Maryland Geological Survey 113 



diagnostic species of tlie Maiilius, are therefore represented in this zone, 

 two of which occur as varietal forms. 



The fauna of Maryland differs from that of the Manlius of New Jersey 

 in containing species of a^ more normal marine habitat including many 

 corals. The most striking difference, however, is the presence of a number 

 of species of distinct Helderberg affinities in which respect it resembles 

 the transition beds at the top of the Manlius of Schoharie, and elsewhere 

 in New York. The significance of this fact will be considered later. 



The preceding facts indicate that the Favosites helderhergice var. 

 prcecedens zone of the Keyser is, in a general way, of the age of 

 the Manlius-Rondout interval of New Jersey and that both occupy a 

 similar stratigraphic position, being limited above by the Coeymans and 

 below by the Chonetes jerseyensis zone. The difference between them may 

 be in part geographic, arising from differences in the conditions under 

 which they were deposited. It is, however, not improbable that they may 

 occupy a slightly different stratigraphic position. As has been shown, 

 the lower beds of the Manlius of New Jersey may be older than the upper 

 strata of the Chonetes jerseyensis zone and hence older than the base of 

 the Favosites helderberg ice var. prcecedens zone, while it is possible that 

 the upper beds of the latter zone are younger than the upper beds of the 

 Manlius of New Jersey, since both appear to be bounded above by an 

 unconfonnity. 



Wcller showed that the Coeymans, New Scotland, and Becraft of New 

 Jersey are equivalent to the formations bearing the same names in New 

 York. The corresponding formations of Maryland are also correlated 

 with them as is shown elsewhere in this volume. 



If these conclusions are true the Keyser limestone of Maryland lies 

 between approximately the same limits as the combined Manlius, Eondout, 

 and Decker Ferry of New Jersey to which formations it appears to be 

 equivalent. Their relations are indicated in the following diagram : 



Maryland Pennsylvania New Jersey 



Coeymans Coeymans Coeymans 



fManlius 

 Keyser Keyser ] Rondout 



[ Decker Ferry 

 Tonoloway Bossardville Bossardville 



