DESCRIPITON 



Green colour. Ferriferous rocks and Has. Ferriferous 

 slate underlays, and ferriferous grit overlays, the vast stratum 

 of red argillaceous iron -ore. The lias overlays bolh, and em- 

 braces the gypsum and shell-limestone. It is the true lias or 

 hydraulic cement, as above stated. 



Green spots. Basaltic rocks; which have been used, af- 

 ter burning, for water cement. Agate, chalcedony and other 

 gems, are found in this rock. 



Blue spots. Sheil-marl, when of the fifth series ; which 

 is a most excellent manure on silicious and clay soils. It is 

 burned for mason's lime in the Allegany mountains. 



When BLUE spots are made in the yellow colour, which 

 does not overlay the fifth quartzose yellow, it is intended to re- 

 present the oolitic formation, reposing on the fourth quartzose 

 formation. It then represents the fields of silicious limestone 

 which repose on the quartzose formation of the fourth series ; 

 being the lowest layer of oolitic formation. It may also repre- 

 sent the oolite which lies on ihe silicious limestone in New- 

 Jersey and Ohio, and the chalk of Europe. 



DESCRIPTION OF THE PROFILE SECTIONS ON THE 

 MAP. 



1. From Jefferson Couvti/, N. Y. to Nortliampton County, 

 Penn. 2. From Niagara Falls to Sa?idi/-Hook. 



The district of country embraced in this map, gives the geo- 

 logist three remarkable views of the order of superposition 

 amijng the strata. First, along the Erie canal line, from east 

 to west. A profile section of which I published in lS24r. Se- 

 cond, along the west side of the Hudson river, at a greater or 

 less distance from it; a section of which is given at the top of 

 the map. Third, from Niagara Falls to Sandy-Hook ; a sec- 

 tion of which is given at the bottom of the map. 



The section at the top of the map, is intended to represent 

 the lateral wedge-form terminations of strata. Their precise 



