Eighteen Mile Creek, New York USA
 In this picture, the creek is very low. It is easier to see where the Turtle Stones have settled. |
 Turtle Stones and other rocks are carried by the creek when the water is high and runs quickly. When the creek slows down when it goes around a bend or when the water level drops, then rocks get snagged along with tree limbs and come to rest in a jumble. See the Turtle Stone nestled in among the other rocks in this picture. |
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ROCKS & MINERALS: septarian nodules, favosite coral fossil, concretions,
Turtle Stones, fossils
| Concretions | ||
 Concretions that are oval in shape and have ridges on their surface are known as "Turtle Stones" because they look like a turtle shell. |
 Most Turtle Stones are over 50 cm in length, but if you look, you can find "Baby Turtles" For more pictures of Turtle Stones, CLICK HERE |
 The shale banks of the creek have concretions in them. When the shale erodes and crumbles away, the concretions, which are harder than the shale, roll down the bank into the river. Not all concretions are Turtle Stones. |
 Some concretions do not show the distinct markings of the "Turtle Stone", so we call them "Smoothies". This one is lumpy with pyrite nodules and possible fossil pieces sticking out. |
 When broken open, the concretions show crystal growth within the rock. |
 This concretion has a large pyrite nodule embedded in it and the pyrite is causing the rust stain. |
 Sometimes concretions grows together when they form in the sedimentary rock, like this grouping. |
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| Fossils | ||
 This rock is full of fossils. The rust stains are from pyrite nodules. |
 Fossil Favosite |
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 Limestone "pillow" - a well-weathered rock that has been tumbled smooth in the creek with 2 favosite fossils. |
 Fossils - sponges and crinoid stems |
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 Fossil - favosite |
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| Interesting Rocks | ||
 Some of the rocks tumbled and carried by the creek, like this granite boulder, come from far away and may have been deposited by glaciers. |
 Not all rocks are actually rocks. This is a piece of concrete that has been tumbled smooth in the creek. The black "inclusions" are most likely shale. |
 Shale is very soft and splits into flat pieces. When tumbled, the corners are quickly rounded. These pebbles make great "Skipping Stones" for anyone who has ever enjoyed throwing stones on the water. |