CLAYS OF SUSSEX COUNTY. 505 



SUSSEX COUNTY. 



The clays of Sussex county so far as known are exclusively 

 glacial or alluvial in origin, and are not extensively worked. 



Newton. — A black clay containing much organic matter is dug 

 for common brick at Newton (Loc. 285). The clay is about 8 

 feet in thickness and is found at the margin of the large tract of 

 swamp land lying just north of the city. It is highly probable 

 that clay underlies the whole of this area, although somewhat 

 buried by swamp muck towards the center. The tract was prob- 

 ably a shallow lake at the close of the Glacial period. The 

 presence of the organic matter indicates that swamp conditions 

 prevailed to a greater or less extent when the clay was formed. 



Branchville. — A sandy glacial clay of the following composi- 

 tion is found near Branchville : 



Chemical analysis of clay near Branchville. 



Silica (Si0 2 ), 80.03 



Alumina (AI2O3) and ferric oxide (Fe 2 3 ), 12.94 



Lime (CaO), 0.48 



Magnesia (MgO), 0.36 



Water (H 2 0), 2.67 



Total determined, 96.48 



Ogdensburg. — Highly calcareous clays are found on the prop- 

 erty of A. D. Tallman, at Ogdensburg (Loc. 292), but so far as 

 known they are not worked. 



Clays are also known to underlie the drowned lands along the 

 Wallkill river, but they are not available commercially. 



Sussex (Deckertoimi). — Clay was formerly dug for brick along 

 Clove brook not far from Fuller's mill. 



These probably do> not exhaust the localities in this county at 

 which shallow clay deposits occur, but they include the more im- 

 portant ones which have been brought to the notice of the Survey. 



