215 



degree both in the character of the fossils aucl in physical appearance. 

 This Niobrara occupies a belt of the country next adjoiniug the Plio- 

 cene, about thirty miles in width in the northern part of the State, but 

 gradually widening to more than twice that extent in the Smoky Hill 

 Valley. At the latter district, it extends from the western line of Ellis 

 County to the Colorado boundary. It is composed of chalk and chalky 

 shales. The former is of various shades of color from buff to pure white, 

 and is seldom sufficiently hard to be used as a building-material. Some 

 of the buildings at Fort Wallace were constructed of it, but did not 

 prove substantial. The whiter portions are almost pure carbonate of 

 lime, and cannot be distinguished from the best specimens of foreign 

 chalk. Professor Dana, in the last edition of his .\lanual of G-eology, 

 p. 455, says there is no chalk in Xorth America except in Western 

 Kansas. 



G. E. Patrick, professor of chemistry in the Kansas University, has 

 published, in the Transactions of the Kansas Academy of Science, an 

 article on this chalk, from which we extract the following remarks, with 

 his analyses : 



Examined under tlie microscope, it appears perfectly amorphous— a simple aggrega- 

 tion of shapeless particles. The Rhizopod shells, which almost universally occur in the 

 chalk of the Old World, sometimes comprising nearly its entire substance, seem to be 

 quite wanting in our Kansas chalk. With a good microscope, and a high power, I 

 have been unable to detect a trace of them. 



The amount of impurity varies, of course, in different samples of the chalk, but in no 

 specimens that I have seen does this amount exceed 15 or 16 per cent. Two 

 samples yielded, upon analysis, the figures given below. No. 1 was a fine specimen of 

 snowy whiteness ; No. 2 had a little yellowish tinge, and was as poor a sample as I 

 could select. 



Xo. 1. iTo. 2. 



Moisture .34 .58 



Insoluble in acids (silica, lime, and alumina) .69 11.40 



Alumina (little oxide of iron) 43 .97 



Ferrous carbonate .14 2.53 



Calcium carbonate ; 93.47 84.19 



100.07 99.97 



This chalk is found at various strata, in thickness varying from one 

 to eight feet. It differs in purity and other features, in the same 

 stratum, in different localities. Unlike the European chalk, it never 

 contains flint nodules. 



The shales of this division contain lime mingled with clay and sand 

 in varying proportions. They are harder than the chalk, requiring the 

 pick in extricating the fossils. They are of all shades of slate-color, 

 sometimes bleaching on exposure to the weather. Near Fort Wallace, 

 some strata are so much like the Benton in Nebraska, that Professor 

 Hayden,- on a hasty inspection, mistook them for a portion of that 

 group. (Final Eeport on Nebraska, p. G8.) 



These shales, in some localities, are traversed by seams, from one to 

 six inches in thickness, of firm, pure calc-spar, usually in flat crystals. 

 Inclosed in these seams are small crystals of barite. At Sheridan, Wal- 

 lace County, we find the latter spar in the dark shales. One beautiful 

 crystal, of a rich amber-color, weighed eight and one-fourth pounds. 



The darker shales also sometimes contain numerous small lenticular 

 nodules of pyrites, frequently in fine crystals. 



This Niobrara is from 75 feet in Trego and Ellis Counties to 200 feet 

 in Eooks County. The fossils are scattered very similarly in all this 

 thickness; some localities will furnish more from the chalk, while others 

 will give more from the shales. We hunt for fossils in all alike, and on 

 the whole with equal success. 



