148 Annals of the Carnegie Museum. 



Locality. — This is a rather rare species, and has been found only 

 in the red fissile shale of the Upper Devonian at Three P'orks, Montana. 



Family MODIOLOPSID^ Fischer. 

 Genus Goniophora Phillips. 

 Goniophora subrecta Hall ? 



(Plate VI, figures 1-3.) 



Goniophora subrecta Hall, 1885. " Paleontology of Ahw York,'' Vol. V, pt. 2, Vol. 

 II, p. 304, PI. 42, figs. 14, 15; PI. 44, figs. 19, 21. 



To this species is referred with considerable doubt a shell which is 

 very common in all but one of the zones of the Upper Devonian in 

 the vicinity of Three Forks, Montana. The specimens differ from those 

 described by Hall in having a somewhat longer hinge, a more nearly 

 square posterior end, and a more rounded anterior margin. The speci- 

 mens from the red shale are all much smaller than those obtained from 

 the limestone and the green shale. 



Class CEPHALOPODA. 



Subclass TETRABRANCHIATA. 



Order NAUTILOIDEA. 



Family ORTHOCERATID^ Hyatt. 



In the fauna obtained from the red shales there are several species 

 of straight-shelled nautiloids, represented in large part by small frag- 

 ments of the chambered portion of the shells. Three of these forms 

 are sufficiently abundant and represented by enough material to make 

 them worthy of description. All are circular in section, with smooth 

 surface, small, slightly eccentric siphuncles, and short siphuncular 

 collars. While the material at hand is hardly sufficient to render the 

 generic reference certain, yet it seems very probable that they belong 

 to the family Orthoceratidfe as defined by Hyatt, and that one 

 of them is an Orthoceras, while the other two have the very small 

 siphuncles of Geisonoceras. 



Genus Orthoceras (Breyn.) emend. Hyatt. 



Orthoceras montanense sp. nov. 



(Plate VI, figures 4-6,) 



This species is known only from fragments, none of which are large. 

 The shell is circular in section and tapers very gradually. The 



