2012 Geology Posts That Never Quite Made It

Puddingstones in Brookline, Massachusetts; Pleistocene Coral in the Bahamas; Dinosaurs Tracks in Connecticut; Monster Sea Scorpions in Upstate NY; Diatreme Volcanoes in New Mexico and Deadly Poisonous Mushrooms in Chestnut Hill, Massachusetts

Every blogger knows the challenge. What shall I blog about next? What photos should I use? By the time the end of the year rolls around, there are always a few posts that never quite made it. And so, with this final post of the year, here they are from here and there.

January

This massive, foot-long clast of Westboro Formation quartzite is embedded within an arkosic sandstone matrix of the Late Proterozoic Roxbury Conglomerate, one of two surficial rock units that comprise the Boston Basin. The Roxbury arrived in (better stated to have participated in the formation of) New England within the terrane of Avalonia, having rifted from the supercontinent of Gondwana in the middle latitudes of the southern hemisphere. Avalonia and its accompanying Roxbury made the tectonic journey across the closing Iapetus and Rheic seas during the Early to Middle Paleozoic. This puddingstone initiated my personal geological journey some twenty years ago.

Brookline, Massachusetts

February
A paper-thin veneer of new ice supports a bevy of gulls.
Chestnut Hill Reservoir, Newton, Massachusetts

March
Evidence for changing sea levels exists around the world including the Bahamas.
Low tide has exposed "shore rocks" along the island's north coast which are in reality
150,000 year old fossilized star, starlet and brain coral. This former patch reef was once covered by water considerably deeper during the last interglacial period. During the ensuing glacial period, the sea floor became exposed on land and covered by a limestone-derived soil. The crusty soil is eroding and can be seen on the coral, that is if you can take your eyes off the Caribbean's incredibly blue-green water.
Cable Beach, New Providence Island, Bahamas

March
This is a positive (upper member) cast of a portion of a trackway of a bipedal theropod in shallow-water, arkosic sandstones of the Lower Jurassic Portland Formation. This brownstone, the building stone that shaped America during the late 1800's, was deposited in an aborted rift basin called the Hartford Basin in response to the opening of the Atlantic Ocean. The foot-long footprint is likely that of a Dilophosaurus or Coelophysis, early carnivors of the Mesozoic. Not too far from here in South Hadley, Massachusetts, in 1802 a farm boy named Pliny Moody discovered the first trackway in North America. That was in the Deerfield Basin, a failed rift basin almost identical stratigraphically to the Hartford. The local preacher, seeing the print's three-toed anatomy, called it Noah's Raven, a prophetic analysis considering the evolutionary relationship between reptiles and birds.
Meehan Quarry, Hartford Basin of the Connecticut Valley, Portland, Connecticut

March
This hexagonal tholeiitic basalt, with its characteristic geometry of extremely regular polygonal joints, formed as a consequence of its cooling history. These erratics fractured from a colonade of the Lower Jurassic Holyoke Basalt Flow, the middle of three flood basalts that were generated in 1,200 miles of Mesozoic rift basins along the eastern margin of North America (and across the Atlantic as well) during early rifting of the Atlantic Ocean. This trap rock, as it's called colloquially, has its name derived from the Swedish word for stairs ("trappa") referring to the step-like pattern the extrusive igneous rock assumes once cooled and contracted. Interestingly, the generation of massive volumes of this flood basalt is cited as a possible cause of the Permo-Triassic extinction event.
Tilcon Trap Rock Quarry, North Branford, Connecticut

  

April
Preserved in the famous Bertie Waterlimes of Central New York, these are exoskeletal molts of Eurypterus remipes, also known as a "sea scorpion," a necessity of growth for all body- and limb-jointed arthropods. Classified as a chelicerate (along with spiders and horseshoe crabs) based on the morphology of its anterior appendages, it was a marine creature actually related to a similarly marine scorpion. Both plied the hypersaline seas that formed cratonward within the foreland basin of the Taconic Orogeny during the Late Silurian. Eurypterids went extinct at the end of the Paleozoic during the end Permian extinction along with up to 96% of marine species. Scorpions survived the Great Dying and now enjoy a terrestrial existence.
Bertie Waterlimes, Lang’s Quarry, Passage Gulf, Ilion, NY

