384 DESCRIPTIVE GEOLOGY. 



On the lo-w foot-hills to the north of Parley's Park, enclosed within the 

 bend of East Canon Creek, and near Kimball's Station, is a small body of 

 brick-red trachyte, mostly concealed by debris from the Tertiary rocks 

 of the hills above. It has probably broken through the Jurassic or Creta- 

 ceous sandstones, which are found at the contact altered into quartzite. 

 This rock mineral ogically is like the usual type of the Walisatch trachytes, 

 being rich in crystals of sanidin", plagioclase, rather fresh brown horn- 

 blende, and biotite, often containing augite, and occasionally tridymite. 

 One variety is extremely porous, almost pumice-like, and very rich in red 

 bronze-colored mica, resembling somewhat in external appearance the pum- 

 ice-like leucite rock from the Leucite Hills in Wyoming. 



Weber Canon. — In the mountain-mass immediately north of Morgan 

 Valley, and in the canon of the Weber River above this valley, another 

 considerable portion of the Palaeozoic and conformable series of rocks has 

 been denuded of its Tertiary covering, so that the complete suite from 

 Cambrian up to Jurassic may be followed almost continuously. The section 

 afforded in Weber Canon, being nearly at right angles to the strike, presents 

 the best opportunity possible for the study of the series, and has served as 

 the basis of the division of the formations adopted throughout the range. 

 The mass of Morgan Peak is formed of beds of the Wahsatch limestone, 

 having a general north and south strike, and dipping to the eastward. From 

 the peak itself, about 200 or 300 feet below the summit, a few corals were 

 obtained, generally too poorly preserved for specific determination. Among 

 them the following were recognized: 



Syringopora multattenuata. 



Lopliojpliyllum proliferum. 



Biphyphyllumf 



Zaplirentis f 

 The lower beds of the limestone body which forms this peak are gen- 

 erally of a dark-bluish gray limestone, with occasional cherty bands. Near 

 the top, they are characterized by intercalated bed^.of granujar limestone, 

 some thin shales, and reddish calcareous sandstones, with one prominent 

 narrow band of purplish-gray quartzite. Directly east of the summit, there 

 is a slight depression, occupied by beds of a fine-grained, cream-colored 



