828 



E. O. ULRICH CORRELATIONS OF CHESTER FORMATIONS 



Yases sandstone, the upper member of which consists of 25 to 30 feet or 

 more of massive sandstone. AYhat I am calling the lower member of the 

 Aux Vases consists of 10 to 12 feet of more calcareous and thinner bedded 

 sandstone. Between the two we found, for the first time, last summer a 

 good exposure of calcareous red and green shale and layers of suboolitic 

 limestone, out of which a fauna of 41 species was gotten. These fossils 

 consist mainly of types found in preceding and succeeding occurrences 

 of the well-known Spergen fauna. It is. of interest and importance 

 chiefly because it comprises species the vertical ranges of which are in 

 dispute, the most noteworthy of these being Platycrinus penicillus or 

 liuntsvillce and Pugnoides ottumwa. Among the Bryozoa there are two 

 out of three species of Polypora and one of Fenestella that I can only 

 regard as mere varieties of later Chester species which so far have not 

 been observed in any Sainte Genevieve fauna, including, of course, the 

 Upper Ohara beds (zones 2 and 3) that correspond to the Shetlerville 

 formation of Weller. 



A marine fauna in the Aux Yases sandstone. — The fossils listed below 

 were obtained from a layer of suboolitic limestone in an 8-foot bed of 

 calcareous red and green marly shale 10 to 18 feet above base of Aux Yases 

 sandstone, exposed in roadside gulley between Sainte Genevieve and Saint 

 Marys, Missouri, half a mile south of Aux Yases Eiver. 



Platycrinus cf. penieillus (one ring of 

 basal plates and a columnal) 



Two kinds of round columnals of un- 

 determined erinoids 



Pentremites sp. (ambulacra only) 



Stenopora tuuerculata 



Fistulipora — 2 undet. species 



Fenestella serratula 



Fenestella cestriensis 



Fenestella n. sp. (dissepiments thick- 

 ened at expense of fenestrules. so 

 that the latter are very small) 



Polypora cestriensis 



Polypora aff. approximata, but with 

 spines 



Polypora n. sp. aff. spinulifera and 

 nodocarinata 



Crania chesterensis 



Orthotetes sp. 



Pugnoides ottumwa 



Pugnoides n. sp. (same in Sainte 

 Genevieve limestone) 



Composita trinuclea (typical form) 



Composita trinuclea var. with Ungu- 

 late production of fold 



Euwetria rerneuilana (large form, 



with about 50 plications) 

 Spirifer leidyi (2 forms — one small. 



the other of medium size) 

 Spiriferina su bsp in osa 

 Aviculopecten (4 species, all closely 



allied to or the same as Fredonia 



and Gasper species) 

 Pteronites sp. 

 Modiola cf. foiuitaincnsis 

 Sphenotus sp. 

 Pdrallelodon sp. 

 Ci/pricardella sp. 

 Xucula illinoisensis 

 Lcda sp. 



Cijpricardinia cf. indianensis 

 Acroculia cf. acutirostris 

 Euphemus aff. randolphensis 

 BclleropJion aff. sublwvis 

 Bucanospira aff. textilis 

 Orthoccras sp. 

 Cytherellina cf. glandclla 

 Phillipsia sp. 



