Umpire Rock is a rock formation in New York City. It is made of schist, which formed when shale was changed by high temperature and pressure.

The schist in Umpire Rock formed about 450,000,000 years ago, long before the first dinosaurs. The rock is made of minerals such as quartz, mica, feldspar, and garnet.
What type of rock is Umpire Rock made of?