Sedimentology & Stratigraphy class in Wooster Memorial Park. Watch this space!

April 23rd, 2016

1 Glacial 042316This morning Wooster’s Sedimentology & Stratigraphy class visited Wooster Memorial (“Spangler”) Park for some field experience. A few of the students are shown above exploring a magnificent glacial deposit. I never did get a photo with all 21 students in it.

2 Logan Rathburn RunThe students are each writing a blog entry about the geology of this park as a writing assignment. You can see the instructions and additional images on our course page. The best entry will soon be posted in this blog under the student’s name. Above is a nice stream-side outcrop of the Logan Formation (Lower Carboniferous).

3 Trillium trail 042316It was a chilly but mercifully dry day for us. Classic early spring foliage for northeastern Ohio. [Dr. Lyn Loveless, our expert botanist, comes through in the comments: “Classic Spring Foliage – mostly (it seems from this scale) Dutchman’s Breeches, Dicentra cucullaria.  One stray Trillium.  Ah, Spring in Ohio!”]

4 Trillium grandiflorum 042316 585The most noteworthy flower this week is Trillium grandiflorum, a beautiful three-petaled white flower with six stamens.

5 Purple flower 042316This purple flower is unknown to me so far. I hope a kind expert adds its name in the comments![Lyn Loveless again is the kind commenter: “Phlox divaricata – Wild blue phlox.”]

 

Wooster’s Fossil of the Week: A crinoid stem internal mold from the Lower Carboniferous of Ohio

April 8th, 2016

crinoid internal mold 1The Biology Department at The College of Wooster is in the midst of a massive move in advance of the construction of the new Ruth Williams Hall of Life Science. The staff has been combing through old specimen collections, giving away items they don’t need for teaching or research. Among the objects are occasional fossils they gave to the Geology Department. The above specimen is one of the most curious: a combination internal and external mold of a crinoid stem from the local Lower Carboniferous rocks.

crinoid internal mold lumen copyThis is a closer view of the fossil. It is a cylindrical cavity with faint rings in a regular distribution. (These are external molds of the individual crinoid columnals.) Suspended down the axis is a segmented pillar with a stellate cross-section. (This is the internal mold of the crinoid stem lumen, a central cavity that runs down the center of the stem.) It appears that an iron-rich cement (probably siderite) filled this lumen after the death of the crinoid. The stem fragment was enveloped in a siderite concretion and the calcite stem columnals dissolved away. This leaves us with both an external mold of the stem and an internal mold of its lumen.

Carb stem 1For comparison, this is a crinoid stem fragment in its original calcite. It was found in a local Carboniferous limestone.

Carb stem 2Here are cross-sections of the same stems showing sediment-filled stellate lumens in their centers.

Wooster’s Fossil of the Week: A blastoid from the Lower Carboniferous of Illinois

August 21st, 2015

Pentremites IL 585It is sometimes hard to believe that exquisite fossils such as the above are sometimes very common. The above is a theca of the blastoid Pentremites godoni (DeFrance, 1819) found in the Lower Carboniferous (Mississippian) of Illinois. (Thanks to expert Colin Sumrall for the identification.) In some places these fossils can be picked up by the hundreds.

Blastoids are stemmed echinoderms that appeared first in the Ordovician and went extinct at the end of the Permian. They were most diverse and abundant in the shallow carbonate seas of the Lower Carboniferous, especially in North America. They are much beloved and studied fossils.
Pentremites IL basal 585The basal side of the above theca shows that blastoids had a small circular stem attachment, much like their cousins the crinoids. They extended numerous feeding appendages (brachioles) from their ambulacra (the five “petals” on the upper surface and sides) for filter-feeding. The theca is made of calcitic plates that are tightly fused together, thus ensuring they survive the vicissitudes of preservation.
Pentremites close 585In this close view of the top of the theca are five holes (spiracles) surrounding a central pit (the mouth) One spiracle (in the upper right) is larger than the others. It contains the anus and is thus called an anispiracle. The spiracles are openings into the interior of the theca, which contained a complexly-folded respiratory system called the hydrospire.