May
I have been jogging around this reservoir for thirty-five years. It was constructed in 1870 to supply the fresh water demands of growing Boston and its environs but is now a haven of tranquility in the heart of the city. I’m continually astounded by the diversity of the wildlife that one finds here: geese, ducks, swans, gulls, hawks, falcons, turkeys, heron, egrets, fox, coyote, raccoons, muskrats, mice, snakes, frogs, fish, and the usual collection of squirrels, rabbits, dogs and humanoids. And it's decorated with fantastic ledges of the Roxbury Conglomerate!
Chestnut Hill Reservoir, Chestnut Hill, Massachusetts

May
...and even turtles.
Chestnut Hill Reservoir, Chestnut Hill, Massachusetts

June
It's the world's tallest freestanding stone structure, standing sentinel over our nation's capital since 1884. The Washington Monument is incredibly photogenic. It virtually begs to be photographed. The challenge is to capture it in a uniquely individual way. Architectural geology can be a lot of fun especially if you're familiar with the quarry of origination.  The obelisk's exterior is marble from Maryland, Texas and Massachusetts, while its interior backing is composed of sandstone and crystalline rocks (glassy intrusive igneous rocks) from Maryland. The Massachusett quarry is named the Lee Lime in my home state. Its carbonate rocks were part of a coastal shelf along the then, southern seaboard of the supercontinent of Rodinia over a billion years ago. They were subsequently metamorphosed into marble by the collisional events of the Taconic and Acadian orogenies during the Paleozoic. Knowing the geology seems to give greater depth (no pun intended) to any subject.
National Mall, Washington, District of Columbia 

July
My colleague and I, while traveling through northwestern New Mexico, spotted the stone edifice from a distance. Not intending to stop, we became overwhelmed by its mystical presence and stayed for a day. Unlike our conventional perception of volcanoes that exude lava and build up a conical, vertical structure, Ship Rock emplaced within the Earth's crust phreatomagmatically, gas-charging its magma when it hit the water table. Its maar-crater at the surface and over 3,000 feet of overburden have eroded away in the last 25 million years, give or take. That left the erosion-resistant diatreme as testimony to the fury, topping out at 1,583 feet. The wall-like linear structure off to the left is a radial dike, one of three major feeder-conduits that emanate from Ship Rock.
Ship Rock, San Juan County, New Mexico



 July

Between the San Juan Mountains on the west and the Sangre de Cristo Range on the east is an eight mile-long, 700 foot-high sand sea where you'd least expect it, in western Colorado. In fact, it's the tallest dune field in North America! Although its shifting sands rejuvenate with the whim of the wind, the erg remains in one place

in a perfect balance of sediment supply (from the only-true-desert-in-Colorado sands of the San Luis Valley), means of transport (wind and water) and accommodation space (embraced within the Sangre de Cristos). Although cast in the shadow of the late day sun, the dark color of the sand is due to quartz and the volcanic rocks of the San Juans. 

Wind-driven sand drifts up the windward slopes of the dunes and then cascades down the leeward slopes. The wind will sculpt the dunes until its windward side slopes gently and the leeward side is short and steep. Can you tell the direction of the prevailing wind?

  Great Sand Dunes National Park and Preserve, Colorado

July

I couldn't resist one more view.

Great Sand Dunes National Park and Preserve, Colorado

July
Volcanoes to the west in the Thirtynine Mile volcanic field and the Sawatch Range periodically filled the air 
with volcanic ash 35 million years ago. Carried by the wind, ash rained down on the region of ancient
Lake Florissant in Colorado, and along with mudflows, preserved a diverse Upper Eocene ecosystem of fish, insects, mammals and plant material. Silica derived from the ash, in a scenario remniscent of Pompeii, and its interaction
with planktonic blooms produced biofilms that retarded organic decomposition. Perhaps most remarkable
to be silicified are the VW-size tree stumps of Sequoia's, members of an ancient redwood forest
that blanketed the lake region. Notice the two, rusted ends of a saw embedded within the "Big Stump,"
a vestige of wanton and destructive fossil collecting in the late 1800's.
Florissant Fossil Beds National Monument, Florissant, Colorado

July

This amiable little fellow actually tried to sell me some auto insurance.

