Protoscience is to be distinguished from pseudoscience by its adherence to the Scientific Method and standard practices of good science, perhaps most notably a willingness to be disproven, or supplanted by a more-predictive theory.
Examples of protosciences might be the theory of continental drift as originally proposed by [Alfred Wegener]? (which eventually became an accepted scientific model when the mechanisms of [plate tectonics]? became understood), or the various string theories of physics.