340 Prof. T. R. Jones on 
less depth. Wemust remember that, as a cast, this specimen 
cannot be so good for such strict determination as either of 
the valves would be. . 
It exhibits the nearest approach among British specimens 
to Hisinger’s L. phaseolus * that I have met with; but still 
it does not correspond with it by any means in full, being 
much too short on the back and too elliptical behind. More- 
over it more closely resembles in outline the valve of L. amyg- 
dalina from Canada (fig. 9, a); but its convexity is more 
central. 
I prefer, therefore, to regard it as a small, narrow, and very 
oblique form (variety gracilenta) of L. Hisingerti, Schmidt. 
To the same category we must relegate the imperfect speci- 
men from Kington, figured in the Ann. & Mag. Nat. Hist. 
ser. 2, vol. xvi. pl. vu. fig. 15, and (with another cast) 
quoted as “Leperditia marginata?” at pp. 95 and 100. Both 
of these specimens, from the Downton Sandstone (‘Tilestones) 
of Herefordshire, are in the British Museum. For some 
similar casts in these light-brown micaceous sandstones +, 
and in the olive shales of the passage-beds near Ludlow, I 
have been indebted to the late Mr. J. W. Salter and Mr. 
Lightbody, of Ludlow. One specimen in the Ludlow Mu- 
seum in 1864, from the passage-beds (‘olive shales” or 
“'Tinmill shales’) in the railway-cutting at Ludlow, was 
4 inch long. Several smaller specimens were collected there 
by Mr. G. Cocking and the late Mr. Lightbody, together with 
Eurypterus, small Brachiopods, &c. 
To this kind of Leperditia we must also refer those 
noticed by Mr. Salter in the ‘ Catalogue of the Collection of 
Cambrian and Silurian Fossils in the University Museum at 
Cambridge,’ 1873, pp. 189 and 193, as “LZ. marginata?” 
from the Upper Silurian of Ledbury and Ludlow. 
In the same Downton Sandstone (from Mr. R. Banks, of 
Kington) and in greenish micaceous shale (from Prof. J. 
Morris) of the uppermost Ludlow series I have had some 
casts of small Leperditiw, from less than 7%; to 7% inch long, 
that have the same outline as that shown in our fig. 2, a, as 
above mentioned. 
Pl. XIX. fig. 16. This is the outline of a small left valve 3 
inch long, 2 inch high, and convex in the middle. It bears 
the structural marks of eye-spot and muscle-spot, and has a 
* Carefully figured from the original type by Dr. Kolmodin in his 
‘Ostrac. Sil. Gotl.’ 1880, pl. xix. figs. 4 and 5. 
+ With Lingula and Beyrichia Wilckensiana, 
