RECORDS -tUO 



uianelLi testudinaria, Plcctambonites and Rafiiicsqiiina, the same 

 combination found in the Hudson shales at Poughkeepsie and 

 at Rondout. At one locaHty was found a fauna with Am pyx 

 and Harpes. In eastern New York these genera of trilobites 

 are found only in the Chazy limestone, and the discovery is of 

 great interest in that it indicates the presence of this formation 

 at a distance of almost 250 miles south of what has hitherto 

 been recognized as its southern limit. Further to the northwest, 

 along the Delaware river, were found the Silurian and lower 

 Devonian formations. The finest section is seen in the face of 

 the cliff of the old Nearpass quarry, about five miles south of 

 Tri-States, where all the formations from the upper Ordovician 

 to the Esopus shale of the lower Devonian appear, with numer- 

 ous fossils. At Otisville the Shawangunk grit is finely exposed 

 in a large quarry. All the evidence at hand points to the con- 

 clusion that this formation, of a thickness of at least a thousand 

 feet, was formed as a flood plain deposit. Its characteristics, 

 except color, are the same as the New Jersey and Connecticut 

 valley Triassic sandstones. Ripple-marks, sun-cracks, cross- 

 bedding, channel-fillings, etc., are abundant. In the railroad 

 cut west of Otisville the grit lies upon the Hudson shales, with 

 coincident dip. On the contact there occurs a few inches of 

 clay, which next the shale is quite free of pebbles, while next 

 the grit it is filled with quartz pebbles. This was interpreted to 

 be residual clay caused by the decomposition of the shale, 

 through subaerial agencies, before it became covered by the 

 grit. The old notions regarding rock-formation required the 

 presence of a body of water in which the sediments might be 

 deposited. Several of the geological subdivisions showed char- 

 acters which would not have been present had these formations 

 been laid down under water, for this mode of origin results in a 

 sorting- of the rock-formingr materials, and no sortingr is detected 

 in these grits. Flood plain deposits are very irregular, both as 

 to stratification and sorting of materials, and these features are 

 well exhibited in the grits. Other formations that are probably 

 flood-plain deposits are parts of the Potsdam sandstone in eastern 

 New York, the Medina sandstone, the sandstones of the Cats- 



