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The past two weeks I've been able to go out collecting a couple of times- two different locations, both Lower Devonian. Where I live the bedrock is all metamorphic. Nice scenery, wooded hills, lakes and wetlands, but metamorphic rock, so I have to drive over an hour to get to the nearest sedimentary exposures that are fossil bearing. My favorite locality that's within an hour and a half is Glenerie, which is located between Kingston and Saugerties just west of the Hudson River. It represents the type locality for the Glenerie Limestone. New York's Lower Devonian is divided into two groups: the Helderberg and the Tristates. The Tristates is the younger of the two and that's where the Glenerie Limestone is placed. I first visited the Glenerie site when I was a teenager. When I resumed fossil collecting 12 years ago, it was one of the first sites I revisited and quickly became a favorite (I lived much closer to it then.) For a while, I was there almost every week and this site was the first one I built up a collection from. As I became acquainted with other fossil sites, I visited Glenerie less often, but in recent years, inspired in part by my fossil hunting comrades, I've been going more. 

 

The Glenerie site is very rich in brachiopods which probably make up over 95% of the marine fauna. The vast majority of those are single valve. which display amazing detail in ornamentation, muscle scars, etc. Gastropods, tentaculites, bryozoans, and trilobites make up most of the rest of the fauna. Corals have been found by some of my friends on very rare occasions. I have found a single small nautiloid there as well as a partial crinoid calyx. I saw another this time, but unfortunately, was unable to extract it. The fossils are usually preserved in silica which resists the weathering that dssolves the limestone. Some of the limestone is densely packed with fossil shells. However, the rock is so hard that extracting the fossils which are actually softer than the matrix, is impossible. There are areas of the outcrop, near the top and in crevices where shells weather out complete and can often be obtained intact surface collecting. 

 

It was a good day for finding gastropods. I was able to collect a half dozen, including this one, a Platystoma ventricosa- actually two shells side by side, two and a quarter inch across. 

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Some of the other gastropods: The three on the left are also Platystoma. The one on the right , just over an inch and a quarter, is Platyceras "spirale."

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And this is a sample of the brachiopods: The one on the far left is Cryptonella exima, a Terebratulid, the two in the upper center are Leptocoelia flabellites, an Atrypid. Both of these have both valves. Leptocoelia are the most abundant brachiopods at Glenerie. Below them are two single valve spiriferids, Acrospirifer arreutus, around an inch and a half in width. Finally, the one on the right is Cyrtina varia (both valves). 

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A week and a half later, (just a few days ago), I drove up to Schoharie, N.Y., about three hours away and visited a limestone exposure of the Kalkberg Formation which is part of the older Helderberg Group. At this marine site the fossils are preserved in calcite. Although the biodiversity is greater than the Glenerie Limestone, brachiopods are still predominant. Most specimens have weathered from the matrix and can be picked up surface collecting. These are two specimens of the large spiriferid, Macropleura macropleura (the one on the left is two and a quarter inches across):

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These are Meristella, an atrypid brachiopod, species yet to be determined. The bigger ones are about an inch.

 

 

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A couple Eatonia medalis, a rhynchonellid brachiopod, the most common at this exposure. I picked up a few. They're about an inch across. 

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Some (so far) unidentified spiriferids. The biggest is less than an inch across.

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And a pair of (so far) unidentified Strophomenids. The partial specimen on the left is an inch and a quarter in length. 

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The other most common species of brachiopod at this site is the orthid, Discomyorthis oblata. The one in the upper right hand corner is the largest I've ever seen, one and seven eighths of an inch across. 

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In addition to brachiopods, I also found these Hindia sphaeroidalis, a demosponge. 

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And a trilobite, mostly buried in matrix Unclear how much of it is there besides the thorax although it appears to have some of the free cheek exposed.

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You're probably wondering if both Lower Devonian sites have any of the same species. While most are different, ones like Discomyorthis, the Meristellas, and the Strophomenid, Leptaena rhomboidalis and Tentaculites are found at both sites. I am fortunate to have collected at other Lower Devonian sites including ones in New Jersey, Tennessee, and Oklahoma so opportunities to compare and contrast the different faunas should keep me busy for years to come. Thank ou for accompanying me on this journey. Hope you enjoyed it.

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Nice finds Jeff. Glad you were able to get out there. I really like the gastropods! :thumbsu:

Edited by FossilNerd
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The good thing about science is that it's true whether or not you believe in it.  -Neil deGrasse Tyson

 

Everyone you will ever meet knows something you don't. -Bill Nye (The Science Guy)

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Hi Jeff, I really enjoyed your very informative report as well as your pics.:thumbsu:

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I like Trilo-butts and I cannot lie.

 

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 Very cool. I collected in the Oriskany earlier today (roughly equivalent age).

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