HUDSON RIVER BEDS NEAR ALBANY 533 



are overlain by the Upper Siluric and Devonic strata of these 

 mountains. \ 



Extension of zone of TJtica shale 



The stations 5 to 21 comprise all the localities with Utica fosh 

 sils known to the writer in this region. They are arranged, as a 

 glance at the map will show, in a zone which, beginning at the 

 banks of the Hudson river at Laveny's point, passing over the 

 islands at the mouth of the Mohawk and following thence the 

 edge of the plateau to the west of the Hudson valley, crosses the 

 upper part of the city of Albany and extends to the Normans kill, 

 where it passes under the drift. As this series of oiutcrops lies in 

 the general direction of the strike of the rocks, and the latter 

 form a mass with uniform easterly dip, it may be safely concluded 

 that this zone represents a continuous terrane of Utica beds over- 

 lying the Lorraine (beds of equal dip in the tilted region, and un- 

 derlying the latter in the undisturbed region to the west of the 

 separating fault. Toward the north the zone probably connects 

 with the Utica shale known from the neighborhood of Mechancis- 

 ville, Saratoga Springs, Sandyhill, etc. 



C MIDDLE TRENTOX BEDS 



Station 22. Watervliet arsenal 



The next group of stations (stations 22-26) comprises five locali- 

 ties which may be arranged in two rows extending from n ne to 

 s sw on both sides of the Hudson river south of Watervliet and 

 Troy. These localities furnish Trenton fossils. The occurrence 

 of the latter was first made known by Whitfield (see p. 496), who 

 reported the finding of Diplograptus amplexicaulis 

 at the Watervliet arsenal (station 22), and south of Troy in shaly 

 partings between layers of metamorphic limestone. The locality 

 at the arsenal is no more accessible, but part of the material 

 collected at that time is preserved in the state museum. It con- 

 sists of very soft bluish black, argillaceous shale, which does not 

 effervesce with HOI and is thickly packed with a long, narrow 

 graptolite which in dimensions, arrangement and form of thecae 



