42 University of Texas Bulletin 



These facts indicate that subdivision 6 is equivalent to the Weno and 

 Pawpaw and to part of the Denton formation. The overlying sand, lack- 

 ing Exogyra arietina, contains near its top Hemiaster calvini Clark and 

 Exogyra whitneyi Bose. The former fossil is upper Washita, Weno to 

 Buda, and the latter is known from the Buda, although from the present 

 record it is evident that it ranges as low as the Mainstreet formation. 



It may be of interest to add a list of species described from Cerro de Muleros, which 

 have been found in North Texas. The number cited is that of the corresponding divi- 

 sion at Cerro de Muleros, and the following formation names refer to the location 

 of the fossil in North Texas. 



Epiaster aguilerae Bose, 5; basal Fort Worth. 



Enallaster bravoensis 5, 6, 8; Weno to Grayson. 



Holectypus limitis 5; Weno to Grayson. 



Ostrea marcoui 4, 5, 6; Weno to Grayson. 



Pinna guadalupae 2, 6; basal Weno. 



Pecten subalpinus 2, 3, 5, 6, 8, 9; Goodland to Grayson. 



Pecten irregularis 1, 2; Walnut to Kiamitia. 



Plicatula subgurgitis 2, 5, 6 ; Duck Creek to Pawpaw. 



Helicocryptus mexicanus 6; Pawpaw. 



Turbo chihuahuensis, 'Lei Encantada; Weno. 



Tylostoma chihuahuense 1, 2; Glenrose to Goodland. 



Schloenbachia trinodosa 5, 6; Duck Creek. 



EUROPE AND NORTHERN AFRICA 



It is unquestionable that the aggregation of Pawpaw pyrite ammonites 

 here described parallels Pervinquiere's Vraconian fauna more closely than 

 it does his Cenomanian fauna. This might mean that the Pawpaw fauna 

 is Vraconian, or that some later (Cenomanian) species are included in his 

 Vraconian fauna; or the Pawpaw fauna may be one which has persisted 

 with little change from its Vraconian ancestors. Scaphites aequalis-like 

 species in Texas are known to range from the Duck Creek marl to at least 

 the Pawpaw clay; in Europe they are of Upper and Lower Cenomanian, 

 Vraconian, or even Albian age, so that this species decides little ; the Paw- 

 paw or the Duck Creek aequalis may be contemporaneous with the Vra- 

 conian examples. Flickia decides nothing, since the range of the genus is 

 unknown and is extended with each new species discovered. Hamites sim- 

 plex ranges from Aptien to Mid-Cenomanian. Attempts have been made 

 to correlate the Texas Washita division on the basis of Schloenbachia in- 

 flata. This brings us face to face with the question, What is inflata? Is it, 

 as sometimes claimed, a Schloenbachia with low, sigmoidal ribs and two 

 tubercles, one umbilical and one marginal; or is it a Mortoniceras, with 

 square volutions and coarse short ribs having three tubercles, an umbilical 



