172 GEOLOGICAL SURVEY OF THE TERRITOSIES, 



been directed away from it because of its being somewhat upturned 

 aj^aiust the Medicine Bow ridge of metamorphic rock lying just east 

 of it. 



From these four masses the country descends in slopes, which are 

 broken up into innumerable small ridges, to the main drainage of Wil- 

 low and Troublesome Creeks. There is a tendency throughout to a ter- 

 race form, but nowhere is it so pronounced as in the breccia " spoon " 

 above the Hot Springs. Just north of the White Face group, this is 

 partially due to the gentle northward dip of the beds, the inclination of 

 the surface being in the same direction, while the northern part of the 

 region is in the upper portion of the liguitic series, where there is less 

 difierence in the hardness of the beds, and hence less opportunity for 

 the erosion to create terrace forms. The tendency still exists, however, 

 the form of Park View being very graceful, the steeper slopes running 

 out in ilattish spurs to become rather abruptly steep again, but not at- 

 .taining escarped edges. The valleys of the Willow and Troublesome, 

 therefore, show forms characteristic of the geology of this lignitic re- 

 gion, and are very different from the forms of valleys elsewhere in the 

 district. Nowhere in the lignitic area are the streams bordered by low, 

 flat, terraced banks like the lake-beds adjacent to portions of the Wil- 

 liams Eiver and the Grand, nor do they flow in sharp-cut, rugged 

 caijons, as in archtean areas. Instead, a bottom usually but a few 

 times wider than the water-course accompanies the streams, often 

 marshy from the presence of beaver-dams, but not terraced, from which 

 steep slopes rise on either hand for several hundreds of feet in escarp- 

 ments which show the edges of the harder sandstones, with lesserslopes 

 of softer beds between, and finally merging by curves, rather than 

 abruptly, into a pretty general terrace-like level, rising on and on, per- 

 haps, with other indistinct terrace steps to the higher masses beyond. 

 In the Eastern or Willow Creek ridge these slopes run quite evenly to 

 the top. In the White Face mass the last slopes up to the lava are 

 abrupt and lined with some palisades of lava. The slopes up Park View 

 are steep but graceful, while the western mass is surrounded by great 

 palisades of black lava, white volcanic tuffs, and conglomerates eroded 

 into pinnacled forms, and looking down into the upper canons of the 

 Troublesome. The southern border of this great lignitic mass as it 

 occurs near the Grand River has been already described. 



In ascending Willow Creek from its junction with the Grand, and 

 after passing through the rounded hills of lake-beds, most of which 

 dip gently eastward, and the accompanying basaltic lava, as before 

 described, there is found crossing the stream about eight miles from its 

 mouth the same ridge of dolerite breccia that crosses the Grand at its 

 upper gate-way. About half a mile before reaching the principal ridge, 

 however, an outcrop of similar material (breccia, &c.) is found on the 

 east side of the stream, dipping 20° to the northeast, and just beyond 

 and between the latter and the main continuous breccia ridge, which 

 dips 60° to the northwest, are several outcrops ; also, on the east side 

 of the stream, of Cretaceous No. 5, here containing many fine cretaceous 

 fossils. The upper outcrops near the main ridge dip 20"^ northwest, but 

 following along them northeastward, they swing more and more east, 

 dipping north 10°, and appear as if they swung around to become con- 

 formable beneath the lower occurrence of the breccia. The dips are 

 given in the Hot Springs map, (Figure 10,) and would seem to indicate 

 a small local anticlinal, with the axis dipping north. These beds were 

 not directly traced farther northward along their outcrop. The main 

 breccia ridge, however, after crossing Willow Creek, appears to pass 



