Dear Christine,
I found some more information on the rock quarry which might interest you. It is actually a fairly involve story. I found several files related to the site. In brief, this is what I found:
When M. H. Sherman was putting together the syndicate to build Hollywoodland, Woodruff and Shoults insisted that Clark and Sherman include the Brushwood Canyon quarry site in the deal. Unbeknownst to them, Sherman had already deeded the land to his adopted son, Robert P. Sherman, through an intermediary, F. G. Feraud. Moses Sherman and Robert Sherman then had a falling out. Robert Sherman would not deed back the land when MH asked him to in 1923. Feraud had issued a 20 year lease to Southern California Rock and Gravel Co., which in turn transferred the least to Union Rock Co. I believe Union Rock maintained operation in Brush Canyon through the 1920s.
In the early 1930s M. H. Sherman Company regained title to the land through foreclosure due to an unpaid loan. Both before and after M. H. Sherman Company acquired the land, the site was frequently used by film companies. One of the files includes a number of letters from studios asking for permission to film at the quarry, which includes some large tunnels. Apparently the tunnels were used as the “batcave” entrance for the 1960 Batman television show.
You are welcome to come see the files. Most of the materials are legal documents. Nothing I have seen indicates that Western Construction Company (Woodruff’s construction company) purchased materials from the quarry. I wish I had something more definitive.

Paul Wormser
Library Director
Sherman Library & Gardens

614 Dahlia Ave.
Corona del Mar, CA 92625
(949) 673-1880
paul@slgardens.org