CAMBRIAN PLATEAU. 413 



western, and the overlying limestones are found resting conformably 

 upon tlie quartzites at the same angle of 2" and 3°. In the region of 

 Blacksmith's Fork, the beds lie horizontally in isolated hills, rising several 

 hundred feet above the plateau level. An interesting feature in the 

 scenery of the quartzite summit is formed by the picturesque falls and 

 rapids found on the northern branch of Blacksmith's Fork before it 

 enters the main canon. There are several of these falls, the finest of which 

 is about 30 feet in height, whose waters break over a ledge of quartzite, 

 which is inclined 2° or 3° to the eastward, against the course of the 

 stream, while rapids occur along the river between the more abrupt falls. 

 The stream varies very considerably in width, running in narrow channels, 

 and, in part, forming small lakes or ponds, surrounded by green meadows. 

 The strike of the quartzite beds is approximately north 10° to 15° east. 

 A thickness of from 1,500 to 1,600 feet is probably exposed beneath the 

 Ute limestone, but the base is never reached. In lithological habit, these 

 rocks present a close resemblance to the Cambrian quartzites, as seen in 

 Ogden Caiion and other localities throughout the Wahsatch Range. The 

 different beds vary somewhat in texture, but are mostly fine-grained, of 

 a steel-gray color and slightly vitreous lustre where not concealed by the 

 discoloration of ferruginous material. The presence of iron in consider- 

 able amounts would appear to be highly characteristic of the Cambrian 

 formation. It occurs disseminated through the rock in thin seams or cracks, 

 and in small concretionary masses, usually, however, decomposed into yel- 

 low ochreous earth. In the stream-beds of the north fork of the Muddy, 

 and on the lower slopes of the ridges, were found fragments and rounded 

 pebbles of specular iron; also, in the Cambrian quartzite on Mill Creek, 

 which runs to Morgan Valley, similar fragments were found. It is not 

 improbable that future explorations may discover iron masses of consider- 

 able economic importance. 



In several localities in the Cambrian quartzite, but more especially in 

 the region of Muddy Canon, there were observed certain peculiar markings 

 and groovings, suggesting imperfect borings and tracks of worms, such as 

 usually have been described as worm-burrowings of the genus ScoUtJms. 

 They do not appear to be abundant, but where noticed were generally in a 



