drawn between each broken and its corresponding dotted curve. These are
shown in solid lines, and represent the widths of wall which were used
in the construction. Typical sections of the wall and pipes back of it
are shown on Fig. 3.

The extreme positions of the back of the wall on the two streets having
been determined, as previously stated, the width of base required at
those points fixed the toe of the wall at the top of rail as 254.5 ft.
south of the center line of the Terminal in 31st Street, and 258.5 ft.
north of the center line in 33d Street.

[Illustration:
Fig. 3.
TYPICAL SECTIONS OF RETAINING WALL IN THIRTY-FIRST STREET]


CONTRACTS.

The construction was done under the following contracts:

_1._--The principal contract, dated June 21st, 1904, was with the New
York Contracting and Trucking Company, later assigned by that company
to the New York Contracting Company-Pennsylvania Terminal, for the
performance of the following works:

(_a_).--The excavation for and construction of a retaining wall in
Seventh Avenue, 31st Street, Ninth Avenue, and 33d Street.

(_b_).--Excavation over the area enclosed by the retaining wall.