The boundary of every industrial farm established under the provisions of this article shall be marked by a fence, hedge or by some other visible line. Every person confined on any industrial farm who escapes therefrom or attempts to escape therefrom shall upon conviction thereof be imprisoned in a state prison, or in the county jail or industrial farm for not to exceed one year. Any such imprisonment shall begin at the expiration of the imprisonment in effect at the time of the escape.
Ca. Pen. Code § 4133