C&O Canal Biking / Dam #4 Cave Trip

Williamsport-Little Pool

• My Previous Trip
• C&O Canal Virtual Tour: Mile 100-110, Mile 110-124
• C&O Canal Biking Guide: Mile 82-105, Mile 105-115, Mile 115-130
• Maryland Geological Survey: Two Locks Caves

Continuing my dual purpose of cycling the C&O Canal and hunting for caves along the way, Nick Cross and I headed out early Sunday morning. Two hours later we arrived in Williamsport and hit the trail. The day was beautiful and sunny but the weather report promissed temperatures in the 90s and high humidity. The biking was largely uneventful and the canal beautiful.
At mile 106 we passed Dam #5 and had a bite of lunch. Soon thereafter we passed Two Locks and a set of cliffs and caves presented themselves. A promissing-looking square hole up a short trail became very tight, though probably humanly passable; I suspect that this is the actual Two Locks Cave. In biking clothing, we decided not to push it. We spent some time scrambling around looking for further caves and found nothing. Around the corner, however, a nice-looking series of solution pockets showed up in an overhanging, sheer cliff face. These cavities culminated in a human-sized entrance about 20' off the path. Impossible to tell where it went from down below, but it looked promissing. More interestingly, the cliff was covered in patches of boxwork! While I've seen this phenomenon of harder calcite veins sticking out of softer limestone before, I've never seen it outside a cave!

Nick reaches maximum penetration in a nice-looking entrance; probably the largest of the Two Locks caves. Unfortunately, the passage soon became smaller than we wanted to deal with.

The spectacular fissure in the sheer cliff. Next time I'll come back with rope and rappel in! Click for a larger view.

Beautiful boxwork on the cliff just to the left of the cave entrace. These calcite intrusions remain after the softer limestone matrix has erroded away. More info on Boxwork and many other cave formations

Around the next bend, another series of small holes were seen in a gulley but didn't progress more than ten feet or so. But again, a sheer cliff presented itself with a large cave. This time, however, we could scramble up through some breakdown blocks to the airy perch inside the cave. The only room was roughly spherical and about ten feet across with a good view to the outside.

Nick perched in the spacious cave in the second set of cliffs.	Several small holes near Two Locks were dirt-filled and didn't go very far.
An intriguing hole near Charles Mill didn't go very far either.	A close-up view of the fascinating column outside the entrance above.

The diversion of promissing-looking holes in the ground taken care of, we set about biking. The day grew hot and we became dehydrated. Fort Fredrick provided a nice stopping spot at mile 113 but we pressed on past the lovely Big Pool all the way to mile 120 at the eastern end of Little Pool. From there, we took the paved Western Maryland Rail Trail (which parallels the canal for several miles) back to the Fort where cold drinks were purchased to stave off parching.
Two-thirds of the way done with the trip, we hit the Canal again and made it back to Williamsport (mile 100) in fairly short order. By the time we arrived, we were dripping with sweat and thoroughly grimy from crawling around in the dirt and spiders. Tony's Pizza provided a sumptuous repast in a luxuriously airconditioned environment. Ahhh!
Both of us were less-than-satisfied with the quantity of caving we'd managed to do (though there was no complaint about the 40 miles of biking), so after pizza, we headed down to Dam #4 and walked out to Dam #4 cave, about a mile down the towpath. I've been 20' inside the entrance twice now, but have turned around for lack of companions.

The impressive entrance to Dam #4 Cave is hard to miss from the Canal

Girded this time with the intrepid Nick, I was braver and we quickly explored the cave. It's not huge, but there are several interesting grottos and some decent formations. I felt very much out of place being underground in bike shorts and bike helmet instead of my normal, tougher cave helmet and full-body coveralls. Kneepads and gloves would have been nice, too. Two large domes can be accessed on the eastern side of the north-south trending passage. The limestone dips sharply to the east at an angle of 55 degrees (much like Sinnett Cave in West Virginia) and thus much of the passage is triangular in cross section. Nick found a three-foot wide passage of triangular nature at the back of the larger passage near the domes and we headed off. In cycling clothing, without kneepads, it was a painful trek across stream gravel and grit, but we probably penetrated a few hundred feet of slightly tapering passage. By the time we got sick of sharp rocks in the knees, the passage had shrunken to two feet in height and width with no end in sight. During wetter times, this is evidently pooled in water, but there was no sign of water this time around. After checking out the pair of 30' domes to the east of the main passage, we made our way back out of the cave and into the humid twilight. The walk back to the car was illuminated by Venus and the rising full moon.

...North....East...South...West... A cluster of tiny bats, possibly a maternity group, near the back of the cave on the east wall.	Much of the cave is shaped by the 55-degree dip of the limestone. Here we are looking north along the strike from right next to the bats.
From the same spot as the other pictures, looking west (up-dip) into a small grotto.	Looking south, we can also see the dip headed down to the left. We also see Nick looking out of place and surprised in street clothing.

Quite a lot of wildlife was seen on this trip proving that, the farther from big cities you get in Maryland, the better the wildlife viewing it. Six deer, including one largish-but-still-spotted fawn were seen. One wood chuck, a five-foot black snake, assorted geese and squirrels and a fox were all seen from the tow path. Quite a number of cave crickets and spiders were seen in the caves and holes and a cluster of very small bats hung from one wall in Dam #4 Cave. Finally, driving home I nearly ran over a large owl, probably the same one we'd been hearing on the walk back from the cave!

It was a most enjoyable trip. Total cycling distance, 40 miles.

The Home Cave

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