The Tar Springs sandstone is a unit in the standard Chesterian section. The lower boundary was established at the top of the main or massive part of the Glen Dean Limestone. In Indiana, the Tar Springs Formation is primarily shale, but it also contains scattered thin beds of limestone and massive local lenses of sandstone. The formation is commonly about 65 feet thick but reaches 100+ feet in places.
The Tar Springs sandstone represents deposition by prograding fluvial-deltaic and paralic sedimentary environments. Interpretations of the depositional history of the Tar Springs Sandstone suggest the following sequence of events. Fluvial and distributary channels traversed a broad coastal plain and built high-constructive lobate deltas which prograded into a shallow eperic sea. Marine currents reworked the deltaic sand bodies, and northwest flowing longshore currents provided sands to strike-fed mainland beaches. To the northwest of the deltas, where fluvial sediment contributions were minor, thin marine sheet sands were deposited. In these distal areas, sedimentation was dominated by tidal processes, and extensive tidal-flats developed.
Honeycomb Weathering
Much of the sandstone at Hemlock Cliffs is “honeycombed” by weathering of iron ores. The Tar Springs sandstone is inconsistent in its strength and friability. In the past, when waves would splash on to the sandstones, the soluble minerals would dissolve and be flushed into the sea, leaving behind pit-like features on the rock surfaces. This process is called honeycomb weathering and can be seen in the photo below:
See the additional waypoints for coordinates of areas where good examples of honeycomb weathering can be seen. This type of weathering occurs throughout the world for various reasons, including wind erosion, exfoliation, frost shattering, and salt weathering, in addition to the wave-related weathering of iron ores seen at Hemlock Cliffs.
Hiking the Trail
A 1.4-mile hiking trail leads you down into the canyon under a lush canopy of large trees, through rock shel¬ters, and past high seasonal waterfalls. Parts of the trail are steep and slippery when wet, so use caution. It could take two leisurely hours to complete the loop.
As you walk the loop trail, you will sense what powerful waters, combined with millions of years of time, sculpted this truly unique place. Springs, small caves, and subterranean drainage conduits can be found throughout the underlying limestone. Archaeological excavations indicate Native American occupation as early as 10,000 B.C. Through¬out the canyon are rock shelters, which undoubtedly provided cover and defense to the early occupants of this area.
The loop trail begins at the Hemlock Cliffs parking area (see the posted coordinates). The trail is marked with white diamond blazes every few yards. You can go either way on this loop trail, but the falls are closest to the eastern (right) end of the parking lot. From the parking lot follow the trail to a fork in the trail. The spur to the right goes to the top of Hemlock Cliffs Falls. Continue left down a set of “natural” stairs to a beautiful view of the falls and rock overhang. Spur trails lead down to the falls plunge pool.
Directly across from the falls is another canyon finger whose creek merges with Hemlock Cliffs creek. Continue down more steps with a hand rail and cross a foot bridge. The trail begins to move away from the creek, ascending slightly. About halfway through the loop trail, you will come to a junction with a high cliff warning sign. Going right will lead you below the 70-foot Messmore Falls. The falls can be disappointing during dry weather, but the rock cavern (known as Hemlock Cavern or Indian Cave) is impressive (see additional waypoint).
After seeing Messmore Falls, continue left on the loop trail. The trail follows the creek for about a half-mile before crossing over. The moderate climb passes a small pond on the left. The trail eventually levels out and returns to the parking area.
Safety/Restrictions
Please use caution in the area during hunting seasons. Blaze orange clothing is recommended (do not wear white!) during deer season. Motorized vehicles are prohibited, except on designated roadways. Foot traffic is restricted from some areas for resource protection. Rappelling is also prohibited in designated areas for resource protection (see map). Archaeological sites and artifacts may not be disturbed.
Directions: Take Interstate 64 to State Road 237 and go north. Take Union Chapel Road west 2.6 miles to the intersection with Eckert-Hatfield Roads. Continue on Hatfield Road 2.1 miles to the parking area. Here are a couple of maps for your reference:
To Log This EarthCache
[OPTIONAL: Although it’s completely optional, I would greatly appreciate it if you could take a photo of yourself with your GPSr at your favorite location along the Hemlock Cliffs trail. There are so many beautiful, scenic spots along the trail. It will be interesting to see which areas cachers prefer the most.]
To demonstrate the educational value of your visit, please email me the answers to the following questions: (click on the El Pollo Loco Gang link at the top of the cache page to reach our profile, where you will see a link to Send message)
1. What is the approximate change in elevation from the trailhead (near the Hemlock Cliffs signboard) to the floor of the box canyon (can be measured anywhere at the base of the descent from the “natural” stairs)? Using your GPSr’s altimeter will be the easiest way to measure the approximate elevation change. If your GPSr does not have an altimeter, you will have to guesstimate the approximate elevation change using whatever landmarks and known distances you can find along the trail.
2. Find an example of honeycomb weathering, and post the coordinates of its location. Describe the weathering of the sandstone. How deep are the pits? What are the average sizes of the holes?
3. Estimate the approximate width and depth of Hemlock Cavern/Indian Cave.
For more information about Hemlock Cliffs, click on the User’s Web Page link above (just below the cache size).
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El Pollo Loco Gang