THE POPULAR SCIENCE MONTHLY, 



of Saugerties, in Ulster County, is reached, when it takes a west- 

 ward drift, being interrupted on the east by the older limestone 

 formations, and on the north by the quartzose and conglomerate 

 or pudding-stone formations of the Catskills, the latter of which 

 undoubtedly rests on a foundation of bluestone, as it again makes 

 its appearance on the westward side of the range. In the town of 

 Saugerties the gray color of the stone disappears, and the forma- 

 tion takes on the deep-blue tinge whence it gets its name. Here 

 also the belt begins to widen, and when the broad plateau at the 

 foot of the Catskills, covered by the adjoining towns of Kings- 



FIG. 2. AN ULSTER COUNTY MONOLITH. 



Size, twenty by twenty-four feet; nine inches 

 thick. 



ton, Woodstock, Olive, Marbletown, Hurley, and Shandaken, is 

 reached, the quarries are distributed over a range of country at 

 least fifty miles broad. Here the stone varies but little in color, 

 touching only the shades from medium to dark blue. The pres- 

 ence of ferric oxides is found in. all the quarries, but only in the 

 seams on the surface of the slabs, which have a rusty color from 

 the oxidation. The stone produced in Ulster County has always 

 commanded the largest prices, it being the best quality produced 

 in the entire belt. 



Leaving Ulster County, the bluestone belt crosses the Catskills, 

 takes in a corner of Delaware and Orange Counties, and then 



