1888.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 441 



DESCRIPTION OF NEW GENERA AND SPECIES OF FOSSILS FROM 

 THE MIDDLE CAMBRIAN. 



BY CHARLES D. WALCOTT. 



In a collection of Middle Cambrian fossils, sent to ine for study by 

 Dr. Karl Romiuger, I find several new forms, which he permits me to 

 describe. With these, two other species are described — one collected 

 by Dr. Cooper Curtice, in northern Georgia, and the other by me in 

 Newfoundland. 



It is my intention to fully illustrate the species described in this paper 

 in a review of the Middle Cambrian fauna. 



Lingulella mcconnelli n. sp. 



Shell subspatulate, height and breadth as 7 to 4J. Ventral valve 

 subattenuate towards the apex, broadest midway, with the sides con- 

 verging slightly towards the front and rather rapidly towards the apex; 

 front broadly rounded. Dorsal valve short, height and breadth sub- 

 equal; the broad front is squarely rounded, and the apex broadly 

 rounded. 



The specimens are somewhat flattened in the shale, but the rather 

 strong shell preserves a moderate convexity. Surface marked by con- 

 centric stride of growth and radiating longitudinal lines. 



Formation and locality : Middle Cambrian, 2,000 feet above the Ole- 

 nellus zone, Mt. Stephen section, British Columbia. Collection of Dr. 

 Karl Romiuger. 



Crania (?) Columbiana n. sp. 



Shell small, circular or slightly longer than wide; apex central or 

 nearly so. Surface marked by fine costa? that radiate from the apex to 

 the margin. Traces of fine spines appear about the margin. Diam- 

 eter 2 mm . 



The generic reference is made on account of the surface characters 

 being more like those of shells referred to Crania than to those of other 

 genera: Crania grayi Davidson, Crania Icelia Hall (21th Rep. X. Y. 

 State Cab. Nat, Hist., p. 220, pi. 7, fig. 16). 



Formation and locality: Middle Cambrian, 2,000 feet above the Ole- 

 nellus zone, Mt. Stephen section, British Columbia. Collection of 

 Dr. Karl Romiuger. 



Acrotreta gemma var. depressa n. var. 



The specimens from Mt. Stephen are relatively much lower and 

 broader in proportion to the height than the typical forms of A. gemma. 

 On this account they are considered as a variety. 



