Maryland Geological Sukvhy 575 



fauna with Schizoplioria striatula it seems wiser at the present to dis- 

 tinguish it by a varietal term only. 



Length 13 mm.; width 18 mm. 



At some localities a few shells have been seen which pass the limits of 

 size of var. marylandica and lack the marked median depression in both 

 its valves. These are probably yoimg shells of S. striatula. 



Occurrence. — Jennings Forjmation, Chemung Member. National 

 Eoad west of Frostburg; Oakland-Altamont Road; Deer Park Station 

 and between there and Oakland; south of Oakland at crossing of Cherry 

 Creek; % mile west of junction of Oakland-Deer Park Eoad with Deer 

 Pnrk-:\Iountain Lake Park Road, abundant; Allegany Grove, 2020, 2070; 

 Town Creek, -1769. 



Collection. — Maryland Geological Survey. 



Order TELOTREMATA 



Superfamily RHYNCHONELLACEA 

 Family RHYNCHONELLIDAE 



Genus CAMAROTOECHIA Hall and Clarke 



Camarotcechia congregata var. tarkiieadensis n. var. 



Plate LIII, Figs. 11-16 



Description. — Shell ovate, width usually a little greater than length, 

 front rounded or slightly truncate; apex pointed. Ventral valve convex 

 at sides, depressed in middle; mesial sinus beginning near apex, becoming 

 deep in front where in some cases it may form a lingua-form extension; 

 beak closely incurved over that of dorsal valve in older shells, slightly 

 curved in younger shells. Dorsal valve convex to gibbous, mesial fold 

 beginning near apex and becoming prominent towards front. Surface 

 marked by angular plications of which 3, less frequently 4 and occasion- 

 ally 5, occupy sinus, and 4 to 6 occur on each side of fold. 



The individuals here described differ from the typical form in fre- 

 quently having a deeper sinus bearing 3-5 plications, and in being less 

 rotund and more transverse. Thev resemble C. contrata but differ in 



