Hell Creek Formation in Montana?
812920
Google earth, Montana Dept. of BLM, and geological survey maps of Montana.
409581
http://www.gly.uga.edu/railsback/BS/BS-Loa.html\n\nA Basalt building in Loa, Utah\n\nhttp://www.gly.uga.edu/railsback/BS/BS-Arco.html\n\nGym in Arco, Idaho
1050953
I think that one is called Mud Lake, and it is a glacial feature, as are most of the lakes in the area, including Fremont lake.   \n\n(If you look at the loose rock around it, you will notice it is polished smooth and round, which is evidence of glacial activity. If it were volcanic, there would be thick ash layers, flows, and other clear evidence in the bedrock of the area. A meteor impact large enough to make a lake that size would leave a shatter cone and most likely there would be layers of ejecta with many sharp shards of rock.)
223366
I think you may mean MiSSoula Montana/:)
161023
Not likely. The reason is that most of the drainage of the American River is coming from metamorphic terranes. \n\nI don't have a very good geologic map of that area, but you are only likely to find geodes where they have weathered out of extrusive igneous rocks, like basalt flows, or in rhyolite beds (volcanic ash). If you can find an area that has volcanic rocks, other than the granitic plutons that are common in the Sierras, you might find some. I think you are more likely to find placer gold in that area than geodes. \n\nYou are fairly close to Sacramento and the California State Geological Survey sells a printed map of the states surficial geology. You can buy a paper geology map for any part of California from them at:\nhttp://home.att.net/~amcimages/mozley.html\nhttp://www.consrv.ca.gov/CGS/information/publications/pub_index/products_that_we_sell.htm\n\nI think to find geodes you are going to have to go over the hill to the east side of the Sierras, or head north towards Shasta. \n\nGood luck.\n\nHere's an interesting link to a Washington geode collector:\nhttp://www.washington-state-rockhounding.info/red-top-cliffs-collecting.htm\nHere's a locale near Blythe:\nhttp://www.desertusa.com/magjan98/stories/hauserbeds.html
264375
They truly do exist. There are 7 or 8 in Montana.\nThe Federal Government made all the indians move or settle down on land the government picked and to live there for the rest of history. The land was really poor land with (the government thought) no minerals nor could it be farmed as the soil was too thin or too poor. Their original hunting grounds were seldom within within the lands set for them.
763943
Did you know there is a town in Montana called Circle? FYI....
620491
Montana,Beaverhead, USA.
523327
Check with Arizona State park service. good luck
125390
I would go to www.usgs.gov  this is the site for the united states geological survey
277806
Geologists state that 200 million years ago a series of 'bucklings' caused by shifting tectonic plates created the Appalachian chain of mountains, which run from Tennessee across the Canadian Border. The Catskills are a portion of this plateau which simply "refused to go along." Their bedrock refused to "buckle". Instead this bedrock rose up by easy stages from the shallow sea in which its rocks (sedimentary?) had been formed (deposited?) from ancient mountains to the east. Raised high in the air the plateau became easy prey to the cutting action of the streams which carried off the plateau's rainwater. The plateau was carved up over 100's of thousands of years...the tough, hardest parts remained while the softer material was disposed of by various erosion techniques and actions including frost, water action and wind. Geologists explain the Catskills are simply a tough part of the Allegheny Plateau which the streams, even with the help of frost and gravity have not yet cut down to size. Over vast geologic time, of course, these forces will do away with the whole thing. In the meantime, scientifically speaking, the Catskills should be described as 'a maturely dissected part of the Allegheny Plateau".
493267
That was on Discovery Channel the other day.  They were not permitted to reveal the specific location, but I think they said it was in Arizona.
1025954
You might try contacting the Wyoming Geological Survey.
524139
This site has the answers you have been looking for\nhttp://www.emjc3.com/helland.htm
126605
There is a picture of one on this website:\n\nhttp://www.pertlowell.com/
308654
Seems that you want to look for the "New Almaden Mines"...One of the sites below has directions to the trail head.  I can't find anything that indicates there are any actual mine tours in the area.\n\nBTW, thanks for the question...I learned something today about the area I live in!  I can't wait for the sun to come out so that I can take the hike!
526792
Contact Mitchell Colgan (Geology Department Head) at the College of Charleston, Charleston, South Carolina at:\n\ncolganm@cofc.edu\n\nIf you do, tell him Jim sent you.