situated beyond, or not associated with, a moraine.
ΚΠ
1891 Amer. Geol. VIII. 239 The thickness of this extra-morainic till ranges from 30 to 70 feet.
1968 R. W. FairbridgeEncycl. Geomorphol. 460/2 These features are best termed ‘proglacial lakes’, though the term ‘extra-morainic lakes’ has also been used.