LOWER CRETACEOUS. 623 



Kootenai coal, to which Weed had assigned a thickness of 736 feet, is in reality only about 300 

 feet. According to the present classification the lower 120 feet of these beds has been assigned 

 to the EUis; an equal thickness immediately overlying, in which fresh- water invertebrates and 

 land animals occur, to the Morrison; and the upper 60 feet, which is plant bearing, to the 

 Kootenai. * * * 



The Kootenai has the greatest areal distribution of aU the formations outcropping within 

 the area. It caps the surface for a great part of the district lying between Smith River and 

 Belt Creek and is the surface formation of the high plateaus south of Otter Creek. Beyond 

 Otter Greek it is exposed ae a band of varying width which narrows toward the east. 



Fisher gives columnar sections measured along the Belt Creek valley which show 

 the character and thickness of the several formation^. As to fossil evidence and 

 correlation he states : 



The Kootenai formation of the Great Falls district carries an abundant fossil flora of Lower 

 Cretaceous age. Fossil plants of Kootenai age were first discovered in the Great Falls coal 

 field in 1889 by J. S. Newberry. From these fossils, which consisted of only a few species, it 

 was possible to correlate the rocks of the Great Falls region with the Kootenai north of the 

 international boundary Hne, described by George M. Dawson. * * * 



During the present investigation fossU plants, aU of which were studied and reported on 

 by F. H. KJnowlton, were collected from five different horizons — 15, 60, 70, 150, and 300 feet 

 above the base of the Kootenai formation. * * * ^he collection * * * ^g jjq^ large, 

 but it is of unusual interest in that it contains a number of species before unknown in the 

 Kootenai beds of this age; it contains also a species of the genus Protorhipis not previously 

 found in North America, as well as some believed to be new to science. 



In addition to the plants, some fresh-water invertebrates were collected from the upper 

 part of the Kootenai during the investigation. * * * These fossils are too imperfect for 

 positive identification, but the species with which they are compared occur a few miles south 

 of Harlowton, Mont., in beds that belong to either the Kootenai or the Morrison. 



M 10. WASHINGTON AND BRITISH COLtTMBIA. 



A belt of Cretaceous strata crosses the international boundary from Washington 

 into British Columbia. The rocks were described by George Otis Smith "^^ in 1904 

 and by Camsell ^^^ in 1907. The following is quoted from Smith's account of the 

 eastern belt on Pasayten River. Camsell's description is briefer and to the same 

 effect. 



Prof. Russell, in his reconnaissance of 1901, examined an assemblage of folded sedimentary- 

 strata in the neighborhood of Barron and Crater Pass." From these rocks he collected fossils 

 which are conmiented on in the following extract from his report : 



"A thick bed of bluish sandstone at the base of Gold Ridge, penetrated by the tunnels of 

 the St. Paul and Minneapolis mines, contains fossil ferns and nearly upright tree trunks. One 

 sample of fern collected has been determined by F. H. Knowlton as approaching closely 

 Dryopteris cerstedi, from the Cretaceous rocks of Greenland. A siliceous limestone in the same 

 ridge, but several hundred feet higher in the series and extending southward to the border of 

 Crater Pass, is abundantly charged with bivalve shells, which, as determined by T. W. Stanton, 

 are of a species of Actseonella. The evidence furnished by the fossils just mentioned indicates 

 a Cretaceous age." 



The authors of this paper found that these Cretaceous beds extended eastward along their 

 route to the Hidden Lakes and were very extensively developed to the north, and believe that 

 they extend west to a point not far above the mouth of Granite Creek. In this, however, they 

 differ from Prof. Russell, who believes that the slaty rocks with steep dips exposed along lower 



o Rusaell, I. 0., Geology of Cascade Mountains: Twentieth Ann. Rept. U. S. Geol. Survey, pt. 2, 1900, pp. 114-117. 



