104 Cretaceous. 



stone of the Lignitic, which is there covered. The surface of 

 the ridge formed by the upthrow is pierced by the edge 

 of the perpendicular strata, especially of the hard sandstone, 

 and there the characters of the lowest beds are recognized at 

 many places as the same as those of the fucoidal sandstone of the 

 Raton mountains. At the cut made across the measures by Clear 

 creek, the lower sandstone appears proportionally thin, 10 to 20 feet. 

 It is a white, soft-grained sandstone, hardened by metamorphism, con- 

 taining, beside remains of dicotyledonous leaves, some species of 

 finely preserved fucoids. In following the same sandstone to the south 

 it is seen increasing in thickness, and near and under the Roe coal, 

 five miles from Golden, it forms a high, isolated ridge, at least 200 feet 

 thick, barren of any kind of remains, except some fucoids. 



By its compound, the alternance of its coarse-grained and soft- 

 grained strata, these being often mere clay or mud beds, its characters 

 appear the same as those of the lower lignitic sandstone of the Raton 

 mountains. It has, too, broken, undeterminable fragments of wood, 

 Cj'peraceae, etc. Beside the species of fossil dicotyledonous leaves 

 found in the white sandstone of Golden, most of them homologous, or 

 even identical with some species of the Raton and other localities, 

 it has one of those very rare land plants, which has been described an-d 

 recognized in Europe as pertaining, as yet, exclusively to the Eocene. 



The finest and best preserved specimens of fossil leaves that have 

 ever been found in this country, with the exception, perhaps, of 

 those of Black Butte, have been found at and around Golden, in the 

 hard metamorphosed white sandstone, under and interlying the beds 

 of coal, and in the beds of white clay upheaved against the sides of the 

 basaltic dike; a clay, hard as silex from metamorphism, having mostly 

 remains of palm leaves; and from three miles south of Golden, from 

 a sandstone still upheaved, near the tail of the dike, but scarcely 

 changed by heat, and easily cut in large pieces. The continuity of 

 the Lignitic formation is traced north toward Cheyenne, where the 

 conglomerate sandstone covers the face of the countr}^ and all the 

 facts discovered, tend to confirm the statement made by Dr. Hayden 

 in 1868, that all the lignite Tertiary- beds of the West are but frag- 

 ments of one great basin, interrupted here and there by upheaval of 

 mountain chains, or concealed by the deposition of newer formations. 



At Medicine Bow, the line of connection with the underlying Cre- 

 taceous is, perhaps, more difficult to fix than at other localities, the 

 fucoidal sandstone here being mostly barren of remains of marine 

 plants. But from its base to its top, in a thickness of, perhaps, 200 



