(reulugij of Hudson County, 2s ew Jersey. 61 



Point, no more salubrious soil could be desired. The conclu- 

 sion naturally follows, that in order to make the 11,000 acres of 

 retentive and badly drained soil on the top of Bergen Hill, 

 where upwards of 60,000 people have their homes, as salubrious 

 and desirable for a city, as the identical soil occurring at Castle 

 Point, the proper course is to secure a more complete drainage. 



Fourth.- — -In this class Ave place the salt marshes, for even 

 these, owing to the rapid increase of population, are built upon ; 

 sometimes the marsh is filled in with garbage containing decay- 

 ing organic substances, which for a long time at least must 

 render such artificial soils unhealthy. 



CoiS'CLUSIOX. 



The salt mai'shes form the last of the series of geological for- 

 mations occurring in this county ; these are still in process of 

 accumulation, and form the top of the grouped section of the rocks 

 of Hudson County, (Plate II). 



Prof. Cook in the ''Greology of New Jersey," 1868, presents 

 many interesting facts indicating that a slow subsidence of the 

 land is now in progress along the Atlantic border of New Jersey. 



As I have been unable to glean any new facts in relation to 

 this subject in Hudson County, I can only refer the reader to 

 the above report for information in this regard. 



At many places on the knolls along Newark and New York 

 Bays, accumulations of oyster-shells may be observed : these at 

 first sight might lead to the conclusion that the land hadsuifered 

 a subsidence and a re-elevation in very recent times. These 

 shell-heaps, however, are due to other causes, and in some cases 

 at least, were accumulated by the aborigines, before the coming 

 of the Europeans. On the knoll at the mouth of Mill Creek 

 northeast of Lafayette, one of these accumulations of oyster- 

 shells or ^'hjohhen-moddings," may be seen ; with the broken 

 oyster-shells, a foot below the surface, I found the shells of land- 

 snails ; the occurrence of stone impalements and human bones in 

 the same association was reported by the gardeners familiar with 

 the locality. At Constable's Hook and along the shore of 

 Newark Bay, similar shell-heaps are very common. 



Erosion and Denudation. — From the table at the end of this 

 article, showing the depth of wells and of soundings in the salt 



