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the entire hill consists of no other rock than the trap, the huge 

 weathered masses of which, covering the summit and flanks, 

 impart an aspect of extreme ruggcdness. In other instances, the 

 predominant rock at the surface is the red shale, indurated, baked, 

 and altered in colour, by the excessive heat that has been ap- 

 plied to it, while the trap either does not appear at all, or has 

 reached the day only in a series of narrow dikes. The hills of 

 the latter class, have a more round and swelling contour, than 

 those consisting solely of the trap, and admit of tillage to a cer- 

 tain extent. 



To enumerate the principal trappean belts of the region we 

 shall commence on the northeast with that called the Closter 

 JMountain. This long range follows the western shore of the 

 Hudson, from the Tappan Sea to Bergen Point, presenting a bold, 

 unbroken ridge, which overlooks the river in the lofty mural pre- 

 cipice of many miles' length, known as the Palisadoes. The 

 next belts west of this are the two extensive parallel ranges 

 usually called the First and Second Newark Mountains. They 

 commence at the Passaic, near Paterson, and keeping east of 

 that river, pursue a course about south-southwest almost to its 

 source, observing a nearly straight line until they approach the 

 Raritan, where they curve, first gently westward, and after- 

 wards more abruptly northwestward. The more eastern of these 

 ridges is usually single ; but the westernmost, especially near its 

 southern termination, where it takes the name of Stony Hill, is in 

 parts of its course double or even triple. West of the Passaic 

 and east of Pompton river, Preakness Ridge, with its spurs, 

 which united compose a continuous belt of trap, having almost 

 the form of a horseshoe, encircles the Preakness Valley. 



Somewhat similar in shape is the next principal outburst of trap 

 rock called the Hook Mountain (Towakow on the map), which 

 has the form of a nearly perfect semicircle, embracing in its 

 concave the bend of the Pjissaic river, called the Horse Neck. 



Still further to the southwest we meet several partial exposures 

 of the trap, in the ridges west of the Passaic, near Bottle Hill, 

 Green Village, and New Vernon, and in the more continuous belt 

 called Long Hill. 



If we add to these the hill extending from south of Basking 

 Ridge to Pluckemin, immediately east of Mine brook, we shall 



