OK. Admit it, you thought this would be a note about the spectacular doubly terminated clear quartz crystals hiding in vugs in dolostones. Referred to as Herkimer diamonds, and known to mineral enthusiasts from across the country simply as “Herks” there has sure been enough written about them to last a lifetime. And goodness knows we all like to travel to Herkimer County to collect them. But no, this is not just another article about quartz.
Stromatolites are bio-chemically supported structures formed in shallow water when microscopic cyanobacterial material (formally known as blue-green algae) acts to bind and eventually cement sedimentary grains into what are essentially microbial mats. Changing climatic conditions, water depth, sediment influx, or the biology of the micro-organisms themselves leads to finely layered biochemical accretionary structures.
There are many well known fossil collecting sites in the creeks and gullies draining into the Finger Lakes (places like Kashong Gully, Deep Run, and Portland Point to name a few). But for every well documented site there are a dozen lesser known locales where drainages into the Finger Lakes expose the fossil rich strata of the 385 million year old Middle Devonian Hamilton Group. Indian Creek, near Williard on the eastern side of Seneca Lake, is one such location.
The New York State Geological Association (NYSGA) held its annual meeting in Plattsburgh in September. The event, hosted by SUNY-Plattsburgh, featured field trips to several Adirondack sites and I attended one on both days of the event. But we will leave that to a subsequent post. This note focuses on an outcrop just outside Plattsburgh where the gastropod Maclurites magnus can be found. Encouraged to visit the site by a SUNY-Plattsburgh geology student, I found time Tuesday September 15th to spend a couple hours walking the outcrop with New York Paleontology Society Field Trip Leader Ray McKinney, who just so happens to live in Plattsburgh. Meeting him on this trip was an unexpected bonus to attending NYSGA.
Having been rained and flooded out in June, the WCGMC found a way to squeeze a trip Alden into its August schedule visiting the ever popular site on Saturday August 29th. This time the weather was perfect, the water was low, and, as always the fossils were there to be collected. The formidable Ledyard shale cliffs in the creek bed have been a favorite site for collectors for several decades, but winter erosion always seems to expose new ones to extract with a little digging.
Sometimes things get named too fast and once labeled incorrect associations are very difficult to rectify. Have you ever seen “turritella agate” at your favorite fossil dealer’s table? It has often been polished into cabochons designed to display the whorls of the spiral shaped shell and the agate that has filled the apertures. Raw specimens are attractive as well.
It was a large, enthusiastic group of all ages from two local clubs that gathered on August 9th to trek into Green’s Landing on a fossil hunt. Stephen Mayer led the Wayne County Gem and Mineral Club contingent while Dan Krisher (also a WCGMC member) led the Rochester Academy of Science Fossil Group. The total group numbered 27 with about an equal number from each organization. It was a wonderful way for folks in each group to meet fellow fossil enthusiasts while doing what they enjoy most, digging in the Middle Devonian. And Green’s Landing was ready for us with as diverse and prolific assemblage of fossils as one could imagine.
There are so many known fossil collecting sites in western New York that one rarely elects to “explore” new creeks or seek out new locations. And the Middle Devonian Hamilton Group is so well known in quality, quantity, and diversity of species that there seems little reason to hunt elsewhere. But on July 11, that is exactly what five members of the Rochester Academy of Science Fossil Group decided to do. We stepped up section into the Upper Devonian and headed for a gully exposing the Cashaqua Formation near Middlesex, NY. Continue reading Awesome Ammonites→
Sheds, NY roadcut was the “Site of the Month” in the June 2015 WCGMC News
Many of us have become familiar with exposures of fossil-bearing Middle Devonian Hamilton Group in the creeks and gulches draining into the Finger Lakes. And we may have ventured west to Penn-Dixie or other Buffalo region sites. But there are also numerous sites within these same geologic units in central New York. One small site is a simple roadside exposure on Dugway Road, just 2.4 miles northeast of Sheds, Madison County, NY (GPS N 42º 49.94’, W 75º 47.72’).
Pennsylvania and the Limestone Products Quarries in Mt. Pleasant Mills and Middlebury beckoned a number of Wayne County Gem and Mineral Club collectors south for May Day. The day started with the annual dig atop the quarry collecting wavellite. As the cover photo suggests, we dug high, low, left, and right in the third cut atop the hill, but unfortunately we were not as successful as in past years. Lots of color but not many full balls and none of the deep green the Buffalo Club had on display at its show in March. We probably did not dig deeply enough to deserve quality pieces. But, yes, that is Jerry Donahue in the middle of the photo with his sampling tool. It was great to see him back in the field with us.
Fellow fossil collector and stamp collector Stephen Mayer wrote this piece for the May, 2015 WCGMC News and has permitted me to add the piece to my blog. Thanks, Stephen
In the WCGMC March 2015 Newsletter, Fred Haynes introduced a method of collecting minerals and gems in the winter when the ground was covered knee-deep in the white stuff. Simply they can be acquired by collecting postage stamps. Fossil hunters shall not be left behind! Fossils are also depicted on many postage stamps. In fact, the American Topical Association (ATA) lists more stamps with fossils than minerals. The ATA recognizes 3535 stamps from around the world depicting fossils ranging from diminutive invertebrates to enormous dinosaurs.
