76 GEOLOGICAL SURVEY OF NEW JERSEY. 



suggestions which will enable them to derive a greater profit 

 from their holdings, that they will not be slow to receive and 

 adopt practical suggestions, or to improve on their present meth- 

 ods, and that a great deal can be done to aid the cause of forestry 

 in this section of the State by instruction. 



PASSAIC VALLEY. 



This valley, lying between the trap ridges variously known 

 as Watchung, or the First and Second mountains, and the east- 

 ern slope of the Highlands, is a portion of the red sandstone 

 plain, and is all glaciated excepting the portion lying south- 

 west of the line of the Delaware, Lackawanna and Western 

 Railroad, between Summit and Morristown. This unglaciated 

 portion, however, partakes to some extent of the character 

 of the rest, rather than of the unglaciated portion of the 

 red sandstone plain south of the trap ridges, both in the 

 variety and the extent of its forest growth. This fact may 

 possibly be due to the prevalence of gravel deposits traceable 

 to Lake Passaic, which once occupied the whole valley, and 

 partly due to a number of trap hills and ridges contained 

 within the area ; but, whatever may be the cause, it is a 

 fact that the whole valley may be classed together in relation 

 to its forests. Generally, the percentage of forested area ranges 

 from 20 to 40, averaging for the whole valley about 30 per cent. 

 Pompton plains is the most sparsely wooded section of the 

 valley. Over the northern part, generally, oak from 10 to 20 

 inches in diameter and 60 to 80 feet high is common enough to 

 indicate that the soil is able to produce heavy timber, but the 

 prevailing growth is quite irregular both in size and variety, 

 and is generally smaller than that above noted. Softer woods, 

 such as gum, maple, willow, etc., prevail on the flatter portions 

 of the valley. There are also over the cultivated portions many 

 scattering trees, planted forest trees, fruit trees, etc., many of 

 which are of a large size, so that a general view of the valley 

 from any commanding point gives the impression of a well 

 wooded country. Riker Hill, Hook mountain, and the other 

 trap ridges within the valley have timber resembling closely 

 that of the Watchung mountain ridges, which we shall describe 