Florissant Fossil Beds National Monument, Florissant, Colorado

August
Minutes from Lake Placid in northern New York State, we're viewing the High Peaks Region
across a dry, pro-glacial lakebed drained by an active Holocene stream. Both formed 
after the retreat of the Laurentide Continental Ice Sheet at the end of the Pleistocene.
The bedrock throughout the region, unless buried below glacial erratics, till and outwash,
is Middle Proterozoic Grenville metanorthosite, final vestiges of the supercontinent of Rodinia.
North Elba, Adirondack State Park and Reserve, New York State

September

This over three-inch monster was spinning its web on my patio. Its the largest spider I've seen outside of the zoo. I've found the web-sheathed dens of tarantulas in the Grand Canyon but never any inhabitants. Taken at night, I illuminated the critter with a flash light to try and photograph its web.

August
For the second consecutive year, this brightly-colored, orange-yellow cluster of mushrooms arose from exactly the same location and at precisely the same time of year in my neighbor’s yard. They fruited on the stump of an aging Maple tree following a week of humid, soaking rains. Their scientific name is Omphalotus but are commonly known as the Jack O’Lantern mushroom. Under suitable conditions of day length, heat,
humidity and nutrition, spores in the soil germinate to produce hyphae. When hyphae of the opposite mating type meet (a romantic love affair made in the soil rather than in heaven), a fruitbody is produced, in this case a mushroom. Mushrooms possess the spore-shedding organs of a new generation. The mushroom and its spores is analogous to an apple and its seeds. The hidden mycelium beneath the soil is the "tree" (sort of). Mushrooms are fungi, nature’s morticians in the natural environment, beneficially biodegrading and nutrient-recycling. As we all know, not all of them are edible. These delectable-looking delicacies are deadly poisonous (as in difficulty breathing, drop in blood pressure, irregular heartbeat and respiratory failure). They also exhibit bioluminescence by glowing in the dark. I returned the following day to harvest a few and observe that peculiar property in a dark room, but my neighbor unfortunately excavated his crop before I could. Based on my calculations, next August there’ll be new specimens to collect. Lesson learned? Don't eat mushrooms that glow in the dark, and you never know what’s growing in your neighbor's yard.

November

Back in D.C. again, I couldn't resist one more shot of the Monument illuminated by the setting sun.

National Mall, Washington, District of Columbia

November

This was my very first try at High Dynamic Range (HDR) photography.
Taken at sunrise, the autumnal colors are totally natural.
This pond is in the heart of town next to a parking lot at the back of a shopping center.

Hammond Pond, Chestnut Hill, Massachusetts



 December

The last snow storm of 2012 was a mild nor'easter in Boston. It gets its name from the direction the wind is coming from. Regardless of the site of origin of the storm, the nor'easter has a low pressure area whose center of rotation is just off the east coast of New England and Atlantic Canada. Its counter-clockwise rotation produces leading winds in the left-forward quadrant onto land from the northeast. That usually translates into heavy snow or rain depending on the time of the year along with high winds, pounding surf and coastal flooding. By the way, "down east" refers to coastal New England and has its origins as a Maine term for sailing down wind to the east. Can you tell which direction is northeast from the accumulation of snow on the trees?
Chestnut Hill, Massachusetts

 That's it for 2012. Happy New Year!

From Doctor Jack (and Franklin the Border Collie)

The Eurypterid “Eurypterus remipes” is the Official Fossil of the State of New York: Part III – The R.A. Langheinrich Museum of Paleontology in Eastern Central New York

The honor of “Official Fossil of the State of New York” was bestowed upon Eurypterus remipes in 1984, attributable to its abundance within the state’s borders. Now extinct, eurypterids were marine arthropods that bore a striking resemblance to contemporary scorpions, evolutionary relatives classified within a sister taxon. “Sea scorpions,” as they are affectionately called, reached their heyday of diversity during the Silurian Period and their demise during the Great Dying of the Permian along with 96% of marine species. In spite of their wealth of preservation within the state, eurypterid paleobiology, ecology and environments have remained a source of conjecture and speculation.

