Pennsylvanica seems to have longer antennae; how are you determining between these two species?

I did not know they had longer antennae. The one in your photo looks like it has broken antennae. :) If this roach was from my area (around Raleigh, NC), then I would say most likely P. lata from it's coloration, since the morph of P. pennsylvanica we have here is dark in color and is small.

I am making a guess of the species from it's coloration/markings, area it was found, and maybe it's body type... not sure about that one.

P. virginica are found in moist rotting wood and sometimes in leaf litter in my experience, while P. lata, P. pennsylvanica, and P. divisa are found underneath bark in slightly moist to dry. How high above the ground was it from where you found this roach?

Tree was fallen onto the ground and about 12" diameter.

Ooh, that is interesting. Was underneath the bark very moist or just a little moist where you found the roach? Where on the tree was it, near the ground?

It was moist underneath the bark but not wet and the roach was on the portion of the fallen tree farthest from the ground.

Usually P. virginica would be underneath the log, but often they are inside the log, and in very soft and moist pine logs, P. virginica I think I remember finding them in the log far away from the ground, but your's does not look like P. virginica, I am kind of rusty though I identifying roaches...