California Code, Business and Professions Code - BPC § 7833

This chapter does not prohibit one or more geologists or geophysicists from practicing through the entity of a sole proprietorship, partnership, or corporation.  In a partnership or corporation whose primary activity consists of geological services, at least one partner or officer shall be a professional geologist.  In a partnership or corporation whose primary activity consists of geophysical services, at least one partner or officer shall be a professional geophysicist.