14 ELIOT BLACKWELDER 
formation containing in random arrangement an abundance of bowl- 
ders and smaller fragments of rocks of various sizes, shapes, and com- 
positions. It seems probable that the shale conglomerate of the 
Yakutat series had a similar origin—that it is in fact a marine shale 
enclosing the contributions of icebergs derived from local glaciers of 
late Paleozoic or early Mesozoic age. 
