1872.] BLAKE TOEKSHIRE INPKALIAS. 141 



more numerous gastropods and fewer bivalves found at the latter 

 place ; for whilst there the proportion is 8 gastropods to 22 bi- 

 valves, at Cliff it is 7 to 38, 3 gastropods only being common to 

 both ; these, however, and the other common species being those 

 which are most characteristic of the horizon. It appears, however, 

 highly probable that the Marton fossils are from a slightly higher 

 part of the zone of Am. angulatus. 



The beds at Eedcar, when compared with those already described, 

 are very insignificant. On the shore at that place are seen narrow 

 ledges striking seawards, consisting of Lias shale hardened at the top ; 

 some few of the most easterly of these contain Am. angulatus and 

 other associated fossils. The beds above these contain Atn. BucTc- 

 landi; and no lower beds are anywhere visible, these being only 

 brought up by an anticlinal elevation, and the next beds visible in 

 the same direction being again higher in the series. As, however, 

 all these form part of what I have called the typical Yorkshire basin, 

 their character and contents are best studied in conjunction with the 

 other Liassic beds of that series, and are therefore here passed over. 



At Eston, not a mile from the Middle-Lias iron-mines, I saw, in 

 the refuse heaps of a gypsum-shaft, several impressions of Rhsetic 

 and Infraliassic fossils, from which we may conclude that the series 

 is complete in this neighbourhood. 



Heferences and l^oTES OjSt the Fossils. 



Plesiosaurus. Tooth not unlike that described by Owen as that of 

 P. rostratus. Lias Eeptiles, pi. 9. I. 4.* 



Ichthyosaurus. Vertebra, 1| inch diameter, probably from III. 18 ; 

 also a phalange ^ in. by | in. in the oyster-bands. 



Acrodus minimus (Ag.), Poiss. Foss. vol. iii. pi. 22. figs. 6-12. I. 4. 



Dapedius. Tooth. III. 14. 



Hyhodus (cf.) minor (xig.), Poiss. Poss. vol. iii. pi. 23. fig. 23. III. 

 16. 



Ammonites angulatus (Schl.), Petref. p. 70 ; Q,u. Jura, pi. 3. fig. 1. 

 The form of this, from Cliffy, diff'ers much in the narrowness 

 and number of the whorls from that from Pedcar. It is rare 

 full-grown at Clifi"; but small young specimens are commoner. 

 I. 2, 4. 



Am. Johnstoni (Sow.), M. C. pi. 449. fig. 1. There are two varieties of 

 this, not worth separating into species: — 1, the ordinary form, 

 with 28 ribs per whorl ; and, 2, one with 36 finer ribs. Com- 

 mon in all the upper beds. 



Am., planorhis (Sow.), M. C. pi. 448. fig. 1. III. 18 only. 



Nautilus striatus (Sow.), M. C. pi. 182. I. 2, 4 ; 11. 1 ; III. 1, 23. 



Trochotoma striatum (Horn.), Stoliczka, Gast. & Aceph. Hallst. Sch. 

 pi. 5. fig. 2. 1.4; II. 1. There are some smaller shells (those 

 in pit I.) which I think are the young of this. This has some 

 resemblance to Pleurotomaria trocheata (Terq.), but is less 

 depressed, and the aperture is more rounded. The genus may 

 be doubtful. 



* I. 4. indicates that the fossil is found in pit no. 1, bed 4. 



