The Fort Union Formation of Montana and Adjacent Areas

The Fort Union formation is one of the most import­ant and best known geologic formations of the northern Great Plains, and is found lying almost horizontal at the surface over large areas in this region.

Stratigraphy and Paleontology of the Eagle Formation in Montana and Adjacent Areas

A conspicuous two hundred and fifty foot sandstone of central Montana, known as the Eagle Formation, constitutes part of the some five thousand feet of Cretaceous sediments in the state. It stands out in steep cliffs which stretch for many miles in the outcrop area from Wyoming to Canada.