The coal layer in this outcrop has sharp contacts with both the underlying and overlying rock units. It is black and fractured looking bituminous coal.

Note the fine layering in the coal in this close-up to the right. Fluids moving through the rock leach out some elements more easily than others. These get re-deposited as new minerals on the outcrop surface. Here the white-yellow crumbly mineral on the surface of the coal is melanterite, a hydrated iron sulfate which is taking its sulfur from the coal.

 

(See 3 Stratigraphic Units video - Part 2 from Station 1.)

Melanterite links:

http://mineral.galleries.com/minerals/sulfates/melanter/melanter.htm

http://www.mindat.org/min-2633.html

 

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