os) Cincinnati Society of Natural History. 
Witches’ Rock, Eagle Rock, Hanging Rock, Conglomerate Peak, Sen- 
tinel Rock, Monument Rock, etc. Monument Rock is a regular 
obelisk of conglomerate, standing at the junction of the Echo with the 
Weber valley, and being about 250 feet high. Descending the Echo 
canon, the more rugged picturesque scenery is exhibited on the right 
hand, and descending the Weber the same lofty perpendicular walls; 
weathered here and there into all sorts of fantastic forms, continue to 
the Narrows, where the Weber river makes a bend to the left, and the 
conglomerates disappear. The whole series of these beds is referred to 
the Wasatch Group, and the thickness estimated at from 3,000 to 5,000 
feet, the conglomerate portion being from 1,500 to 2,000 feet. 
He proposed the name of the “ Sweetwater Group,” for a lake deposit 
found in the Sweetwater valley. There is a high ridge or divide, 
between the drainage of Wind river, North Platte, and Sweetwater, 
300 to 400 feet above the channels of these streams, which is com- 
posed ofthe Tertiary beds. The Sweetwater forms a distinct concavity, 
with this high divide on the north and east, and the valley has been 
scooped out so that until we reach the Sweetwater Canon, near the 
South Pass, only the massive granite ridges rise up among the modern 
Tertiary beds, which jut close up against their base. This is a valley of 
denudation, over a space of at least 30 to 50 miles in width. All the 
unchanged formations, from the lignite Tertiary down to the massive 
feldspathic granites, have been worn away, leaving the granites scat- 
tered over the valley in the isolated ridges. At that time there was a 
fresh-water lake which occupied the entire valley, much as Salt 
Lake once occupied the.great basin, concealing most of the granite 
ridges, while others rose above the waters like islands. Then was de- 
posited what he called the Sweetwater Group, or perhaps a series of 
beds identical with the upper portion of the Wind river deposits. 
These were scooped out again in time, and the Pliocene marls and 
sands were deposited; and then again there was another scooping out 
of the valley, and finally a covering of the hills with drift. 
The mountainous portions of Northern Utah* are full of beautiful 
park-like areas, which contain the evidences of an ancient lake. At 
Copenhagen there is a considerable drift or bowlder deposit with fine 
white or yellow marly sands and clays, in regular layers, showing the 
deposit to be Post-pliocene, and that the waters of the lake were com- 
paratively quiet. Near Box Elder Canon are two kinds of terraces, 
* U.S. Geo. Sur. of Montana, ete. 
