stanton.] HUERFANO PARK, COLORADO. 29 



tained fossils indicate that the bed was deposited in shallow waters 

 not far from land. 



The band of brown calcareous sandstone above the Puguellus sand- 

 stone is rather more persistent, and it always contains sharks' teeth and 

 impressions of Prionocyclus wyomingensis, and usually Ostrea lugtibris. 

 Its thickness varies from 1 to 4 feet. 



The Cretaceous section of Huerfano park, Huerfano county, Colorado, 

 is entirely similar to that of the Arkansas valley just described, but as 

 it has furnished so large a proportion of the species here described it 

 deserves a separate notice in order that the evidence on which these 

 species are referred to the Colorado formation may be given. 



The "park" is a synclinal basin almost surrounded by the uplifts of 

 the Wet mountains on the east and north and of the Sangre De Cristo 

 range on the west and southwest. The central and larger portion of 

 this basin is filled by a thick series of sediments of Eocene and later 

 Tertiary age. 1 The Cretaceous strata are exposed at many places 

 around the margin, especially on the east, north, and west sides. The 

 entire series from the Dakota to the Laramie, inclusive, is represented, 

 but the Montana and Laramie are not often well exposed. 



The fossils were nearly all collected from a single bed, the Puguellus 

 sandstone, which is easily recognized in all its outcrops both by its 

 position and by its fossils. The most prolific localities examined are 

 near Quillian's ranch on Williams creek, on Muddy creek about 10 miles 

 above Gardner post office, in Poison canyon, and near Malachite post- 

 office on the north side of Huerfano river. The Pugnellus sandstone at 

 these four localities has yielded the following list of species, the major- 

 ity of which were found at all the localities : 



Ostrea lugubris. Mactra huerfanensis. 



Ostrea malachitensis. Turritella whitei. 



Exogyra suborl>iculata. Xenophora simpsoni, 



Anomia subquadrata. Gyrodes depressa. 



Gervillia propleura. Gyrodes conradi. 



Avicula gastrodes. Amauropsis bulbiforniis. 



Inocerainus labiatus. Mesostoma occidentalis. 



Inocerainus fragilis. Pugnellus fusiformis. 



Solemya? obscura. Fusus (Neptunea?) vencnatus. 



Pinna petrina. Tritonidea? huerfanensis. 



Yoldia subelliptica. Fasciolaria? (Cryptorhytis) utalicnsis. 



Trigonarca obliqua. Pyropsis coloradoeiisis. 



Lucina juvenis. Rostellites dalli. 



Cardiuin pauperculum. Rostellites ambigua. 



Tapes cyprimeriforinis. Rostellites gracilis. 



Legumen? . Cancellaria malachitensis. 



Tellina (Paheorncera) whitei. Actaeon propinquus. 



Siliqua huerfanensis. Haininea truncata. 



Pholadomya coloradoensis. Placeuticeras . 



Anatina lineata. Prionotropis hyatti. 



Liopistha (Psilomya) concentrica. Cassidulus stantoni. 



Mactra eimuonsi. 



1 Hills, R. C: Tertiary beds of the Huerfano river basin. Proc. Colo. Sci. Soc, vol. m, 1890, pj>. 

 148-164, 217-223. 



