Alluvium: It refers to material, such as sand, silt, or clay, deposited on land by streams.
Till: It refers to unsorted, nonstratified glacial deposits consisting of clay, silt, sand, and boulders transported and deposited by glacial ice.
Both are brought by streams but one by water stream and other by glacier. Therefore, in the former, boulders are not there and in latter these are found.
