. Engineering and Contracting. st bank of the Hudson River,is about 64 ft. below mean high water; and atthe Western Portal, or Hackensack end, therail is about 17 ft. above; the grade through-out is ].3 per cent, ascending from east to >^yeftt Line the heading. The full face of the tunnel waswholly in trap at about Station + 30, andcontinued in this through to the Western Por-tal, where the top of the trap was slightly be-low the roof of the tunnel, with hardpanabove. The contact between the sandstoneand the overlying trap was very clearly de-fined, the angle of dip being approximately
. Engineering and Contracting. st bank of the Hudson River,is about 64 ft. below mean high water; and atthe Western Portal, or Hackensack end, therail is about 17 ft. above; the grade through-out is ].3 per cent, ascending from east to >^yeftt Line the heading. The full face of the tunnel waswholly in trap at about Station + 30, andcontinued in this through to the Western Por-tal, where the top of the trap was slightly be-low the roof of the tunnel, with hardpanabove. The contact between the sandstoneand the overlying trap was very clearly de-fined, the angle of dip being approximately17^ 40 toward the northwest. The character of the trap rock varied con-siderably. At the contact, at Station 275, andfor a distance of approximately 200 ft. west,corresponding to a thickness of about 60 at right angles to the lin? of thecontact, a very hard, fine-grained trap, almostblack in color, was found, having a specificgravity of , and weighing 186 lbs. per The hardness of this rock is attested by.
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