I’m from Crimea and found a seashell inland once. Someone told me “of course, this was all covered with water long time ago!”. I guess the seashell had nothing to do with the lake, but it’s still amazing how the Earth isn’t static at all.
The "that's a long time" for me occurred when I learned about the Mississippian Period (named after Mississippi in the United States) - part of the Carboniferous period, and only really useful within the US because the rock beds within that period are different than the adjacent Pennsylvanian period rocks.
In this period, you've got crinoids - related to starfish (and still around - https://youtu.be/ror_fFswejM ). The classic ones had "stems"...
I was doing student summer job for a month in Crimea sometime in 70s. We were building dwellings for locals. The walls were made of stone that was billions of shells cemented together. It was very soft and we were all covered in dust. In combination with the summer heat it was awful.
> Deep Time: If the timeline of Earth were mapped onto the human arm, it would begin around the shoulder where the earth formed about 4.6 billion years ago. Animals originated within the palm, but the myriad forms alive today exploded onto the scene around the first knuckle, in the Cambrian period. Blocks along the fingers represent the periods that followed, such as the Jurassic (dinosaurs!) and the Cenozoic (in which humans evolved, a microscopic sliver at the tip of a fingernail)..
