Lower Cave

Lower Cave. How Strata Shaped Strategy: The Hupp's Hill Civil War/Karst Interpretive Walking Trail. Crystal Caverns. You are standing approximately 60 feet above Crystal Caverns' Hall of Masonry, so named for calcite-filled fissures that resemble mortar. The fissures resulted from compression of limestone strata that occurred when the north American and African tectonic plates collided some 265 million years ago. The resulting orogeny (mountain uplift) folded, warped, and cracked open miles of rock while it lifted the mountains and hills that define the Shenandoah Valley. Perhaps as much as 50 million years ago, this limestone solution show cave began forming within Hupp's Hill's warped strata, ultimately comprising several rooms and passages decorated with speleothems. These decorative formations formed when slightly acidic water containing carbonic acid slowly dripped into the cave's chambers, re-depositing calcite extracted from the limestone strata. In the Hall of Masonry, however, the calcite eventually filled the tectonic fissures formed at about the same time as the folding and faulting of the rock. Geologists often refer to these features as tension gashes, which represent a "rehealing" of the rock after it had been deformed by tectonic forces., Sixty-five feet below the Civil War infantry trench is the Ballroom. From the Ballroom, the visitor can view the deepest chamber of Crystal Caverns, which is at or just above today's water table at approximately 95 feet below the surface. These chambers are thought to be the oldest section of the cave, and contain speleothems that are as much as two million years old., Infantry Trenches. The sod-covered man-made mound running parallel to the driveway is the only surviving remnant of a mile-long Union infantry trench built across Hupp's Hill in 1864. On its southern side, a deep ditch preceded the steep downward slope of the mound, which was studded with sharpened stakes and thorn brush (abatis) to repel Confederate troops advancing up Hupp's Hill. The noticeable bend in the trench line is a revetment that provided Union infantrymen manning the northern side of the trench with converging fields of fire on attacking Confederate troops moving up the Hill's reverse slope., [Captions:] Curious Civil War soldiers explored the cave, but deserters also hid inside. In addition, the cave was used as a field hospital and a temporary holding pen for prisoners., On the evening of 19 October 1864, to the last organized action of the Battle of Cedar Creek, a desperate Confederate cavalry rear-guard action against Union troopers on Hupp's Hill allowed the Confederate infantry to escape [unreadable]'s Hill, although they had to abandon some of their artillery and wagons because of a bridge collapse in Strasburg., Hupp's Infantry trenches constructed by Federal VI Corps after the Battle of Cedar Creek were similar to this re-creation at Pamplin Park, Petersburg, VA.