0. E. Beecher — Cambrian Fossils of Missouri. 363 



is a suggestion of affinity with the Potsdam fauna of Wiscon- 

 sin and Texas. A careful comparison, however, reveals that 

 these resemblances are more general than specific and that the 

 species seem to be distinct. Nevertheless, the facies of this 

 fauna seems to indicate Upper Cambrian, though further 

 studies with additional material may show it to belong to the 

 middle member. 



Owing to the small number of specimens in the present col- 

 lection, the number of species is necessarily limited. It will 

 doubtless be considerably increased by future collections. 

 Among the trilobites the genera Btychoparia, Ptychaspis, 

 Chariocepfialus, and Crepicephalus, are more or less clearly 

 identifiable. A species of Chariocephalus closely agrees with 

 the O. onustus of Whitfield. 



The species of brachiopods seem to be fairly abundant, 

 especially an orthoid shell resembling in some respects Bil- 

 lingsella. It occurs in the shaly partings between the layers 

 of limestone. A species of Acrotreta and a Lingulella are 

 common both in the limestones and arenaceous beds. 



Hyolithes primordialis Hall and a small species of Platyceras 

 also occur in the limestones, together with segments of cysti- 

 dean or crinoidal columns. 



Abundant remains of a linguloid shell are found on the 

 lower, or La Motte, sandstones constituting the basal member of 

 the clastic rocks of the section. Making allowances for differ- 

 ent conditions of preservation, this species may be identified 

 with the Lingulella Lamborni of Meek, which occurs in some 

 green shales of the same age in Madison County, a little fur- 

 ther south. In the absence of other evidence, the diagnostic 

 value of this brachiopod is very slight, and it is impossible to 

 say whether the Bonne Terre, or St. Joseph, limestones and the 

 La Motte sandstones represent Lower Cambrian terranes or 

 whether they with the Potosi all belong to the Middle or Upper 

 Cambrian. 



The important point of this correlation is that, upon paleon- 

 tological evidence which has hitherto been largely wanting, an 

 extensive area and thickness of sedimentary rocks are definitely 

 placed in the Cambrian. 



Yale University Museum, New Haven, Conn., June, 1901. 



