What an incredible find. I will just copy off the info that I received.
This was the first ever 35mm film shot by a camera mounted on the front of a Market Street Cable Car. It was "lost" for many years, and was taken just 4 days before the catastrophic 1906 earthquake. The level of activity, commerce and transportation in action is quite impressive; and the amount of automobiles is staggering for 1906.
And you'll notice the familiar Ferry Building Clock Tower at the end of Market Street on the Wharf. This film was originally thought to have been taken in 1905; that was until David Kiehn with the Niles CA Essanay Silent Film Museum did some research and figured out exactly when it was shot, by analyzing everything from New York trade papers which first announced the films showing, to wet streets resulting from heavy rainfall, to shadows that indicated the exact time of year and related weather conditions; which are a part of actual historical record. He even discovered when the cars were registered and who owned them; as well as when the plates were issued! And considering that this was filmed only four days before the 1906 earthquake and successfully shipped by train to NY for processing, is absolutely amazing.
Here is Market Street Railway site with a couple shorter videos and more history:
Anyone interested in film, cameras, or just Americana will love it!