94 J. B. TYEEELL ON THEEE 



boine river, from the mouth of Arrow river to the A'iciuity of Oak lake, on the Canadian 

 Pacific Railway, and near the latter place was found to contain a few fragmentary fish 

 remains, with the shell of an Ostrea ?, and impressions of portions of the prismatic shell of 

 Inoceramus. Piof. Culver ' also states that similar shale outcrops as far south as La Moure, 

 near the south line of North Dakota, and that in it he succeeded in finding a few fossils, 

 the best an Inoceramus, and casts of a little Eaculite. These observations clearly prove 

 an extensive areal development for this series of brittle light grey clay shales, and also that 

 it belongs to the marine Cretaceous of the "Western Plains. As was stated in the introduc- 

 tion, it is overlain by the coarse Laramie ? sandstones of the base of the Turtle Mountains. 



No. 6. — A considerable flow of water was obtained from this thin baud of sandstone. 

 The almost utter absence of sandstone in the Pierre of this section is very noticeable, since 

 sandstone enters so largely into the composition of the same formation farther west. 



No. 1. — Apparently the same as No. 5, giving the Odanah series a thickness in this 

 well of 290 feet. 



Nos. 8 and 9. — In all probability these are both included in the Millwood series, 

 representing the lower dark-grey shales of the Pierre formation. The " boulders " are 

 nodules of calcareous ironstone such as are found in abundance in this formation on the 

 banks of the Assiniboine river, in the vicinityof Mill wood. Some shells of spiral gastero- 

 pods are stated to have been found at a depth of 845 feet, but none were seen by the writer. 



No. 10. — This band has been placed at the base of the Millwood series, which thus 

 is given a thickness of 664 feet, but some or all of it may more properly belong to the top 

 of the underlying Niobrara formation. If it were given the latter position it would 

 represent the band of dark unctuous clay with much carbonaceous matter, etc., that is 

 placed at the top of the Niobrara formation in Messrs. Meek and Hayden's Missouri sec- 

 tion. A specimen from 1010 feet consists in part of a soft blueish-grey clay shale, and 

 ill part of a light grey clayey limestone. Another specimen from near the same depth 

 contains a considerable amount of crystalline pyrite. 



No. 11. — A very dark grey soft unctuous and very slightly calcareous clay shale, 

 containing a few fragmentary remains of fishes, and at the top few foraminifera (Auoma- 

 lina sp.), with the cells filled with pyrite. Mr. Hoffmann, of this Survey, states that the 

 loss from this rock on ignition is 18 per cent, representing the amount of carbonaceous 

 matter and water in the dried material. 



This band has been placed at the top of the Niobrara formation in the section, as it is 

 the highest bed from which foraminifera have been definitely recognized. 



No. 12. — A mottled grey calcareous shale or marlite, containing, in varying numbers, 

 foraminifera, prisms of the shells of Inoceramus, fragments of fish remains, crystalline 

 masses of pyrite, occasional fragments of the pearly shells of Ostrea, and crystals of sele- 

 nite. The following list gives the results of the examination of the specimens from every 

 five (or ten) feet : — 



1075. Slightly calcareous shale, with fish remains, a few foraminifera, Inoceramus prisms, 



and crystals of selenite. 

 1080. Soft moderately calcareous dark-grey mottled clay shale, with small crystals ond 



crystalline masses of pyrite. 



' A report on the preliminary investigation to determine the proper location of artesian wells, etc. U. S. Senate 

 Document, No. 222, Washington, 1890, p. 59. 