Many of this eurypterid’s spinose appendages are missing, the integument of the carapace has partially flaked off and the telson is almost severed, all possibly due to disarticulation, transportation and burial. This fossil measures about four inches, whereas members of the species are thought to reach two feet. Of the six pairs of grasping, walking and swimming appendages (legs), five pairs are visible.

(From my personal collection from Lang’s Quarry)

THREE POSTS ON EURYPTERIDS

In my first post (Part I), I discussed basic evolution, phylogeny, morphology and tectonics of the eurypterids of New York (http://written-in-stone-seen-through-my-lens.blogspot.com/2012/05/eurypterus-remipes-official-fossil-of.html).

In my previous post (Part II), I received a private tour of the Lang Quarry, located just south of Ilion in Herkimer County of eastern Central New York at a famous outcrop known as Passage Gulf. Eurypterids are found within the thinly stratified, limy muds of the quarry's waterlimes (http://written-in-stone-seen-through-my-lens.blogspot.com/2012/06/eurypterid-eurypterus-remipes-is.html.

In this final post on eurypterids (Part III), I headed to the nearby R.A. Langheinrich Museum, the repository for almost three decades of excavating, preparing and studying eurypterids by Allan Lang, its owner and curator.



 

Dorsal and ventral aspects of Eurypterus tetragonophthalmus from Jan Nieszkowski's 1858 dissertation

(From wikidedia.com)



THE R.A. LANGENHEINRICH MUSEUM OF PALEONTOLOGY

Allan and Iris Lang maintain the R.A. Langheinrich Museum of Paleontology (Allan’s more-difficult-to-pronounce official surname). The museum not only includes an incredible assortment of eurypterids from the quarry but Allan’s enormous collection of meteorites from around the world. Allan is a skilled metal worker, and many of the meteorites have been sliced into thin sections for viewing.

Allan (below) is proudly posing with a cast of a gigantic Pterygotus (Acutiramus). The over seven foot tall fossil is actually a composite that was assembled from three slabs of dolostone from the Lang Quarry and is the largest of its kind ever found. The original resides as the centerpiece of the Royal Ontario Museum’s paleontological exhibit.

Allan Lang and the massive Pterygotus that he excavated from his quarry

(Photographed at the R.A. Langheinrich Museum of Paleontology)

For size comparison notice two small eurypterids and the disarticulated carapace (head structure) alongside the composite. Gigantism reflected in Middle Paleozoic marine eurypterids such as Pterygotus was a foreshadowing of the enormous size that existed amongst Late Paleozoic terrestrial arthropods such as "monster millipedes, colossal cockroaches and jumbo dragonflies" (Braddy, 2007).

Giant arthropods from the fossil record compared with average height of a human male (British):
(a) the eurypterid Jaekelopterus rhenaniae, Early Devonian, Germany; (b) the trilobite Isotelus rex, Late Ordovician, Manitoba, Canada; (c) the dragonfly Meganeura monyi, Late Carboniferous, France; (d) the millipede Arthropleuro armata, Late Carboniferous, Europe. Scale bar (a-d), 50 cm.
(From Braddy, 2007)



Model of a gigantic, yet life-sized Pterygotus eurypterid

(Smithsonian Institution’s Museum of Natural History.



The eurypterids of Passage Gulf

The eurypterids of New York were originally thought to be preserved within two “pools” which are now considered to be distinct stratigraphic horizons. The eurypterids listed below were considered representative of the “Herkimer pool” (from Herkimer County) of New York, the eastern locality such as Passage Gulf. Eurypterids found in western localities of the “Buffalo pool” include Hughmilleria, Paracarcinosoma and Eurypterids such as lacustris:

The three eurypterid families most commonly found at Lang’s Quarry of Passage Gulf:

 1.) Pterygotus possessed narrow, spine-less walking legs, a rounded-trapezoidal head (carapace) with compound eyes near its margin, a flattened and expanded tail (telson) with a dorsal-keel down the midline, and most notably, a pair of large chelicerae claws in front of the mouth fortified by the presence of large, well-developed teeth. Its size ranged from a few inches to well over 3 feet with gigantic specimens exceeding 7 feet. Based on partial remains, Pterygotids likely exceeded 10 feet in length. An example is Acutiramus macrophthalmus. 

