OKISKANY FAUNA OF BECKAFT MOUNTAIN 25 



Proetus conradi Hall 



Plate 2, flg. 11-16 



1S61. Proetus conradi Hall, Descriptions new species of fossils, p. 69 

 1892. Proetus sp. nov. ? A ; Proetus, sp. nov. B, Clarke, op. cit. p. 412 



Separated cranidia and pygidia of a species of tliis genus are suffi- 

 ciently common and these vary greatly in size. Though some of them 

 attain much greater dimensions than any specimens of Proetus 

 conradi, yet they all seem to agree in structure among themselves 

 and with typical examples of that species from the Schoharie grit. 

 Specific distinctions among such Devonic forms of this genus as express 

 the old division G e r a s t o s, and are represented in the New York 

 series by P. angustifrons, conradi, clarus and r o w i, are 

 pretty close and yet dependable. The special traits of P r o e t us con- 

 radi are its subovoid or subtriangular and quite convex glabella, tan- 

 gent at its extremity to the inner margin of a flat frontal border, and 

 a pygidium with sloping pleurae bearing three or four rather indistinct 

 duplicate ribs, the axis having from 8 to 10 annulations which 

 curve backward along the median line. 



But a single entire example of the species has been observed and 

 this is of medium size, attaining the proportions usual to species of this 

 type throughout the early Devonic faunas. 



Acidaspis tuberculata Conrad 



Plate 2, flg. 26 



1840. Acidaspis tuberculata Conrad, Ann. repH geol. sur. N. Y. p. 205 



This species, common in certain layers of the New Scotland beds, 

 is here represented by specimens of various sizes, often attaining con- 

 siderable dimensions. 



Lichas cf. pustulosus Hall 



1859. Lichas pustulosus Hall, Paleontology of New YorTc. 3 : 366 



There have been found a few fragments of pygidia and other parts 

 of the test which may prove to belong to this Helderbergian species. 



