fi4 CAKJiOWlFKUUl'S FilKMATlDNS /VNl) [''AUNAS <IK ('(>H»KAJJ(). 



i)i)lli Ix'iiiii' npix'i" CiirboiiitVrou.s. It .seems piKhiiblr lliat Ix'd.s aH, 25, and possibl}^ 

 al.so 11 ])()i'lion ol' 28, represent the Lciidvillo-Weber interval, usiiifj' th(> term Weber 

 a.s it is cinpioN I'll in the Aspen monogTaph. This leave.s the i'drinatidn w ithout any 

 dcteriiiinuMi' bdundai-ics uiid with a Ihickiicss only approximately determinable. 

 ^Beds '2i) and 20 ha^•e a combined thicknes.s of from 1,000 to 1,500 feet; and if to this 

 be added 100 or 200 feet from the base of 23, we obtain 1,200 to 1,700 feet as the 

 approximate thickness of the Leadville and Weber formations. In the Asjjen district 

 these formations have an aggregate thickness of 1,350 feet, while in the Tcnniile dis- 

 trict their thickness is only 500 feet. It thus appears that Peale's Eagle River section 

 in the matter of the two formations mentioned above is close to the Aspen section, 

 but dillers widely from that of the Tenniile district. 



The remainder of Peale's Carboniferous series, with an aggregate thickness of 

 about 2,300 or 2,400 feet, corresponds in position and character to the lower part of 

 the Maroon formation of the Aspen district. There seems to be, however, a much 

 smaller proportion of dark-red or brownish members. This series also is similar to 

 and probably represents the Weber grits of the Tenmile district, and as the thick- 

 ness is nearlj' the same in each case, it may be that the horizon taken by Peale as the 

 top of his Carboniferous series about corresponds to the line dividing the Weber 

 grits irom the Maroon formation of Emmons's section. 



The C'.irboniferous series continues upward into one which Peale calls Permian. 

 The evidence for this reference consists of three species of plants, one of which is 

 exclusively Permian, the two others being especially Coal Measure, though ranging 

 np to or into the base of the Permian. As the evidence of invertebrate fossils found 

 elsewhere at the same horizon" indicates that the geologic age is not Pex'mian but 

 Upper Carboniferous, it vould be desirable to have the paleobotanical evidence 

 reviewed and a larger flora collected. Of the Permian, in the section under consid- 

 eration, Peale gives 1,276 feet before the top is reached. This Permian series is 

 lithologically similar to tnat called Carboniferous, and like it, 1 believe, represents 

 the Maroon formation, belonging to the upper portion, which was not ditferentiated 

 by Spurr, but to which Emmons restricts the name Maroon. 



Peale's other Eagle River section, made near the second canyon, comprises series 

 referred to the Permian, Triassic, Jurassic, etc. The two Permian sections are by 

 no means strikingly similar lithologically, and I doubt if any more than the basal 

 portion of the second corresponds to the top of the first. Possibly they are even 

 entirelj^ superimposed. Indeed, Peale remarks * that " Farther down Eagle River, 

 where the Red Beds are present, the strata immediately beneath are so changed that 

 I could not positivelj^ recognize any of the beds of the section made further \rp the 



a Probably about the Kico formation of the San Juan and the upper Maroon of the central part of the State. 

 iV. S. Geol. Geog. Surv. Terr., [Eighth] Ann. Eept., for lS7i. 1876, p. 118. 



