GEOLOGICAL SURVEY OF THE TERRITORIES. 465 



12. Bathy lints, or Dilelocephalus .. .Fragments. 



13. BathyurcUus {Dlkelocephalus {'!) 



truncaUis, Meek Described iu this report. Occurs also 



at Flat-Head Pass. 



14. Asaphus (AFegalaspis (?) gonio- 



cercus, Meek Described in this report. Occurs at 



Fhit-Head Pass. 



WEST FACE OF BIG HORN MOUNTAIN, HEAD BUFFALO FORK. 



Names. Remarks. , 



1. ' Conoco7'yphe, and, -perhaps, BUce- 



locephalm* , . . Mere fragments. 



CARBONIFEROUS SPECIES. 



OUTLET OF MYSTIC LAKE, MONTANA. 



Names. Remarks. 



1. Zaphrentis A small species. 



2. Zaphrentis ., Fragment of a large species appar- 



ently of this genus. 



3. Ptilodictya {Stictopora^) dicty- 



ota, Meekf 



4. Ftylodictya A merely branching species. 



5. Fenestella One or two species. 



Q. Hemipronites cremstria,'Phil\i\)s.'Rather more finely striated tluin 



usual. 



7. Chonetes An abundant medium sized species 



with very fine, dichotomous, radi- 

 ated strise, crossed by very minute 

 concentric striae ; spines of cardi- 

 nal margin, five on each side of 

 beak. 



8. Productus longispimis, Sowerby .A small form, apparently agreeing 



with Sowerby's species. 

 d. Productus scahricidus, Martin (?). Specimens fragmentary. 



10. Bhynchonella. 



11. Spirifer, {Martinia) Of medium size. 



12. Spirifer {Martinia) Uneata,Miir- 



tin. 



13. 8x)irifer Similar to some varities of S. incre- 



hescens. Hall, which Mr. Davidson 

 thought not distinct from S. hisul- 

 cata, 



* The only part iu the collection certainly kno-vrn to belong to this species is the 

 pygidium. This has much the general appearance of the corresponding part of atrilo- 

 bite, figured by Mr. Billings, under the name of Asaphus qitadraticandatiis, (Paleout., 

 Canada, p. 271, Fig. 258,) but its lateral margins are straighter and its mesial lobe 

 proportionally longer, with only three to five segments that pass straight across, in- 

 stead of eight or nine arching forward. Its lateral lobes show three or four short seg- 

 ments, instead of only one, while they and the lateral margins show no traces of the 

 stria) seen on Mr. Billings's species. Its lateral and posterior flattened margins are 

 more suddenly defined from the swell of the lateral lobes. 



t An anastomosing species, with divisions about 0.10 to 0.12 inch iu breadth, by 0.04 

 to 0.05 inch in thickne.ss, and connecting so as to form a reticulated structure, with 

 fenestrules of a more or less oval form, about 0.24 inch in length by 0.16 inch iu breadth. 

 Pores small, with slightly raised ma gins, having the usual (piincnncial arrangement, 

 and forming six to eight longitudinal rows; uou-poriferous margins rather sharp, and 

 of moderate breadth. 



30 G S 



