312 ANNALS NEW YORK ACADEMY OF SCIENCES 



To summarize the matter so far as considered, the Bedford fauna is 

 in many respects unique. It can be traced southward into Kentucky, but 

 it cannot be traced eastward into Pennsylvania. Its place in the "Brad- 

 fordian" of Pennsylvania has not been determined. It is distinct from 

 the "Bradfordian" fauna. It is distinct from the Chemung fauna. It 

 is quite distinct from the Chagrin fauna, which underlies it in the same 

 section, and which, while differing in important particulars from the 

 typical Chemung fauna, has nevertheless more of a Chemung aspect. It 

 is equally distinct from the overlying Berea ("Corry") fauna, which has 

 more of a Mississippian aspect. It has a Devonian, or, as has sometimes 

 been said, a Hamilton facies, because, while it consists mostly of genera 

 which range into the Carboniferous and of species many of which have 

 Carboniferous affinities, it is nearly lacking in the strictly Carboniferous 

 types which abundantly accompany the latter at higher horizons and 

 proclaim the geologic age, and because it contains a few Devonian types 

 which very rarely and in the region under consideration never, so far as 

 known, range up into the Carboniferous. 



The Bedford and Cleveland formations may be lacking in northwestern 

 Pennsylvania owing to pre-Berea erosion, or to some other cause, but I 

 hardly believe this to be the case. If the Bedford does represent part of 

 the typical "Bradfordian" section, and if its fauna is a peculiar and local 

 development of the "Bradfordian fauna," then we must enlarge the dis- 

 cussion to include the "Bradfordian" ("Upper Chemung") faunas, 

 whose Devonian facies is conspicuous. 16 In the one case (if properly 

 lying above the "Bradfordian" but removed by erosion in the typical sec- 

 tion) the stratigraphic evidence, and in the other the paleontologic evi- 

 dence, is stronger for classifying the Bedford shale as Devonian. To 

 this must also be added the fact of a conspicuous faunal break between 

 the Bedford and the Berea, and the fact already noted that in the Berea 

 ("Corry") we have, for the first time in this region, a fauna with a pre- 

 dominating Carboniferous aspect, one which shows many new features 

 when compared with the typical Mississippian, but which is distinguished 

 by the absence of most of the Devonian types of lower horizons and the 

 presence of many characteristic Carboniferous ones. 



Thus far it seems that the evidence has been strongly favorable to 

 classifying the Bedford with the Devonian. If we broaden the discus- 

 sion so as to include a larger field, that of the typical Mississippian area, 

 which apparently represents a conspicuously different province, or at 



18 See the "Upper Chemung" species of Hall's New York reports and Butts's lists of 

 the faunas of the Knapp and Oswayo formations. These show a fairaa with well 

 marked differences from the typical Chemung, yet with, in my opinion, a distinctly De- 

 vonian aspect. 



