There are several very interesting petrology databases available on the web.PetDB: Information System for Geochemical Data of Igneous and Metamorphic Rocks from the Ocean Floor.British Geological Survey: Mineral and Rock…
Link to PA Geological SurveyPennsylvania's Trail of GeologyPark Guides Trough State Park (PG 1) Huntingdon County, Ridge and Valley province—Ice Mine and Balanced Rock erosional remnant.Hickory Run State Park (PG…
The Giant Crystal Project - A cool web site dedicated to giant crystals. I have personally seen the giant spodumene in the Etta Mine, Keystone South Dakota.
Geofacts are very interesting short publications concerning geology in OhioFrom the Ohio Dept of Natural Resources:GeoFacts No. 1 - Bedrock topography of Ohio [530 KB PDF] GeoFacts No. 2 -…
Pennsylvania Trail Geology - Swatara State Park. pdf fileEducational PDF on Geology of Pennsylvania. pdf filePennsylvania Dept of Natural Resources. Site