Il6 THE HABITAT OF THE EURYPTERIDA 



posited on flood-plains or the lower reaches of two rivers, then the litho- 

 logical peculiarities of the deposit are readily explained. In that 

 case we would expect these muds to become more marine southward, 

 where they are now covered, and where the subaqueous delta part 

 was situated. Between the deltas the Bertie should be impressed 

 with certain marine characters, as it actually is in sections in Ca- 

 yuga and Ontario Counties. In the Auburn-Geneva quadrangle, Ca- 



Fig. 3. Block Diagram Illustrating the Two Principal Deltas of Bertie 



Time 



B, Buffalo; U. S., Union Springs, H, Herkimer. 



Fig. 4. Cross Section (on the 43RD Parallel) or the Bertie and Herkimer 



Deltas 



yuga County, the Bertie is an evenly bedded, impure, magnesian lime- 

 stone, which when freshly broken is dark colored and of medium hard- 

 ness. In portions it shows faint deposition lines, but heavier layers, 

 from one to two feet thick, are usually quite compact. Some layers 

 weather into a hard slaty shale. The fossils which have been found 

 are: a fewLingulas, two species; one Orbiculoidea, a Rhynchonella, 

 Leper ditia alta, and fragments of eurypterids. In the Canandaigua- 



