14 
Pleurotomaria Tunstallensis , n. sp. This species resem¬ 
bles the P. Permiana in form, but it is non-umbilicated, and 
its pillar lip is oblique : it is also related to P. carinata, Sow., 
but instead of the umbilicus being closed “par une callosite 
assez epaisse et assez large,” as stated by de Koninck of the 
latter, it is without any callosity, and its pillar lip is trail- 
chant. Tunstall Hill. 
Nautilus Freieslebeni , Geinitz. Humbleton quarry, Tun¬ 
stall Hill, Silksworth, Dalton-le-dale, and Whitley. 
Gyracantlius formosus, Agassiz. The Newcastle Museum 
possesses a fragment of a fossil, which I am happy in making 
out to be an Ichthyodorulite or dorsal spine of an extinct 
family of sharks. It is the impression of the inferior part 
of the anterior face, shewing the entire length of the root and 
a small portion of the obliquely ridged part : the root is 
longitudinally striated, and the obliquely ridged part tapers 
off to a point on the mesial line of the anterior face : the 
point is an inch and a quarter from the termination of the 
root. I feel persuaded that it is the Gyracantlius formosus. 
Lower new red-sandstone near Westoe. 
Palceoniscus comtus, Ag. 
Palceoniscus elegans, Sedgwick. 
Palceoniscus glaphyrus, Ag. 
Palceoniscus longissimus , Ag. 
Palceoniscus macrothalmus , Ag. The foregoing species are 
found in nearly all the localities where the marl slate is ex¬ 
hibited, as at Midderidge, Thickley, Whitley, Cullercoat.s, 
Thrislington, Boldon, Ferry Hill, Houghtou-le-Spring, &c. 
Two imperfect specimens of the genus have been found in 
the magnesian limestone, north of Marsden. 
Palceoniscus angustus ? Ag. The Newcastle Museum pos¬ 
sesses a specimen from the marl slate, Whitley, resembling 
the fossil of this name figured by Agassiz, with this difference, 
that it has both lobes of the tail of the same length: in other 
respects, as the relative position of the fins, and the arrange¬ 
ment of the scales, it agrees with the P. angustus. 
