The clean up brought out the beauty of the box. The box and lid are built of 3/4" pine boards and would accommodate a person up to a height of 5' 11". That would probably cover most folks in 1920s.
The box tapers from bottom to top in all dimensions. Exterior dimensions at the base are 73-1/2" length by 19" width. At the top the box measures 77" length by 22-1/8" width. The sides and ends are solid boards of 11-1/4" height. Two boards of 9-1/2" width compose the bottom of the box.
The lid is constructed of two 11" wide boards overlapped by a 9-1/2" board. Overall dimensions of the lid are 77-1/2" length by 22-3/4" width.