404 H. Wood — Cretaceous of JS 1 orthwestem Montana. 



east and west while the range west of the Flathead at the 

 boundary has a northwesterly trend, the rocks as noted by 

 Dawson, " greenish close-grained quartzites* and red sand- 

 stones " being altogether likely the same geological horizon as 

 those farther south.f He notes, however, farther west " a 

 hard greenish amygdaloidal diorite." If such intercalations 

 are present south of here they escaped my notice. 



The Cretaceous beds rest with their upturned edges against 

 the greenish gray quartzose slates of the Cambrian. It consti- 

 tutes a series of clays, clay shales, coarse and fine-grained 

 sandstones of about 7,500 feet in thickness;}: corresponding 

 with that of the North Kootanie series. At the base of the 

 Cambrian range the dip of the Cretaceous is 50° E N.E. and 

 If miles north across the strike the dip is 8° and 10° 

 E.N.E., this section at Coal Creek showing the greatly 



Section at Coal Creek. 



1. Cambrian. 4. Grave] Deposits. 



2. Cretaceous. 5. Flathead River. 



3. Carnb. Dev. Sub-Carb. (Rockies). 



denuded southern margin of a synclinal fold. The basal por- 

 tion of 1,000 feet of the series is coal-productive, exhibiting 15 

 or 20 seams of lignite. The upper portion of the series con- 

 sists of heavily bedded sandstones with shaley partings with 

 some small seams of impure lignite. A phenomenal local 

 thickening! of the coal seams was observed two miles south- 



* Dawson : Rep. 1886, p. 55. 



f One hundred miles directly south of this in the vicinity of Missoula, a few 

 fossils were obtained m the siliceous limestone (dolomite) identified by Mr. Chas. 

 Schuehert as Obolella. One or two fossils were found in the red semi-argilla- 

 ceous slates also but are not yet identified. 



% This is the result of a tape line measurement and foot traverse made at Coal 

 Creek. 



§ Coal 6 inches. 



Clay shale 16 •' 



Coal 33 " 



Clay shale 6 " 



Coal 45 " 



Sandy clay 96 " 



Coal 2 " 



Clay 3 



Coal .. t " 



Clay 3 " 



Three additional seams of coal outside the tunnel aggregated 12 feet- 



Coal 22 inches. 



Free Sandstone 77 " 



Coal.-- 3 " 



Clay shale 58 " 



Coal 40 " 



Clay 38 " 



Coal \Z\ feet. 



Clay 21 inches. 



Coal 48 " 



