62 CAEBONIKEROUS FORMATIONS AND KAUNAS OF COLORADO. 



section, husiMl apparently upon both of the foregoing ones, wliicli he ]iulilisli('(l in 

 the aiinuiil ropoi't for 1875. 1( includes only sli'iila believed to belong to the Kocar- 

 bonifei't)us. Coal Measures, and IVrmian. There ap[)ear to be important (h'partures 

 from the original section from which the summary was derived. 



<leriiTiiUze.il seelkn} on tin' Km/le Hirer, dinlriel of J 87. 'i. (After Peak)."- 



I'UKMIAN. 



Fri'l. 



Micin'oous sandstones and gyp.sil'erous shales of variegated folors, with thin beds of liine.stone at 



the base. Fo.ssils: Calamitex xiiclcorii, ('. gif/Kx, Stigmaria ficoides, Spirifer, Frodudiix, Orbiculti. . 2, 0(.1U 



COM. MHASCHHS. 



White, greenish, ami reddish, lainiiuited, iiiicaceuus saud.stoni'S an<l black slialcs, with ijatches 

 of carbonaceous material; near tlie base are limestones,'' with Avipula, Avieuhpeden, 

 I'teiirojihoruis 2, 500 



si;bc.\rbonifkrous. 



Limestone, soineAvhat shal y above, 1 int massive as we descend, about .500 



Total 1 - 5, 000 



The tirst section quoted was made, as I have already stated, along the upper 

 portion of the Eagle River, the Carboniferous beds being chiefly exposed near the 

 mouth of Roche Moutonnee Creek. This section is northeast of the A.spen district 

 and northwest of the Tenmile district, the three points forming a ti'iangie with nearlj^ 

 equal .sides. This section is subdivided into a Silurian, a Carboniferous, and a 

 Permian series, with the possibilitj'' that a thin Devonian series may be included 

 with the Carboniferous. In the section quoted it is apparent that the lowest group, 

 consisting of 400 feet of quartzite, which Peale refers to the Primordial, is the 

 Sawatch quartzite of the Tenmile and Aspen sections, and that the 200 feet of 

 magnesian limestone at the top of his Silurian section, which is otherwise unclassified, 

 belongs to the Yide limestone. The question then presents itself of the disposition 

 of the 200 feet of siliceous beds which he refers to the Calciferous group. It is 

 possible that the bed of glauconitic sandstone which Peale cites just over his 

 Primordial quartzite can be correlated with a similar bed which SjDurr described as 

 occurring in the upper poi'tion of his Cambrian quartzite. The two beds agree 

 with singular closeness in thickness, lithologic character, and stratigraphic ijosition.'' 

 The strata which overlie the glauconitic quartzite at Aspen and are transitional to 

 the Silurian dolomite are also similar to the Calciferous group of Peale's section.'' 



aSee sections, Report of 1874, pp. 115-119. 



h This layer may possibly be Subcarboniferous [Peale] . 



c Spurr calls attention to the wide extent of this glauconitic horizon on page 7 of the Aspen monograph, Mon. U. S. 

 Geol. Surv., vol. 31, 1898. 



<l The upper, transitional portion of the Sawatch quartzite of the Tenmile district is not unlike Peale's Calciferous 

 group, although very much thinner. The latter also resembles the lower or quartzite member of tlie original Yule. 



