1162 NEW YORK STATE MUSEUM 



Rondout waterlime. Only tbe basal portion of the Rondout is 

 shown in this section. The rock here is brecciated and filled 

 with cavities, some of which are quite large. Many of the 

 smaller cavities are due to the dissolving out of the coral 

 Cyathophyllum hydraulicum Simpson. In appear- 

 ance this rock is similar to the " bullhead " rock of Erie county. 

 The Rondout is burned to a small extent for cement, and then 

 only when it is mixed with the cement rock of the upper 

 horizons. 



The section as above given agrees essentially with one near 

 Jamesville, published by Vanuxem. 1 Number 5 of his section 

 is the Salina waterlime and according to his statement this was 

 the only locality in the third district south of the Erie canal 

 where cement was made from the rock of these lower horizons 

 [p. 110]. Number 6 includes what is now recognized as the 

 Cobleskill limestone and the lower portion of the Rondout 

 waterlime. The cyathophyllum mentioned by Vanuxem [p. 110] 

 is unquestionably the one that is now identified as Cyatho- 

 phyllum hydraulicum Simpson. The section given by 

 Vanuxem is described under the third or gypseous deposit of the 

 Onondaga salt group and is important in showing that in the 

 type locality of the original waterlime group in Onondaga 

 county not only Salina waterlime, but also the formations now 

 known as the Cobleskill limestone and the Rondout waterlime, 

 were included in the Onondaga salt group and not in the Water- 

 lime group as has been generally supposed. 



Section at Brown's falls 



Cobleskill limestone. On the west branch of Limestone creek 

 1% miles southwest from Manlius village the Cobleskill lime- 

 stone is exposed in the bed and banks of the creek 200 yards 

 below the foot of the falls. The Cobleskill is here a compact 

 limestone. The strata below the Cobleskill are only obscurely 

 shown. 



Rondout waterlime. The basal portion of the Rondout is filled 

 with cavities, and is similar to the lower portion as seen in 



1 Geol. N. Y. 3d Dist. 1842. p. 105. 



