12 NEW YORK STATE MUSEUM 



Going up the dip (that is, lower down in the formation) the rock 

 improves somewhat in quality. These beds are slightly pinkish to 

 brownish gray conglomeratic quartzites. They are variable, even 

 in the same bed, frequently contain streaks and patches of clay, and 

 are often cross-bedded. Samples selected from these beds present 

 the following characteristics : 



Lithologic character. Practically all the grains are quartz ; most 

 of them are clouded with inclusions, both heterogeneously distri- 

 buted, and in trains which often terminate abruptly at the margins 

 of the grains and also pass indiscriminately from grain to grain 

 regardless of boundaries. The trains are composed of liquid and 

 gas inclusions; the rest of the included matter consists of rutile 

 needles, minute zircon crystals, magnetite, and many minute specks 

 and crystals of indeterminate nature. Occasional larger patches of 

 sericite, chlorite, granular aggregates of rutile, rounded grains of 

 hornblende, tourmaline, zircon, leucoxene, magnetite, iron oxide, 

 are very sparingly disseminated ; both iron oxide and sericite occur 

 between the grains to some extent. 



The rock has been subjected to considerable crushing and granu- 

 lation. A photomicrograph of rock from one of the quarries oper- 

 ated by the Lawrence brothers is shown in figure 8, which exhibits 

 some of the features enumerated; more especially granulation. 



Chemical analyses (table i) of samples selected from different 

 beds yield 98.46- per cent and 98.68 per cent SiO, respectively. The 

 best rock will probably average not over 98.50 per cent SiO 2 . 

 . The Shawangunk at Ellenville. In the vicinity of Ellenville, 

 rock was at one time quarried for use in a local glass factory, not 

 now in operation. The Shawangunk in this locality dips steeply 

 toward the valley (47 northwesterly) ; a strong thrust from the 

 southeast up-turned the conglomerate and at the same time 

 overthrust the underlying Hudson River formation on it. In climb- 

 ing the Shawangunk slope the Hudson River slates will be 

 encountered at an approximate elevation of 1500-1800 feet. 



The coarse conglomerate possesses the same general characteris- 

 tics as that described as occurring at Accord ; certain beds, however, 

 are grayish white quartzite, and it was from these beds the rock 

 used in the glass factory at Ellenville was taken. Rock of this 

 description may be seen about 2 miles south of Ellenville, along the 

 road to Mount Meenahga, at an elevation of about 800 feet, rising 

 for at least 100 feet or more at an approximate angle of 47, and 

 almost free from overburden. 



