MM. Wilson and Crick—The Lias Marlstone of Tilton. 299 
Without further preface I proceed to the consideration of certain 
of these fossils which are either new to science, or to the British 
Lias, or which call for more complete description or revised nomen- 
clature. These fossils have all been derived from the Marlstone 
Rock of Tilton, Leicestershire, with the exception of the remarkable 
form first noticed, which is from the Upper Lias of East Norton, 
Rutland, and the peculiar interest of which must be my apology 
for noticing it in an essay not strictly dealing with Upper Lias 
paleontology. 
Norronta (Purpurina) Parroctus, D’Orbigny, 1847, Plate IX. 
Figs. la, 1b. 
1847. Turbo Patroclus, d’Orbigny, Prodrome de Paléontologie, vol. i. 
248 
p. 248. 
Syn. 1850. Purpurina Patroclus, @Orb., Pal. Frang. Terr. Jur. vol. ii. Gast. 
pl. 329, fs. 9-11. 
P 5 Purpurina Philiasus, d’Orb., Pal. Frang. Terr. Jur. vol. ii. Gast. 
pl. 329, fs. 12-14, as Turbo Philiasus in the Prodrome, 
vol. i. p. 248. ; 
1856. Littorina Patroclus, d’Orb. sp. Piette, Bull. Soc. Géol. France, 
2nd ser. vol. xiii. p. 587. 
1860. Hucyclus Patroclus, d Orb. sp. Eudes Desl. Bull. Soc. Linn. Norm. 
vol. v. p. 138. Ibid. Hug. Desl. op. cit. p. 135. 
non Purpurina subangulata, Mu. sp. Oppel, ‘‘ Der Jura,’ p. 386.' 
nec Turbo subangulatus, Munster, Goldtuss, Petref. Germ. vol. iil. p. 98, 
pl. 124, f. 5. 
Description.—Shell thin, elongate, conical, apex acute; whorls 
9, angular, screw-like, with a very prominent acute and crenulated 
keel, situated about two-fifths of the breadth of the whorl from the 
anterior suture; the whorls slightly concave and gently sloping from 
the keel to the posterior suture, more deeply excavated and steeply 
inclined inwards to the anterior suture; the sutures are bounded 
posteriorly by a raised simple spiral, anteriorly by a finely granulated 
one; the base is convex and faitly inflated, bearing five equidis- 
tant raised granulated spirals, between the middle three of which 
are two simple ones; the whole surface of the shell is covered 
with very fine spirals; the posterior border of the last whorl rises 
near its termination at the aperture, so as to slightly embrace the 
penultimate whorl: aperture ovate, a little oblique, the outer lip has 
its inner border considerably expanded, and its outer edge is thickened 
by a very narrow rim, and digitated by the keel and basal spirals ; 
columellar border with a thin shelly deposit, columella outwardly 
twisted anteriorly; a narrow umbilical slit; anterior canal a 
broad shallow groove directed obliquely outwards, and effuse in 
front; posterior canal a narrow groove concealed beneath the over- 
lapping portion of the last whorl. Length, 16mm. Greatest diameter, 
9mm. Spiral angle, 87° Sutural angle, 125°. Proportion of last 
whorl to whole shell, 7 to 16.? 
1 Oppel was evidently mistaken in considering Turbo Patroclus, d’Orb., as the 
equivalent of Turbo subangulatus, Mu. 
* Figs. la, 1b, accurately represent this form, except that in Fig. 1a the shelly 
callus on the inner lip should have been shown to continue as far as the end of the 
posterior canal, 
