisms found in the Marlstone 
blocks of the Hast Norton embankment have been derived from 
that horizon. ; 
Going south from Tilton, the Marlstone Rock rapidly dies away. 
In the railway-cutting near Hast Norton Station it can still be traced 
as a concretionary bed two or three feet in thickness, whilst between 
Keythorpe and Hallaton it is less than one foot thick; and nearing 
Market Harborough, it locally disappears altogether. 
In the Hast Norton railway-cutting the grey clays of the “Com- 
munis zone” of the Upper Lias are exposed, and have yielded the 
following characteristic Upper Lias fossils :— 
Stephanoceras commune, Sow. Inoceramus dubius, Sow. 
‘i crassum, Y. & B. Nucula Hammeri, Defrance. 
Harpoceras bifrons, Brug. »,  elaviformis, Sow. 
Belemnites subtenuis, Simpson. Serpula tricristata, Goldfuss. 
Nortonia (Purpurina) Patroclus, d’Orb. 
Paleontological Notes, by E. Wilson, F.G.S. 
Although it has fallen to my lot to undertake the critical paleon- 
tology connected with the subject, I have to acknowledge very 
considerable assistance from my colleague in this department of our 
joint work. Mr. Crick has not only collected the great majority of 
the fossils mentioned in the Appendix, but he has also identified the 
whole of them, with the exception of the Gasteropoda and the species 
which I have described. The success attending Mr. Crick’s re- 
searches in the neighbourhood of Tilton will be understood when I 
mention the fact that five years ago the total number of species 
which had been derived from the Marlstone Rock of the Leicester- 
shire district, including Rutland and 8.W. Leicestershire, did not 
exceed sixty, and that it is chiefly through his labours that this total 
has been increased to one hundred and ten.” Seeing that scarcely 
anything has been found in the Leicestershire district which has 
not also been found at Tilton, the Marlstone fauna of this single 
locality may be considered to fully represent that of the larger area 
referred to. 
1 As an illustration of the effect of atmospheric action in producing this change, it 
may be mentioned, that under the railway bridges where the Marlstone ballast has 
been protected from the rain, the rock remains in practically the same hard state 
as that in which it was first quarried. 
* We are indebted to Mr. B. Thompson, F.G.S, of Northampton, for the 
privilege of inspecting his collection, and also for the loan of some of the most 
interesting of the fossils here described. 
