Petrographic analysis of coals of the Ferris and Hanna Formations of Wyoming show these coals to have a high total vitrinite content (average 84.2%) and a modest liptinite content (average 5.9%). Compared to coals of similar rank (0.45-0.55% reflectance) from central Utah, these coals have about twice as much pseudovitrinite and about half as much total liptinite. Although sporinite is generally the most abundant type of liptinite maceral, resinite and sporinite occur in about equal amounts in these Wyoming coals, and resinite greatly exceeds sporinite in the central Utah coals.

Results of fluorescence spectral analysis of resinite macerals in the Wyoming coals show that there are five distinct resinite types present. Four types occur in primary globular forms exhibiting scratches and fractures indicating a brittle solid substance. In places, these four types also occur as secondary fracture fillings. Two of the four types fluoresce with a green color; one a dark green peaking at less than 440 nm and the other a yellow-green peaking at 500 nm. The third type fluoresces yellow and peaks at 580 nm, and the fourth type fluoresces orange-brown and peaks at 610 nm. These yellow and orange-brown resinites are similar to those found in central Utah coals except that the Wyoming resinites peak 30-40 nm higher. In the Utah coals, only one green resinite peaks at 460 n ; however, its spectrum has a shoulder at 470-490 nm. The fifth resinite type fluoresces a red-brown and peaks at 690 nm. It occurs only as a void-filling substance showing no brittle properties. It is indistinguishable from a similar resinite type in the central Utah coals.

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