Section 50.2 - Scope of regulations(a)In general. The regulations in this part relate to the tax imposed with respect to hydraulic mining, the debris from which flows into or is in whole or in part restrained by dams or other works erected for the detention of debris by the California Debris Commission in the area drained by the Sacramento and San Joaquin river systems in the State of California. The regulations have application to taxable years beginning after August 31, 1959. For definition of the term taxable year, see § 50.3(g) .(b)Extent to which the regulations in this part supersede prior regulations. The regulations in this part, with respect to the subject matter within the scope thereof, supersede Treasury Decision 4952 (26 CFR (1939) part 317).