Definitely looks like scales of some sort. I would guess that it is the bark of some kind of woody plant, but only because fossilized skin is quite rare. Cool find for sure!
It's very likely a bark imprint from a Lepidodendron trunk. That's a great find; during the Carboniferous time period (about 325 million years ago) Lepidodendron trees were one of the plants that made up the vast forested swamps that covered much of the planet and eventually formed the coal seams that we now mine. The bark and leaf imprints are typically found in the layers above and below the coal seams, but it's still a great fossil find because in general plant matter only fossilized rarely. Congrats!