254 



Report of the State Geologist. 



47. Modiomorpiia subalata, Conrad. 



1885, Hall, Pal. N. Y., vol. 5, pt. 1. p. 288, pis. 35, 39. 



This is the most abundant lamellibranch in these shales, being at the same 

 time one of the best preserved. It is very common in the limestone layer 

 which lias been named from it the Modiomorpiia sublata bed, and which is 

 twenty-five feet below the Encrinal limestone. The specimens are of average 

 dimensions and though mostly denuded of the shell, show the surface markings. 

 It is common in the Trilobite beds, but otherwise it is not abundant. 

 A few fragments and valves have been found up to ten feet below the Encrinal 

 limestone. A doubtful specimen was obtained at Section C, about three feet 

 below the Encrinal limestone. It occurs occasionally in the upper Pleurodic- 

 tyum layer of Avery's creek and rarely in the shale immediately above. 



48. Modiomorpiia alta, Conrad. 



1885, Hall, Pal. N. Y., vol. 5, pt. 1, p. 278, pi, 37, 80. 



A single specimen denuded of the test, but having the proportions of this 

 species, was found in the middle Pleurodictyum layer at Avery's creek. The 

 dimensions are : length (38 mm.; greatest height 43 mm. 



Genus Goniophora, Phillips. 



49. GONIOPIIOR.V MODIOMORPHOIDES, sp. IIOV. 



Description. Shell of medium size or larger; length one and a half 

 times the height. A'entral margin nearly straight for about two-thirds of 

 the distance from the anterior end, with a slight constriction at about the 

 anterior third delimited by the oblique sinus. Posterior portion gently 

 deflected upwards, to the unibonal ridge. Cardinal line arcuate, extending 

 for about three-fourths of the length of the shell; margins inflected. 

 Posterior end obliquely truncate, margin sometimes slightly curving. 



Valves more or less convex below the unibonal ridge, rarely almost flat ; 

 a slight concavity just beneath the ridge, sometimes observed. Above the 

 ridge, the slope to the cardinal line is ilat or slightly concave. Beaks nearly 

 anterior, incurved, not shown in the typical specimens. Unibonal ridge 

 angular, extending from the beak to the post-inferior margin, regularly 

 and evenly arcuate in the posterior two-thirds of its extent, more abruptly 

 bent downwards in the anterior third. The cardinal region above the ridge 



