98 THE GLACIAL LAKE AGASSIZ. 



where they are found it may be taken for granted that the lignite-bearing formation 

 has either been removed by denudation or has from the first been wanting. Though 

 usually in appearance quite horizontal, these beds must have a slight westerly dij), 

 which carries tliem beneath the Lignite group of the Souris Eiver.' 



Since this was written, Mr. J. B. Tyrrell has examined the Fort Pierre, 

 Niobrara, and Lower Cretaceous formations in this district, as ah'eady cited, 

 and has determined their thicknesses, chiefly made known by deep well 

 borings. Rocks belonging- to the Niobrara formation have also been 

 examined and described by Director Selwyn, of the Geological Survey of 

 Canada, on the southeast or right bank of the Assiniboine, in section 36, 

 township 8 north, rang-e 11 west, about 4 miles east from the mouth of the 

 Cypress River, at an elevation approximately 950 feet above the sea. "The 

 outcrop extends along the bank of the river for about 500 yards, and con- 

 sists of beds of highly fossiliferous sandy limestones, brown freestone, and 

 dark, almost black, soft shales. The sandstone and limestone, when broken 

 or struck, emit a strong odor of petroleum."^ 



From my own notes of this locality I may add that the most conspicu- 

 ous stratum, in which some quarrying has been done, is a light-yellowish, 

 hard, sandy limestone, exposed from the low-water line of the river to a 

 height of about 8 feet. It is horizontally stratified in layers from an inch 

 to a foot in thickness. Fossil shells, chiefly Ostrea congesta Com-ad, occur 

 frequently tlu-oughout its whole thickness, being most abundant 3 or 4 

 feet below its top, where they sometimes form nine-tenths of the rock. 

 With these are occasional specimens of Belemnitella manitobensis, a species 

 recently described by Mr. Whiteaves.^ This stratum along the greater part 

 of its extent is overlain by till 20 feet or more in thickness, which in turn 

 is overlain liy the delta deposits of gravel and sand that the Assiniboine 

 here brought into the west side of Lake Agassiz. But at the south end of 

 its exposure, where the limestone sinks beneath the river, it is seen to be 

 conformably overlain along a distance of some 25 rods by soft, dark shale, 

 probably the base of the Fort Pierre formation, portions of which contain 



' Geol. and Nat. Hist. Survey of Canada, Report of Progress for 1879-80, pp. 14, 15 A. 



'^Ibid., Annual Report, new series, A^ol. I, for 1885, p. 38 A. 



3 Ibid., Contributions to Canadian Pal»outology, Vol. I, p. 189, PI. XXVI, 1889. 



