THE PALISADES STLL AND ITS EXTENSION 205 



the strata for several feet. These sections have been described in detail 

 and illustrated in the reports, while the numerous conformable contacts 

 have very naturally been passed over vs^ith a simple statement of the facts. 



Kiimmel* has described four conformable upper contacts, two uncon- 

 formable, and two doubtful, while of the under contacts along the Hudson 

 river only three are conformable, fifteen are unconformable, and one is 

 doubtful. Yet, in spite of the numerous irregularities of the under sur- 

 face of the trap and its constant shifting from one horizon to another, it 

 is evident that in a broad, general view it is approximately conformable 

 to the sedimentary strata. Even less irregularity is known in its upper 

 surface, but probably if an equal number of contacts could be observed 

 the conditions would be found about the same. At any rate, there seems 

 to be no good reason why these upper contacts should be regarded as in- 

 dicating the fissure arising from the deep-seated origin of the lava when 

 it is evident that similar contacts beneath the palisades, where the lava 

 sometimes breaks across more than a hundred feet of the strata, are in no 

 wise susceptible of such interpretation. It is therefore contended that 

 there is no evidence whatever to show that the Palisades sill is any less 

 conformable to the inclosing strata westward down the dip than in its 

 exposure along the strike. Of course, it must have come up through a 

 fissure or other vent somewhere, but it would be a remarkable coincidence 

 if this fissure should happen to follow the western flank of the present 

 outcrop from Weehawken to HaverstraAV (see cross-sections, plate 1). 



Extension of the Palisades sill. — Various workers in this region have 

 pointed out the probability that the Palisades sill is continuous with that 

 of Eocky hill. Dartonf states that "the interval between the Staten 

 Island outcrops and those at Lawrence brook is mostly covered by Cre- 

 taceous clays, under which the Newark is known to extend for some dis- 

 tance, and it is possible that the trap continues southward and is similarly 

 overlapped." The accumulation of data from deep well borings in the 

 sixteen years since this was written now makes it practically certain that 

 this supposition is true. 



As pointed out by Darton, the shallow wells on Staten island show the 

 continuation of the trap southward to the vicinity of Fresh Kills, oppo- 

 site Carteret, New Jersey. Three wells at the car works at Carteret, 

 after passing through sand and clay 60 feet and 90 feet respectively, 

 struck hard rock that "dulled the drill in 15 minutes," and was reported 

 by the contractor as "evidently trap rock." At Boynton Beach, three 

 miles southwestward, the following well section was found : 



• Annual Report of the State Geologist of New Jersey for 1897, pp. 62-72. 

 t Bull. U. S. Geological Survey, no. 67, 1890, p. 39. 



