1142 NEW YORK STATE MUSEUM 



far as I am aware, it has always been considered the equivalent 

 of the Cobleskill, or "Coralline", limestone of Schoharie county. 1 



Upper Siluric section at Rondout 



The following section at Rondout, from about the middle of 

 " the Vlightberg ", was measured with the aid of Mr P. E. Clark, 

 mine superintendent of the Newark Lime & Cement Co. Included 

 between the Coeymans limestone above and the Lower Siluric 

 (= Normanskill?) shales we have: 



» Feet Inches 



1 Manlius. Three layers of thin laminated lime- 



stone, representing the " Ribbon limestone " 



of some of the older writers 12 7 



2 Manlius. Stromatopora layer 7 6 



3 Manlius. Banded limestone 5 5 



4 Manlius. Three layers of dark, thin bedded lime- 



stone. Spirit er vanuxemi and Ten- 

 taculites gyracanthus are found in 

 the basal member. 12 



5 Rondout. The " paving block " 7 5 



6 Rondout. The "prismatic" layer. Makes a 



good cement, but, together with the under- 

 lying Leperditia bed, it is usually left to form 

 the hanging wall 4 8 



7 Rondout. Limestone containing Leperditia. ... 2 2 



8 Rondout. Impure layer of cement known as the 



" curly " 1 5 



9 Rondout. Soft " gray cement " 3 1 



10 Rondout. Hard " gray cement " 5 



11 Cobleskill limestone 7 



12 Salina. Hard " black cement " 5 6 



13 Salina. Soft " black cement " 4 5 



14 Salina. Wilbur limestone (= Niagara or "Cor- 



alline " limestone of Hall and other authors) . . 7 



Total 78 9 



1 1 am indebted to Mr Gilbert van Ingen for much information relative to the 

 geology of the sections studied in Ulster county. 



