The Rock Cycle: USGS 

 

Introduction to Soils: USGS Natural Resources Conservation Service 

 

Introduction to rock types: Utah Geological Survey 

 

Weather and Soil:  USDA 

 

Lichens of North America: Online details of the Brodo, Sharnoff, and Sharnoff book

 

Weathering: Tulane University 

 

Example of Weathering Rates: University of Georgia 

 

   

 

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