2.) Eurypterus, the most common eurypterid of the Fiddlers Green Formation, comprising 90-95% of the Bertie Group eurypterids, possessed spinose appendages, more centrally-located eyes, a pointed tail and larger swimming paddles. Its size ranged from under an inch to a foot or two in length. An example is Eurypterus remipes. 

3.) Dolichopterus had compound eyes located near the edge of its prosoma, stout spinose-walking legs, swimming legs with serrated margins, a somewhat flattened carapace, lateral projections on its abdominal segments and a lance-like tail. Its size ranged from under an inch to about one foot. An example is Dolichopterus jewetti. 

Pterygotus, Eurypterus and Dolichopterus

(Modified from Ernst Haeckel’s Kunstformen der Natur, 1904)



THE BERTIE BIOTA

The Late Silurian Bertie Group of New York, in particular its muddy dolostones called waterlimes, supported (or at least preserved) a rich eurypterid biota (see my two previous posts for details). Although the waterlime fauna and flora are considered to have been sparse, members of the marine paleocommunity in addition to eurypterids included horseshoe crabs, scorpions, phyllocarid crustaceans, a Lichid trilobite, gastropods, orthocone cephalopods, Lingulid brachiopods, ostracodes, graptolites, bryozoan corals, fish (rare in New York), stromatolites and other algal forms. Cooksonia, which grew in dense mats along the shoreline and considered to be amongst the earliest plant “pioneers” on land, has been recovered from waterlime deposits.

Cooksonia

(Photographed at the R.A. Langheinrich Museum of Paleontology)

This model depicts a eurypterid venturing onto land with Cooksonia growing along the shoreline.

(Smithsonian Institution’s Museum of Natural History)



SHEDDING ONE’S CHITINOUS SKIN

This slab of waterlime displayed in the museum contains a multitude of molted eurypterids and a disarticulated carapace. In fact, most eurypterid fossils are presumed to be molted exoskeletons as opposed to carcasses (Braddy, 1995; Ciurca personal communication, 2012). The problem of distinguishing between eurypterid exuviae and carcasses has remained a paleontological exercise for almost a century (Clarke and Ruedemann, 1912; Tetlie, 2008). One of the challenges is that eurypterid exuviae, like horseshoe crabs, remain so intact defying inclinations to label them as molts.

Typical of all arthropods, eurypterids shed or molted their chitinous, semi-rigid exoskeletons in order to accommodate growth. Similar to cellulose in its supportive function, chitin is a modified polysaccharide like glucose that contains nitrogen. Contemporary horseshoe crabs (Xiphosurans) and scorpions (Arachnids) are frequently used, phylogenetically-related, modern-analogues for investigating aspects of eurypterid paleo-biology, ecology and behavior (Braddy, 2001; Tetlie 2008). Horseshoe crabs molt perhaps 10 times in its lifetime which provides some explanation for the vast numbers of preserved exoskeletons. 

Amongst the articulated eurypterid molts, notice the disarticulated carapace and the beautifully preserved spinose appendages. The chitinous exoskeletons have a brown color largely due to carbonization. The original components of the cuticle have undergone in situ polymerization during diagenesis (Gupta, 2007). The prevalence of "ventral-up" specimens is not necessarily an indication of supine-ecdysis (Tollerton, 1997) but may be related to transportation and burial (Tetlie, 2007).

(Photographed at the R.A. Langheinrich Museum of Paleontology)



The actual shedding event is called ecdysis, whereas molting is the term reserved for the entire process that includes a period of inactivity both before and after ecdysis. Molting subjects arthropods to susceptibility from predation during the soft-shell stage. With horseshoe crabs, refugia are sought out, regions in which to safely molt. Reduction of suitable refugia near the end of the Silurian has been cited as a potential cause for eurypterid decline and extinction of some genera (Tetlie, 2007), although others site their decline to quicker, more heavily-armored fish prototypes that developed during the Devonian.

Recurrent patterns of disarticulation and telescoping of exoskeletal elements are some of the means used to distinguish fossil-exuvia from fossil-carcasses. Analyses of eurypterid exoskeletons, which at first appears to be a random dissociation, is in reality a non-random taphonomic pattern that suggests the underlying biological process of ecdysis (Tetlie, 2007).

