428 GEOLOGICAL EXCURSION TO THE BOCKI MOUNTAINS. 



Harding sandstone that in the section near Canyon City are concealed 

 by the overlap of the Harding sandstone. The section is as follows: 



Feet 



5. Fremont limestone (est im:ii «o 80 



•l. Hah sites limestone (estimate) LOO 



IJ. Barding sandstone 146 



2. Galoiferoos reddish limestone I 



1. Chert. v, reddish Camhrian limestone 28 



Characteristic Cambrian fossils were found in No. 1. and in 'So. 2 the 

 genera OpMleta and Bathyurw occur. 



The finest exposure of this series is found in Garden Park, north of 

 Canyon City, where a plateau formed by the Ilalysites limestone is 

 traversed by numerous canyons that cut down into the crystalline rocks 

 beneath the Cambrian. 



[Hv S. F. F.MMONS.] 



In the beds immediately underlying the Dakota sandstones about 

 10 miles north of Canyon City abundant Saurian remains of upper 

 Jurassic types [Atla/n&osaurus, Stegosaurm, etc.) 72 have been found. 



Prom Canyon City the road passes out upon the Great Plains, whose 

 surface from here to Pueblo is formed of the nearly horizontal clays 

 and limestones of the Montana and Colorado Cretaceous. A short (lis 

 tance southeast of Canyon City, in comparatively close proximity to 

 the foothills, a small synclinal basin of coal bearing Laramie rocks has 

 escaped erosion, and coal is actively mined, dust before reaching Flor- 

 ence the northern end of this basin is crossed, and the Laramie sand- 

 stones can be distinguished capping some high bluffs to the north of 

 the river. 



About Florence is an oil field whose product reaches 2,000 barrels 

 per day. The oil comes mainly from the Pierre shales of the Montana 

 Cretaceous, and is obtained from depths of 000 to 2.000 feet (27:»-(J10 m.). 

 The accompanying map (PL ix), from a paper on the Florence oil field, 

 by George II. Eldridge, 711 shows the geological structure of this region. 

 It is on a scale of 3 miles tcthe inch, or about ttoVtfg- The contours are 

 at vertical intervals of 25 feet. The letters indicating geological subdi- 

 visions are: A=Archean; 8= Silurian; 0= Carboniferous j T= Trias; 

 J = Jura; Kd = Dakota (Cretaceous); Kb = Benton; Kn = Niobrara; 

 M = Montana; Kl = Laramie Cretaceous; q=s Quaternary. 



Beyond Florence the rocks rise slowly, and the road follows the river 

 bottom a hundred feet or more below the level of the surrounding 

 plains. In the bluffs which border this bottom can be distinguished 

 the harder beds of Niobrara limestone, which rise and fall in gentle 

 undulations along the route. 



