Abstract: At the present time two kinds of fossil ice margins have been found, con-gelifolds and fossils sand (loess) wedges in the strata of the studied area. The former is mainly found in the limnetic strata at the top of the Salawusu Group(Q₃¹), The middle Chengchuan Group (Q₃^2-2), The middle and the lower Dagouwan Group (Q₄³) and at the bottom of Dishaogouwan Group (Q₄³) along the Salawusu He in the southeastern depression Among them the middle Chengchuan Group is the largest and the widest.Besider, it can also be found in certain horizons along the wuding He, Lu He, Hailuitu He, yulin He and Salawusu He near the loess hilly areas. The latter is mainly presented in the Tertiary mud stone or red earth, in the lower-middle Pleistocene loess or the lower part of the late Pleistocene sand (earth) gravel layer and on the top of the middle Chengchuan Group in the central-western dry denuded upland and the flat and lower areas on the low ridge land of its extending part to the depression.According to the morphological characteristics of the profile, these folds and wedges had not any relation to the genesis of tectonic movement fluvial-erosion, accumulation, glacier, mudflow, hard press of landslide and drying crack of ground surface, but to the stratum deformation or disturbance caused by seasonal nonhomogeneous melting and freezing processes for a long time in the frozen eartn area.The big or medium type of nondeveloped congeli-folds (mainly situated in the upper late pleistocene strata) and sand (loess) wedges(situated in the middle and lower profile)were related to the seasonal process of the permafrost and the other congelifolds located in the middle and lower Holocene strata and the small type of sand (loess) wedges located in the upper profile might possibly be formed under the condition of the deep seasonal frozen earth and even the other year's frozen earth.