54 PROCEEDINGS OP THE ACADEMY OP [1884. 



the second lateral lobes with three teeth, the median one of 

 which is the longest. The saddles are simply rounded, and 

 exhibit, as far as can be seen in the specimen, no traces of crenu- 

 lation or denticulation along the anterior margin. 



This is the first Ammonite, as far as I am aware, that has been 

 detected in any American formation below the mesozoic series. 

 The association with it of characteristic palaeozoic forms of life, 

 such as Zaphrentis, Phillipsia, Bellerojjhon, Gonularia, Chonetes, 

 and Productus, leaves no doubt as to its position, and hence we 

 must conclude that here, as well as in India, where Waagen first 

 announced the occurrence of true carboniferous ammonitic forms, 

 the distribution of this highly characteristic group of organisms 

 was not so rigidly defined by the mesozoic line as geologists had 

 been led to conclude. That pre-mesozoic Ammonites will be 

 discovered elsewhere besides in India and Texas there is no 

 reason to doubt ; indeed, no assumption could be more illogical 

 than the contrary — and, therefore, the present discovery is in no 

 way specially surprising, and only rather interesting than impor- 

 tant. Special interest, however, attaches to this form, as through 

 it and the individuals or fragments of individuals that have been 

 found in the Tejon (Tertiary) rocks of California,' we have 

 established in this country the extreme range of the group 

 which it represents. 



As to the relationship of the species which I propose to desig- 

 nate Ammonites Farkeri, it may be stated that, judged by such 

 characters as the fragment presents, a position must be assigned 

 to it near to A. antiquus, Waag., from the Productus-limestone 

 (Salt-Range), of Kufri, India, described and figured in the Palee- 

 ontologia Indica (ser. xiii, pp. 28-9, 1879), of the Geological 

 Survey, and which Waagen refers to the genus Arcestes of Suess. 

 A comparison between the septal sutures of our specimen and the 

 Indian one shows a remarkable similarity, indeed, one might 

 almost saj'' identit}', existing between the two, the type of struc- 

 ture being practically the same. The principal difference seems 

 to be some very slight and unimportant modification in the lobal 

 dcnticulations, and the emargination or depression which exists 

 in the saddle, or rather in some of the saddles of the Indian 



^ Heilprin, " On the Age of the Tejon Kocks of California, and the Occur- 

 rence of Ammonitic Remans in Tertiary Deposits." Proc. Acad. Nat, 

 Sciences of Philadelphia, July, 1882. 



