Mold or dry sourdough starter? (pic included) I fed my starter and left it out for two days.  See attached pic.  It smells like beer (which as I understand it is good), the top is dried out a bit with a rubbery surface, underneath it seems nice and active with no signs of mold.  I can't tell if the white spots are surface mold or if its just the dried out flour.
it looks like it's just dried out on top and a little overfermented. pour off as much liquid as you can and feed it using a small portion of this starter and a lot of flour and water, i would recommend a 1-10-10 ratio.