244 r 



of its spine, the small and more oblique rods, and non-dentate edge of the 

 same. 



It was originally established on a spine which, when complete, measured, 

 according to Professor Mudge, forty-one inches in length ; the portion now 

 before me measures thirty-one inches. The margin is exceedingly acute, and 

 is coated with an enamel-like layer, which conceals the extnemities of the 

 rods of which the spine is composed. Near the middle of its length, these 

 rods number thirty; but whether the entire width of the spine is preserved 

 is uncertain. The transverse section is a crescent from the base to beyond 

 the middle ; the surface being thus somewhat trough-like. The spine has 

 been somewhat distorted by pressure; but I cannot discover that the form in 

 question is entirely due to that cause. The edge is excavated and notched, 

 at irregular points, indicating the frequent use to which this formidable 

 weapon was put during the life of its possessor (Plate LII, fig. 3). 



Measurements. 



M. 



Total length (fide Mudge) 1.040 



Width near the middle 0. 175 



Thickness posteriorly near the middle 0.012 



A second specimen, found by myself in the blue limestone-shale in 

 Fossil Spring Canon, is composed at the base of about twenty-six narrow 

 double rods. A few appear between the others beyond the base, making 

 thirty-one altogether. They are very oblique to the general base, but curve 

 so as to become nearly straight, and enlarge distally. They terminate in 

 a thickened portion, which bears an acute edge, which truncates them 

 obliquely. This portion is enameled ; the edge is slightly convex at the 

 base, and slightly concave at a point probably beyond the middle (Plate 

 XLIV, fig. 12). 



Measurements. 



ir. 



Length of fragment (12 inches) 0.30 



Width at the baso ". 0. 12 



Thickness at the base 0.012 



Thickness at the broken end an inch from the edge 0. 007 



This is a formidable weapon, and could be readily used to split wood in, 

 its fossilized condition. 



