sr. john.] BLACKFOOT RANGE CARBONIFEROUS. 341 



not so clear. Their tilted condition points to a time of elevation, but 

 whether it was contemporaneous with that which uplifted the Carbon- 

 iferous beds, or whether it marks a later period of elevation in the range 

 or subsidence in the basin area along its eastern foot, our examinations 

 failed to show. To the south, where we touched, the range, the slopes 

 lie over debris and volcanic deposits which effectually conceal the un- 

 derlying rock strata, until gaining the higher portions Avhere the Car- 

 boniferous again appear, and which constitute the bulk of the range 

 throughout. 



South of the Wolverine gorge, 4 or 5 miles, the range is again cut by 

 Elder Creek Gallon, a branch of which also rises in the range just south 

 of Station VII, in which similar exhibitions of Carboniferous limestones 

 were observed. In the summit of Station VII a thickness of a hundred 

 feet or more of dark bluish and gray, spar-seamed, cherty limestone is 

 exposed, the ledges dipping west of south at an angle of 30° to 40°. To 

 the north the strike seems to trend more to the northeast, at one point 

 noted, E. 15° to 25° jS"., the strata uniformly dipping to the southward 

 at angles ranging from 2o° to 40°. A heavy, even-bedded, dark bluish- 

 gray, rather coarse, even-textured limestone, with drab thin-bedded or 

 shaly partings, forms the upper 50 feet of the summit, and is charged 

 with fossils of a Lower Carboniferous fades, a large and small species of 

 Zaphrentoid corals, Chcvtetes f SStictopora, Fen-esteMa, Polypora, tSpirifer, &c. 

 On the surface of a layer only a few feet below the crest, exposed in a 

 narrow shelf on the northeast side of the ridge, a few species of Selachian 

 teeth were found, representatives of the genera Antliodus, Petalodus, 

 Cladodus, Helodus, and fragments of JMtodus. The discovery of the 

 latter fossils, forms with which I had previously acquired some familiar- 

 ity, was like meeting old acquaintance ; and to one familiar with the 

 occurrence of similar remains in the Lower Carboniferous rocks of the 

 Mississippi Valley, their presence here afforded nothing in contrast with 

 their abundant prevalence and association in some of the lower members 

 of the earlier period of the Carboniferous in the region of the Upper 

 Mississippi. Indeed, the occurrence of the fossils, as also the lithological 

 character of the rock, to say nothing of the specific relations of the cor- 

 als, mollusks, and fishes, is so like what obtains in the Keokuk lime- 

 stone of the east as at first thought to preclude the supposition of mere 

 resemblances instead of actual identity. But, unfortunately, it was not 

 possible to ascertain with precision the exact position of these deposits 

 in the few thousands of feet which sum up the thickness of the Carbonif- 

 erous rocks of this region ; more than that the present beds undoubtedly 

 occur low in the series, and their contained fossils have not as yet afforded 

 a single form peculiar to the Upper or Coal-measure division as it is 

 recognized in the Western States. In the instance of the fish-remains 

 above alluded to, the facts are still more strongly in favor of the Lower 

 Carboniferous age of these beds ; one of the genera, Antliodus, being 

 confined in its vertical range to the lower division, while of the other 

 forms found not one is referable or even nearly allied to Upper Carbon- 

 iferous species. 



The whole southwest slope of the mountain at this locality is composed 

 of a facing of Carboniferous limestone. The steep slopes lower down are 

 strewn with more or less water- worn debris, consisting of limestone; red- 

 dish sandstone, and quartzite pebbles, which in the debouchures of the 

 little streams are molded into terraces. At the foot of the ridge the 

 country rapidly slopes away and soon enters the region of the bordering 

 volcanics which fill the Blackfoot Valley at this point, and which rise in 

 long, grassy ascents into the smooth, rounded hills capped by trachytes 



