Through making particularly study of grain-size characteristics and minerialcharacteristics of the yellow silt-like deposits at the eastern sector of the nor-thern foot in the Tiansan Mountain

this article states that these deposits in theregion are not formed by the moving wind

but by the activity of water medium. For the grain-size characteristics

the yellow silt-like deposits can be basical-ly divided into two main classes. One is caused by the glaciofluvial activity

whose main characters are with small average value

bad sorting and flat kurtosis

with frequency curve turning out Maltpeak and arising high-peak at about 5φ and9φ and with discompletely conforming to the distribution of normal probabilityand displaying various line segments of curve on the cumulative diagram of normalprobability. Another is caused by floodwater

whose main characters are withsmaller average value and worse sorting

with containing high percent of coarsesand and small gravel

frequency curve turning out single-peak

and with slightslope but well symmetrical form of peak

normal probability curve consistingfour line segments. The yellow silt-like deposits dispersed at both north andsouth foot of the Tiansan Mountain mainly belongs to the latter. For the minerial characteristics

the minerial assemblage of the yellow silt-like deposits in this region is epidote-common amphibole-ilmenite type

which con-forms to the minerial assemblage of deposits around the bedrock region

withquite small contents of quartz

high contents of plagioclase and rock waste withquite low maturity index and ratio of quartz to feldspar. All these facts showthat the yellow silt-like deposits in this area is nearby bedrock region

withoutlong distance moving and entirely sorting. Therefor

according to the strict definition

the yellow silt-like deposits dis-persed in this region should be called as loess-like rock.