460 Canadian Record of Science. 



Horizon and Locality. — In a fine gray shale, containing 

 grains and lumps of calcium phosphate, included in the 

 Coldbrook volcanic rocks at Dugald Brook, Escasonie. 

 Scarce. 



This ancient Ostracod has the outline of a Beyrichona, 

 but there is no flattened cardinal area of the valve, nor 

 any trace of the deep muscle-pit of that genus. It is 

 separated from Bradoria by the absence of ocular tubercle 

 and posterior cardinal slope. It is provisionally placed in 

 Escasona, though lacking the high elevation of the cardinal 

 third of the valve, peculiar to that genus. 



INDIANA, n ffen. 



Two forms of Ostracods of the Etcheminian Fauna differ 

 from any of the preceeding by their marked oval form 

 and do not seem to fall into any of the later genera. The 

 author has heretofore referred resembling forms to 

 Aparchites and Primitia, but omitting from consideration 

 the large size of most of the Basal Cambrian species, they 

 also have usually a well developed ocular tubercle, or 

 the rudiments of one. 



In a decorticated example there is a faint muscle mark, 

 where the muscle scar is placed in Bradoria and Bradorona, 

 but it projects less toward the middle of the valve than in 

 those. 



The genus consists of large to medium-sized Ostracods, 

 oval or ovate in form, the outline somewhat straightened 

 along the hinge, somewhat sharply rounded at the anterior 

 end, more broadly at the posterior. A ventral angle is 

 scarce traceable, and the greatest fulness is in the posterior 

 half of the valve. The valves are evenly rounded, and 

 highest about the middle. An ocular tubercle, or traces 

 of one, can usually be seen in the upper anterior region of 

 the valve. 



Length of the known specie, 3 to 6 mm. 



