The Siedlec Sandur (Zedlitzer Sander) in Silesia, Southwest Poland, was at first described by M. Schwarzbach in 1942. It was interpreted as the Wartanian proglacial outwash, formed at the southern margin of ice-pushed ridge (Trzebnica Hills, Trebnitzer Katzengebirge). Some recent investigations reject this interpretation and denay the occurrence of the Wartanian ice-sheet in Southwestern Poland. The paper presents new sedimentological investigations from deposits of the Siedlec Sandur. The main result of this study is detailed description of some classical, described by Schwarzbach, and some new sections. From them, it was concluded that the Siedlec Sandur represents the proglacial alluvial fan with sedimentary structures typical for fans deposited in semi-arid climates. In turn, the glaciofluvial material of the fan suggests that sedimentation took place in polar desert conditions. This conclusion confirms rather Schwarzbach's view, than views of his opponents, and confirms indirectly an occurrence of the Wartanian ice-sheet in Silesia. The paper discuss also a possible extent of this ice-sheet in Trzebnica Hills.