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| | GORP - Modern History, Mammoth Cave National Park |
 | | Cave sediments with abundant quantities of nitrate, an essential ingredient of gunpowder, were mined by slaves during the war. |
 | | The area, with its multitude of limestone caves, underground rivers, springs, and sinkholes, is known as a karst landscape. |
 | | Many of the cave animals are blind, or nearly so, and some lack skin pigments as a result of living in the total flness of the cave. |
| gorp.away.com /gorp/resource/us_national_park/ky/mammhis.htm (695 words) |
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