230 



angular plications on each valve, of which four to .seven 

 mark the fold or sinus; concentric undulating stria?. 



Found iii the lower Moscow shale, at Sections 4 and 5 

 (rare); Encrinal limestone, at Section 5 (rare); Stictopora 

 bed, at Section ~> (rare); Nautilus bed, in Erie Cliff (?), (very 



rare). 



Camarotggchia sappho. Hall. (Fig. 140.) ( Pal. X. V.. 

 Vol. IV.. ].. 340, PL LIV.) 



Fie. 140. Camarotcechia sappho. Front, cardinal, dorsal (brachial), ventral (pedicle), 

 and lateral views of a characteristic specimen (from Hall). 



Distinguishing Characters.— Rather large size; robust 

 character; broader than long; shallow pedicle valve, which 

 is prominently convex only at the umbo, and is depressed 

 tow aids the front into a sinus, which first becomes percepti- 

 ble near the middle of the length ; more or less incurved beak 

 of pedicle valve ; gibbous brachial valve, with the fold con- 

 spicuous only near the front; coarse plications, twenty to 

 twenty-four on each valve in mature specimens, all incised 

 towards the front, for the reception of the opposite plica- 

 tion; sinus and fold with four to six plications each. 



Found in the Encrinal limestone, at Section 5 (frequent); 

 Lower shales, down to three feet below the Encrinal lime- 

 stone, a1 Sections 5 and 6; seventeen to twenty-one feet 

 below the Encrinal limestone, at Section 7 (common); mid- 

 dleTrilobite bed (very rare); also in the Pleurodictyum beds, 

 in Averv's < 'reck. 



