418 DESCRIPTIVE GEOLOGY. 



of occupation by the waters of the ancient Lake Bonneville, which pene- 

 trated Cache Valley by the "Gates" at its northern end, just beyond the 

 limits of the map. 



Copenhagen Valley, so named from a little Danish settlement of that 

 name, which lies at the head of Box Elder Cailon, has an elevation of about 

 5,000 feet above the sea-level, and 750 feet above the present level of Salt 

 Lake, It was, therefore, covered by the waters of the ancient lake, although 

 the terrace-lines are less conspicuous than in either Cache or Ogden Val- 

 leys. A large portion of its area is covered with recent Quaternary deposits 

 of very unequal thickness, with exposures showing clearly the fine white 

 sands and conglomerates of the Tertiary beds, which have been, like those 

 of the other lake- valleys of the Northern Wahsatch, referred to the Hum- 

 boldt Pliocene. 



Ogden Valley, in its general features, is not unlike Cache Valley. It 

 is, however, much smaller, measuring about five miles in width by six 

 in length. The surface of the valley appears to have a much laj'ger 

 deposit of coarse Quaternary material than is found in Cache Valley, 

 which may in part be owing to the quartzite slopes on the surround- 

 ing mountains, which have sent down an immense amount of rubble and 

 fragmentary debris covering the surface of the ground, so as to render 

 it for the most part unavailable for agricultural purposes. Beneath these 

 Quaternary deposits, however, especially on the north and east sides, may 

 be seen, underlying the sandstones and limestones, fine conglomerates, 

 which bear a marked resemblance to the beds of Cache Valley, though it 

 is necessary to bear in mind that, owing to the close proximity of these 

 beds to the high mountain-ranges, they have in each case a somewhat local 

 character. These beds also have been referred to the Humboldt Pliocene, 

 although it should be stated that they are too far removed from any well- 

 defined Humboldt formations to trace any direct connection, and palseonto- 

 logical evidence is yet too meagre to throw any important light on the 

 question. The lake-terraces can here also be traced with more or less dis- 

 tinctness. The divide between Ogden and Morgan Valleys reaches an 

 altitude of about 900 feet above the Weber Eiver, measuring some 7 

 miles from valley to valley, with a width between the two high mountain- 



