Maryland Geological Survey 533 



Description. — " This species resembles the last [K. sussexensis'] but 

 is smaller, with the anterior furrow narrower and with the posterior one 

 produced further toward the ventral margin, giving to the median lobe a 

 more elliptical outline. 



"' The surface is also very differently marked, it being covered with 

 rather large, irregular pits. The ventral margin is nearly straight in the 

 central portion, the anterior and posterior extremities of the valve being 

 of nearly equal height. 



"The dimensions of the type specimen are: Length 2.3 mm.; height 

 1.5 mm." Weller, 1903. 



Occurrence. — Helderberg Formation, Keyser Member. Tonoloway. 



Collection. — U. S. National Museum. 



Genus KLCEDENELLA Ulrich and Bassler 



Klcedenella pennsylvanica (Jones) 

 Plate XCVII, Figs. 18-21 



Ela-denia pennsylvanica Jones, 1889, Amer. Geol., vol. iv, p. 341, pi. figs. 5a-d, 



6 (not 7a, b, 8, 9). 

 Kladenella pennsylvanica Ulrich and Bassler, 1908, Proc. U. S. Nat. Mas., 



vol. XXXV, p. 304, fig. 54, p. 318, pi. xliii, figs. 1-3. 



Description. — As noted in the remarks under Kladenella turgida several 

 distinct species were referred to Klcedenia pennsylvanica by Jones in his 

 original description. The present writers have restricted this species to 

 Jones's figs. 5 and 6. The differences between these several species are in- 

 dicated in the remarks under KloedeneUa turgida and Elwdenella turgida 

 ventrosa. 



Occurrence. — Helderberg Formation, Keyser Member. Tonoloway, 

 and other localities in Maryland. The species occurs also in the lower 

 beds of the Helderberg in Pennsylvania and other states. 



Collection. — U. S. National Museum. 



Klo:denella claukei (Jones) 

 Plate XCVII, Fig. 21 



Beyrichia clarkei Jones, 1890, Quart. Journ. Geol. Soc. Lond., vol. xlvi, p. 17, 

 text fig. 2. 



