NEWARK ROCKS OF ROCKLAND COUNTY, N. Y. 43 



In addition to these, others can be seen at two points in the 

 sandstones beneath the Palisades sill. At neither locality can 

 their connection with the greater mass be traced, but it can 

 hardly be doubted that they are downward protrusions from it. 

 These dikes have already been described in connection with the 

 basal contact phenomena of the Palisades. 



STRUCTURE 



Dip and strike 



In general the sedimentary rocks form a monocline which 

 dips gently northwestward. Within comparatively narrow 

 limits there is considerable variation in the strike and 

 also in the dip. But the limits are comparatively well fixed. 

 With few exceptions the strike varies from north to n 45° e. It 

 rarely exceeds these limits, though in a few cases the easting is 

 as much as 60°,, and sometimes the beds have an abnormal west- 

 erly strike. The dip is usually between 5° and 15°, and is ap- 

 parently slightly less in the western than in the eastern half of 

 the area. In consequence of this uniform westerly dip, the lower 

 beds of the formation outcrop nearer the Hudson river, and as one 

 travels westward higher beds are found. 1 



Compared with some parts of the Newark area in New Jersey 

 the structure is simple. Over most of the area there are ap- 

 parently no folds, not even very gentle ones. The monoclinal 

 structure is practically supreme. 



A few qualifications to the above statements must be made. 

 West and northwest of Haverstraw, the sandstones dip to the 

 southwest instead of to the northwest or west. Near Stonypoint 

 the boundary of the Newark formation extends northwest to a 

 point a mile from the Hudson river, where it makes a somewhat 

 abrupt turn to the southwest, a course which is held uninter- 

 ruptedly for nearly 60 miles. For the first mile back from the 

 river the border conglomerates trend parallel to the border and 



iThis is true of course only so far as faulting has not caused a repetition 

 of the strata. 



