82 
Kirtley F, Mather 
muricatus 
multistriatus 
Chonetes granulifera 
platynota 
Hemipronites crenistria 
Meekella striatocostata 
Spirigera subtilita 
Spirifer cameratus 
rockymontanus 
Spiriferina octoplicata 
Aviculopecten occidentalis 
Myalina sp. 
Allorisma subcuneata 
Edmondia aspenwallensis 
Pleurophorus sp. 
Schizodus wheeleri 
Bellerophon sp. 
Euomphalus sp. 
PI eurotom aria excelsa 
Naticopsis remex 
Phillipsia sp. 
In Colorado the Molas formation, less than 80 feet in thick- 
ness, overlain by the Hermosa limestone, occurs at the base of 
the Pennsylvanian section in the San Juan region. The faunas 
of these formations have been described by Dr. Girty^^ and a 
comparison with the fauna of the Morrow makes it clear that 
they are probably somewhat younger than the Arkansas fauna. 
The fauna of the Molas is a very meager one and although every 
one of its eight species is represented in the Morrow fauna by 
either an identical or closely related form all of its fossils are 
species which occur at higher horizons in the Pennsylvanian and 
usually with greater abundance there than in the Morrow. 
Twenty of the Hermosa species have been identified in the Mor- 
row but, again, they are long-range forms rather than those 
characteristic of the marine Pottsville. The absence of the resid- 
ual Mississippian element from the Hermosa is as conspicuous as 
the absence from the Morrow of certain of the Hermosa forms, | 
such as Triticites secalicm. 
Toward the southwest from the Morrow outcrops there are 
known at several localities in Oklahoma and Texas limestones 
whose stratigraphic position is suggestive of a near relationship 
cf. Chonetes choteauensis 
cf. laevis 
cf. Orthotetes robusta 
ibid. 
cf. Composita ozarkana 
ibid. 
cf. Spiriferina transversa 
= Deltopecten occidentalis 
cf. Myalina recurvirostris 
cf. Edmondia subtruncata 
cf. Pleurophorus tropidophorus 
cf. Schizodus morrowensis 
cf. Bellerophon crassus var. 
wewokanus 
cf. Euomphalus catilloides 
cf. Strophostylus subovatus? 
cf. Griffithides morrowensis 
