1. A partially plastic or somewhat brittle material derived from the chemical weathering of glacial debris beneath a partially drained area.
2. A semiplastic or semifriable derivative of chemically weathered till; forms beneath a partially drained area.

Semifriable refers to that which is easily broken into small fragments or reduced to powder while till is unstratified soil deposited by a glacier which consists of sand and clay and gravel and boulders mixed together.