186 



Gexus CRAXIELLA. Oehlert. 



[Ety. : Diminutive of crania] 



( 1888: Bull, de la Soc. d'Etudes Scieutif. d'Aiigers, p. 37. 1892: Pal. N. Y., 

 Vol. VIII., Pt. I., pp. 153, 170.) 



Shell 8omewhat irregulai-, with an outline varying- fi'oni 

 nearly circular to almost qiiadrangular ; no pedicle opening, 

 but lower valve cemented, by its whole surface, to rocks 

 or other shells; upper valve more or less elevated, apex 

 behind the center; four large adductor muscle impressions, 

 one pair near the center; outside of these lie S-shaped vas- 

 cular impressions. 



Craniella HAMir>To.\i.E. Hall. ( Fig. 87. ) (Pal. X. Y., 

 Vol. IV., p. 27, PL III.) 



Distinguisliiiig Characters. — Large size; adaptation to 

 surface on which it is attached; irregularly rounded outline; 

 and concentric lines of growth about an eccentric apex. 



Fig. 87. Craniella hamiltonici' . Tdp 

 ventral valves attached to a valve of Cijii 

 of a ventral valve (from Hall). 



I l.ii.ral views of a dorsal valve: a group of 

 (trdi'llit bellistriata; enlargement of the intei-ior 



Found in the coral layer of the Moscow shale, at Section 

 5 (?) and just above it; also in the Stictopora and Demissa 

 beds, at Section 5 ; in the shale below the A. spiriferoides bed 

 and two feet below the Trilobite beds, in Avery's Creek. 



Gents PHOLIDOPS. Hall. 



[Ety. : PlioUdos, a scale.] 



(1859: Pal. N. Y., Vol. III., p. 489. 1892: Pal. K Y., 

 Vol. VIII., Pt. I.,p. 155.) 



Shells small, with ef^ual valves, patelladike in outline; 

 they are inarticulate and unattached, without pedicle 