Spring has arrived and Wayne County Gem and Mineral Club did not let any grass grow under its feet before activating its field season. In fact, we did not even let the snow melt.
It was April, it was opening day, and there were diamonds involved. But no, it was not baseball. Rather, April 1 is opening day for “Herkimer diamond” hunting at Ace of Diamonds Mine in Middleville, NY and 12 intrepid WCGMC members put on their boots and their woolies and made the annual trip. Exposure was limited and the snow prevented the owners from bringing in new rock. But there were still “diamonds” to be found and the sun was out to warm our hearts if not our hands. April 1 may actually be more tolerable than August 1. We even signed up a new member while digging, welcoming Donna Dow to our growing family of crazed collectors.
The weather outside was frightful, but the fossils inside delightful! Twelve local Science Olympiad students from five Rochester area schools and their coaches braved the freezing rain to take advantage of the Rochester Academy of Science’s Fossil Night on March 3rd to bone up for their upcoming competition on March 14th. The event was held in the Brighton Community Center behind the Public Library.
The students brought their notebooks and their inquisitive minds while several club members set up labelled exhibits from their personal collections. In addition, a test table was set-up where the students could work on their own to try and identify more than two-thirds of the fossils from their Science Olympiad list of 93 animals and plants. [Continue Reading to see some pictures of the event]
A Middle Devonian Trilobite of New York State By Stephen Mayer
Stephen Mayer is a member of the Wayne County Gem and Mineral Club and wrote this piece for the March 2015 newsletter. It is certainly an informative and appropriate entry for my blog and with Stephen’s permission I have included it.
Whether collected by oneself in a creek bed, road cut or quarry or just simply observed in a museum’s exhibit, trilobites have fascinated people for thousands of years. Excavation of early burial grounds 50,000 years old have revealed trilobites with human remains (AMNH, 2015). Their fossil forms have been the basis of numerous studies by everyone from paleontologists to school children.
Trilobites are extinct arthropods distantly related to the modern marine lobsters and horseshoe crabs. In the Burgess Shale in the rugged high peaks of the mountains of British Columbia, Canada an amazing group of soft-bodied organisms have been found including Trilobitamorpha – fossils that appear to be like trilobites but just have not fully evolved yet. Then true trilobites first appeared during the Cambrian Period about 521 million years ago during the “Cambrian Explosion” as a result of the development of a chitinous exoskeleton which permitted fossilization of these organisms.
I have had an active interest in mineral collecting for several decades (five years in Arizona can do that to anyone), but have developed a growing interest in fossils since moving to western New York two years ago. Having completed my first full season of mucking up creeks and stopping at roadcuts in the Silurian and Devonian strata of western New York I can announce that I now have a favorite fossil.
I realize many are, and for very good reason, enamored with trilobites. Be they DiPleura, Greenops, Dalmanites, or Eldredgeops , those are certainly great finds and I will be more than happy to pick one up when I come upon it. But I took a fancy to a simple tabulate coral species this summer: Pleurodictyum americanum, a species first described by the German paleontologist Carl Ferdinand von Roemer in the late 19th century. Note his original drawings in the featured image for this post (Roemer, 1876).
Perhaps it is the near perfect symmetry of the colonial coral that grabbed my eye. With a rounded top and a fairly flat bottom they certainly look grand once clay and shale is washed from the polygonal corallites covering the surface. Even better presentation results when multiple specimens of variable size are displayed together. My interest was also sparked because “pleuros”, as I have come to affectionately call them, are not as common as horn coral or many of the brachiopods species that are ubiquitous at many sites in the Finger Lakes region, but they are also far from rare and when found they are typically complete and recoverable.
“Site of the Month” article I wrote for Nov. 2014 WCGMC News
More than two decades ago, WCGMC member Stephen Mayer did his M.S. at SUNY-Fredonia focusing on the stratigraphy and fossil assemblages of the Jaycox member of the Ludlowville Formation. A small creek on the east side of Canandaigua Lake provided wonderful exposure of the section and became the key exposure for his work. On Saturday September 27th Stephen returned to his old haunt, this time leading 17 members of our club on a fossil hunt at Green’s Landing. Naturally we learned a little about the local stratigraphy from Stephen also as we hiked about 1200’ up the creek, mostly through Wanakah member shales.
My fledging knowledge of fossils grew this month when University of Rochester Fossil Technician Gerry Kloc introduced me to Eldredgeops and his book on Trilobites of New York.
For over 150 years the common Devonian trilobite of New York and other North American locations had been referred to as Phacops rana, after the description and identification of Phacops latifrons in Europe. The literature, museums, and individual collections carry the name. As it turns out, this North American trilobite is not a Phacops genus, but rather an Eldredgeops. Although this has been known in the paleontology world for two decades, many specimens continue to be misnamed.
