Quadrangle Maps
| Carbondale | Drift Thickness | 2013 |
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| Carbondale | Bedrock Geology | 2013 |
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| Carbondale | Surficial Geology | 2013 |
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| Carrier Mills | Bedrock Geology | 2007 |
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| Cave-In-Rock | Bedrock Geology | 2013 |
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| Cave-In-Rock, Dekoven, Repton, Saline Mines | Surficial Geology | 1963 |
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| Chana | Bedrock Geology | 2018 |
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| Chenoa | Surficial Geology | 2014 |
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| Chester | Bedrock Geology | 2006 |
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| Chicago Loop | Surficial Geology | 1939 |
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