178 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 53 



WEEKS FORMATION (continued): 



16 (continued) : ^ Feet 



Fauna: 



The fauna ranges through about 100 feet of the lower por- 

 tion of this division. 

 Obolus (Fordinia) perfectus Walcott [igc&d, p. 65]. 

 Agnostus (2 species). 

 Ptychoparia. 



Crepicephalus texanus (Shumard) [1861, p. 218]. 

 Anomocare. 

 Bathyuriscus. 

 Asaphisciis minor, new species. 



-The fauna is much like that of ic. Its most characteristic trilo- 

 bite is Asaphiscus minor, new species. 

 ic. Shaly, bluish gray to dark gray limestone in layers one-eighth 

 to I inch thick, with occasional layers 2 to 6 inches thick; 25 

 feet from the top a band of layers of arenaceous, dirty gray, 

 finely oolitic limestone, 3 feet thick, occurs, and a second 

 similar band 38 feet below 170 



Fauna: 



The fauna is rich in numbers of specimens and quite 

 varied. The best specimens occur on the surface of the 

 shaly layers in the lower portion of the division. 

 Lingulella isse (Walcott) [1905, p. 330]. 

 Obolus (Fordinia) perfectus Walcott [igoSd, p. 65]. 

 Acrotreta ophirensis Walcott [1902, p. 591]. 

 Acrotreta ophirensis descendens Walcott [igo2>d, p. 94]. 

 Hyolithes. 



Agnostus (several species). 

 Ptychoparia (several species). 

 Crepicephalus texanus (Shumard) [1861, p. 218]. 

 Soknopleiira. 

 Asaphiscus minor, new species. 



id. Reddish tinted, more or less arenaceous, shaly limestone 30 



Fatma: 



Same as ic, but not abundant. 



le. Shaly, bluish gray to dark gray limestone, similar to ic 270 



Fauna : 



Same as that of ic. 



if. Evenly bedded, bluish gray to dark gray, fine-grained lime- 

 stone, in layers 2 to 16 inches thick, with shaly limestone 

 partings 330 



Fauna: 

 A few traces of Agnostus and Ptychoparia similar to those 

 above. 



i^. Calcareous shales with thin layers of limestone 60 



Total thickness of Weeks formation 1,390 



