60 Geology of Hudson County, New Jersey. 



have been deeply eroded by currents of water^ the channels of 

 which have since been filled in with mud and peat ; the islands 

 known as Paulus Hook, Harsimus, and Pavonia, are separated 

 from each other and from Communipaw, Bergen Hill and Ho- 

 boken by deep-buried channels of this nature. 



The Sanitary Influence of the Soils of Hudson Coynty. — ^The 

 salubrity of a region depends largely on the pervious or im- 

 pervious nature of the soil ; the lowering of the consumption 

 death-rate especially, is closely connected with tlie decrease of 

 water (especially fresh water) in the subsoil. Id Salisbury, 

 England, the death-rate from consumption has been lowered 

 one-half by improved drainage. The following conclusions on this 

 important subject are taken from an article by W. Whitaker, 

 in the Geological Magazine for November, 1869. 



(1) That on pervious soils there is less consumption than on 

 impervious soils. 



(2) That on high-lying pervious soils thei'e is less consump- 

 tion than on flat pervious soils. 



(3) That on sloping impervious soils, there is less consumption 

 than on flat impervious soils. 



(4) Wetness of soils is the great cause of consumption. 



With these considerations in mind, I have arranged the soils 

 of Hndson County as follows, referring especially to their per- 

 vious or impervious character. AYlien considered geographic- 

 ally, the conditions of elevation, drainage, etc., come in, and 

 greatly modify these general laws when applied to limited areas. 



First. — The most desirable soils, from a sanitary point of 

 view, are those formed of modified drift, composed of strata of 

 sand, gravel and boulders. 



Second. — The second best soils are those composed of the fine 

 yellowish loamy sand frequently mentioned on the preceding 

 pages. 



Third. — Next in the series comes the soil formed of reddish 

 drift, which covers so large an area in Hudson County ; if well 

 drained, this soil has but few objectionable features ; these in- 

 crease rapidly, however, as drainage is obstructed. When un- 

 derlaid by a porous and elevated rocky substratum, as at Castle 



