I've been surveying the Alvars, an extremely rare habitat type here in Ohio, for the Lakeside Daisy. Here's a rundown of this incredible habitat. An alvar is a very shallow soil system over limestone, dominated by red cedar and containing all kinds of extremely rare plants. In North America, Alvar communities are only know from a handful of locations near the Great Lakes shores of the U.S. and Canada.
Fossils from the Columbus Limestone, which is the top layer of limestone in the pictures above.