The pavement laid was bitulithic and the subgrade was an old macadam road built by the County.
In each grade and subgrade date of commission, appointment, or warrant determines the order of precedence.
When the work was finished, a subgrade reversed-grade drain carried the water to the shaft sump by gravity.
In the subgrade telephone and telegraph ducts east of the Manhattan Shaft, much trouble was caused by grout in the ducts.
Some engineers advocate that in preparing the subgrade, the earth be thoroughly rolled; others prefer not to roll the subgrade.
The side-walls and subgrade electric conduits were water-proofed with felt and pitch.