Pentremites godoni has a complicated taxonomic history. The original type specimen of the species (a specimen used as the definition of the species — a Platonic ideal form!) was destroyed in the middle of the 19th Century in a museum fire. The specimen was illustrated and described (although not named) in 1808 by James Parkinson (see below).
Screen Shot 2015-07-21 at 4.55.39 PMScreen Shot 2015-07-21 at 4.59.30 PMParkinson (1808, pl. 13) referred to this specimen as “an asterial fossil from America; probably of the nature of the encrinus.” Encrinus was a term used at the time for crinoids. Fay (1961) describes the convoluted way Parkinson’s specimen above became the type not only for the species, but also how P. godoni came to define the genus Pentremites as well. That Parkinson (1808) diagram, though, is the only image of the original specimen, and probably the first illustration of a blastoid.

References:

Atwood, J.W. and Sumrall, C.D. 2012. Morphometric investigation of the Pentremites fauna from the Glen Dean Formation, Kentucky. Journal of Paleontology 86: 813-828.

DeFrance, J.M.L. 1819. Dictionnaire des Sciences Naturelles 14, EA-EQE, p. 467.

Fay, R.O. 1961. The type of Pentremites Say. Journal of Paleontology 35: 868-873.

Parkinson, J. 1808. Organic remains of a former world. London, Noraville & Fell, v. 2, p. 235-236, pl. 13.

Waters, J.A., Horowitz, A.S. and Macurda, D.B., Jr. 1985. Ontogeny and phylogeny of the Carboniferous blastoid Pentremites. Journal of Paleontology 59: 701-712.

Wooster’s Fossil of the Week: A conulariid revisited (Lower Carboniferous of Indiana)

July 31st, 2015

Conulariid03 585

This summer I’ve been updating some of the photos I placed in the Wikipedia system (check them out here, if you like; free to use for any purpose). I was especially anxious to replace a low-resolution image I had made of an impressive conulariid (Paraconularia newberryi) from the Lower Carboniferous of Indiana. The new version is above. Since I used the same specimen as a Fossil of the Week exactly four years ago to the day, I thought I’d take advantage of a slow summer and update that earlier text for this week:

I have some affection for these odd fossils, the conulariids. When I was a student in the Invertebrate Paleontology course taught Dr. Richard Osgood, Jr., I did my research paper on them. I had recently found a specimen in the nearby Lodi City Park that was so different from anything I had seen that I wanted to know much more. I championed the then controversial idea that they were extinct scyphozoans (a type of cnidarian including most of what we call today the jellyfish). That is now the most popular placement for these creatures today, although I arrived at the same place mostly by luck and naïveté.

The specimen above is Paraconularia newberryi (Winchell) found somewhere in Indiana and added to the Wooster fossil collections before 1974. A close view (below) shows the characteristic ridges with a central seam on each side.

Conulariid01 585Conulariids range from the Ediacaran (about 550 million years ago) to the Late Triassic (about 200 million years ago). They survived three major extinctions (end-Ordovician, Late Devonian, end-Permian), which is remarkable considering the company they kept in their shallow marine environments suffered greatly. Why they went extinct in the Triassic is a mystery.

ConulataThe primary oddity about conulariids is their four-fold symmetry. They had four flat sides that came together something like an inverted and extended pyramid. The wide end was opened like an aperture, although sometimes closed by four flaps. Preservation of some soft tissues shows that tentacles extended from this opening. Their exoskeleton was made of a leathery periderm with phosphatic strengthening rods rather than the typical calcite or aragonite. (Some even preserve a kind of pearl in their interiors.) Conulariids may have spent at least part of their life cycle attached to a substrate as shown below, and maybe also later as free-swimming jellyfish-like forms.

It is the four-fold symmetry and preservation of tentacles that most paleontologists see as supporting the case for a scyphozoan placement of the conulariids. Debates continue, though, with some seeing them as belonging to a separate phylum unrelated to any cnidarians. This is what’s fun about extinct and unusual animals — so much room for speculative conversations!

