In the case of the universal ice-sheet (ice-flood) there are, of course, no upper formed or angular blocks at all--there is nothing borne on the surface.

The moraine, therefore, consists wholly of nether-formed and nether-borne severely triturated materials (_moraine profunde_).

The bowlders are, of course, all rounded.

This is one extreme.

In the case of the thin moving ice-fields, the _glacierets_ which still linger among the highest peaks and shadiest hollows of the Sierra, on the other hand, the moraines are composed _wholly of angular blocks_.