60 UNIVERSITY OF MISSOURI BULLETIN 



Mr. Rowley says of the occurrence of these fossils: "I 

 have found them in the one-foot dark blue shale under the 

 Louisiana or lithographic limestone, from the top of the shale 

 quite to the bottom, but most abundant from the middle to 

 the top. Just under the Louisiana limestone is a thin band 

 of yellow sandy shale, from a fraction of an inch to two and 

 one-half inches thick, well filled with the same fossils as the 

 limestone above. In places, especially where the yellow shale 

 is thin, the fossils extend downward, sometimes two or three 

 inches, thus invading the fish bone horizon. 



"Near the bottom of the three and one-half feet of black 

 shale that underlie the blue shale at Louisiana, is a siliceous 

 sandstone band of less than an inch in thickness that yields 

 fragments of teeth and bones and the black objects identified 

 as coprolites. On Grassy Creek, where the blue as well as 

 the black shales increase greatly in thickness, there appears 

 to be more than one band of siliceous sandstone, and the upper 

 band is often two to four inches thick."* 



ARTHRODIRA 



Dinichihys rowleyi sp. nov. 



(Plate I, figs. 1, 2, 4, 5, 6) 



This species is based on a left upper dental plate, the pos- 

 terior end of a mandible, an occipital, external occipital, and 

 dorso-median, all of which are in the collection of Mr. Rowley. 



The left upper dental is almost perfectly preserved. Its 

 greatest length is 59 mm., and the greatest width of the cutting 

 blade is 22 mm. The cutting blade is almost straight and 42 

 mm. long. The tooth has no lateral flange and its surface is 

 smooth. (Fig. 5). 



The mandible has only the posterior part preserved. It 

 is 7 cm. wide at the widest part. (Fig. 6). 



The occipital is 75 mm. wide at the posterior end, 40 mm. 

 at the anterior end, and 72 mm. in length. The bone is pecu- 



"Letterfrom Mr. Rowley, dated Sept. 6, 1912. 



