Kinda like peat bogs around northern Minnesota... I was riding up there, & you can nearly surf on one... ( ride the wave )... they are spongy, but if you spin through the carpet of plants on the surface, look out ( kind of like an over grown lake, a lake with a carpet of plants on top )... some may only be a few feet deep, while other, like Brent said, you couldn't touch bottom...

for this type of driving, IMO, as wide & light a tire as you can get, would be the best... I'd probably get a set of 26" X 12.5" x 12" Interco TSL's ( these would ride much smoother than the Outlaws ), or a set of Outlaws, if you can handle the ride between pits... the 26" TSL's are "special", the have the same lug pattern, as the smaller TSL's, but have a 1" lug, rather than a 5/8" lug, like the smaller ones... the lugs go more sideways across the tire ( providing more forward push ) than their bigger brother, the Vamps, or the Outlaws... & the lugs, are agressive enough to get you through most mud, but not too agressive, to spin through any supporting vegitation...

 

I use 28" Swamp Pros. 28x12x12/28x10x12 and with them on the prairie, mud isnt a problem. They have a vampirish tread (cheaper), 6 ply and pull like a tractor. I live in FLorida and we have MUD.

I love my swamp pros. They arent light, but they are agressive.

 

Its not to risky if you know not to spin the tires. There usually is a pretty thick surface because of all the years on dead vegetation falling on top of it over the years. So it can get thick, the thin stuff I don't go on, unless you know how deep it is.

I like the outlaws for this type of riding because of the sidewall lugs. When the tire sinks down into the muskeg your sidewalls make contact, so with the outlaws you get some traction there too.