!()() CAUBONIKIOHOI'S KOKMA'l'lONS AND KAUNAS OK COLORADO. 



lain liy sliulos luul other liiiicsloncs luid contain.s a fauna which 1 ]i:i\<' little doubt 

 correlates it with tiu> Lendviile and Ouray limestones. In the two South Pai-k sec- 

 tions no transitional or interniediate series is mentioned above the upper limestone, 

 and (he diagnostic fossils, so far as they are diagnostic at all. arc rcpoi-(e<l only from 

 the lower member, so that if the Weber formation is present it would probably 

 embrace some of the beds tentatively placed with the Leadviile foi'niation. In the 

 other case the change of the Leadviile, which farther north appears to be a homo- 

 geneous limestone series, to two limestones with an interbedded shale is worthy of 

 note. 



Though the older Paleozoics whose distribution the Lead\'ille limestone closely 

 follows, are said b}' Endlich to occur for a short distance south of the Arkansas, and 

 the "Lower Carboniferous" color appears in the Hayden atlas in the north end of 

 the Sangre de Cristo Range, the Mississippian limestone is wanting over most of the 

 region. We have, however, no description of its occurrence at its northern localities. 

 The Hayden atlas also represents a small area of Lower Carboniferous at Trinchera 

 Peak, and this Endlich describes as a grayish-brown, compact shale, sand}' in part, 

 and interbedded with limestone, and conformably underlying the I'ed Carboniferous 

 sandstone. He suggests that this m&j represent the Lower Carboniferous. There 

 realljr seems to be no evidence sufficient to determine whether it is the Leadviile 

 series (though from the lithology this hardly seems likely), the Weber formation, or 

 part of the Arkansas sandstone." Lee has recently examined part of the area where 

 Lower Carboniferous is represented on the map and found only the Arkansas sand- 

 stone, from which the inference ma}' be drawn either that the limits of the area are 

 incoi'rectly represented on the map, or that Endlich ei'red in separating these beds 

 from the younger formation. Stevenson describes no formation older than the 

 Arkansas sandstone south of the river, and if he met with any occurrences he pre- 

 sumably included them iu the Pennsylvanian. While these formations pinch out and 

 disappear south of the Arkansas it is possible that they may occur in local patches 

 beneath the sandstone. The somewhat doubtful occurrence of the Leadviile limestone 

 at Trinchera Peak, and the appearance of the Sawatch quartzite and the Yule lime- 

 stone northeast of San Luis, reported b}' the Van Diests, indicate that other similar 

 instances may exist. 



The equivalent of this formation in the Uinta Mountains is well-nigh as uncer- 

 tain as that of the earlier Paleozoic beds. It can be correlated with the lower portion 

 of the Wasatch limestone of Utah and with the Red Wall limestone of the Grand 

 Canyon country, the lower portion of which belongs in the Mississippian, as Meek, 

 Walcott, and Freeh report. Though Meek's reference was made with hesitation, and 



a The strata above the Archean in Lee's section have more the character of the Maroon than of the Weber limestone, 

 which is absent or has lost its calcareous character. 