Molting follows a sequence of events beginning when feeding and activity stops, and a tear develops in the anterior carapace margin. Eventually, the animal emerges from the molted exoskeleton (exuvia). Current thinking (Brady, 2001) considers the “Bertie” assemblages to consist predominantly of exuviae due to lack of scavenging, frequent crumpling, partial telescoping and dispersal of disarticulated remains.

WINDROWS

Eurypterid fossils frequently occur in linear aggregations called “windrows” (Ciurca). It is believed that this is an indication of current or storm-related transportation and orientation into the area of deposition (Tetlie and Ciurca, 2005). Hence, the entombing stratum is classified as a tempestite. Contemporary windrows of fragmentary, current-sorted bivalves, crabs and marine debris can be seen while strolling along the Atlantic shore after a tide or storm as seen below. These shoreline deposits ("strandlines") are segregated by weight and size (Ciurca personal communication, 2012). The waterlimes of New York are quite unusual and not your typical beach deposit. They are peculiar carbonates deposited in peculiar lagoons that researchers are still trying to understand today.



DEATH ASSEMBLAGES, MASS MOLTS OR BREEDING GROUNDS?

Displayed in the museum are two incredible mirror-image slabs of Bertie waterlime that contain a half-dozen articulated molts and sundry disarticulated bodyparts. Deceivingly, the two halves are not positive and negative casts of upper and lower members of strata entombing the fossils, but are “part” and “counterpart” slabs with each containing a portion of the preserved eurypterids. This is likely a small section of a windrow.

(Photographed at the R.A. Langheinrich Museum of Paleontology)

One of the many questions surrounding eurypterids is whether large aggregations of molts are reflective of refugia or transportation from a freshwater estuary to a region of hypersaline waterlime for burial. Not surprisingly, other hypotheses exist. Based on fossil remains (which may falsely confer a taphonomic or collection bias), one theory suggests that “breeding grounds” were utilized in mudflats and sandbars for survival protection accounting for the large eurypterid assemblages (“mass molts”) or for ecdysis (“mass molts”) (Braddy, 2001). Mass mortality (“death assemblages”) seems less likely an explanation, since the remains are concentrations of exuviae rather than carcasses (Vrazo, 2011). As mentioned, possibly storms brought exuviae down river into muddy deltaic sediments near and offshore for burial, even additionally mixing with marine biotas (Ciurca, 2010). Horseshoe crabs were transported and preserved in the hypersaline Jurassic lagoons of Solnhoffen (Barthel, 1994).

(Photographed at the R.A. Langheinrich Museum of Paleontology)



THE APPENDAGES OF PTERYGOTUS

This massive Pterygotus chelicera-claw includes both a fixed and free ramus as well as a full array of formidable denticles (teeth). Some researchers have questioned the common belief that Pterygotids were the high-level predators once thought based upon tests showing the lower mechanical advantage of its claw. In addition, due to its lack of an “elbow joint”, its limited movement would have made it more adept at grasping than capturing its prey. In fact, they posed that Pterygotids may have been scavengers (Laub et al, 2010).

(Photographed at the R.A. Langheinrich Museum of Paleontology)



This museum specimen is a large, distinctive swimming leg, the sixth prosomal appendage, of Pterygotus.

(Photographed at the R.A. Langheinrich Museum of Paleontology)

Notice the expansion on the last segment of Pterygotus’ swimming-leg and the numerous serrations on its marginal aspect (below). Not to deny the animal’s aquatic capabilities, but upon observing the serrations on the outermost aspect of the leg, I can’t help but wonder if the “swimming” leg was equally or better suited as a “crawling” or “digging” leg. Such are the challenges associated with attempting to reconstruct an animal’s ecology and behavior from fossilized remains.

SEX AND THE EURYPTERID

This large structure (almost two feet across) is a eurypterid’s genital appendage located on the median ventral surface of the abdomen. Eurypterids were thought to be sexually dimorphic differentiated by genitalia of varying lengths. Numerous opinions exist concerning the exact nature of the appendage. If from a male, its clasper might grasp the female during mating, might be used in immobilization-defense of being eaten by the female during courtship, or be associated with the discharge of sperm or the transfer of a spermatophore (an advanced mode of external fertilization seen in crustaceans). If belonged to a female, it might have functioned to scoop out a hollow in the substrate in anticipation of fertilization. Extant horseshoe crabs mate annually en masse at specific breeding sites that coincide with lunar and tidal rhythms (Rudloe, 1980). They lay their eggs in clusters of nests along the beach (Shuster, 1982).

