Eric Eggen'sTrek Around the USA: Miles City, MT to Great Falls, MT

Over the past two days I have traveled gradually up in elevation as I have crossed the upper Great Plains and have approached the Rocky Mountains from the East. Most of the trek consists of rolling hills composed of deep sedimentary rocks from Cretaceous Period, 146 to 66 million years old. This was the height of the Age of Dinosaurs, up to the point of their extinction. The sediment itself was the result of a shallow sea that covered the middle of the North American continent during much of this period. Thus, most of the landscape consists of relatively 'young' rocks that have been subject to some uplift, but not to tectonic and volcanic activity. The gradual elevation change is due to the uplift of the Rockies, which came from land shifts originating on the western side of the mountains.

I found the landscape quite beautiful and varied. It appeared green and lush, particularly for July. Here were the great fields of grain, alone with corn and soy. Land unsuited for crops was used for cattle range. And there were areas with trees, particularly along the river valleys and stream beds.

As I approached the Rockies I got my first glimpses of Precambrian rocks, igneous and metamorphic, capped by the thin overlay of Cretaceous sandstone. These pictures were taken in central Montana, just south of Great Falls:

My objectives in Great Falls were to see the Lewis & Clark Expedition Interpretive Center, Giant Spring and the Roe River, and the Charles Russell Museum. I did them all this afternoon.

Great Falls was a major event on the Lewis & Clark Expedition because it involved a portage up over the falls that took almost two weeks to accomplish. There are interpretive centers at several sites along the expedition trail. This one is operated by the National Park Service and is quite extensive. As you walk through the exhibition, one side tells the story of the expedition and the other side tells about the Indians that occupied the land along the route. It is very nicely done.

Here are the pictures from the Charles M. Russell Museum: