G. B. Richardson — Paleozoic Formations. 481 



the Hueco limestone has not yet been determined, but it is 

 more than 3000 feet. 



The Hueco limestone carries an abundant fauna of Penn- 

 sylvanian age, of which the following, identified by G. H. 

 Girty, is a partial list. According to Dr. Girty, this fauna 

 with some modifications is similar to that found over much of 

 the Cordilleran region, and the Hueco limestone is tenta- 

 tively correlated with the Aubrey formation and the Weber 

 quartzite.* 



List of fossils from the Hueco limestone. 



Fusulina, several sp. 

 Archceocidaris cf. A. biangulaia Shum. 

 Axophyllum sp. 

 Fisttdipora sp. 

 Septopora sp. 

 Schizophoria sp. 



Fnteletes cf. F. hemiplicatus Hall. 

 Orthotetes sp. 



Productus cf. P. inflatus Tsch., non McChesney. 

 Productus cf. pustulatus Keys. 



Productus cf. P. longus Tsch., non Meek, and P. porrectus 

 Kut. 



Productus, cf. P. irginae Stuck. 



Productus, several sp. type of P. semireticulatus Martin. 



Marginifera, cf. M. wabashensis Nor. and Pratt. 



Spirifer, cf. S. marcoui Waagen. 



Spirifer, cf. S. cameratus Morton. 



Squamularia (?) sp. 



Spiriferina cf. S. cristata Schlot. 



/Seminida, cf. 8. subtilita Hall. 



Hustedia, cf. H. Mormoni Marcou. 



Camarophoria cf. C. mutabilis Tsch. 



Pugnax, cf. P. utah Marcou. 



Dielasma, cf. D. truncatum Waagen. 



Myalina sp. 



Naticopsis sp. 



Fuomphalus sp. (large.) 



Ompkalotrochus obtusispira Shumard. 



Bellerophon sp. 



Patellostium, cf. P. Montfortainum Nor. and Pratt. 



Phillips ia sp. 



GUADALUPIAN. 



In the Van Horn quadrangle and north of it the bolson 

 plain known as Salt Flat, which is occupied by an unknown 

 depth of unconsolidated Quaternary deposits, lies between the 

 Sierra Diablo on the west and the Guadalupe-Delaware 

 Mountains on the east and completely conceals the relations of 



* Proceedings Washington Academy of Sciences, vol. vii, p. 14, 1905. 



