Marker Logo HMdb.org THE HISTORICAL
MARKER DATABASE
“Bite-Size Bits of Local, National, and Global History”
“Bite-Size Bits of Local, National, and Global History”
Near Hagerman in Gooding County, Idaho — The American West (Mountains)
 

Ancient Lakes

 
 
Ancient Lakes Marker image. Click for full size.
By Barry Swackhamer, August 8, 2019
1. Ancient Lakes Marker
Caption: (upper right) About 15,000 years ago, the Bonneville Flood scoured out the Hagerman Valley and left behind numerous water-rounded boulders called "melon gravel.
Inscription.  Can you find traces of the three ancient lakes that helped form Hagerman Valley and preserved the fossils found here? The first, known as Lake Idaho, covered most of present-day southwestern Idaho about three to eight million years ago. Over time, the ancestral Snake River deposited sediment layers into this lake. Those layers are still visible today in the bluffs along the river and are part of geologist call the Glenns Ferry Formation.
About 50,000 years ago the ancestral Snake River was dammed by lava flows from the eruption of McKinney Butte to the north. Water trapped behind the lava dam turned the Hagerman Valley into Lake McKinney. Sediments brought in by the river formed the Yahoo Clay which built up and filled the valley. Isolated outcrops of the clay are present in the fossil beds and parts of the Snake River Canyon today, but most of the formation was scoured away by the breach of the third ancient lake - Lake Bonneville.
Massive Lake Bonneville covered present-day western Utah until about 15,000 years ago, when the natural dam shorelines overtopped and ruptured. The resulting enormous flood lasted about eight weeks, widened
Ancient Lakes Marker image. Click for full size.
By Barry Swackhamer, August 8, 2019
2. Ancient Lakes Marker
and deepened the Snake River Canyon, and carved new alcoves, side canyons, and the valley before you.
 
Erected by Hagerman Fossil Beds National Monument, National Park Service, U.S. Department of the Interior.
 
Location. 42° 45.786′ N, 114° 55.346′ W. Marker is near Hagerman, Idaho, in Gooding County. Marker can be reached from Bell Rapids Road near Upper Salmon Falls Road, on the right when traveling west. Touch for map. Marker is in this post office area: Hagerman ID 83332, United States of America. Touch for directions.
 
Other nearby markers. At least 8 other markers are within 2 miles of this marker, measured as the crow flies. Sediments and Fossils (here, next to this marker); A Changing Climate (here, next to this marker); Where are the Fossils? (within shouting distance of this marker); "The People" (within shouting distance of this marker); Right Beneath Your Feet (approx. 1.8 miles away); Volcanoes Along the Snake (approx. 1.9 miles away); Manifest Destiny (approx. 1.9 miles away); The Great Westward Migration (approx. 2 miles away). Touch for a list and map of all markers in Hagerman.
 
More about this marker. This marker is located at Snake River Overlook in Hagerman Fossil Beds National Monument.
 
Categories. Natural FeaturesNotable Events
 
Ancient Lakes Marker image. Click for full size.
By Barry Swackhamer, August 8, 2019
3. Ancient Lakes Marker
Marker on the left
 

More. Search the internet for Ancient Lakes.
 
Credits. This page was last revised on September 14, 2019. This page originally submitted on September 14, 2019, by Barry Swackhamer of Brentwood, California. This page has been viewed 68 times since then. Photos:   1, 2, 3. submitted on September 14, 2019, by Barry Swackhamer of Brentwood, California.
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