References:

Driscoll, E.G. 1963. Paraconularia newberryi (Winchell) and other Lower Mississippian conulariids from Michigan, Ohio, Indiana, and Iowa. Contributions from the Museum of Palaeontology, The University of Michigan 18: 33-46.

Hughes, N.C., Gunderson, G.D. and Weedon, M.J. 2000. Late Cambrian conulariids from Wisconsin and Minnesota. Journal of Paleontology 74: 828-838.

Sendino, C., Zagorsek, K. and Taylor, P.D. 2012. Asymmetry in an Ordovician conulariid cnidarian. Lethaia, 45: 423-431.

Van Iten, H.T., Simoes, M.G., Marques, A.C. and Collins, A.G. 2006. Reassessment of the phylogenetic position of conulariids (?Vendian–Triassic) within the subphylum Medusozoa (Phylum Cnidaria). Journal of Systematic Palaeontology 4, 109–118.

 

Wooster’s Fossils of the Week: Chaetetids from the Upper Carboniferous of Liaoning Province, North China

June 12th, 2015

1 Benxi chaetetid 2a 585Last year I had a short and painful trip to China to meet my new colleague and friend Yongli Zhang (Department of Geology, Northeastern University, Shenyang). The China part was great; the pain was from an unfortunately-timed kidney stone I brought with me. Nevertheless, I got to meet my new colleagues and we continued on a project involving hard substrates in the Upper Carboniferous of north China. Above is one of our most important fossils, a chaetetid demosponge from the Benxi Formation (Moscovian) exposed in the Benxi area of eastern Liaoning Province. We are looking at a polished cross-section through a limestone showing the tubular, encrusting chaetetids.
2 Chaetetid Benxi Formation (Moscovian) Benxi Liaoning China 585This closer view shows two chaetetids. The bottom specimen grew first, was covered by calcareous sediment, and then the system was cemented on the seafloor. After a bit of erosion (marked by the gray surface cutting across the image two-thirds of the way up), another chaetetid grew across what was then a hardground that partially truncated the first chaetetid. This little scenario was repeated numerous times in this limestone, producing a kind of bindstone with the chaetetids as a common framework builder.
3 Chaetetid Benxi cross-section 585Here is the closest view of the chaetetids, showing the tubules running vertically, each with a series of small diaphragms as horizontal floors.

Last week’s fossil was a chaetetid, introducing the group. They are hyper-calcified demosponges, and the classification of the fossil forms is still not clear. Their value for paleoecological studies, though, is clear. This particular chaetetid from the Benxi Formation preferred a shallow, warm, carbonate environment, and it was part of a diverse community of corals, fusulinids, foraminiferans, brachiopods, crinoids, bryozoans, gastropods, and algae. Such hard substrate communities are not well known in the Carboniferous, and this is one of the best.

References:

Gong, E.P, Zhang, Y.L., Guan, C.Q. and Chen, X.H. 2012. The Carboniferous reefs in China. Journal of Palaeogeography 1: 27-42.

West, R.R. 2011a. Part E, Revised, Volume 4, Chapter 2A: Introduction to the fossil hypercalcified chaetetid-type Porifera (Demospongiae). Treatise Online 20: 1–79.

West, R.R. 2011b. Part E, Revised, Volume 4, Chapter 2C: Classification of the fossil and living hypercalcified chaetetid-type Porifera (Demospongiae). Treatise Online 22: 1–24.

Zhang, Y.L., Gong, E.P., Wilson, M.A., Guan, C.Q., Sun, B.L. and Chang, H.L. 2009. Paleoecology of a Pennsylvanian encrusting colonial rugose coral in South Guizhou, China. Palaeogeography, Palaeoclimatology, Palaeoecology 280: 507-516.

Zhang, Y.L., Gong, E.P., Wilson, M.A., Guan, C.Q.. and Sun, B.L. 2010. A large coral reef in the Pennsylvanian of Ziyun County, Guizhou (South China): The substrate and initial colonization environment of reef-building corals. Journal of Asian Earth Sciences 37: 335-349.

