Cleversburg Cave Description

Cleversburg Sink Preserve

March 2

CURRENT STATUS: This gated cave is located on property owned by Southampton Township.

A full description of the original section of the cave, which was written by Bernard Smeltzer and is reprinted below, is located. in MAR Bulletin 4, pages 6-9.The description and map of the Straight Gorge Extension, by C. Miller and H. Rudisill, are reprinted from MAR Bulletin 6, pages 13-17.

DESCRIPTION—ORIGINAL SECTION: One mile east of Shippensburg Route 33 passes along the northern border of a field that is dotted with numerous tree-encircled collapse sinks and dolines. A large cave underlies the hillside 2000 feet south of the highway. One can best approach this cave, Cleversburg Sink, from a dirt road leading southeast to the Franklin Crouse farm. A narrow strip of woods 1700 feet from Route 33 lies 150 feet west of the dirt road. By going along the south edge of the woods 700 feet to the corner of a field, one is only 40 feet from the mouth of the cave. The entrance is at the bottom of an impressive funnel-shaped sinkhole 30 feet deep, 80 feet long, and 45 feet wide.

The 3 foot entrance opens into an inclined shaft 10 to 20 feet high sloping down over leaves and wet mud for 40 feet to a point where a peninsula of fallen rock juts into the Entrance Room which is 70 feet long, 25 feet wide, and up to 40 feet high. The lower part of the floor is 95 feet below the surface of the hill. At mid-length, the room is divided by a 15 foot cliff and at the far side a clay slope extends steeply upward. In a short passage that cuts east across the bedding there is a remarkable display of wall protuberances composed of a brittle, clayey material. These impurities showing wavy laminae project up to a foot from the walls but few are more than an inch thick.

A narrow slot branching from the west wall of the entrance room leads to a scarp overlooking Giant Hall which is usually occupied by water 20 or more feet deep. When this lofty passage is dry one can drop vertically 12 feet and slide down a clay slope to reach the floor. Travertine shelves on the south wall indicate a floor level once 20 feet higher. This passage is wedge-shaped and wider at the top than at the floor. It is up to 15 feet wide and 60 feet high. Development follows a tilted joint or fault plane, resulting in a steeply sloping south wall and a hanging north wall.

Giant Hall extends west 150 feet, ending in an irregular chamber piled high with enormous breakdown blocks. Here there is an eroded stalactite resembling a molar. Two pits nearby drop down about 10 feet to a short passage under the blocks. Jagged pendants of various shapes are developed low on the north wall. Several club-shaped forms are attached to the ceiling by only a thin stem. By climbing up a 10 foot scarp above the pits, one can reach a 60 foot room with a floor sloping down to a clay-walled pit than appears to be about 30 feet deep. Thirty-five feet west of the ledge leading to this room there is a similar climb to a small hole in the wall. This hole leads to a constricted channel running northwest 15 feet where it intersects a vertical crevice. The floor of the crevice is reached by climbing down 5 feet onto several large wedged blocks and dropping six feet between these blocks. A slick clay floor slopes steeply down 25 feet to a crawlway 10 feet long connecting to a high slanting fissure.
One can proceed by climbing the sloping wall to the top of the fissure and crossing a pit, or by entering a crawlway 20 feet lower near the floor. Both routes lead southwest to New Hall, which is 75 feet long, 10 feet wide, and 25 feet high. A 10 foot blue-gray flowstone cascade fills an alcove on the south wall. The character of the opposite walls differs considerably. The south wall is composed of impure clayey beds containing grains of quartz sand. The north wall is a massive light gray formation.
Giant Hall is crossed at mid-length by a passage trending NE-SW. The passage to the southwest leads to the most extensive portion of the cave. With a height of 15 feet it decreases to a crawlway leading to a network. After 85 feet it connects to the Sand Bank Room, which is 40 feet long, 28 feet wide, and 18 feet high. It gets its name from the large mounds of sand and sandy clay that cover the floor. The passage continues from the far end of the Sand Bank Room across a travertine bridge.

The next 170 feet is very fatiguing because it is a succession of upward sloping crawls, slippery slopes, and narrow passes. This terminates in the small Flowstone Room that is decorated with mud- stained flowstone and rimstone. A slump in the floor contains stream-scoured sandstone cobbles. One can look through a tiny hole above the flowstone and see a grotto filled with fine stalactites.

From the Flowstone Room, two crawlways continue southwest. A larger passage opening to the southeast across the strike has a travertine ceiling for 15 feet to a point nearly choked with speleothems. Beyond this the passage continues with an average height of 4 feet past numerous blind cross branches. Here it enlarges into a gallery 37 feet long, 10 feet wide, and 12 feet high.

