247 



4. FROM THE " AGGLOMERATES," OR SUBDIVISION D. OF DR. G. M. 

 DAWSON'S REPORT. 



The only fossils collected from these rocks are three fragments, 

 apparently of the shells of Lamellibranchs, one of which looks rather 

 like a piece of the exfoliated valve of an Ostrea, but the specimens are 

 far too imperfect to admit of their specific relations being ascertained. 



5. FROM THE " LOWER SANDSTONES," OR DIVISION E. OF DR. G. M. 

 DAWSON'S EEPORT. 



CEPHALOPODA. 



SCHLOENBACHIA PROPINQUA. (N. Sp.) 



Plate 33, figs. 2, 2a, 2b, and 2c. 



Shell thin, strongly compressed at the sides, and distinctly keeled on 

 the periphery: maximum thickness about one-fifth of the greatest 

 diameter. Whorls about four, increasing rather rapidly in size in the 

 dorso-ventral direction, but very slowly at the sides : umbilicus about 

 one-third or more than one-third of the maximum diameter, with gently 

 sloping and obliquely convex sides : keel prominent, simple in the 

 largest individuals but more or less crenate in young specimens : aper- 

 ture nearly twice as high as wide, flattened at the sides, narrowly 

 subelliptical in outline, but emarginated below, though not deeply, by 

 the encroachment of the preceding volution. 



Surface marked by numerous and rather crowded flexuous costse 

 which extend from the umbilical margin to the keel and which are 

 most prominent on the outer half of the sides. In very young speci- 

 mens the ribs pass over the keel, but in larger ones they are distinctly 

 interrupted or cut through by it. Outer lip broadly concave at the 

 sides and produced on the periphery into an obtusely pointed beak, 

 whose lateral margins are obliquely concave. Septation unknown. 



Dimensions of the largest specimen, not counting fragments : maxi- 

 mum diameter forty-nine millimetres : greatest breadth or thickness, ten 

 mm. : width of umbilicus, as measured from suture to suture, eighteen 



