350 DESCEIPTIVE GEOLOGY, 



color, more compact, and heavily bedded. No fossils of a lower horizon 

 than the Coal-Measures were found, though it is probable that along the 

 base of the main ridge the Sub-Carboniferous beds of the Wahsatch lime- 

 stone could be detected by a more careful examination. The hills forming 

 the outlying shoulder to the west are in general covered with soil and 

 debris, and no details of their structui-e were obtained other than that the 

 general dip of their beds is eastward, though toward the northern end of 

 the ridge a western dip may be recognized in the extreme foot-hills. 



Ameeican Fork Canon is a still more narrow and precipitous gorge 

 than Provo Canon, but its course is also more sinuous; in its central portion, 

 the limestone walls tower up thousands of feet, almost perpendicularly, above 

 its bottom. Since it was visited by our parties, a narrow-gauge railroad _ 

 has been built through it to connect with the mines near its head, and much 

 of the picturesque beauty due to the groves of poplar and pine, which 

 nestled in its secluded nooks, doubtless destroyed. The upper portion of 

 the canon, beyond the main high ridge, runs approximately with the strike 

 of the beds, but, in its lower portion, it crosses them almost at right angles. 

 At its western mouth are found beds of massive, compact limestone, with 

 others of a more shaly character dipping westward, and having a strike 

 somewhat west of north. The western dip holds for about 2 miles up the 

 caSon, when a body of white and pinkish saccharoidal quartzite is found, 

 which forms the axis of a gentle anticlinal fold. This quartzite contains 

 almost no lime, as is generally the case with those of the higher bodies. It 

 gave, by analysis, nearly 90 per cent, of silica, the impurities being mostly 

 alumina. To the eastward of this, the limestones come in again, dipping 

 gently eastward, and showing on the face of the cliff evidences of the ver- 

 tical movements, which must have lifted up the ridge of Timpanogos, in the 

 contortions and dislocations which have twisted and broken beds of massive 

 limestone, hundreds of feet in thickness. The fossil remains, fragments of 

 Prodiictus, jEuomphalus, and Crinoid columns, obtained from these limestones, 

 though too poor for specific identification, were considered sufficient at the 

 time of our visit to determine the Carboniferous age of these beds. With 

 the experience which has been since gained, a careful search, more particu- 

 larly in the beds immediately overlying the quartzite, which is without doubt 



