beds of volcanic ash in the high hills   of Missoula and within a mile of the   .



Their    age is little uncertain as I was not able to procure fossil mammals from the same beds as the leaves.  They might be lowest Miocene but I have always been inclined to the opinion that they were Oligocene.



I also collected fossil leaves form the Miocene of the Lower Modison Valley and form the    of the Missouri Valley, below Helena.  They were associated with later   Mammals but