Wooster’s Fossil of the Week: A chaetetid demosponge from the Upper Carboniferous of southern Nevada

June 5th, 2015

1 Chaetetid Bird Spring Upper Carboniferous Nevada 585I collected this lump of a specimen during my dissertation research in the Bird Spring Formation (Carboniferous-Permian) of southern Nevada. It was found in a richly-fossiliferous Upper Carboniferous (Moscovian) portion near Mountain Springs Pass, which is about 40 km southwest of Las Vegas. It is a chaetetid, which at the time I interpreted conventionally as a singular extinct sponge in the genus “Chaetetes“. Since then we’ve learned a lot more about chaetetids. (And about the stratigraphy of the Bird Spring Formation. I wish we had sequence stratigraphy way back then!)
2 Chaetetid Bird Spring closer Upper Carboniferous Nevada 585Excellent and thorough work, especially by Ron West, has shown that the chaetetids are “hyper-calcified” members of the Class Demospongiae of the Phylum Porifera. They are sponges indeed, but the tubular chaetetid skeleton is found in at least three orders of the demosponges, including living ones. The chaetetid skeleton, which consists of very thin tubes (as shown above) is polyphyletic, meaning several groups of organisms converged on the same form.
3 Chaetetid Bird Spring closest 585In this oblique section of a chaetetid you can see the calcitic tubules, somewhat blurred by recrystallization.
4 Chaetetid Bird Spring cross-section Upper Carboniferous Nevada 585Here is a cross-section through one of the Bird Spring chaetetids. The tubules are very thin and long, somewhat resembling hair. Chaeto– comes from the Greek chaite for “hair or hairy”.

Now we know from systematic studies that the fossil “chaetetids” cannot be classified from their tubular skeletons alone. Without evidence of the spicules (which are rarely found, or at least recognized) and original mineralogy of the skeleton (many are recrystallized or, like the one at the top of this entry, replaced with silica) we can only refer to skeletal specimens such as ours as “chaetetid hyper-calcified demosponges”.

This is enough, though, for me to reintroduce them into my Invertebrate Paleontology classes. I had removed them from the teaching collections several years ago because of the confusion as to their status. Now they are at least demosponges, hyper-calcified at that.

References:

Almazán, E., Buitrón, B., Gómez-Espinosa, C. and Daniel Vachard. 2007. Moscovian chaetetid (boundstone) mounds in Sonora, Mexico. In: Vennin, E., Aretz, M., Boulvain, F. and Munnecke, A., eds., Facies from Palaeozoic reefs and bioaccumulations. Mémoires du Muséum national d’Histoire naturelle 195: 269–271.

Martin, L.G., Montañez, I.P. and Bishop, J.W. 2012. A paleotropical carbonate-dominated archive of Carboniferous icehouse dynamics, Bird Spring Fm., southern Great Basin, USA. Palaeogeography, Palaeoclimatology, Palaeoecology 329: 64-82.

West, R.R. 1994. Species in coralline demosponges: Chaetetida. In: Oekentorp-Küster, P., ed., Proceedings of the VI International Symposium on Fossil Cnidaria and Porifera, Munster Cnidarian Symposium, v. 2. Courier Forschungsinstitut Senckenberg 172: 399–409.

West, R.R. 2011a. Part E, Revised, Volume 4, Chapter 2A: Introduction to the fossil hypercalcified chaetetid-type Porifera (Demospongiae). Treatise Online 20: 1–79.

West, R.R. 2011b. Part E, Revised, Volume 4, Chapter 2C: Classification of the fossil and living hypercalcified chaetetid-type Porifera (Demospongiae). Treatise Online 22: 1–24.

West, R.R. 2012c. Part E, Revised, Volume 4, Chapter 2D: Evolution of the hypercalcified chaetetid-type Porifera (Demospongiae). Treatise Online 35: 1–26.

Wilson, M.A. 1985. Conodont biostratigraphy and paleoenvironments at the Mississippian-Pennsylvanian boundary (Carboniferous: Namurian) in the Spring Mountains of southern Nevada. Newsletters on Stratigraphy 14: 69-80.

Wooster’s Fossil of the Week: A molded brachiopod from the Lower Carboniferous of Ohio

February 20th, 2015

Syringothyris bored Wooster CarboniferousWe haven’t had a local fossil featured on this blog for awhile. Above is an external mold of the spiriferid brachiopod Syringothyris typa Winchell, 1863, from the Logan Formation (Lower Carboniferous, Osagean, about 345 million years old) of southeastern Wooster, Ohio. The outcrop is along the onramp from north Route 83 to east Route 30. Older Wooster geologists may remember this area was called “Little Arizona” because of the large roadcuts made for a highway bypass that was never completed. That original outcrop was destroyed several years ago, but the same rocks are exposed in this new section. This is the area where Heather Hunt (’09) did her Senior Independent Study work, and long before her Brad Leach (’83) worked with the same fossils.

The Logan Formation is primarily fine sandstone, with some subordinate conglomerates, silts and shales. It was likely deposited in the proximal portion of a prodelta at or below wavebase. The fossils in the Logan are mostly these large Syringothyris and the bivalve Aviculopecten, along with scattered crinoids, gastropods, bryozoans, nautiloids and ammonoids. This fauna needs more attention. Funny how the fossils in your own backyard are so often ignored.

This brachiopod was first buried in sediment and then the shell dissolved away, leaving an impression behind. Since it is an impression of the exterior of the shell, it is called an external mold. Curiously, all the external molds (and the internal molds as well) in the local Logan Formation have an iron-rich, burnt orange coating much finer than the fine sand matrix. This means that details are preserved that are of higher resolution than the matrix alone would allow. In the case of this fossil, that coating extended down into long, narrow borings in the shell, casting them (see below).
Syringothyris borings 585These borings are odd. Most of them are parallel to the ribs (plicae) of the brachiopod, and appear to have been excavated from the shell periphery towards its apex. This was in the opposite direction of brachiopod shell growth. I suspect they were made by boring annelid worms that started at the growing edge of the shell where the mantle ended. These traces need attention, like most other aspects of this local fossil fauna.

References:

Ausich, W.I., Kammer, T.W. and Lane, N.G. 1979. Fossil communities of the Borden (Mississippian) delta in Indiana and northern Kentucky. Journal of Paleontology 53: 1182-1196.

Bork, K.B. and Malcuit, R.J. 1979. Paleoenvironments of the Cuyahoga and Logan formations (Mississippian) of central Ohio. Geological Society of America Bulletin 90 (12 Part II): 1782-1838.

Leach, B.R. and Wilson, M.A. 1983. Statistical analysis of paleocommunities from the Logan Formation (Lower Mississippian) in Wayne County, Ohio. The Ohio Journal of Science 83: 26.

Wooster’s Fossils of the Week: Upper Carboniferous seed casts from northeastern Ohio

October 31st, 2014

Trigonocarpus trilocularis Hildreth 1838We haven’t had a paleobotanical fossil of the week for awhile, so here are a couple of nice seed casts from the Upper Carboniferous Massillon Sandstone exposed near Youngstown, Ohio. They fall within the “form genus” Trigonocarpus Brongniart 1828. A form taxon is one that may not have any systematic or evolutionary validity, but it is a convenient resting place for taxa that share a particular morphological pattern but can’t be easily classified elsewhere. Trigonocarpus consists of seed casts that are “radially symmetrical, decorticated, and have their surface marked by three prominent ridges” (Gastaldo and Matten, 1978, p. 884). These particular seeds appear to be Trigonocarpus trilocularis (Hildreth, 1837). The taxa here are problematic, of course, because these seeds belong to larger plants that have their own names.
Trigonocarpus trilocularis Hildreth 1838_585These seeds appear to be from medullosalean trees, which were small relatives of today’s cycads. They were common in wetlands throughout North America and Europe during the Carboniferous, especially the Late Carboniferous. The seeds we have were likely attached to small stalks. You can see what appears to be a circular attachment scar above.
Samuel Prescott Hildreth (1783–1863)
Dr. Samuel Prescott Hildreth (1783-1863) was a physician and historian with a keen eye for natural history, especially including fossils and rocks. He was born in Massachusetts of strong Patriot stock and moved to the dangerous territory of Ohio in 1806, settling in Marietta in 1808. Dr. Hildreth is often cited as one of the first scientists in the country west of the Alleghany Mountains. His prolific writing is fast-moving, diverse and interesting, so he must have been a great traveling companion. Dr. Hildreth served in the Ohio Legislature and was on the first Ohio Geological Survey.
HildrethNutThe above is a figure from Hildreth (1837, p. 29) showing the fossil seed he named Carpolithus trilocularis. He wrote that “[t]his nut is probably the fruit of some antediluvian palm”, which is not far from what we think now (apart from the Flood reference!).

References:

Gastaldo, R.A. and Matten, L.C. 1978. Trigonocarpus leeanus, a new species from the Middle Pennsylvanian of southern Illinois. American Journal of Botany 65: 882-890.

Hildreth, S.P. 1837. Miscellaneous observations made during a tour in May, 1835, to the Falls of the Cuyahoga, near Lake Erie: extracted from the diary of a naturalist. American Journal of Science and Arts 31:1-84

Zodrow, E.L. 2004. Note on different kinds of attachments in trigonocarpalean (Medullosales) ovules from the Pennsylvanian Sydney Coalfield, Canada. Atlantic Geology 40: 197-206.

An Epic Geologic Competition in Cuyahoga Valley National Park

October 26th, 2014

VIRGINIA KENDALL, CUYAHOGA VALLEY NATIONAL PARK (CVNP) — What an absolutely awesome day for geology in the field!!  One of my geologic mentors once told me that “every day in the field is a day of vacation”, and today proved to be just that day.  Late October…temperatures above 60 degrees…with the fall colors everywhere!!  I could not have asked for a better day to take my Structural Geology class to “The Ledges”, part of Virginia Kendall, which is only about an hour north of campus.  Essentially, we have a National Park right in northeast Ohio, and fall is the best time to visit the area.

However, we were not just going there for a day hike.  We were on a mission.  I set up a scenario for my class:  CVNP exposes strata that in the subsurface is rich in oil and gas.  The goal for the students was to undertake a complete geologic study (including the stratigraphy, sedimentology, structure, and geomorphology) of the exposed rock in the area as an analog in order to better assess oil and gas fluid migration in the subsurface.  The class was split into two teams — seniors vs juniors.  Each team is not permitted to talk to one another about data collection, analysis, or synthesis.  Eventually, these Research and Development (R&D) Teams will share their findings with Wooster’s Production Experts (Drs. Pollock, Wiles, and Wilson) via a poster presentation later in the semester.

So, while there were literally hundreds of people out for a day hike near The Ledges, Wooster’s geologists were busy at work.  The Ledges is located just south of Happy Days Visitor Center and southeast of Peninsula, OH.

lock-29-location-map_585blogThe area between State Route 303 and Kendall Ledges Road (where there are all the green hiking trails) was our field area for the day.

DSC01285_585blog

The R&D Teams quickly noticed the amazing joint sets that are exposed all along The Ledges.  Essentially, we have ledges in this area due to the large fracture system (i.e., joints) affecting the rocks.  These joint sets are very easy to measure and to access due to a wonderful trail system next to the exposures in Virginia Kendall.  Notice above that these joints can be at various orientations and that those in the photo above appear to be nearly perpendicular to one another.

DSC01271_585blogLet me introduce the R&D Team of Woo seniors (’15), from left to right: Coleman Fitch, Zach Downes, Willy Nelson, and Leo Jones.  It appears that they are discussing their team’s strategy early in the day.  Michael Williams (’16), of the opposing team, is in the background.  Is Michael trying to eavesdrop on the opposing team?

