THE RED BED LIMESTONE. 138 



the cutting - of the canons of the outgoing drainage one could drive many 

 wagons abreast entirely around the Hills on this encircling limestone pave- 

 ment. At Warren Peaks, which exhibit in miniature all the main points of 

 the geological structure of the Hills, the limestone forrns also an encircling 

 slope. 



Underlaid by 75 to 100 feet and overlaid by over 200 feet of soft red 

 clay, the limestone rests between two cushions, so that in the uplifting of 

 the rocks at the time of the elevation of the mountains it was not shattered 

 and dislocated so extensively as if it had been inclosed between more rigid 

 strata. It is found bending and warping suddenly, especially about some 

 of the volcanic peaks, and conforming to all the little irregularities of the 

 outer slope of the Hills, without exhibiting any great fractures or disloca- 

 tions. Though it is usually A^ery fragmentary in its structure, filled with 

 cracks and joints perpendicular to its bedding, they seem rather due to its 

 composition and mode of weathering than to the bending of the strata. 



The color of the limestone is graj'ish, pink, or purple; it is somewhat 

 mottled and often deeply stained by the red filtration from the overlying 

 clay. It is hard and gritty, and is rarely massive, but usually thinly 

 bedded. A qualitative analysis was made by Dr. Ricketts, who reports that 

 "it contains lime, carbonic acid, iron as protoxide, alumina and silica, in 

 quantity; and traces of manganese, potash, soda, magnesia, and sulphuric 

 acid. It consists essentially of carbonate of lime, with some silicate of 

 alumina and iron (clay) ; has an odor when ground like Canada petroleum." 

 The fetid odor noticed b\' Dr. Bicketts is plainly discernible whenever the 

 rock is crushed or a fresh fracture is made. It is a common characteristic 

 of limestones and is believed to be due to the presence of organic matter 

 derived from the organisms — plants or animals — that inhabited the water at 

 the time of their deposition It is worthy of remark that with this strong 

 evidence of the presence of life at the time of the formation of this deposit 

 there should be such an absolute dearth of fossil remains. 



The rock appears to be quite soluble in water, for many of the springs 

 that flow from its base precipitate large quantities of calcareous tufa. 



Above this limestone is a great development of brick-red clay, that in 

 its ordinary exposures exhibits no lamination nor other evidence of sedi- 



