The Riverside Quarry which was uncovered in 2004 was covered again to prevent looting.  The location here is the Gilboa Museum which has examples of the fossils.

As the trees decayed, the casts left behind were filled with sand which became sandstone.  The tree casts remain in the upright position just as the original trees existed.  The fossils date to 380 million years ago when New York was near the equator.  

Gilboa Fossil Forest

Gilboa Fossil Forest, New York, USA, is cited as home to the Earth's oldest forest. Located near the Gilboa Dam in Schoharie County, New York, the region is home to tree trunks from the Devonian Period, which occurred roughly 380 million years ago. The fossils, some of the only survivors of their type in the world, are remnants of the Earth's earliest forests. This location has been of great interest to paleobotanists since the 1920s when New York City began a water project and excavation for a dam. The project turned up large upright tree stumps from a fossil forest, some of which are on display at the Gilboa Dam site and the New York Power Authority Blenheim-Gilboa Visitor's Center in Schoharie County and at the New York State Museum.

• http://en.wikipedia.org/wiki/Gilboa Fossil Forest
• Page 138 - Dicka, A. B., 2012, 101 American Geo-sites you've gotta see: Mountain Press Publishing Co., 250p.