4. The Government may, by regulation, withdraw from the application, in whole or in part, of this Act all or part of the territory of Québec described in the Agreement referred to in section 1 of the Act approving the Agreement concerning James Bay and Northern Québec (chapter C-67) and the Agreement referred to in section 1 of the Act approving the Northeastern Québec Agreement (chapter C-67.1) except the territory of municipalities situated south of the 50th parallel.