text: Supporting the turbidity current origin theory is that deposits of greywacke are found on the edges of the continental shelves , at the bottoms of oceanic trenches , and at the bases of mountain formational areas .
simplified: Support for the turbidity current origin is the fact that deposits of greywacke are found on the edges of the continental shelves , at the bottoms of oceanic trenches , and at the bases of mountain formational areas .