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MUSKUM OF COMPAliATIVK ZOOLOGY. 



271 



trap, and their metamorphism, are excellently shown. The branch diko 

 cannot be traced quite to the greater mass, but they undoubtedly join 

 below the talus; tho^ branch is about four feet thick, generally lying 

 evenly between the layers, but at one point crossing them in an irregu- 

 lar, ragged passage ; it is clearly traced two hundred feet horizontally ; 

 and where it is lost to sight the main trap mass of the high cliffs above 

 has risen nearly half this distance over it. All the bedded rocks here 

 are thoroughly baked, and near the junctions are more or less clearly 

 crystallized ; their color varies from light gray to black, but there arc 

 no red beds ; the beds above the branch dike are affected quite as 



stongly as those below it. 



Half a mile farther north, where the tunnel of the West Shore road 

 (New York, Lake Ontario, and Western Railroad) opens on Day's Point, 

 another contact was found. Here the fine dense trap lay evenly on the 

 baked and crystallized layers below it, of which some eight feet were 

 shown ; their color was dark or black, not red. This contact will prob- 

 ably bo covered by later work. Day's Point, a low triangular projection 

 into the Hudson, where the wharves of the West Shore Eadroad are in 

 process of construction, now shows a small ledge of sandstone, rapidly 

 being cut away in the work of grading. It is separated from the" trap 

 by eighty or one hundred feet of sandstone, measured at right angles to 

 the dip of 12°. The upper layers of the ledge are firm, fine-grained, and 

 red ; the lower are looser, clear white, with some coarser grains of trans- 

 parent quartz. Similar white sandstone occurs under the cliffs a third 

 of a mile southwest of the Duel Ground. 



K. Jersey City, N. J. — The recent work of straightening the old cut 

 on the Pennsylvania Railroad gives an excellent section with many fresh 

 exposures through this lower part of the Palisade Range. The trap ia 

 generally coarse ; in some small patches there were crystals of pyroxene 

 half to three quarters of an inch in length. It was nowhere found to be 

 the least vesicular. Broad joint faces are very common, and faulting 

 has taken place on some of them. Near the eastern end of the cut 

 there is a vein or dike, six inches wide, vertical, trending about north 

 and south, in the trap. It is light gray in color and is composed of a 



fine granitoid mixture. 



Its texture is uniform throughout, and the 



I have found no 



trap shows no change of structure on approaching it. 



other example of the kind. 



Both Cook {h, 216) and Russell (i, 43) give evidence to show the 

 existence of a soft bed, probably of sandstone, between the eastern and 

 western part of the trap. Its place in the cut is marked by an open hollow 



