78 O. D. VON ENGELN 
may have been too fluid to register so temporary a disturbance as 
the rocking and melting of a stranded berg. 
Almost similar conditions of deposit of débris by icebergs have 
been observed on a tidal flat adjacent to the end of the Columbia 
Glacier, Alaska. There, at low tide, were exposed wide areas of 
fine-grained clay deposits. All over the surface of these clay 
deposits were scattered ‘‘nests”’ of glacial bowlders deposited by 
icebergs (calved from the adjacent Columbia Glacier) that had 
floated over the area at high tide (Fig. 3). The streaks on the mud 
Fic. 3.—Bowlders dropped by icebergs on tidal mud flat adjacent to front of 
Columbia Glacier, Alaska. Streaks are due to the dragging of the bottoms of bergs 
floating in and out with the flow and ebb of the tide. 
are occasioned by the dragging of partly floating bergs with the ebb 
of the tide. Similar “nests’’.of iceberg-deposited bowlders were a 
common feature on the sand beaches of the west side of Yakutat 
Bay, Alaska (Fig. 4). Here the pits in which the bowlders are 
nested are conspicuous because successive tides rocked the stranded 
bergs (Fig. 5) back and forth sufficiently to make quite an excava- 
tion before the ice melted completely. . 
Significance of observations —From the foregoing observations 
of deposits adjacent to Pleistocene ice fronts and near living glaciers 
it is apparent that icebergs can and do carry notable quantities of 