(Photographed at the R.A. Langheinrich Museum of Paleontology)



A FRESH, BRACKISH OR SALT WATER HABITAT?  

Late Silurian waterlimes are thought to have been brackish to hypersaline based upon the prevailing arid landscape and basins of evaporite deposits, salt hoppers and mud cracks without access to normo-saline seas. A slab of waterlime from the quarry was sectioned (below) by Allan and shows a vesicular cavity presumably formed by the dissolution of an evaporite such as crystalline halite. Did eurypterids live under these highly saline conditions, were they saline-tolerant visitors or were they washed down from freshwater estuaries and deposited in windrows?

(Photographed at the R.A. Langheinrich Museum of Paleontology)



MARINE SCORPIONS

In this slab of dolostone from Lang’s quarry, a few eurypterids and disarticulated bodyparts are preserved in conchoidal areas (Allan’s “dishes”). Easy to overlook is the small marine scorpion at the upper left. This confirms that both of these related chelicerates coexisted as members of the same paleocommunity and at a time period before scorpions had conquered the land. The first marine scorpions evolved from stem-group chelicerates along with eurypterids during the Middle Silurian (about 428 Ma), and terrestriality was acquired by 340 Ma.

(Photographed at the R.A. Langheinrich Museum of Paleontology)



This is a close-up of the scorpion seen above next to disarticulated eurypterid segments. Scorpion fossils from the Silurian and Devonian are exceedingly rare partially due to their lack of a mineralized integument. Scorpions, along with spiders, are arthropods within Class Arachnida, the sister taxon of eurypterids. Both possess four pairs of walking legs. Recall that their inclusion within subphylum Chelicerata is based upon the small anterior appendages used to grasp food. Their second appendages are pedipalps (or chelae) that function as the distinctive pincers. Currently, three different species are known from the Bertie Waterlime.



LANG’S QUARRY AND THE R.A. LANGHEINRICH MUSEUM OF PALEONTOLOGY

The Lang’s facility is open by appointment only. Contact information is available on their website. 

SUGGESTED READING
Distribution and Dispersal History of Eurypterida (Chelicerata) by O. Erik Tetlie, 2007.
Testing the Mass-Moult-Mate Hypothesis of Eurypterid Paleoecology by Matthew B. Vrazo and Simon Braddy, 2011.
The Eurypterida of New York VI by Clarke and Ruedemann, 1912.
The Rise and Fall of the Taconic Mountains by Donald Fisher, 2006.

Geology of New York by Y.W. Isaachsen et al, 2000.

The Trilobites of New York by Thomas E. Whiteley, 2002.

Eurypterids Illustrated by Samuel J. Ciurca, Jr., 2008-2010.

Fieldtrip Guidebook, NYS Geological Association, Fiftieth Annual Meeting (1978), Fifty-fourth (1982), Sixty-second (1990), Sixty-sixth (1994) for publications by Samuel J. Ciurca, Jr.

SUGGESTED WEBSITES

Eurypterid.net and eurypterids.net/EurypteridLinkIndex.html by Samuel J. Ciurca, Jr.
Statefossil.org/news.htm by Allan and Iris Lang

ACKNOWLEDGEMENTS

I wish to thank Allan and Iris Lang for their time and generosity in making their incredible collection at the museum available for viewing and photography. I also want to thank Allan for his private tour of the quarry.

Many thanks also to paleontologist Samuel J. Ciurca, Jr. of Rochester, New York for his personal communications. Sam has been studying, collecting, meticulously documenting and publishing on eurypterids, their associated flora and fauna, and the entombing stratigraphy for over 50 years. He has donated thousands of specimens from his personal collection to institutions such as the Yale Peabody Museum’s Division of Invertebrate Paleontology recognized as the Ciurca Collection, the Smithsonian Institution and the Buffalo Museum of Science.