THE REGION ABOUT GOLDEN. 89 



thickness of the Fox Bills is taken at between mid and 1,000 feet, the 

 Pierre has not been deposited for a long distance in the middle portion of 

 the region, having gradually thinned from the confines of the area toward 

 the center of Golden by successive losses of its lower beds. The Fox 

 Hills alone is of general occurrence, although its thickness also over the 

 central portion varies greatly and often. 



The Laramie. — 'Plic prominent feature of ihis formation is its remarkable 

 bend from a course approximately parallel to the foothills and to the 

 formations below to a broad, sweeping curve, by which it is gradually 

 carried to the westward until at Golden, its point of greatest deviation, it 

 lies between 2 and .'! miles to the west of its former course. The general 

 trend is slightly wavy, but with reference to the early Cretaceous and 

 older formations is of notable steadiness, passing all their individual 

 deviations without the least disturbance of its own. Its dip is vertical or 

 slightly overthrown for the entire length of the area under consideration, 

 and its basal sandstones form along their trend a characteristic series of 

 combs. 



Arapahoe and Denver. Tile formations allOVe tile Laramie, although ill 



reality markedly unconformable with it and with each other throughout the 

 broad area over which they have been deposited, nevertheless in the present 

 tract so closely follow the former in strike and dip that they display no 



peculiarities worthy of note in the present discussion, and, in fact, are only 

 incidentally connected with the special geological history here discussed. 



--I Kiel ORAL FEATURES. 



Dips. — A geological cross-section along Hear ('reek would present a 

 gradual increase in the dip of the several formations from the Arcliean 

 outward at a rate about as follows: 35' E. for the Trias; 38 to 10 for 

 the Dakota, Kenton, and Niobrara; I.V tor the lower part of the Pierre, 



increasing to 55 to (;."> ' in the upper part; 65 to 80 \v base to 



summit for the Fox Hills; and SO to 90 c and overthrown tor the Laramie, 

 Arapahoe, ami lower members of the Denver formation. Three or four 

 miles north of Bear Creek, in to 1.V may lie added to the lesser of the 

 foregoing dips, while from Coon Gulch to the vicinity of the hogback first 

 north of Golden the formations of higher dip, having now become vertical 



