You inspire me to search YouTube. Someone must have videotaped them. I’m glad you liked it.
I am confused. Do you mean the Monarchs of Arroyo del Seco, or The Beach Boys?
If you mean the song, understand it is the third part of a suite; it is the third part:
California Saga: Big Sur
California Saga: The Beaks of Eagles
California Saga: California (On My Way to Sunny Californ-I-A)
The second part includes spoken word taken from poet Robinson Jeffers.
This is from the album, Holland [1973], which was during the period when they toured with The Grateful Dead, and played at The Big Sur Folk Festival. It is country-western/folk in style. It was a favorite album of artists like Elvis Costello and Tom Petty.
P.S.
It is just called Arroyo Seco (I was not thinking clearly when I wrote that); it is also in the Monterey area, the region the song cites.
The song later mentions Country Joe; that is Country Joe McDonald, of Country Joe and the Fish.