Bullock's Wilshire Department Store:

The Big Sleep, Chapters 26 & 27
"I'll meet you in half and hour. Beside Bullock's Wilshire, the east entrance to the parking lot."

. . .

The violet light at the top of Bullocks green-tinged tower was far above us, serene and withdrawn from the dark, dripping city.
Bullock's Wilshire, located at 3050 Wilshire Boulevard, is a branch of a downtown department store and a Los Angeles landmark. The art-deco building, which has a massive base with a slender six-story tower rising above it, was completed in 1929. The top of the tower is sheathed in copper, which quickly became tarnished green, and once contained a violet light that could be seen for miles.