A most thorough and readable note on the distinction between the two genus can be found on the Fossil Forum website (www.fossilforum.com). The discussion, dated June 8, 2014, is called Phacops Vs Eldredgeops and is found in the General Discussion Forum of the website. The author is Gerry Kloc, a Rochester paleontologist who has studied trilobites extensively. Gerry has identified numerous subtle, but definitive, differences in the cephalons between the European Phacops rana and the so called North American variety. He concludes that the Middle Devonian New York species is actually an Eldredgeops and proposes it be given the full name Eldredgeops rana. If you have one, it is time to update your label.
NOTE ADDED OCTOBER 4, 2017: The property in Deep Run has changed ownership and the new owner is NOT allowing collecting or trespassing. The fossil-rich beds described in this note can no longer be visited. WCGMC will not schedule any more trips to Deep Run.
SECOND NOTE December 2019: The creek is still posted No Trespassing, however, the beach is public. In 2019, I started to collect sands and Deep Run Beach was one of my first to collect.
Article I wrote for “Site of the Month”, WCGMC News, Sept. 2014
Devonian Fossils at Deep Run
Most residents of western New York carry on their daily business without any knowledge that they live in a region with some of the richest and most diverse fossil collecting in the United States. Those of us in the WCGMC are lucky to know how blessed with are with our collecting opportunities. But do we know the series of geologic events that led to this unique opportunity?
There are other fossil-bearing stratigraphic units in New York, but here we discuss the prolific Middle Devonian Ludlowville Formation within the Hamilton Group. About 385MY ago an inland shallow sea occupied much of western New York and both the sea and the benthic bottom literally teamed with marine life. Corals (both rugose and tabulate), brachiopods, gastropods, crinoids, and, of course, those highly sought after trilobites thrived communally in the shallow seas behind the continental mass to the west and inboard of the Catskill Delta and Acadian Mountains to the east.
WCGMC has been informed by the new owner of the property off Route 20 in Alden that the Spring Creek area where we have enjoyed collecting pyritized fossils for a long time is now off limits to collecting. The new owner has informed us that in the future he will treat “fossil collectors as trespassers”. Given the new owner’s wishes, as of June, 2016 WCGMC is not planning any future trips to this area and the site should be considered closed to collecting.
Many of us have a special passion for collecting aesthetic and/or unusual minerals, while others prefer the varied forms and diverse variety offered by the early-mid Paleozoic fossil collecting that can be done in western New York. There is one site that can please both groups of collectors. Along Spring Creek in Alden, NY, the rich and diverse Devonian fossil assemblage we have all come to know and love is locally fully pyritized. Opening the fissile shale surface not only reveals a 380 MY old fossil, but a shiny mineral specimen as well. The prize is a pyritized fossil. Cephalopods, brachiopods, and ammonites are the most common, but two species of trilobites have also been found completely replaced by the iron sulfide mineral pyrite.
Just north of US Route 20 as it passes through the small town of Alden, NY, Spring Creek has carved itself deeply into the Middle Devonian Ledyard Shale Member of the Ludlowville Formation. Known for decades, the site is readily available to all with two legs, a hammer, a backpack (or even large pockets), and the willingness to perhaps get a little wet and mostly certainly muddy. A short hike along well beaten trails leads to the creek which can be accessed at several sites. Fourteen of us can be seen at one of those sites in the cover photo above.
Article I wrote for “Site of the Month” in May 2014 WCGMC News
Technically, Mount Pleasant Mills is not in New York, but I am going to claim editor’s license to divert this month’s “Site of the Month” south of the border and to invoke multiple sites. You see, on April 12th and 13th, thirteen Wayne County Club members gathered up their passports and headed south across the border in search of warmer weather and mineral/fossil treasure. We found both!
With temperatures well into the 70’s, the group converged on National Limestone Quarry in Mount Pleasant Mills where we were cheerfully greeted by the quarry owner Eric Stahl, who had cleared the road to the ridge atop the quarry in anticipation of our visit. Up we went, backing in the final section until we were all lined up adjacent to one of the wavellite spots atop the hill and collecting commenced (see cover photo).
The Rochester shale comprises the upper 85’-90’ of the Middle Silurian Clinton Group in upstate New York and southern Ontario. The upper two-thirds of the unit contain numerous grey limestone beds, which can be sufficiently resistant to form outcrops, but which are poor in fossil content. The lower 20’ of the Rochester shale is notoriously susceptible to erosion such that outcrop exposure is rare. Unfortunately, it is this rapidly weathering unit at the base that contains the abundant fossil assemblage (specifically trilobites) for which the formation is famous. The best visible exposure of the full Rochester shale section is in the gorge walls of High Falls on the Genesee River. However, this section is agonizingly unapproachable for fossil collection, particularly so the lower 10-20’ of section best known for fossil diversity and abundance.
Over 200 invertebrate fossil species have been identified from the Rochester shale including corals, brachiopods, bivalves, gastropods, cephalopods and crinoids. But, it is the spectacularly preserved trilobites that have attracted collectors to the Rochester shale since James Hall first detailed their occurrence in the 1840’s. The diverse fauna combined with the fine grained shale beds and thin limestone units indicate that the Rochester shale was deposited in warm, well oxygenated marine waters of intermediate depth. But where does one find outcrop to search for fossils?