RECAPITULATION OF PALEOZOIC FORMATIONS. 159 



southern border of the South Park region. At that localitj'^ 75 feet of sandstone 

 described as "partially altered, with layers of quartzite; somewhat argillaceous; 

 weathers to ochery color; contains many large fragments of jasper," can be referred 

 to the Parting formation. It here rests upon 112 feet of limestone which represent 

 the Yule, about 20 feet of red calcareous clay intervening between the two formations. 

 The overlying beds are not known, and Stevenson remarks (p. 359) that it is more 

 than probable that the Arkansas exposures do not exhibit the complete section, 

 being defective on top. 



Endlich also gives two sections in this region which include beds belonging, it 

 would appear, to the Parting quartzite. Thej' are situated in the southern part of 

 the South Park region, but their exact location can not be known. One of these, 

 which was made at station 56, contains a series of yellow to light brown hard quartz- 

 ites, followed by white and pink quartzites of very fine texture, covered by j^ellow 

 ish shales which are later said to be interstratified with quartzites. Above these 

 occur shales and limestones which appear to belong to the Leadville series. The 

 underlying rock is a porphj-ritic granite which is more probablj' an intrusive than a 

 portion of the Archean complex. In the other section, that made at station 53, the 

 series is of a similar character. It consists of thick beds of white, yellow, and pink 

 quartzites passing into light red sandstone. To this must probably be added a thick 

 stratum of yellow and 1)rown sandy shale covered by light yellow and gray shales. 

 Beneath the quartzite are limestones whose partially identified fossils are suggestive 

 of the Ordovician faunas, and above the shale a blue limestone with a fauna which 

 appears to be Carboniferous. It will be observed that in the two sections cited from 

 Endlich the strata which occupy the position of the Parting quartzite consist of a 

 series of quartzitic beds below and another of variegated shales which rest upon them. 

 The quartzitic portion possess considerable resemblance to thet}'pical Parting quartz- 

 ite, while the shales resemble the beds which at Fossil Ridge, Crested Butte, and 

 Aspen, have been referred to the same series. It is possible that these occurrences 

 at the same time indicate a dual nature for the strata referred to the Parting forma- 

 tion and demonstrate the stratigraphic relations of the constituent members. 



The Parting quartzite probabl}' forms part of the Silurian of the Hayden reports, 

 as it does in the case of Stevenson's. Endlich found Silurian strata along the 

 northern edge of the Sangre de Cristo region in that portion of his San Luis district 

 which he designates as sections 5 and c. Here it comprises the Sawatch and Yule 

 beds, and he describes nothing which has the lithology and stratigraphic position of 

 the Parting series. It may be recalled that at stations 53 and 56 north of the 

 Arkansas this author describes two sections in which beds of light-colored quartzite 

 are reported as overlying a limestone of probable Ordovician age. These quartzites. 

 which hold the position of the Parting quartzite, resemble the Sawatch auartzite 



