It's porous. Pay attention to the first picture. Probably you see a "duck house", don't you? On the left side of it there's a bit higher place than average. Once it was such floating island... Why it happens and how? I'm not sure but maybe it's caused some gas (most probably methane) pressure from the bottom. Methane is charasteristic to such swampy areas.
By the way, look at the last picture too. Do you see some black stuff in that hole? These are pieces of that soil.
