Rick Is The Best Also NWP Expert Wrote:
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> The name of Larkspur comes from "Lark" as in
> having fun or doing something enjoyable mixed with
> "Spur" as in a set of sleepers that come off the
> main line sleepers, with rails naturally, where
> cars or engines or brake vans can be placed. Hence
> Larkspur.

Rick's self-proclaimed explanation is "excremento de caballo."

A more scholarly explanation of "Larkspur" from Gudde, E.G. 1949. California Place Names. U.C. Press:

"The town was founded in 1878 and named because blue Larkspur grew profusely in the vicinity."