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It's Sedimentary, My Dear Watson (and Igneous Too) EarthCache

Hidden : 05/02/2007
1.5 out of 5
3 out of 5

Size: Size:   not chosen (not chosen)

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Geocache Description:

This earthcache is located in Essex County, NJ., within the town of Roseland. The only place I was able to find this area marked was on Google Earth. It is called Roseland Quarry, Riker Hill Fossil Site, and Walter Kidde Dinosaur Park. There is a well-marked trail which leads to the cache area. There is also some steep climbing involved, as well.


This is a very interesting and unique area. First, it is not to be found on any map. Second, one needs to walk through the woods for about .14 miles until the actual trail is reached, which after a short .12 mile walk quickly opens up into a dark red landscape of rock. The uniqueness of this area is characterized by flaggy, fresh exposures of sedimentary red beds. Once you reach ground zero, there are large fields of flagstone strewn everywhere. About 200 feet further, there is a bonus feature, a high wall of basalt, which is an igneous rock intrusion feature.

The red beds are from the Early Jurassic Towaco Formation, consisting of layered shale and intervening flaggy sandstone that preserve a variety of very well-preserved sedimentary structures and some cool features including ripple marks, desiccation cracks and occasionally, if you are lucky, trace fossils (rare dinosaur tracks which are very tiny). It is illegal to remove anything, especially fossils, from the area. Please look and handle gently but do not destroy. At ground zero, there are a few fantastic areas where you can see the layers of the shale on some larger rock samples. FYI: There is a considerable amount of 3/4" Red Shale which goes for about $79.00/yard at your local landscaper commercial supply store.…don’t get any ideas!

How is sedimentary rock formed?

For thousands, even millions of years, little pieces of earth have been eroded and worn away by wind and water. These little bits of earth are washed downstream where they settle to the bottom of rivers, lakes, and oceans. Layer after layer of eroded earth is deposited on top of each, pressed down more and more through time, until the bottom layers slowly turn into rock. Shale rock is a type of sedimentary rock formed from clay that is compacted together by pressure. They are used to make bricks and other material that is fired in a kiln. The small amounts of sandstone you may encounter are also sedimentary rocks made from small grains of the minerals quartz and feldspar. They often form in layers as seen in this picture. They are often used as building stones.

To log this cache, you must:
1. With your log, submit a picture of you and your GPSr standing in front of or next to an outcrop of red shale.
2. With your log, submit a picture of a piece of shale and a piece of basalt in your palm.
3. In an e-mail, describe the differences you can observe between the shale and the basalt.
4. In an e-mail, describe the direction of the layers you see of the red shale. Why do you think they run in that direction?



A Few Poison Plants Sharp Pointy Things Along Trail
Restricted Hours Restricted Hours Available in Winter Accessible in Winter
Scenic View Scenic View if You Climb the Cliff Stanky Mud When Rainy Math Teacher Nearby


Practice "Cache In Trash Out"
While out geocaching, bring a bag with you to pick up trash along the way. Visit the Cache In Trash Out page to learn more about CITO.

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