26 UNIVERSITY OF MISSOURI BULLETIN 



species of cephalopod. One specimen was complete but it was 

 pyritized and was found to be entirely ruined within six months 

 of the time that it was collected. 



About sixty-five feet below the Bedford large specimens of 

 Lingula spatulatus occur in abundance. They often reach a 

 length of 19 mm., while those from near the bottom of the Ohio 

 shales are rarely more than 9 mm. long. Though this species 

 is so abundant, no remains of other species have been noted in 

 the same beds. 



Invertebrate fossils are most abundant in the upper four 

 feet of the shales. Twenty-five or thirty species occur here, 

 mostly of brachiopods, pelecypods, and gastropods. This 

 horizon is fossiliferous in every locality where the writer has 

 observed it and the only invertebrates from below are lingu- 

 las and one cephalopod. 



A fact of some significance is that the remains preserved 

 in the Ohio shales to within a few feet of the top are of animals 

 whose hard parts were originally phosphatic. Fishes and the 

 brachiopod Lingula make up nearly all of the fossils, but it 

 seems improbable that they constituted the only life of the sea 

 of the area where the Ohio shales occur. In the Romney shales 

 of northern Virginia phosphatic shells are almost the only ones 

 preserved. The explanation seems to be that the carbonate 

 shells were redissolved and the phosphatic remains fossilized, 

 rather than the usual supposition that the other forms were 

 absent from the seas. A rather superficial examination of 

 literature on the chemistry of the process has failed to show 

 that conditions likely to have existed at that time were peculiar- 

 ily favorable for the solution of carbonates and not of phos- 

 phates, but the investigations were not applied to a problem 

 of this kind and are not conclusive. 



