GEOLOGICAL SURVEY OF THE TERRITORIES. 201 



fully examined, so as to determine the positions of any special horizons 

 which may be marked by special groups of fossils. Time did not per- 

 mit me to make so thorough examinations of the different beds as 

 such determinations would require. 



The finding of distinctively Quebec Group fossils, in such abundance 

 and through so great a thickness of strata, was a matter of considera- 

 ble interest, since this was, I believe, the first identification of this hori- 

 zon on the western side of the Eocky Mountain divide ; and, indeed, 

 but few specimens from that or any other part of the Silurian, had ever 

 been obtained from any part of the country west of Minnesota, Mis- 

 souri, and Texas. As no fossils were found in the lower limestones 

 at Ogden, the age of those beds was in doubt until the identity of 

 stratigraphical position and of lithological character showed that they 

 must be of the same age. The first examination of these Malade rocks 

 was made at a point where the section terminated below in a very 

 quartzitic sandstone, which occupied the relative position of the Pots- 

 dam, and was accordingly referred with doubt to that group in a letter- 

 extract which was published in the August number of the American 

 Journal of Science. Later examinations have shown that this was 

 really a part of the true Quebec, whose base is not here exposed. 



The valley of the Malade is broad and flat ; the stream itself is slug- 

 gish and mostly deep, with steep banks and muddy bed. At a few 

 points there is rock or gravel bottom, but crossings are few. The bor- 

 dering flats are rich, and considerable portions are well cultivated, pro- 

 ducing heavy crops of wheat and some corn. They are well watered 

 by numerous large springs, which burst up at various points, doubtless 

 being supplied by subterranean streams flowing through and escaping 

 from the limestones of the mountain. These are mostly pure and cold 

 springs ; but at one point near the stage-road, about a mile south of 

 Malade City, there is a low mound of calcareous tufa, surrounding a 

 small spring which is rather warm, but still drinkable. Only a small 

 amount of land has yet been irrigated about here. The ridge which 

 forms the western boundary of the valley is lower and more rounded in 

 outline than that upon the east. It was not visited, but the apparent 

 structure and color of its bare slopes render it probable that it also con- 

 sists of Quebec Group rocks. 



The old route across the divide, to the Snake Eiver Yalley, passed on 

 to the head of 'the Malade, and thence to the left and down Bannock 

 Creek. The stage-route now turns a little to the right at Malade City, 

 and crosses to Marsh Creek. Eollowing it, we camped at Keeney's Sta- 

 tion, four .miles above Malade City, and stopped over one day, June 28, 

 to examine the neighborhood. The side valley, which the road follows, 

 makes a broad break through the eastern mountain, up which the ter- 

 races extend, and connects with anarrower valley lying between this and 

 the nest range. Messrs. Taggart and Coulter accompanied Mr. Jackson 

 to the summit of the mountain north of the gap, found it to be the regular 

 continuation of that to the southward, and brought in a few character- 

 istic fossils. Mr. Adams accompanied me to the southward, where we 

 found the back-slopes of the mountain covered with Tertiary beds, con- 

 sisting mostly of thin-bedded, light-drab, clinking limestones, partly 

 pure, partly earthy, with some sillcious shales. Some of these beds 

 would probably make good hydraulic cement. A few minute ostracoids 

 and small, indistinct fresh-water gasteropods were the only fossils found. 

 From the summit of the mountain, it became evident that these Ter- 

 tiary beds extend up this back valley to that of Bear Eiver, and that 

 this crest formed two long, narrow islands in the old Tertiary lake. 

 The beds have a slight easterly dip. 



