Cinnamon Tree, 900 American Street (Way) , San Carlos, CA 94070

The Cinnamon Tree was in an industrial area with roll up doors and had a cement floor. And it had been converted to a teen club.(2)
The Cinnamon Tree opened in July 1965 as a "teen" club, with no liquor served (though no doubt plenty was consumed). The idea was to give teenagers something to do, particularly on weekends. The club was located on an industrial road between El Camino and the Bayshore Freeway. Since it featured teen audiences, one of the popular bills was a "Battle Of The Bands" were numerous groups played a song or two, hoping to win a cash prize (thus insuring that each band's friends came to the show). (1)
In 2012 a business, Lino Valbusa, is at this location.

8/65 Warlocks
"When I was playing guitar in William Penn & His Pals in 1965-66 a battle of the bands was a frequent thing. There was a club owned by an ex-cop called the Cinnamon Tree in San Carlos that sponsored these events. The audience were aged 12 to 17 about 100 or so. They were all sucking down cokes and eating cookies. At one of these battles we went head to head with The Warlocks. You couldn’t have gotten a more odd combination of combatants. We were dressed like Paul Revere in our tri-cornered hats and The Warlocks were the most wildest assortment of characters you could find.  The Warlocks lineup was Jerry Garcia, Pig Pen, Dana Morgan Jr. on bass, Bill Kreutzman and Bob Weir. The William Penn lineup was Mike Shapiro on lead guitar, Jack Shelton on rhythm guitar, Gregg Rolie on keyboards, Steve Leidenthal on bass, Ron Cox on drums.The Warlocks played a set, William Penn played a set and the crowd judged in favor of the Warlocks. It made no sense to me at all. William Penn played radio hits and the Warlocks played blues jams and made other weird sounds. Jerry understood the English sound but didn’t copy it like we did and the audience responded."(2)

"...and for a short time, the lineup also included a second drummer, Mickey Hart.(3)

1.)^The Illustrated Trip, places, Warlocks gig(s) at The Cinnamon Tree in August.
2.)^Shapiro, Mike, guitarist.
3.)^http://www.allmusic.com/artist/william-penn-and-his-pals-mn0001320652