Percent organic carbon and texture composition (percent clay, sand and silt) of 257 specimens taken from equal depth from 30 to 300 centimeters on six transects in Hashillan wetland in north east Kirmanshah were determined. On the basis of relationship between percent organic carbon and particle size it was determined that 19% of the specimens are peat, 6% mucky peat, 7% muck, 13% mucky mineral soil, 16% heavy mineral soil and 37% light mineral soil. Distribution of specimens with different organic content indicates that a stratum of peat exist in Hashillan wetland. The mineral soils in this wetland belong to some 407 small hummocks which are distributed on the surface of the wetland. These hummocks which are circular, ovoid, tear or horseshoe shape are surrounded by a web of pools and strings. The presence of peat in various depths and hummocks on the surface indicate that Hashillan wetland has been evolved from a blanket mire into a patterned mire under the influence of environmental factors.
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