^^°^ ^- Grabau—Ordovician Fossils from North China (i) 91 



Genus GONIOCERAS Hall 



The presence of the genus Gonioceras in the Ordovician rocks of north China, 

 was first suggested by G. C. Crick* in his discussion of the fossils collected by Mr. 

 Samuel Couling, M.A., Editor of the China Review, south of Tsing-tshou-fu (Ching- 

 Chow-Fu) in Shantung. In his plate (fig. B) Crick gives a photographic reproduction 

 of one of the specimens which, if natural size, (the scale is not given) shows an 

 actinoceran shell with apparently empty cameras 2.2 mm. long, and a strongly nummu- 

 loidal siphuncle, the nummuli of which are 15.5 mm. in "diameter. He further refers to a 

 rubbing of another specimen, "about 25 centimeters long, displayed in section on the 

 surface of a slab". Commenting on these specimens, he says "although the relative 

 proportions of the parts of the shell, the relatively wide siphuncle and the very shallow 

 chambers, agree fairly well with those of Adinoceras imbricatum Hisinger, sp. from the 

 Silurian (Upper Ludlow) of the Island of Gotland, Sweden, it seems scarcely hkely that 

 an example of this species could be so worn down as to expose the siphuncle for a length 

 of 25 centimerers ".** Crick therefore refers his specimen to the genus Gonioceras Hall. 



I must confess that the evidence has seemed to me inconclusive, as the specimen 

 might have been an Actinoceras with the siphuncle near one side. Nor is the photograph- 

 ic reproduction given by Crick entirely satisfying, as it leaves many of the characters of 

 the specimen in an indeterminable state, especially the nature of the camerte. A 

 specimen in the Survey collection showing a similarly wide siphuncle and short camerse, 

 appeared to be related to the form described by Crick, but this too I was at first disposed 

 to refer to Actinoceras, as aside from the proportions, it seemed to show no very decisive 

 characters differentiating it from other species of that genus which occur in these rocks, 

 except the empty cameras, a feature not found in any other species of Actinoceras in the 

 Ordovician rocks of China. This led to a more careful study of the specimen, with the 

 result that several of the septa were found to show the true Gonioceras curvatures. This 

 settles the question as to the presence of the genus Gonioceras in the Ordovician of north 

 China, and it lends a strong measure of probability to the correctness of the interpretation 

 suggested by Crick, and to him must be given the credit for the discovery of this unique 

 organism in China, a discovery of very great importance, as already pointed out by 

 Ruedemann. For, as this genus is otherwise only known in the Chazy, Black River and 

 early Trenton of eastern and central North America, extending to the base of the Stones 

 River group in Tennessee, it places beyond the question of a doubt the former intimate 



» Geol. Mag. Dec. IV. Vol. X. pp. 483-484 pi. XXII, 1903. 

 ** loc. cit. p. 483. 



