580 
GEOLOGY OF THE FIRST DISTRICT. 
Opinions of Dr. Horton on the Superposition, &c. op the Rocks of Orange 
County, N. Y. 
The following opinions were expressed by Dr. Horton, after making the geological exami¬ 
nations of Orange county, in 1838 ; and they are, in the main, correct. The equivalency of 
many of the rocks had not then been determined with certainty, and his observations had 
been mostly confined to Orange county. 
That the slate and greywacke interstratified with it are coteraporaneous. 
That the grit of Shawangunk mountain rests unconformably upon the bassetting edges of 
the argillite and greywacke. 
That the limestcaie series at the foot of Shawangunk mountain and Carpenter’s point reposes 
conformably upon the grit. 
That the greywacke of Deerpark* reposes conformably, but with less dip, upon the pre¬ 
ceding limestones. 
That the Neelyt&wn limestone is a bed in the argillite. 
That the blue limestones of Newburgh, Monroe, Blooming-grove, Goshen and Warwick, 
if strata, are interstratified with the slate and greywacke. 
That the conglomerate and fossiliferous limestone of Goshen are newer than those last 
mentioned. 
That the grit and the greywacke of Pine hill, Skunemunk mountain, of Blooming-grove, 
and of Bellvale mountain, are newer than the greywacke, interstratified with the argillite, 
because (like Thompson’s limestone) they rest upon the former, and are piled up into lofty 
mountains. 
That the ends of all our primitive ridges subside gradually to the north : Attested by the 
direction of our streams ; by the eye when on elevated situations; by the position of our 
transition and secondary rocks resting on their subsiding points j and by our anticlinal lines. 
That some of our rocks, to all intents and purposes, are sandstones of the oldest period.t 
* These belong to the Erie and Catskill divisions. 
t Manuscript Geological Notes af the New-York Survey of the Fiast District, Vol. viii, p. 4a?. 
