550 N. H. DARTON FISH REMAINS IN ORDOVICIAN ROCKS 



of the uppermost limestone beds of the Bighorn formation. The fossils 

 obtained at this locality, as determined by Mr E. 0. Ulrich, are as fol- 

 lows : 



Streptelasma rusticum Billings. Strophomena n. sp. (between S. neg~ 



Streptelasma cf. robustum Whit- lecta and S. planodorsata) . 



eaves. Dalmanella meeki Winchell and 



Streptelasma n. sp. (with trilobate Schuchert (? Miller). 



calyx). Dalmanella tersa Sardeson. 



Lindstromia n. sp. Dinorthis n. sp. (distinguished from 



Favosites asper D'Orbigny. D. subquadrata by its coarse ribs) 



Proboscina (near Frondosa, Nichol- Hall. 



son). Plectorthis whitfieldi Winchell (small 



Monotrypella quadrata Rominger. variety). 



Batostoma manitobense Ulrich. Rhynchotrema per lamellosa Whit- 



Bythopora striata Ulrich. field. 



Lcioclemella sp. undet. Rhynchotrema n. var. of increbescens 



Rhinidictya sp. nov. Hall. 



? Goniotrypa lateralis Ulrich. Lophospira (cast) sp. undet. 



Sceptropora facula Ulrich. Cylora depressa ? Ulrich. 



Plectambonites n. var. or sp. (near Eurychilina manitobensis Ulrich. 



sericea). Primitia lativia Ulrich. 



Leptwna nitens Billings Schmidtella sp. undet. 



From extensive exposures of the top member of the Bighorn limestone 

 near the head of Lee creek, 14 miles east-northeast of Tensleep, Mr 

 Ulrich obtained the following species : Holy sites gracilis, Columnaria 

 alveolata, C. halli var., and Calapcecia resembling huronensis and anticos- 

 tiensis, an association regarded as Bichmond. At a horizon 5 feet lower 

 the following species were collected : Streptelasma rusticum, Leptama cf . 

 nitens, Rhynchonella ? argenturbica f, Liospira cf. micula, Lophospira 

 acuminata, Helicotoma cf. marginata, and a small Straparollus-like shell, 

 a Bichmond faunule. About 50 feet lower in the same vicinity there was 

 found in the massive limestone member a Platystroplvia of new species, 

 but believed to be the same as one found in the Trenton limestone of 

 Tennessee. 



OCCURRENCE OF THE FISH REMAINS 



The fossil fish were discovered in the basal sandstone of the Bighorn 

 mountains, in August, 1905, at various points in the south-central portion 

 of the uplift. They were first observed in outlying buttes on the head of 

 the main or south prong of Bed fork of Powder river, 23 miles slightly 

 south of west of Mayoworth post-office, in the southern portion of Johnson 

 county, near the line of Bighorn county. This locality is near the crest of 



