till sheet वाक्य

Nearer the Great Lakes, the till sheets are trenched only by the narrow valleys of the large streams.
The soil is similar to the Appalachian piedmont which though not exhausted by the primeval forest cover, are by no means so rich as the till sheets of the prairies.
The complexity of the glacial period and its subdivision into several glacial epochs, separated by interglacial epochs of considerable length ( certainly longer than the postglacial epoch ) has a structural consequence in the superposition of successive till sheets, alternating with non-glacial deposits.