340 CHARLES K. SWARTZ 



indicating all the species thus far observed in each fauna. (Only those 

 occurring in the three lower brachiopod faunas will be cited here.)^ 



CORRELATION OF THE FAUNAS 



We may now examine the problem of the correlation of the Upper 

 Devonian faunas of Maryland with those of New York and Penn- 

 sylvania by the use of the data given above. 



Genesee Fauna. — The Genesee of Maryland, as has been shown 

 by earlier students of the problem, bears a fauna very similar to 

 that of the Genesee of New York which it also resembles in thinning 

 out and disappearing toward the east. 



Naples fauna. — Above the Genesee, in the western sections, or im- 

 mediately overlying the Hamilton, in the eastern sections, are smooth 

 fissile shales and interbedded sandstones carrying Goniatites, Buchiola, 

 Pterochaenia, etc., as in the Naples fauna of New York, These strata 

 are about 700 feet thick in the Allegany Grove Section. They increase 

 considerably in thickness in the vicinity of Cumberland, and thin to 

 about 500 feet in the eastern sections. The correlation of this division 

 has been previously discussed by Professor Prosser^ who assigned to it 

 a thickness of about 2,000 feet in the central part of the area.^ 



Spirifer pennatus var. posterus fauna. — ^This fauna occurs imme- 

 diately above the Naples fauna. It is of wide extent and is especially 

 developed in the eastern sections. It is characterized by the abun- 

 dance of Spirifer pennatus var. posterus, Productella speciosa, Pugnax 

 pugnus, Cyrtina hamiltonensis, Schizophoria striatula, and Leiorhyn- 

 chus glohuliforme at most of its localities. The complete list of species 

 observed in it is given on a preceding page. Of these, five, Spirifer 

 pennatus var. posterus, Productella speciosa, Tropidoleptus carinatus, 

 Cyrtina hamiltonensis, Spirifer mesastrialis, and Leiorhynchus mesa- 

 costale are placed by Williams'* among the dominant species of the 

 Ithaca fauna, which he has named the Productella speciosa fauna, 

 while Pugnax pugnus and Schizophoria striatula are also prominent 

 members of that fauna. Leiorhynchus glohuliforme is also quoted by 



1 The new species here cited will be described later in the Report on the Devonian 

 0} Maryland, to be issued by the Maryland Geological Survey. 



2 Journal of Geology, Vol. IX, pp. 419, 420, 1901. 



3 Maryland Geology Survey, Vol. VI, Part I. p. 136, 1906. 



4 Bulletin oj the U. S. Geological Survey, No. 210, p. 74, 1903. 



