THE STATE GEOLOGIST. 79 



owing probably to its great thickness, is seldom obtained in a per- 

 fect form." The younger Redfield, commenting on the same 

 species in 1854, pronounced it "the broadest and most ovate 

 species of Palaeoniscus that is known," and added further that "in 

 size of the scales it resembles P. Agassizii, but its form will readily 

 distinguish it." 



This species is recorded by both of the Redfields from the Con- 

 necticut Valley Trias and from Boonton, New Jersey. The same 

 distribution is claimed for it by Newberry, who also identifies 

 with this species a fragmentary individual from the Triassic Coal- 

 field of Virginia, originally referred to- Tetragonolepis by Sir 

 Philip Grey Egerton. It is to be observed that all of the more 

 perfect examples have been obtained from Boonton, and the rec- 

 ognition of this species from other localities depends upon the 

 evidence of more or less fragmentary remains. The original of 

 Newberry's published figure is now preserved in the American 

 Museum of Natural History, in New York. In Plate VI. is repre- 

 sented what is evidently a young individual of this species, and 

 it will be noticed that some resemblance exists between it and the 

 published figure of the so-called S. beardmorei. 



Semionotus robitstus (Newberry). 



1888. Ischyptertis robustus, J. S. Newberry, Monogr. U. S. Geol. Surv, vol. 

 xiv, p. 36, pi. vi., fig. 1. 



A species of slightly smaller size than the preceding, and stated 

 to be distinguished from it by "the great height, breadth and 

 strength of the dorsal fin and its anterior position." Dorsal fin- 

 fulcra very numerous, strong, curved; rays of dorsal fin 11, very 

 strong. Pectorals relatively long and broad; pelvic fins inserted 

 nearly opposite the anterior margin of the dorsal. Dorsal ridge- 

 scales well developed, forming a prominent crest; trunk scales 

 large and strong. 



This species, of which only two or three examples are known, 

 is doubtfully distinct from S. ovatus. During the time this report 

 was in preparation Newberry's originals were packed in cases 

 awaiting rearrangement in the American Museum of Natural His- 

 tory in New York, and hence not available for study. They were 

 derived from Boonton, and no others have since been obtained. 



