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MD - Sideling Hill 'Cline Earthcache EarthCache

Hidden : 5/8/2012
Difficulty:
2 out of 5
Terrain:
1 out of 5

Size: Size:   other (other)

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Geocache Description:

This Earthcache is a park-n-earthcache, available from both eastbound or westbound (if traveling westbound, you'll need to cross a pedestrian bridge but that is an awesome view in and of itself).

Since this is an earthcache, there is NO physical container, and thus logging requirements MUST be met to accomplish this cache. For more information about earthcaching, visit earthcache.org. The Rest Area is NOT always open. This is NOT a drive-by earthcache.

NOTE: NO LOGS FROM DECEMBER TO APRIL will be accepted since this is NOT a drive-by and the Rest area closes annually during these months. PLAN AHEAD!


Logging Requirements:
Send the answers to #1-#4 to me through my geocaching profile. DO NOT post the answers to any logging requirements on this site.

1. List the name “GC3G49D Sideling Hill ‘Cline Earthcache” in the first line of your email. This is automatic if using the Message Center
2. Which rock layer (there is a specific name) is at the top of the ridge and resisted erosion. (read the description)
3. ‘Cline Study:
a. Is this an example of a Monocline, anticline, syncline, or overturned anticline and syncline?
B Estimate the degree of “fold” at road level (may best be seen looking to the south).
  1. width of ‘cline” is dramatically greater than height
  2. width of ‘cline and height are approximately the same
  3. width of ‘cline is significantly less the height
  4. overturn present, thus multiple measurements possible)
4. Color and texture:
a. Describe the color and texture differences between the different layers of Sideling Hill. Starting from the CORE and moving EAST.
b. What is the COLOR of the rock layer further to the EAST?
5. (Required as of July 2022, allowed since 2019) Post a picture of yourself and/or your GPS with your log that shows you near the restrooms or on the bridge at GZ. DO NOT show any of the pertinent information in your picture or your log may be deleted.

I will only respond if you have incomplete logging requirements. Go ahead and log your cache
Congrads to 'Possum for FTF (First to Finish logging requirements)

The Welcome Center used to house a marvelous historical/geological collection -- but that is now available in Hancock (see roadsigns) since budget cuts have closed the welcome center (except for the nearby restrooms).

Whereas it took a VERY long time for the layers of rock to be deposited, and an additional (thought shorter) amount of time for them to be molded into its present shape, “Man just took over one year to make the road cut which now exposes Sideling hill. I would encourage you to complete the other Earthcache at this site (GCM8ND -- A Look Into the Past).

What makes Sideling Hill special?

One of the best rock exposures in Maryland and indeed in the entire northeastern United States is located approximately 6 miles west of Hancock in Washington County, where Interstate 68 cuts through Sideling Hill. Almost 810 feet of tightly folded strata are exposed in this road cut. Although other exposures may surpass Sideling Hill in either thickness of exposed strata or in quality of geologic structure, few can equal its combination of both.

“Sideling Hill lies in the Valley and Ridge Physiographic Province of eastern North America, a region characterized by tightly folded strata. Erosion of these folds has produced a series of subparallel ridges and valleys, in which the ridges are capped by erosion-resistant sandstones, and the intervening valleys are underlain by soluble limestones and easily eroded shales. At first, Sideling Hill may appear to be a somewhat unusual feature, inasmuch as the fold, exposed in the road cut would seem to be more likely to form a valley, rather than a ridge. However, the youngest rocks, or those highest in the stratigraphic section, are the resistant sandstones and conglomerates of the Purslane Formation, which occur in the center of the fold and cap the ridge. (see logging req #2)

The valleys on either side are underlain by more easily eroded rocks of the Rockwell and Hampshire Formations. This topographic inversion, in which the structural low becomes a topographic high, is also seen at Town Hill, the next major ridge to the west and a structural twin to Sideling Hill. Between these two ridges the intervening lower area is composed predominantly of Devonian age shales and siltstones.” (mgs.md.gov)

‘Clines”:
Geology is not static, it is every changing. At this GZ, you are looking at a “’cline.” It is either an early stage “mono cline” where the rock layers are just beginning to form a dominate fold and thus determining what time of ‘cline will develop is impossible. Intermediately, are anticlines and synclines. To be more specific, in geology, terms used to describe folded rock layers where the relative ages of the layers are known. Specifically, anticlines are folds in which the oldest rocks are in the core, or center of the fold, while synclines have the youngest rocks in their cores. In most cases, anticlines are arch-shaped while synclines are trough-shaped. In unusual cases where older rock layers lie on top of younger layers, anticlines are trough-shaped and synclines are arch-shaped.

Further, ancient synclines and anticlines that have continued to received pressure from mountain building events (like plate tectonics) can fold over on themselves, crushing intermediate layers and compressing other layers – nonetheless, all layers within the collapsed folds are still visible – this is called and “overturned” ‘cline. For logging requirement #3b, estimate the “intensity” of the fold.

For logging requirement #3a, identify the nomenclature of the ‘cline present at Sideling Hill (Monocline, syncline, anticline, overturned anticline and syncline). See image below for assistance

cline nomenclature
Interestingly, Anticlines and Synclines can BOTH appear in either a mountain top or valley location, depending on when the resistant-rock portion of the ‘cline is exposed and thus ceases the rapid deposition of the rock (Schmidt 52). Since Anticlines are typically “hill shaped,” so they more commonly form hilltops, but if the resistant layer is well buried in the fold, then erosion can wear down into the anticline significantly, creating a valley, albeit a valley at the TOP of an anticline. In the same way, a syncline often forms a valley, yet, if the top layer that fills the core of the syncline is resistant to erosion, then the “cap” will create a hill/mountain.

In the Valley and Ridge area of Maryland, all ridges are made as a result of the environment interacting with ONE of the following three layers of resistant rock: Purslane Sandstone (Town Hill and Sideling Hill); Oriskany Sandstone (smaller numerous ridges, such as Fort Hill and Roundtop Hill, and Cove Ridge); finally, the Tuscarora makes the highest ridges (Hystack and Wills). Other minor resistant sandstones and/or conglomerates comprise the caps for small/minor formations, but these three resistant layers are immensely important to the formation of the Valley and Ridge province and its ability to withstand the tests of time.

Texture and Color:
Bore samples from the area showed dark grey to black sediment (shale and siltstone). This showed at one time the area was near a marshy area next to a river. A sedimentary rock (quartz-pebble conglomerate) which was found in most areas of the road cut showed that it was deposited in a high-energy enviornment where fast moving water was capable of carrying large pebbles. Possibly during a storm flood. White sandstone was also found. This stone showed little or no impurities of iron. Tan sandstone was found as well which can be mixed with other materials to produce mixed colors. Observe the COLORS and TEXTURES visible in th’cline. Textures may include: sandy, smooth, polished, blocky, mineral-rich, smooth, grainy, glassy, etc. (logging req #4a) Observe the COLOR present furthest to the EAST in the formation for logging requirement #4b.

Special thanks goes to Maryland State Highway Administration for approving the placement of the original EarthCache at this location.


Resources: "Geology of the Sideling Hill Roadcut." Mgs.md.gov. Ed. Dale Shelton. Maryland Geological Survey. Web. 03 Apr. 2012. .

Means, John. Roadside Geology of Maryland, Delaware, and Washington, D.C. Missoula, Montana: Mountain, 2010. Print.

Schimidt, Martin F. Maryland's Geology. Atglen, PA: Schiffer, 1993. Print.

Additional Hints (No hints available.)