Creek Sharks EarthCache
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This cache is located in Eastern Front portion of Petersburg National Battlefield. Parking is available at stop five on the tour road. Entrance fee of five dollars can be paid at the park entrance or visitor center. The cache is accessible by a paved trail that runs past Fort Stedman and then turns into an unpaved trail leading off to the left and down hill. Trail conditions vary so use caution. At certain times of the spring this trail is closed due to nesting bald eagles.
The area around Poor Creek is home to two notable and related geologic occurrences. First, along this section of the creek many fossilized shark teeth have been found. No, this does not mean that sharks live in this tiny freshwater creek. Many of the teeth have been quite large and belong to an extinct species of gigantic shark called Megalodon. Scientists think it may have grown as long as 50 feet (15.25 meters). It could have weighed as much as 50 tons (50,000 kg). During the Miocene Epoch (24 million years ago) most of coastal Virginia was covered by the sea and was one of several places around the world where Megalodon lived and hunted.
Across the creek on the steep bank is a type of stone made of large amounts of clay and calcium carbonite called marl or marlstone. Marl was originally an old term loosely applied to a variety of materials, most of which occur as loose, earthy deposits consisting chiefly of an intimate mixture of clay and calcium carbonate, formed under freshwater conditions. Because of its resistance to erosion and relative impermeability to water marlstone often aids in the preservation of fossils. There are records of soldiers finding fossil imprints in the marl along creek banks during the Siege of Petersburg. During the siege the 48th Pennsylvania regiment successfully tunneled under the Confederate defensive positions at Elliot’s Salient in an attempt to explode the fort with thousands of pounds of gunpowder. While constructing the tunnel, however, the regiment ran into a stratum of marlstone and could not dig through it. The men were forced to angle their tunnel upwards to go around the impediment. The marlstone is quite slick when wet and even in dry conditions can become quite slippery so please watch your footing.
To log this cache you will need to email me the following:
1.Number of people in your group.
2.Compare the color of the marl to other nearby soils. How does it differ in appearance?
3.Estimate the depth of the creek (we’ll see how much it varies).
4.Is there any difference between the near and far banks of the creek.
5.Examine the creek bed and describe the sediment that it is composed of.
Optional but appreciated - Post a picture of yourself or your GPS with the creek in the background.
IMPORTANT: It is illegal to remove anything from National Park lands. Leave any stones, vegetation, or other items where you found them. If you spot a shark tooth notify a ranger. Take nothing but pictures.
Please Note: Periodically this cache may be inaccessible due to nesting bald eagles in the area. The birds are a point of pride for the park and are a protected species. Trail closures most often occur during the early winter and spring but may happen at other times as well. Please check the Petersburg National Battlefield website in advance for news of trail closures - (visit link)
Additional Hints
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