100 The Lower Devonian Deposits of Maryland 



The subzones are characterized as follows : 



Chonetes jerseyensis Zone. — The Warrior Mountain coral reef Suh- 

 zone occurs at the base of the Helderberg on Warrior Mountain. It is 

 well exposed on the mountain side north of the tri angulation station, at 

 which place it contains a profusion of Favosites pyriformis, F. favosus 

 integritahidatus , and Si/ringostroma centrotum. 



Ehynchospira Subzone. — The beds overlying the Warrior jMountain 

 coral reef, or in the absence of the latter, the lower beds of the Keyser, 

 contain a profusion of Chonetes jerseyensis and associated Decker Ferry 

 species. This fauna is especially well developed at Tonoloway where it 

 contains the following species: Favosites pyriformis, Atrypa reticularis, 

 Camarotcechia litchfieldensis, Chonetes jerseyensis, Meristella sp., Ehyn- 

 chospira glohosa, Ehynchospira formosa, Schuchertella deckeretisis, 

 Spirifer modestus, Spirifer oclocostatus, Stropheodonta hipartita, Uncinu- 

 liis convexora, Cyphotrypa corrugaia, Fenestella cumberlandica, and 

 Klcedenella clarhei. 



Cladopora rectilineaia Subzone. — Cladopora reciilineata occurs pro- 

 fusely at many localities beneath the horizon of the second coral reef. It 

 may be identical with the Cladopora rectilineata zone of the Decker Ferry 

 formation of New Jersey. Associated in it are: Favosites pyriformis, 

 Cyathophyllum inequale, Atrypa reticularis, Camarotcechia litchfield- 

 ensis, Camarotcechia lamellata, Dalmanella concinna, Ehynchospira glo- 

 hosa ?, Schuchertella decherensis, Uncinulus convexorus. 



Eawlings Stromatopora reef Subzone. — A second reef, or series of reefs, 

 occurs 50 to 75 feet above the base of the Helderberg at many localities, 

 as at Hancock, Tonoloway, southwest of Eawlings, Maryland, and Hynd- 

 man, Pennsylvania. It is not possible to affirm that these reefs, found at 

 such widely separated points, occupy one horizon, although their strati- 

 graphic position is approximately the same and they bear similar f aunules. 

 Common species are Syringostroma barretti, Favosites pyriformis, Aulo- 

 pora schohariw, and A. schucherti. 



Spirifer modestus-cystid Subzone. — The succeeding subzone contains a 

 faunule of great interest. Species of Spirifer are common in it, including 

 Spirifer modestus, S. eriensis, S. vanuxemi var. prognosticus, and S. 



