Help! Too much salt in my sourdough dough!
This depends on when you recognize the problem.  If your recognition is immediate then:

4 TBS in 1/4 cup.  You basically have enough salt for a 4X recipe.  So, you have to increase everything else by 3 to have the correct proportion of salt in your recipe.  Good point @The Photon (below)...or reduce by 3/4 and replace with salt-free ingredients.

If you are well-into the fermentation stage, the excess salt could certainly be problematic for yeast and bacterial growth.