REPORT OF THE STATE PALEONTOLOGIST 1902 1181 



rocks are graywackes, or quartz sandstones with argillaceous 

 cement and with little lime content. In color they are, when 

 fresh, olive gray and, when weathered, dark gray, brown or 

 blackish. They outcrop along the eastern base of the Vlight- 

 berg, have been exposed in some of the underground work- 

 ings specially in the Level and the Middle quarry, and they may be 

 seen to better advantage on Kingston Point, along the right bank 

 of Ron d out creek at South Rondout, and in the high hill known 

 as Huzzy hill about 2 miles south of Kingston. Their thickness 

 can nowhere be accurately measured, but it is certainly over 

 1000 feet. At some points thin layers of black shale are inter- 

 calated in the sandstone, as at the Middle quarry and on Kings- 

 ton point. Some of the heavier layers of sandstone have their 

 surfaces dotted with flattened pebbles of dark shale from y 2 to 2 

 inches in diameter, which appear to have been soft mud when 

 they were deposited there. These sandstones seem to have been 

 largely of shallow water or even of beach origin, for cross bed- 

 ding is common and at some points, notably at the entrance to 

 the Middle quarry, the thinly bedded sandstones with shale part- 

 ings show ripple marks and sun cracks. Fossils are rare. Some 

 thin calcareous layers 1 to 3 inches thick and very difficult to 

 find, contain abundant water- worn individuals of Plectam- 

 bonites sericea, and Dalmanella testudinaria; 

 and a few graptolites have been found in the shale on Kingston 

 point. 



The Champlainic sandstones are found, in all cases where the 

 contact has been exposed, to be sharply and distinctly uncon- 

 formable to the overlying limestones of the Upper Ontaric 

 (Silurian), as described below. 



Ontaric or Upper Siluric 

 Only the upper members comprising the Cayugan series of the 

 Ontaric system are represented in the Rondout section; the 

 lower members, including the Niagaran and Oswegan series, are 

 absent and their time periods are indicated by marked un- 

 conformity between the upper Ontaric limestones and the subja- 

 cent Champlainic sandstones. The Ontaric formations may be 

 grouped under three heads; the upper Manlius limestone; the 



