106 NEW YORK STATE MUSEUM 



Hydraulic cement beds, i) The lowest stratum of the series is a 

 hard, compact, bluish g'ray silicious limestone, weathering whitish 

 on the exposed faces, and breaking into numerous irregular frag- 

 ments larger near the bottom of the stratum but becoming small, 

 angular and subcubical near the top, where the weathering is 

 similar to that obtaining in the upper parts of the shales. This 

 stratum varies from 7 to 8 feet in thickness being in places divided 

 into two tiers, the upper one, 4 feet thick, appearing as a distinct 

 bed. This weathers to a creamy gray color, and breaks into small 

 angular fragments with no regularity of fracture, and independent of 

 the plane of stratification. On some of the weathered edges of this 

 rock irregular stratification lines are visible, giving the beds the 

 appearance of a fine grained sandstone. Occasionally small geoditic 

 cavities occur lined with dolomite or gypsum. The line of contact 

 between this stratum and the underlying shale is an irregular one, 

 the shale surface having a wavy character. 



2) This rock is succeeded by a 4 foot stratum of arenaceous lime- 

 stone which shows no well marked stratification lines on the 

 weathered surfaces, though in places a distinct cross-bedding struc- 

 ture appears. It peels off in irregular slabs parallel to the cross- 

 section, i. e. at right angles to the stratification plane. Near the top 

 of this stratum are a few thin beds which show the finer stratification 

 structure on the weathered edges, the character of this structure 

 being such as is found in fine grained sandstones. 



Both these strata appear to be wholly destitute of fossils.- It is 

 not improbable however that the scattered geodes represent the 

 places where corals or crinoids occurred, which have subsequently 

 been altered or dissolved out. Aside from this, there is no evidence 

 that this rock ever was fossiliferous, and it is most probable that it 

 represents the accumulation of fine calcareous mud or sand. 



Crinoidal limestone. 3) The compact hydraulic rock is abruptly 

 succeeded by a stratum of highly crystalline limestone, on the 

 weathered surfaces of which joints of crinoid stems and other organ- 

 isms stand out in relief, particularly in the lower part of the stratum. 

 The rock is entirely composed of fragments of organisms which were 

 ground up and mingled together in great profusion. Oblique 