Six slender stalagmites and columns called “The Broomsticks” stand on a ledge high on the east wall. Branching passages with a total length of 125 feet lead east from this ledge. The far end of the gallery tapers to a narrow portal and 15 feet beyond there is a junction with three passages. Here the 20 foot high passage is lined with flowstone and stalactites.

The branch to the left is 70 feet long with a height of 2 to 19 feet. It has a great variety of speleothems The passage continuing straight ahead from the junction enters a room 40 feet long, 17 feet wide, with a floor of fallen blocks studded with stalagmites. To the right at the junction a slope leads up 25 feet past a flowstone shelf, the underside of which is coated with botryoidal forms. At this place a branch to the left connects to the 40 foot room. Near here a short fissure leads to a complex series of interesting chambers extending southwest for 100 feet. In this section there is a compound of speleothems resembling a pipe organ and a serpentine travertine ribbon over 10 feet long.

The two crawlways at the southwest side of the Flowstone Room lead to closely parallel interconnecting’ channels that follow a nearly straight course for 110 feet where they converge. The channel on the right is 20 inches high for most of its length and is 4 feet lower than the left one. The left channel, 2 to 5 feet high, is like a tunnel. A section of the ceiling is perfectly smooth and flat, the only occurrence of a horizontal ceiling in the entire cave. At the convergence of these channels a high passage with terraced flowstone continues for 45 feet to a clay choke. On the left a fallen block obscures an opening leading down a clay bank to a head-high passage 25 feet long with multiple lateral branches. In one branch the usually present high water level has started to disintegrate some pure white drapery, leaving parts of it as thin as tissue paper.

The northeast extension that opens directly across Giant Hall from the southwest passage is surprisingly different although both are in line along the strike. The beds in which it is developed seem to be identical with those in which New Hall occurs. The pattern of development is also similar.

Perhaps the extreme folding of the strata, which is well shown here resulted in a thrust fault marking the course of Giant Hall. The relative displacement of what appears to have once been continuous beds may be represented by the 50 foot offset: that separates these similar passages.

The northeast passage can be traversed on three different levels. Its lowermost or true floor level can be followed 55 feet to where the passage is filled with deep water. The higher levels are merely wall benches or ledges along joints perpendicular to the bedding planes. To pass through here one must go from one bench to another. An upright pendant resembling an eagle’s head marks the start of this upper route. Several narrow canyons cross the passage. A slip here will send the explorer down 10 or more feet to the lower passage and possibly into deep water.

A cross canyon 85 feet beyond has a fissure extending to the left 22 feet to a pit room 40 feet high. Two unexplored openings branch from the far side of the pit. The pit’s clay rim contains a multitude of bat bones. Thirty feet farther the northeast passage changes in character to a straight gorge 10 to 25 feet high and quite narrow. It has been surveyed for 110 feet to where a 3 foot stalactite hangs close to the lower wall. The passage is reported to extend 100 feet or more, ending in a dome pit.
At the bottom of the 12 foot drop between the ‘Entrance Room and Giant Hall, a fissure on the right: 50 feet high leads northeast 112 feet., A small wall’ ledge above water-filled pits must be negotiated for 35 feet. Thirty feet from the end, a ledge on the left leads up to a fissure running west 38 feet. Flowstone curtains occur close to this intersection.

As of November 1957, nearly 3000 feet of passages have been surveyed by William C. Kehm, Barry. B. . Hivner, and the writer. The cave is in the Elbrook limestone of Cambrian age. Most of the passages are along bedding planes and follow the strike. Near the cave entrance the beds dip 70oSE, but throughout the inner part, the dip is 45°SE.

Surface surveys indicate that the far end of the southwest branch of the cave lies within 20 feet of an intersection of Burd Run and Thompson Creek. The stream level of Burd Run is controlled largely by a reservoir near its headwaters. Heavy rains transform the dry stream bed into a sizable brook within two days. When this occurs, the water table pools in the cave overflow, forming rivulets that pour rapidly into various passages. Within a few weeks the largest part of the cave will be filled with water and remain so until the next dry season.

DESCRIPTION—STRAIGHT GORGE EXTENSION:

Though Cleversburg Sink has been explored extensively since the 1957 map (Smeltzer 1958) was published, only two additions of any significance have been reported.
The Straight Gorge section has been surveyed to a terminus, 140’ beyond the 1957 map. This is an upward sloping fissure passage containing domes and bridges. Strangely enough, this passage is now longer than it was a few years ago, when it terminated in a clay-filled fissure beside a dome. Apparently, the fluctuating water table or a stream has undermined the fill, causing it to slump and open 35’ of passage.

A new passage has been mapped, opening from the base of the 30’ pit, shown near the top of the 1957 map. The passage varies from a crawlway to a high fissure. It is quite straight, running N52°E for 83’, ending in a choke near the Bat Bone Pit area.