NO. a.j DESCRIPTION OK THE FOSSILS. 97 



A small fragment of the next succeeding whorl (PI. II, fig. 9 a) shows 

 of widely-separated, coarse ribs, running over the obtusely rounded ventral 

 remains area in a broad curve. 



The lobe-line shows the slender, high saddles, and 

 principal lobes characteristic of young Quenstedtocerates, 

 and in its slender second lateral saddle, it more closely 



Fig. 21. approximates the Marias, than the Lamberti form. The 



Quenstedtoceras ver- 



tumnutn Sintz. exceedingly deep external lobe is worthy of attention. 



Lobc-line of Pi. II. fig. The ^ smal , auxi | ja lob toge |her with the small 



9, at a height of the 

 whorl of 7.5 mm. second lateral lobe, form almost a kind of suspensive 



2 X enlarged. 



lobe. 



The present specimen is embedded in rusty brown weathered clay. It was 

 found near the margin of the glacier, NW. of Elmwood, 100200 ft. above the 

 sea, on July 12th, 1896. 



Remarks: The form here described agrees well in the shape of Ihe 

 whorls, in the sculpturing, and in the outward form, with Quenstedtoceras 

 vertumnum, described by Sintzow. It is somewhat more involute than 

 the above-mentioned form, but it cannot on this account be separated as a 

 new species. Quenstedtoceras vertumnum Sintzow is not identical with 

 Quenstedtoceras vertumnum (Bean ms.) Leckenby sp. 1 Sintzow mentions 

 indeed that Leckenby's species differs in its considerably coarser ribs, and a 

 further difference exists in the more angular section in Quenstedtoceras 

 vertumnum Leek. sp. Leckenby's vertumnum is probably only a modification 

 of a Quenstedtoceras Marice d'Orb. sp. with a wider umbilicus, leading on to 

 the still wider-ribbed Quenstedtoceras vertumnum Lah. 2 and Damon 3 . Niki- 

 tin 4 classes the latter forms and Quenstedtoceras carinatum Sintzow 6 (not 

 Amm. carinatus Eichwald 8 ) together as Quenstedtoceras Damoni Nik. 



1 J. Leckenby, 'On the Kellaway Rock of the Yorkshire Coast'. Quart. Journ. Geol. 

 Soc. London, 1850, p. 21. PI. I. fig. 3. 



3 J. Lahusen, 'Die Fauna der Jurassischen Bildungen des Rjasanschen Gonvernements'. 

 Mem. du Com. geol. St Petersbourg, vol. I. No. 1. p. 46, PI. IV. fig. 9 (not 8 = Marias 

 d'Orb. sp.). 



8 R. Damon, 'A Supplement to the Geology of Weymouth', etc., London, 1880. PI. 1. 

 figs. 3, 3 a. 



4 S. Nikitin, 'Rapports entre les C^phalopodes jurassiques russes et les originaux corre- 

 spondants dans les collections d'Europe occidentale". Bull, de la Soc. Belg. de G^ol. 

 etc., vol. III. 1889, p. 35. 



I. Sintzow, 1. c. p. 109. PI. I. fig. 4. 



8 E. d'Eichwald, 'Lethtra Rossica'. p. 1073. PI. 34, fig. 8. 



13 



