Environmentalists aren't stopping at a million - names, that is - in their drive to oust Interior Secretary James Watt. A petition calling for the dismissal of the outspokenly pro-development Watt was taken to Washington Oct. 19. But petitions still are being circulated and a Sierra Club spokesman in San Francisco says that if another million signatures are collected, they too may be handed over to sympathetic House and Senate members.
A less-publicized drive is also being mounted by the National Audubon Society. Its ''sign up'' says Watt exemplifies the ''misguided'' environmental policies of the Reagan administration.