Cal. Pen. Code § 4119
At its option the board of supervisors may adopt a resolution stating that the county will care for the prisoners of the city on its industrial farm or camp at the rate set forth in the city's resolution specified in Section 4118. A certified copy of the resolution provided for in this section shall be forwarded to the clerk of the city named therein, who shall immediately notify the chief of police of the city.
Thereafter, the chief of police of the city, or his representative, shall meet regularly with the county classification committee for the purpose of determining the eligibility of certain city prisoners for transfer to a county industrial farm or camp. The committee shall consider for transfer only those city prisoners who have been selected and recommended for transfer by the chief of police. In each case, the committee may transfer or reject such prisoners as it sees fit.
Ca. Pen. Code § 4119