

CRETACEOUS AND TERTIARY—WHITE MUD RIVER. : 109 
are also abundant, though other fossils are extremely scarce. A few 
impressions resembling fish scales, but very obscure, were found; 
also a single specimen of Baculites compressus, being a cast of the interior 
of the shell in soft ironstone, with the impressions of two gasteropodous 
shells, which had fallen into its outer chamber. One of the latter is 
of naticoid type, with a short spire, and few volutions rapidly increasing 
in size. Not a trace of the calcareous substance of any of these fossils 
remains ; and the clay-shale shows in many places, obscure impressions, 
which apparently mark the former positions of other calcareous fossils, as 
in the shales of the Pembina Mountain series. ‘The fact that two shells 
of different species, were caught up in the body-chamber of the single 
Baculite, which owed its preservation to an ironstone concretion, taken 
in connection with the indications just mentioned, would tend to show 
that organic remains were originally somewhat abundant, but that they 
have been removed by chemical action in the way already noticed. 
267. Selenite in small crystals abounds, and is generally found 
filling the lines of fissure. Well-marked white bands indicate the 
the stratification lines in some places. They are occasionally several 
inches in thickness, and have evidently been bleached subsequently to the 
deposition of the clays, by the percolation of water charged with sulphuric 
acid, produced by the decomposition of pyrites, along the more permeable 
layers. 
268. Where the Line crosses White Mud River; * or, Frenchman’s 
Creek, numerous and very fine exposures of the Cretaceous rocks occur. 
The stream flows in the bottom of a great trough, cut out of the soft 
Cretaceous strata, over three hundred feet deep, and in some places fully 
three miles wide. Many ravines enter this valley from the sides, and 
numerous land-slips have brought down the upper beds to various levels 
in its banks, and have produced a rugged mass of conical hills and ridges. 
The tops of the banks on both sides of the valley are formed of yellowish 
ferruginous sands, referable to division y., of the Bad Land section. 
They are, in many places, hardened into layers of sandstone, and are 
nowhere very soft. Land-slips have confused the section, but they can 
be traced in their original position as far up and down the valley as can 
be seen. I could find no fossils in these beds, though sixty to seventy 
feet of them must be visible in some places. 
* There are probably half-a-dozen streams of this name in different parts of the North West. The 
best known is that at the south end of Manitoba Lake, with which this must not be confounded, 
