Marylaxd Geological Survey 111 



Weller's second zone, characterized by the bryozoan ' Ptilodidija 

 frondosa, is very thin and has not been recognized in Maryland. 



His upper zone contains a rich coralline fauna of which the more im- 

 portant species are Cladopora rectilineaia, Favosites pyriformis, Cyatho- 

 phyllum inequale, Ilalysites catenulatus, and stromatoporoids. The 

 Cladopora rectilineaia zone of the Keyser of Maryland occupies a similar 

 position and contains Cladopora reciilineata in profusion associated with 

 Favosites pyriformis and Cyatliopliyllum inequale. Ilalysites catenulatiis 

 occurs at a somewhat higher horizon. A zone in a like position in the 

 lower Keyser of central Pennsylvania abounds in Cladopora rectilineaia 

 and Haly sites catenulatus. 



An examination of the entire fauna of the Chonetes jerseyen^is zone of 

 the Keyser of Maryland still further emphasizes its close faunal relation 

 to the Decker Ferry of New Jersey. Of 40 species, other than ostracods, 

 described by Weller from the Decker Ferry 60 per cent occur also in the 

 Chonetes jerseyensis zone of Maryland, including its most diagnostic 

 forms. Eighteen, or 38 per cent, of the previously described species found 

 in the Keyser of Maryland occur also in the Decker Ferry of New Jersey. 

 This difference is due in part to the fact that the Keyser of Maryland con- 

 tains a much larger fauna than the corresponding beds in New Jersey. 

 The table of distribution exhibits this relation more fully. 



The Decker Ferry also resembles the lower Keyser lithologically, some 

 beds being nodular while all are highly f ossilif crous, contrasting strikingly 

 with the underlying fissile, platy, almost unfossiliferous limestone of the 

 Bossardville of New Jersey and Tonoloway of Maryland. 



The close resemblance of the Chonetes jerseyensis zone of the Keyser 

 to the Decker Ferry of New Jersey in fauna, litholog)', and stratigraphic 

 sequence, together with the similarity of the corresponding strata in 

 Pennsylvania is believed to indicate the essential identity of both horizons. 

 It is to be noted, however, that while the lower limit of the Decker Ferry 

 and Chonetes jerseyensis zone of the Keyser limestone seem to be the same 

 their upper limits may differ. This is suggested by the fact that the 

 Cladopora reciilineata zone lies at the top of the Decker Ferry of New 

 Jersey and much below the upper limit of the Chonetes jerseyensis fauna 



