CLAYS OF NEW YORK 585 



for tliis locality is 250 feet above the level of the Hudson river. 

 On either side of the track at Thiells are probably remnants of a 

 terrace. 



The clay bank of the Anchor brick co. at Croton landing is 

 elliptic in outline and" lies on a bed of granite, gneiss, schist, and 

 white crystalline limestone pebbles, cemented together by clay, 

 covered with limonite. Large pebbles are scattered through the 

 clay, the layers of which are undulating, conforming to the shape 

 of the underlying surface. Over the clay is 4 to 6 feet of gravel 

 and sand. South of this yard an excavation has been made under 

 the terrace for obtaining gravel, exposing a section of Croton delta. 

 Projecting up into it is a mass of boulder-till. 



About the middle of Croton point are the clay pits of the Under- 

 bill brick CO. Their clay is overlain by the sandy beds of Croton 

 delta. The material composing it was evidently derived from the 

 crystalline rocks of the surrounding country. It is often micaceous 

 and of a yellow color. Scattered through this sand axe great num- 

 bers of botryoidal sand concretions, some of them forming masses 

 6 feet long and 3 to 4 feet wide. They show the layers of deposi- 

 tion of the sand. 



The clay at Crugers, Montrose and Yerplanck lies in hollows 

 in the rock, being as much as 50 feet thick in some places. At 

 Crugera it is overlain by a few feet of loain; at Montrose by 

 stratified sand, varying in depth from 5 to 20 feet, according to 

 borings made. Along the Hudson River railroad track below 

 Montrose, at Morton's yard, the clay is overlain by from 8 to 

 10 feet of fine gravel, and cross-stratified sand of a dark gray 

 or black color. The materials composing it are, to a great extent, 

 ground up crystalline rocks. The same material covers the clay 

 at McG'onnell & O'Brien's bank. At the clay beds of the Hud- 

 son river brick co. at Verplanck, the clay is covered by yellowish 

 sand and fine dark colored gravel; usually they are unstratified, 

 but in a few spots show cross-bedding. 



A short distance below Peekskill, at Bonner & Cole's yard, is 

 a remnant of a 20 foot terrace. There is here a deposit of clay 



