unconformably's Usage Examples:

The Ordovician and Silurian are absent here, and the Devonian rests unconformably upon the Cambrian; but along the northern margin of the Palaeozoic area, Ordovician and Silurian rocks appear, and beds of similar age are also exposed farther north where the rivers have cut through the overlying Tertiary deposits.

They rest unconformably upon the Carboniferous beds, and have themselves been tilted to a steep angle.

It lies unconformably upon the older rocks; and the limestone contains Fusulina, Phillipsia and Productus, indicating that it belongs to the Upper Carboniferous.

In the eastern border of the Rhenish Schiefergebirge the Permian rests unconformably upon Lower Carboniferous rocks.

The Old Man presents a characteristic section, for it exhibits a thick pile of massive, current-bedded red sandstones, resting, near the foot of the pinnacle, upon a thin bed of amygdaloidal porphyrite, which in its turn lies unconformably upon steeply inclined flagstones.

Under these conditions sediments from the high lands were washed out and distributed widely over the plains, giving rise to a thin but widespread formation of ill-assorted sediment, without marine fossils, and, for the most part, without fossils of any kind, and resting unconformably on Cretaceous, Eocene and Miocene formations.

Widespread changes at the end of the period exposed the areas where deposition has been in progress during the period to erosion, and the (Upper) Cretaceous formations rest upon the Comanchean unconformably in most parts of the country.

Pennsylvanian SystemThe Pennsylvanian or Upper Carboniferous system overlics the Mississippian unconformably over a large part of the United States.

Cambrian System.The lower part of the Cambrian system, characterized by the Olenellus fauna, is restricted to the borders of the continent, where it rests on the older rocks unconformably in most places.

The prairies are, in brief, a contribution of the glacial period; they consist for the most part of glacial drift, deposited unconformably on an underlying rock surface of moderate or small relief.