Geology of New York State

Trilobite

Trilobites were three-lobed organisms that once lived in the ocean. Over 10,000 different species have been discovered but unfortunately they went extinct 251 million years ago.

Crinoid

Crinoids may have looked like plants but they were actually animals. This fossil is a portion of a crinoid stem. It would have had a holdfast to anchor it to the bottom of the seafloor and numerous branching arms at the top.

Stromatolite

These fossils are the remnants of the actions of cyanobacteria. Calcium carbonate would precipitate on the outer layer which was where the microbes were active. Over long periods of time new layers formed over the previous layers.

Pyritized Nautiloid

This rock contains both the cast and mold of a nautiloid fossil that has been pyritized over time. This organism is related to the nautilus that live in the oceans today.

Fossilized Burrows

At one point this area would have been at the bottom of a sea. Organisms burrowed through the mud either for shelter or for food and eventually these burrows were filled with sediment.

Eospermatopteris

The town of Gilboa is known for its fossilized forests. It is one of the fossilized forests environment found anywhere on Earth! I volunteer at the Gilboa Museum during the Summer so stop by sometime!

Favosite

This honeycomb coral went extinct about 251 million years ago.

Anorthosite

The high peaks of the Adirondacks are largely composed of an igneous rock known as anorthosite. This rock formed over a billion years ago at a depth of over 15 miles beneath the Earth’s surface. It is mostly composed of plagioclase feldspar.

Xenolith

There once was a magma chamber deep beneath the crust. At some point part of the bedrock above it broke off, sank, and the magma solidified around it.

Rare Mineral

A large variety of minerals come from NYS. This mineral has only been found in one place in the state and only a few other places in the world. It isn’t worth anything but it is beautiful.

Herkimer Diamonds

Herkimer diamonds are not actually diamonds but a double-terminated form of quartz. This type of quartz has only been found in a few places worldwide.

Sphalerite

Sphalerite is one of the main sources of zinc and can be found in upstate New York. Pictures do not do this mineral justice as you can’t accurately see the reflecting light.

Blue Calcite

A beautiful mineral that can be found in St. Lawrence County. If you leave this mineral out in the sun it permanently loses its blue color. I won’t be doing that…