Cycles of sea level rise and fall often create sandstone at the base, grade up into coal, and are called:

cyclothems

Explanation:

cyclothems

They are the alternating stratigraphic sequence of the non - marine and the marine sediments ,which are interbedded with coal seams .

They consists of the repeated repeated sequence of some meters thick , which are on the sandstone resting on the erosional surface , passing upwards to the pelites and then topped by the coal .