THE SECTION AT SCHOHARIE, N. V. 369 



2. Lower Pentamerus Limestone 



The Lower Pentamerus consists of 33 feet of hard, massive 

 limestone below and 32 feet ^ of alternating hard and somewhat 

 softer limestones above. The lower portion forms a bold cliff, 

 which is distinct on both sides of the Schoharie valley to two 

 miles above the village, where it passes under the river at less 

 than half a mile below Davis's dam. It is equally distinct west- 

 wardl}^ to Howe's cave and eastwardly along the face of the 

 Helderberg for man}- miles. The rock is excessivel)- hard, or 

 better, tough, very difficult to break with the hammer. The 

 bedding is evident, but there is a subordinate structure, so that 

 the rock seems to be made up of irregular lenses separated by 

 coatings of cla}'. This structure is \'ery apparent on the weath- 

 ered surface, and is recognizable without difficulty in the un- 

 weathered rock. The weathered surface is very irregular and 

 suggests a loose structure, but in Mix & O'Reilly's quarry at 

 Schoharie, building-stone of the best quality has been obtained 

 at five feet back from the face. The rock has been exposed to 

 attack from both sides in that quarry, for the joint planes have 

 been converted into open fissures, whose sides are weathered as 

 thoroughly as is the exposed cliff. The clay film may be a 

 cementing material for the lenses. The color is dull grayish on 

 the cliff face, which is often coated with drip lime, but internally 

 the color has more of blue, though wholly different from the 

 blue of the Tentaculite. The full thickness of this portion is 

 not shown on the east side, but is exposed on the west side 

 of the valley, along the road ascending West mountain. The 

 character of this portion is the same as at Howe's cave, where, 

 however, no use is made of the rock except in preparation 

 of road metal. 



The upper portion of the Lower Pentamerus is not exposed 

 in satisfactory detail near Schoharie. An imperfect exposure 

 was found in a dr}- waterway in the park back of Schoharie 

 village on the east side, and another in a similar waterway on 

 the west side, about 200 yards south from the schoolhouse. 



' These measurements are bv barometer. 



