A. R. Horwood—Transition-bed and Crinoidal Limestone. 277 
ft. in. 
A. Broken ferruginous marly rock, sandy and much weathered. Probably 
representing ‘ ‘Transition-bed’ (bed A at Billesdon Coplow) : Se mG 
B. Thickly bedded sandy ferruginous rock with a seam of crinoidal lime- 
stone parted by 10 inches of sandy rock (bed B at Billesdon Coplow) 2 0 
Blue, green, or brown marly ferruginous, laminated beds, with 
Belemnites, Pecten, Tercbratula, Rhynchonella, base not seen ony) een 
(2?) Bed C, Billesdon Coplow. eehEN) 
6 0 
In so far, then, as Leicestershire is concerned the existence of the 
Transition-bed may be postulated in both the southern and the central 
tracts, whilst up to the present, though I have made search for it, it 
has not been met with in the northern tract. But less hopeful of 
finding it at Burrough as I was when it turned up at Tilton Hill, 
after its discovery at Billesdon Coplow, its present further extension 
may be said to give additional reason for prophesying its discovery in 
the future in the more extensive but less easily accessible district 
between Belvoir and Melton, where there is a thick covering of Drift. 
Notr.—Since my previous paper on the occurrence of aragonite in the 
Middle Lias of Leicestershire was published I find that aragonite has 
been discovered in the Cheltenham district at Churchdown,! Gloucs. 
This in no way minimizes, I think, the interest attaching to my own 
observations, which devolved rather upon the mode of formation and 
composition of different parts of the Marlstone, and their physical 
history, rather than upon the bare record of the occurrence of this 
mineral itself, which is not uncommon as a shell-substance in all 
districts. And whilst the Leicestershire specimens are not the first 
recorded examples they add to the significance of the occurrence 
elsewhere by suggesting a definite horizon at which the general 
temperature of the waters of the sea in the Marlstone epoch were 
much warmer over a wide area, than either above or below, and not 
merely locally at one spot. The extension of range, moreover, of 
aragonite in the Middle Lias, as a mineral pure and simple, is in itself 
assuredly of some interest. 
I haye to make a correction in the same paper, having inadvertently 
written Barnstone for Wartnaby in reference to the occurrence of 
stria on the surface of the rock-bed. In the recently published 
Survey memoir on the Melton Mowbray district, a photograph and 
diagram of the quarry where these striae were noticed are given 
(plate iii and fig. 6). 
In the same memoir (p. 40) it is stated that no specimens of 
Amaltheus margaritatus have actually been found in the district 
surveyed (Sheet 142). It may be worth while mentioning here 
that this zone-fossil was found by me in 1908 in that area, not in 
situ but doubtless derived from a local source, on the mineral line 
which runs down from White Lodge to the Great Northern Railway 
south of Harby and Stathern Station. It occurred below the rock-bed 
outcrop and within the area of the margaritatus shales, so was doubt- 
less derived from them at this place. 
1 F. Smithe, Proc. Cotteswold Club, vol. vi, p. 349; Mitchell, Geology of Stroud, 
ps 17. 
