178 NEW YORK STATE MUSEUM 



correlation of the two upper beds of the sections at the 

 latter place with the Stafford limestone suggests the possibility 

 of correlating beds I to VII with the lower Marcellus rather 

 than with the Stafford limestone. To this may be objected 

 the continuity of the Plumbottom creek limestones and their 

 fauna, and the occurrence of characteristic Stafford species 

 throughout the section. The prevailing species in the Stafford 

 limestone at Livonia, as given by Clarke, are: S t r o p h a 1 o s i a 

 truncata, Chonetes scitulus, Meristella bar- 

 r i e i , C a m a r o t o e c h i a horsfordi, and Phacops 

 rana. Of these S t r o p h a 1 o s i a truncata, Chonetes 

 scitulus, and Phacops ran a are characteristic of the 

 lower, and Meristella b a r r i & i , and C a m a r o t o e c h i a 

 horsfordi of the upper beds. 



Beds I to IV as well as VII and VIII are, like the typical 

 Stafford limestone, a dark subcrystalline rock when fresh, 

 ^weathering gray and with the substance of the fossils altered 

 to a dark crystalline calcite. The difference in the thickness 

 may be accounted for by the fact that the section at Stafford 

 has never been described in full, and it may be either that the 

 lower calcareous beds of the Lancaster section are wanting or 

 that they are concealed there. 



Notwithstanding the differences noted above between the 

 faunal lists from Stafford and Plumbottom creek the section at 

 the latter place exhibits all the more characteristic features of 

 the Stafford limestone fauna, and there is no break either litho- 

 logically or faunally sufficiently marked to warrant a correla- 

 tion of the lower and upper portions of the section with different 

 formations. We may therefore conclude that the section at 

 Lancaster represents the westward extension of the Stafford 

 limestone, but with greater thickness and differentiation into 

 distinct beds, of which the lower may be absent at Stafford or 

 more probably, concealed at that place. 



