336 Report of the State GEOLoaiST. 



surface is completely covered with closely set granules which are 

 somewhat coarser toward the margins. A few concentric 

 wrinkles of growth are also visible. Diameter, 18 mm. 

 Hamilton group. Centerfield^ N. Y. 



Crania favincola. 



Plate 3, fig. 18. 



Crania favincola^ Hall. Palaeontology of N. Y., vol. YIII, pt. 1, p. 181, pi. 

 iv h, fig. 33. 1892. 



Two interiors of the lower valve attached to a colony of Favo- 



sites jpirum have very strongly developed muscular and vascular 

 impressions. The posterior scars are large and their strongly 

 elevated margins unite with the broad lateral border of the shell. 

 The anterior scars are situated in front of the center and are 

 partially enveloped by the great elevation of the anterior and 

 median fulcra. The vascular sinuses are broad, slightly undulat- 

 ing grooves, extending from the median region to the anterior 

 border. Length, 17 mm., width, 21 mm. 

 Hamilton group. Crah Orchard^ Kentucky. 



Craniella Ulrichi. 



Plate 3, figs. 15, 16. •' 



Craniella Ulrichi, Hall. Palaeontology of N. Y., vol. VIH, pt. 1, p. 181, pi. 

 iv i, figs. 1, 2. 1892. 



Shell moderately large. Outline normally circular. Apices 

 subcentral, slightly posterior, inclined backwards. Upper valve 

 with the posterior scars large and the adjustors well defined; 

 anterior scars subdivided, the outer or posterior portion possibly 

 representing the insertion of the brachial muscles. The vascular 

 sinuses make a 3-shaped curve on the lateral portions of the valve, 

 with the crest of the double arch toward the center ; narrowing 

 rapidly, becoming indistinct over the anterior region. Lower 

 valve regularly convex, evidently unattached at maturity. An- 

 terior adductors very large, situated on a thickened posterior 

 area. Posterior adductor and adjustor scars very faint, lying 

 just within the margin. The vascular sinuses are a series of low 

 grooves extending forward in subparallel lines from the anterior 

 and lateral margins of the central muscular area. External 



