258 



CARHONIFEROTIS FORMATIONS AND FATNAS OF COLORADO. 



This is clciirly iiol (lie Rico fauiui, aiul its affinities are rather with those of tiie 

 middle and upper portions of the lierinosa formation. It presents, however, a dis- 

 tinctly different facies from any portion of the Herraosa, as will be seen from the 

 fact that Enteletes hemipllcatits, GhoneteH granuUfe)\ Produr.tus j9or<?oc^7'a?7,«.s'. 

 Edmondia Tnortonensisf , and Worthenia tahulata? are not known to occur in that 

 formation. In Sinbads Valley the Hermosa, or what is supposed to be that forma- 

 tion, has a much greater thickness than in the San Juan region. This collection, 

 therefore, which comes from near the top of the formation in Sinbads Valle3', pre- 

 sumably represents a higher horizon than any portion of the Hermosa in the San 

 -Juan region and also a lower horizon than the Rico formation. These facts, taken 

 in connection with the rather marked faunal break and lithologic change between 

 the typical Rico and Hermosa, are all favorable to the supposition that in the San 

 Juan a period of erosion or nondeposition intervened between those two series of 

 sediments, represented b^' the npper beds in Sinbads Valley and indicated by the 

 different facies of their faunas. 



SUMMARY. 



Probably of greater interest than the relation to one another of the faunas of 

 the different formations of the same section are the relations of the faunas of forma- 

 'tions in the different sections which have been studied in different portions of the 

 State. The only sections represented by collections adequate to make such a com- 

 parison are those of the San Juan region. Crested Butte district, and Leadville and 

 Tenmile districts, the last two being considered together. To this end I have pre- 

 pared a summary table, giving the composite faunas of the several formations 

 recognized in these three regions. The character of the local faunas from which the 

 composite list is made up is shown in the tables dealing individually with the 

 different regions. 



Table XVI. — Summary table for comparing the Upper Carboniferous formaiiono.l faunas of the San Juan, 

 Crested Butte, and Leadville and Tenmile districts. 





San Juan. 



Crested Butte. 



Leadville and Tenmile. 





Molas. 



Hermosa. 



Weber. 



Maroon. 



Weber. 



Robin- 

 son. 







Low- 

 er. 



Mid- 

 dle. 



Up- 

 per. 



Low- 

 er. 



Mid- 

 dle. 



Up- 

 per. 



Maroon. 



PROTOZOA. 





1 



4 



4 



1 

 1 



4 



























SPONGIA. 



Hyalostelia sp 





1 

 1 







































. CCKLENTERATA. 



Lophophyllum profundum 





2 



2 



1 



1 



3 



2 













Campophyllum torquium 







I 









