ROCHESTER AND ONTARIO BEACH QUADRANGLES 29 



be referred to the Pittsford, is in one of the south branches of Mover 

 creek, a few miles southwest from Frankfort, Herkimer county. 1 

 At this locality there are 15 feet of dark olive shale exposed directly 

 above the concretionary layers of the Lockport dolomite. The only 

 fossil from this locality is a small Lingula which occurs quite abun- 

 dantly. It is possible that further search will reveal at this locality 

 other species. Above the shale exposed along the south branch 

 of Moyer creek the Vernon shales are excellently exposed, and 

 in some places the dark shales are coated with the red material 

 from above. 



At Pittsford these dark shales have been obtained only from exca- 

 vations made along the Erie canal. Their thickness here is about 

 20 feet. They consist of thin layers of black and green mottled 

 shale with some thin layers of hard dolomite. The eurypterids are 

 found almost exclusively in the dark shale; the most common forms 

 in the dolomite are a Pterinea and a species of Leperditia. 



The most interesting species among the crustaceans is the eyeless 

 form Pseudoniscus roosevelti, 2 described by Clarke and 

 the new genus Hughmilleria3 described by Sarle. The genus 

 Hughmilleria is a connecting link between Pterygotus and 

 Eurypterus and according to Sarle is more closely related to 

 the former. 



The fauna of the Pittsford shale bears but little relation to either 

 the Lockport or Guelph fauna which preceded it. It is not to be 

 considered as derivative from the above faunas, but represents an 

 element quite distinct. As before noted the Guelph fauna was the 

 outcome of peculiar physical conditions, so the Pittsford fauna rep- 

 resents a still more contracted and shallow sea with increase of 

 salinity. This increase in salinity which marks the introduction of 

 the Salina, finally had the effect of displacing the Pittsford fauna. 

 From this time onward, throughout the greater part of Salina time, 

 this sea was practically lifeless, 4 and it is interesting to note that a 

 eurypterid fauna which was the last to survive in the Pittsford shale, 



1 Since the above was written a eurypterid fauna having close affinities with the Pittsford, 

 has been found in the thin intercalated black shales of the Shawangunk conglomerate of eastern 

 New York. 



2N. Y. State Paleontol. An. Rep't. 1900. p. 89. 



3 N. Y. State Paleontol. An. Rep't. 1902. p. 1091. 



4 A species of Leperditia (L. cf. scalar is), and a form of Meristella are known from the 

 Camillus shale. 



