hmm..lol thats actually a tough question.
The trails range from black dirt ...loam to sand...to some hard clay and rock creek bottoms.Some of the creek bottom is sand however and BOTTOMLESS!!!!!
The GP track is mostly clay ...with some sand sections.
The MX track is river bottom clay....hard pack when dry ..peanut butter mud when wet..but perfect loam when groomed.
I'm an official D17 soil sampler and this review is from personal testing.
Usually by scooping up samples of terra firma with my visor...
too bad its normally still attached to my helmet which is on my head.