| Seaward of the sand bar there is a wave-washed shelf composed of cobbles and sediment, part of which is exposed subaerially at low tides. |
| Some external black glass is noted where the tubes may have been exposed subaerially during formation, but no exogenic specimens were noted. |
| The volcanic pile built up above sea level so that lavas began to be erupted subaerially. |
| There are no sediments mapped for the Two Creeks phase because the region was subaerially exposed at this time. |
| The Saint Stephens ridge was shallowly submerged and probably locally subaerially exposed during late Smackover time. |
