28 NEW YORK STATE MUSEUM 



which occur are of limited area and as a rule are found in the depres- 

 sions between the drumlins. Westward from Rochester, on the other 

 hand, the drumlin area has a much more limited extent and large 

 portions of the Salina shales, and the Lockport dolomites, where 

 those shales have been removed, are covered by the Tonawanda and 

 Oak Orchard swamps. The surplus water of this swampy area is 

 carried away by Tonawanda creek,'which empties into the Niagara 

 river ; Oak Orchard and Sandy creeks which empty into Lake Onta- 

 rio; and Black creek which empties into the Genesee at Genesee 

 Junction. It may here be stated that the drainage of the Salina area 

 west of the Oswego river is mainly in an east or a west direction and 

 that of all the streams flowing into Lake Ontario, between the 

 Oswego and Niagara rivers, the Genesee and the Irondequoit are 

 the only ones that cut through all the Siluric rocks of this region and 

 thus provide drainage for all of the Salina area found within the 

 limits of the map. The limited swamp areas which exist are, one in 

 the vicinity of Brookdale in the town of Chili, and the other in the 

 depressions of the Mendon hills. Another small swamp or peat 

 marsh found in one of the depressions of the Pinnacle hills, has been 

 described by Fairchild and Barnum.^ 



The Salina beds include four distinct stratigraphic units recog- 

 nizable here and in sections of central New York. In ascending 

 order these are: (i) Pittsford shalej (2) Vernon shale; (3) Camillus 

 shale; (4) Bertie waterlime. 



Pittsford shale. This shale is the lowest member of the Salina 

 series. The name is from the town of Pittsford a few miles southeast 

 from Rochester. This formation and the Bertie waterlime which 

 marks the upper limit of the Salina are both characterized by a 

 eurypterid fauna and thus the limit of the Salina is determined by 

 the paleontologic as well as by the stratigraphic relations. This shale 

 is a newly recognized element in the Salina series. I. P. Bishop^ men- 

 tions a locality on Grand island in the Niagara river where a black 

 shale is exposed at or near the bottom of the Salina. No fossils are 

 mentioned from the Grand island locality. The credit for finding 

 this shale and its contained fauna at Pittsford is due to C. J. 

 Sarle.3 The only other locality where a slialc is known which may 



iRoch. Acad. Scl. Proc. igoo. 3:201-4. 



2N. v. State (Jcol. 15th All. Rcp't. 1S95. p. 311. 



3N. Y. State Pulcoutol. • An. Rep't. 1902. p. 1080, 



