W. B. DWIGIIT. 79 



Orange, Dutchess, Columbia, &c, after which he adds, 

 ' ' The association of the Helderberg limestone with these 

 red slates, grits, and red and white conglomerates, may 

 be considered as very strong evidence, almost decisive, 

 that these red rocks are the equivalents of those of the 

 west side of the Shawangnnk mountain, and of the cen- 

 tral portions of New York (the Medina sandstones, 

 Oneida conglomerate, Onondaga salt group and grey 

 sandstone,) instead of the red sandstones of the middle 

 secondary of Rockland county and New Jersey." He 

 also says, (p. 365,) " Limestone was frequently seen as- 

 sociated with these red rocks in the valley of Smith's 

 Clove in Orange county, and in the counties on the east 

 of the Hudson River ; but no fossil remains were ob- 

 served in it at any other place than Townsend's iron 

 mine in Cornwall." 



Prof. Mather (pp. 350 and 351) quotes, and apparently 

 adopts, Horton's description already given of the Town- 

 send mine at Cornwall, finding no fault with the state- 

 ment about the position of the ore. Again quoting Hor- 

 toh and speaking of the same mine Prof. Mather says, 

 "For years past this ore has been considerably used, and 

 although a lean ore, it makes excellent iron. It is mostly 

 in powder or very small fragments, mixed with balls and 

 pieces of the hematite of a few pounds weight. It lies in 

 limestone rock and between the limestone and the grit 

 rock. * * * This stratum of limestone and hematite 

 can be traced across this town into Monroe, until we 

 reach the beds of magnetic oxide. It is seen a quarter 

 of a mile north of the Clove mine, and at many inter- 

 mediate places between this and the Townsend mine in 

 Cornwall. The distance between these extreme points is 

 full ten miles." (p. 490.) 



Mather considers this ore bed as an anomaly in its 

 geological situation, as being connected with Helder- 

 berg limestones with its fossils, and he doubts whether 



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