Last year, I took my kids to see Onondaga Cave located in Leasburg, Missouri. The state of Missouri runs this site.  The park rangers present visitors with detailed descriptions regarding the geology of the cave.  These descriptions often include time frames that run in the hundreds of millions of years.  Here’s a sample, from the Onondaga Cave website:

About a billion years ago, the Ozarks were a hotbed of volcanic activity centered about 45 miles to the southeast, in Iron and Reynolds counties. The igneous remains of this activity formed the surface of granites, rhyolites, felsites and basalts that are exposed there. These rocks are the basement layer here, about 1,000 to 1,500 feet below the cave. This basement layer is not flat but tilted. About 600 million years ago, this volcanic activity calmed and the region cooled, condensing great amounts of water vapor, which formed shallow (about 200 foot deep) seas. These seas were the birthplace of the Eminence and Gasconade formations of dolomite, chert, sandstone and shale in which Onondaga Cave is formed. It is believed that the Ozarks were uplifted above sea level (or the seas retreated, take your pick) four times before they fell for the last time about 280 million years ago. One final major uplift (of dry land) took place 50 million to 7 million years ago.

For those who enjoy exploring large case, Onondaga is a terrific place to visit. It is a place to see a spectacular natural wonder and to learn …