﻿242 INFERIOR OOLITE AMMONITES. 



thinner, and yet have more convex sides — its outer area is more pinched, making 

 the ventral area narrower, and the carina more prominent — its inner margin is 

 certainly less marked, and, as a consequence, its umbilicus is much flatter and less 

 graduated — the suture-line has a somewhat differently-shaped, and shorter superior 

 lateral lobe. 1 



This form almost deserves a separate name. It is to a certain extent transi- 

 tional to Dum. radians, especially to the form figured PI. XLII, figs. 11, 12. 

 If the various figures be arranged in the following order they will, in a great 

 measure, show all the stages of progression from Dum. Levesquei to Dum. Moorei 

 — that is, from a gibbous, coarse-ribbed, evolute whorl to a compressed, fine- 

 ribbed, rather involute whorl :— PI. XLV, figs. 15, 16; PI. XXXVII, figs. 6, 7; 

 PI. XLII, figs. 11, 12; PI. XLII, figs. 6, 7 ; PI. XLIV, figs. 7, 8. This series is 

 exactly parallel to the series Gramm. toarcense, Gramm. striatulum, Gramm. mactra. 



I quite agree with Dr. Hang when he remarks that d'Orbigny's name 

 " Levesquei " is better known, and not likely to lead to mistakes, as would be the 

 case with the name " undulatus." The latter name was first used by Smith, in 

 1817, for Ammonites falcifer, Sowerby ; 2 and, in 1824, Stahl 3 applied it to an 

 Ammonite doubtfully identified with the present species.* I make the above 

 remarks upon the authority of Dr. Haug (see foot-notes), because all my efforts 

 to procure Stahl's work have failed. 



The Ammonite which Zieten figured as "undulatus" is probably this species; 

 but the figure is very poor. Dumortier undoubtedly referred to this species by 

 the name " undulatus. " 



This species is very scarce, and I have only been able to obtain inferior 

 fragments from Long Wood and Buckholt Wood near Stroud, and from Wotton- 

 under-Edge, Gloucestershire. Mr. Darell Stephens, F.G.S., procured the species 

 from the vicinity of Yeovil Junction. 



The type form is illustrated by a poor fragment depicted in PI. XLV, figs. 15, 

 16 ; and the variety, about which I have remarked above, is shown in PI. XXXVII, 

 figs. 6—8. 



1 Dr. Haug tells me that this form is identical with the examples found in the Rhone-basin. 



2 Haug, " Harpoceras ;" 'Neues Jahrbuch fur Mineralogie, &c.,' Beil.-Bd. iii, p. 662, 1885. 



3 ' Correspbl. wiirttemb. landw. Ver.,' Bd. vi, p. 49, fig. 10. 



* Haug, " Polymorphidae," 'Neues Jahrbuch,' Bd. ii, p. 130, 1887. 



