154 



Contributions to Palaeontology. 



PLATE III. 



Fig. 22. The glabella, preserving part of the fixed cheeks, frontal limb, 



and posterior spine. 

 Fig. 23. Profile of the same. 



Fig. 24. Pygidium associated in the stone with the specimen fig. 22, and 

 several other similar ones. 



Fig. 27. A smaller specimen, presenting some slight variations from the 

 preceding figure 22. 



Fig. 28. Profile of the same. 



This species occurs at Trempaleau, Wisconsin, and opposite the 

 mouth of the Chippewa river in Minnesota, associated with Ptycha- 

 spis granulosa, Aynostusjosepha, etc., in beds that I have recognized 

 as the second fossiliferous group of the sandstone. The locality of 

 Dr. Owen's specimen is not given ; but from its association with 

 Ptychaspis (Dikelocephalus) granulosus, I infer it to have been from 

 near Trempaleau. 



CONOCEPHALITES HAMULUS. 

 PLATE II, FIGS. 43 & 44 ; AND PLATE III, FIGS. 25, 26. 



Lonchocephalus hamulus : Owen, Geol. Report Wisconsin, Iowa and Minne- 

 sota, page 576, Tab.I A, f.8 & 12. 



The glabella, frontal limb and fixed cheeks, without the 

 posterior limb ; form a suboval figure, which is concave 

 on the sides (fiddle-shaped). 



Glabella subtruncate-conical, narrow, the length greater 

 than its width at the base, subtruncate or slightly round- 

 ed in front ; furrows very obscure, moderately convex, 

 and sometimes subangular along the middle. Occipital 

 furrow not deep, well marked at the sides, and shallow 

 or obsolete in the middle : occipital ring wider iu the 

 middle, elevated above the base of the glabella, and 

 produced into a long slightly arcuate spine. 



Facial suture cutting the anterior margin in a nearly 

 vertical line from the inner margin of the palpebral 

 lobe ; thence, making a gentle curve outwards, it returns 

 to the same line just in advance of the eye, and thence 

 to the posterior edge of the palpebral lobe, leaving a 



