230 J. B. Tyrrell — Cretaceous of Manitoba. 



exhibit any very great thickness, generally ranging from 100 

 to 150 feet. In the Manitoba Oil Co's bore on Vermilion 

 River it appears to have a thickness of 130 feet. Its total 

 thickness is very rarely seen, but on North Pine Creek it is 

 less than 400 feet and possibly is not half that thickness, while 

 on Bell River on the eastern face of the Porcupine Mountain 

 it is probably less than 250 feet. In the Swan River Valley, 

 however, a total thickness of 470 feet in all was seen, and it is 

 not improbable that the lowest 70 feet was not seen, giving for 

 this locality a total thickness of 540 feet ; the strata are very 

 nearly or quite horizontal, and this must be regarded as a local 

 thickening of the formation. 



Grading upward from the top of the Niobrara Group, the 

 Pierre shales are seen to occupy the summits of all the higher 

 lands of the Riding, Duck and Porcupine Mountains. In the 

 Riding Mountain and farther south the Pierre is found to be 

 moderately well marked off into two subdivisions. The lower 

 subdivision, which for convenience may be designated the 

 Millwood Series, is composed of dark gray soft clay shales 

 very similar to those already described by Dr. Dawson, Mr. 

 M'Connell and the writer from Alberta and Assiniboia. These 

 beds are well shown at the village of Millwood on the Assini- 

 boine River close to the crossing of the Manitoba and North- 

 western Railway, and here as elsewhere they include a con- 

 siderable number of septarian nodules of ferruginous limestone. 

 These nodules hold many beautiful specimens of typical Pierre 

 fossils, such as Scaphites nodosus var. quadrangular is, Lucina 

 occidentalis, Baculites compressus, Pteria linguiformis, Ino- 

 ceramus tenuilineatus, I. Sagensis var. Nebrascensis, Nucula 

 sp., Entalis paupercula, Dentalium gracilef elytron of a 

 small beetle, and fragments of scales of fishes and tests of crus- 

 taceans. Professor H. Y. Hind has also recorded, probably 

 from this series, Anomia Flemingi, Inoceramus Canadensis, 

 Leda Hindi, Lunatia obliquata, Cinidea concinna, and an 

 undetermined species of Ammonite. 



On the face of the Duck and Porcupine Mountains in the 

 valleys of North Pine and Bell Rivers, a dark gray clay shale 

 is exposed about the base of this series, which also contains a 

 large number of beautifully preserved Radiolaria, chiefly of 

 the genera Dictyomitra and Sethocapsa f the former genus 

 being represented by D. multicostata Zittel, described from 

 the chalk of Brunswick. 



These dark gray clay shales are overlain by a great thickness 

 of light gray rather hard clay shales which are locally known 

 as " slate," and which from their typical development at 

 Odanah, near Minnedosa, on the Little Saskatchewan River 

 may be called the Odanah Series. Throughout the series are 



