went on a hiking trip yesterday with a group from my university! we did a beach hike by some awesome sandy cliffs on the north shore of long island
long island is mostly made of glacially deposited sediment, but underneath it all is a lot of clay, the original material of the area. in most places that layer is below sea level, but along the north shore, there are hills which were pushed up by advancing glaciers, bringing that layer up. now erode into those hills, and what do you get? exposed 100 million year old clay!!!
the tide sometimes comes right up to the base of the cliffs, so clay is being exposed and running into the ocean, where it gets suspended in the water and creates this cool white cloudy effect. (the clay is white because it's free of biological impurities, which are what turns must clay gray and black.) plus we had a record-breaking rainstorm in the area last week, which probably did a lot more erosion as well
also abundant in the area: hematite! iron oxide! turned my fingers orange!
we saw a bunch of rocks like this, where layers of hematite had formed around another rock. the geology professor with us broke one of them open to look for fossils; this one didn't have anything, but this beach is known for having a lot of fossils eroding out of the cliffs, and he and his research student found some big leaf fossils in only a few minutes of looking. (their research is focused on looking for animal fossils, which haven't been found here yet!)
glacial deposition gives you a lot of weird unrelated rocks; i found this big one, which in person was super black, almost like asphalt, and very sparkly. the professor thought it might be originally from the connecticut bedrock
another section of cliffs; a lot of the clay in these ones was pink, possibly from all the hematite! the recent storm carved some very pronounced channels and created these pink clay deltas, which look pretty cool