86 CAK150NIFEU0US FORMATIONS AND FAUNAS OF COLORADO. 



Comparison of the series tiiiis brioHy fliaraetcrizcd with other known sections 

 in areas adjacent is hampered hj' lack of measurements of thickness which Endlich 

 fails to supply, and iiy the meagerness of paleontologic data. Nevertheless, if this 

 series be closely compared with that of the Leadville monou-raph, though the result 

 shows considerable changes in lithology between Leadville and the southern end of 

 the Park Range, yet certain horizons seem to be recognizable as probabl}' equivalent 

 in the two sections. In view^ of its litholog^y and position, the siliceous limestone at 

 the base of the section can be taken as representing the Yule limestone, and with it 

 woidd probably go the overlying limestone containing corals and sponges. The 

 Cambrian Sawatch quartzite appears from Endlich's statements to be entirel.y lack- 

 ing. The light-colored limestone with Orthis and Prodtictus is probabl}^ the Lead- 

 ville limestone (or its more or less close equivalent, the Ouray limestone). The 

 quartzite between these two calcareous formations should, from its character and 

 position, be the Parting quartzite. The light-red sandstone and the heav}' shale series 

 above it, however, seem to have no lithologic equivalent in the Leadville section. 

 Perhaps they should, in conjunction with the quartzites, be taken as representing the 

 Parting formation. The shales above the supposed equivalent of the Leadville 

 limestone present some claims of similarity to the Weber shales, but the succeeding 

 beds certainly do not at all resemble the Weber grits series as it is described bj' 

 Emmons. It seems rather more probable that the massive blue limestone above, as 

 well as the lower fossiliferous one, belong in the liorizon of the Leadville limestone, 

 and, of course, with it would be carried the intermediate series of shales. The dark 

 sandstones with which the section closes certainly' are more similar to the Weber 

 grits than any of the beds below. 



Results not altogether satisfactory attend the comparison of this section with 

 that described by the same author as occurring at Fossil Eidge in the Elk Mountain 

 region. The series of Ordovician beds in the two sections are probably to be corre- 

 lated with each other and with the Yule limestone. In the South Park region these 

 ■consist of a blue quaitzitic limestone with crinoids and Orthoceras, overlain by a hard 

 gray limestone containing corals and sponges, with a thin interstitial shale. At Fos- 

 sil Ridge this series comprises 320 feet of light-gra}"^ limestone, with quartzitic segre- 

 gations and sparse remains of crinoids. The two limestone series which I correlate 

 with the Leadville limestone are also probably equivalent. At Fossil Ridge these 

 comprise 260 feet of light-gray and yellowish limestones, interstratified with narrow 

 bands of shale; 40 feet of light shale; and 20 feet of dark-blue limestone carrying 

 upper Devonian or lower Mississippian fossils. The bed last mentioned can be 

 assigned with great probabilit}^ to the Leadville or Ouray limestone. Above it 

 come 45 feet of light shale, 150 feet of light-blue and yellow limestone, and 50 

 feet of yellow, reddish, and whitish shales, which may belong with the Leadville 



