REPORT OF THE STATE PALEONTOLOGIST 1902 1179 



Kingston and Rondout are located on the southerly continu- 

 ation of that zone of Appalachian folding to which, in the vicin- 

 ity of Catskill, Professor Davis applied the name of the Little 

 Mountains, and the geologic formations of Siluric and Lower 

 Devonic age are here exposed in more or less parallel folds of 

 northeasterly trend. The particular district in which we are 

 interested, that lying within the small quadrangle on the accom- 

 panying location map [pi. 1], lies at the eastern edge of the 

 Little Mountains along the line of maximum folding, and at the 

 apex of the angle which marks the change of trend of the folds 

 from a southerly to a more southwesterly direction. This fact 

 will be better understood by reference to the geologic map of 

 New York State on which the exposure of the Helderberg lime- 

 stones is shown to bend at Rondout sharply to the southwest 

 through an arc of about 25 degrees. This change in the direc- 

 tion of outcrop is not due to erosion only, but is caused in great 

 extent by variation in the directrices of the folds and thrusts, 

 and is related to the presence of numerous interlocking thrust 

 planes of small width which have been observed in the cement 

 mines and in the quarries of the Becraft limestone. 



The geologic map [pi. 2] is a sketch map based on part of 

 the Rhinebeck quadrangle of the United States Geological Sur- 

 vey topographic atlas, and is approximately correct. The areal 

 distribution of the formations is indicated by symbols which are 

 used also in the cross sections. The italic capital letters on the 

 cross sections are explained in the legend of the map. Certain 

 localities to which frequent reference is made in the text are 

 indicated on the map, by letters, as follows. 



A Gross's residence on Delaware avenue 



B Becraft abutting against Oriskany north of Gross's resi- 

 dence 



C Cloonan's quarry on the first Becraft vein, east side of North 

 hill 



D Delaware avenue quarry 



E Engine house at north end of Vlightberg 



G Gross's quarry in Becraft limestone on Delaware avenue 



H Hill quarry on Glory hole vein on east side of Vlightberg 



