THE 



GEOLOGICAL MAGAZINE 



NEW SERIES. DECADE IV. VOL. I. 



No. X.— OCTOBER, 1894. 



I. — On a Collection op Jurassic Cephalopoda from Western 

 Australia — Obtained by Harry Page Woodward, F.G.S. 

 Government Geologist — with Descriptions of the Species, 



By G. C. Crick, A.E.S.M., F.G.S. , 

 of the British Museum (Natural History). 



(PLATE XIII.) 



[Continued from the September Ximiber, p. 393.) 



Ammonites (Sph^roceras, Bayle). 



Ammonites [SphcBroceras ?) Woodwardi,^ sp. nov. (PI. XIL 

 Figs. 6a and 6.) 



Sp. char.' — Shell (cast) discoidal, somewhat inflated, rather rapidly increasing. 

 "Whorls somewhat inflated, very convex on the periphery, less convex on the sides, 

 rounded near the umbilicus. Umbilicus moderately wide, occupying nearly one-third 

 of the diameter of the shell. Number of whorls and amount of inclusion unknown. 

 Height of outer whorl rather more than one-third of the diameter of the shell. 

 EaciEi whorl ornamented with about 20 short, thick, umbilical ribs, each of which 

 commences at the suture, extends radially or with a very slight forward inclination 

 over one-fourth of the width of the lateral area, and terminates in a radially- 

 elongated tubercle. Each tubercle gives rise to three, or more rarelv to two, 

 subangular ribs (in the cast), which pass uninterruptedly over the periphery. There 

 are about 48 of these ribs to a whorl ; at the periphery, the interspaces are twice the 

 width of the ribs. Length of body-chamber unknown. Margin of the aperture 

 prominent, provided on each side with an apophysis. Septa and suture-line 

 unknown. Test not preserved. 



Dimensions : — 



Diameter of the shell 60 mm. 



Width of umbilicus 20 



Height of last whorl 22 ,, 



Thickness of last whorl 16-}- ,, 



Since the fossil has been somewhat distorted, these dimensions must be considered 

 only as approximate ; the height of the outer whorl has probably been somewhat 

 increased, whilst the thickness of the whorl has been considerably reduced. 



BemarTcs. — The only example repi-esenting this species is a rather 

 crushed natural cast of the greater portion of the outer whorl, 

 much abraded on one side. The inner whorls are not visible, and 

 unfortunately there is no trace of the suture-line. A portion of the 

 mouth-border is preserved, and there are remains of the prominent 

 base of one of the lateral apophyses. 



' Not Ammonites Woodwardi, H. G. Seeley, Ann. Mag. Nat. Hist. [3], vol. xvi. 

 1865, p. 236, pi. xi. f. 3, which probably belongs to the section Hoplites, Neumayr. 



DECADE IV. — VOL. I. — NO. X. 28 



