LOWER CRETACEOUS. 621 



Coast Ranges. The lower Knoxville beds contain a fauna closely related to that of the Mari- 

 posa, still with Jurassic types of Aucella, and with the same poverty of other animals. But 

 the upper Knoxville beds, while stUl retaining reminiscences of the boreal region in Aucella and 

 a few other forms, show a preponderance of life characteristic of more favorable conditions. 

 AuceUas of northerly habit mingle with cephalopods that did not belong in the boreal region, 

 and on the near-by land cycads abounded. The line between Jurassic and Cretaceous should 

 be drawn, not at the beginning of the Knoxville, but between the lower and the upper Knox- 

 ville beds; the former belonging to the Portland and AquUonian, while the latter belong to the 

 Neocomian. 



X, 10. JOHN DAY BASIN, OREGON. 



Merriam ^^'^° refers to exposures of conglomerate and sandstone on the west 

 side of the John Day Basin, from which good collections of fossils were obtained. 

 The outcrops appear to form opposite sides of a syncline, and include 3,000 or 4,000 

 feet of beds. The lower strata are said to "exactly duplicate" those of the Knox- 

 ville as it is usually developed in California and southern Oregon. Stanton has 

 identified the Chico fauna in Merriam's collections. 



L 12. SOUTHWESTERN AND CENTRAL, MONTANA. 



F. C. Calkins contributes the following notes from a manuscript for a folio on 

 the Philipsburg quadrangle, Montana : 



Both Lower and Upper Cretaceous are represented in the PhiUpsburg quadrangle, although 

 they have not yielded very satisfactory fossils. The Lower Cretaceous is represented by the 

 Kootenai formation, which may be described as follows: 



The yellow-weathering beds of the Ellis formation are generally overlain by a heavy reddish 

 sandstone, locally conglomeratic with well-rounded pebbles of quartzite like the Quadrant, 

 which is taken to be the base of the Cretaceous. This bed is generally succeeded by argillaceous 

 buff-weathering limestones, in the upper part of which have been found poorly preserved speci- 

 mens of the fresh-water gastropod Goniobasis which, according to Dr. Stanton, tend to indicate 

 a Kootenai age. Above these there are several hundred feet of maroon and gray-green sand- 

 stones and shales that have yielded no fossils. Near the top is a bed or several beds of gray 

 limestone crowded with shells of fresh-water gastropods. These gastropod limestones, which 

 are very conspicuous in the vicinity of Drummond, on the Northern Pacific Railway, seem to 

 be very widespread and highly characteristic of this horizon. They are probably the same 

 as those that in the Yellowstone National Park were referred to the Dakota. Above the gas- 

 tropod limestones are a few feet of calcareous shale and sandstone. On Mount Princeton, in 

 the Philipsburg quadrangle, there is a gradation to the black noncalcareous shales of the 

 Colorado formation; elsewhere the transition is more abrupt. 



These uppermost limestones have yielded two or more undescribed unios, one related to 

 U. douglassi Stanton, Gordobasisf increhescens Stanton, and Viviparus? sp. The fauna is 

 characterized by Dr. Stanton as probably upper Kootenai. 



The total thickness of the beds referred to the Kootenai is about 1,500 feet. 



The Cretaceous of the Great Falls coal field extends along the northern and 

 Northeastern flanks of the Belt Mountains. The Lower Cretaceous is represented 

 by the Kootenai formation and the Upper Cretaceous by Colorado and Montana 

 strata. The Morrison formation, which is doubtfully referred to the Jurassic by 

 Stanton and others, is described under the Lower Cretaceous by Fisher, '^^^ who 

 states: 



The Morrison formation, which is extensively exposed along the Rocky Mountain Front 

 Range in southern Montana and Wyoming, is also believed to occur along the northern base of 