DSC01269_585blogTwo members of our R&D team of Woo juniors (’16) are taking notes on this rock exposure.  Eric Parker (left) and Kaitlin Starr (right, white hat) appear to be focused on the gorgeous geology.

DSC01276_585blogThe other two members of the R&D team of Woo juniors (’16) were found hiding in a dark “slot canyon” among the joints.  Michael Williams is in the front, while Adam Silverstein is in the orange hoodie, peeking out from deep inside the “canyon”.  It appears that the juniors are separated from one another!!  It is OK; everyone had maps and GPS units, so perhaps their strategy for the day was to divide and conquer?

DSC01274_585blogWow!!  Check out this entrance to Ice Box Cave, which was formed by the intersection of several joint sets.  Unfortunately, we were not able to go any closer to the cave entrance than this, because…

DSC01273_585blog…the National Park Service is trying to save the bats, which are susceptible to White-Nose Syndrome.

DSC01278_585blogNow, I could not just end the blog without showing you such a wonderful photo.  Check out the amazing set of cross-beds that you can see exposed in the upper half of the photo.  These rocks, which are some of the youngest rocks exposed in CVNP, have been interpreted to be deposited by ancient stream deposits.  Superimposed on the cross-bedding is the characteristic honeycomb weathering that affects many of the sandstone exposures along The Ledges.  And, notice that some of the rocks appear to be more brown or rust colored; some scientists have identified limonite and pyrite (two iron-rich minerals) in the unit.

What an awesome day to be a geologist!!  Who else gets to spend a great fall day with friends, enjoy the weather, learn a little more about rocks, and measure joints along the way?  Geology rocks.

 

 

The geological setting of Fort Necessity, Pennsylvania

October 11th, 2014

Great Meadows 101114On July 3, 1754, colonial lieutenant Colonel George Washington fought and lost a small battle on this site in southwestern Pennsylvania. He and his 400 men had built this makeshift fort about a month before in anticipation of an attack by several hundred French soldiers and their Indian allies. The French were incensed at Washington and his troops after they killed or captured most of a French party at the Battle of Jumonville Glen two months before. (Accounts vary as to who was at fault for that deadly encounter as France and Britain were not at war.) The Battle of Fort Necessity was just one day long, and the British under Washington had the worst of it. Washington accepted French surrender terms and he and his men were allowed to march home. This pair of skirmishes between the French and British started the French and Indian War,  known outside of the USA as the Seven Years’ War. It quickly became a global fight between empires; in many ways it was the first modern world war. And it all started in this lonely part of the Pennsylvania country.

Washington chose to place his ill-fated fort, a reconstruction of which is shown above, in a high grassy spot known as the Great Meadows. It is situated near two passes in the Allegheny Mountains, and thus sits strategically beside major trails. Washington liked the area because there was plenty of feed for his pack animals and horses, lots of available water (too much, it turned out), and it was not in the midst of the endless woods of the region.
Screen Shot 2014-10-12 at 5.19.55 PMThis geological map of the area (from the National Park Service) shows that the fort was situated on the Upper Carboniferous Glenshaw Formation. This unit has much clay, trapping water in the thin soil above (“Philo Loam“). Further, the area is a floodplain, thus making the area a kind of wetland with grasses and sedges. Great for horse grazing, not so good for walls, buildings or trenches.
Entrenchments 101114Here we see the shallow entrenchments made by Washington and his men as they awaited attack. The clayey soil and pouring rain made a mess of these boggy trenches.

Fort inside 101114Inside the fort was a simple square building used mainly to keep supplies and wounded men dry, During the battle it was partially flooded with rainwater.

British view 101114This is the British view from the fort of the surrounding woods. Washington miscalculated his placing of the fort because the French and Indians could easily hit it with musket shots while hiding among the trees.

French Indian view 101114The French and Indian view of the hapless fort. It was easy to rain bullets on the British from the woods with little fear of the return fire.

Braddock road trace 101114Nearby is a trace of the military road Washington’s unit had blazed through the Pennsylvania woods on their way to the French Fort Duquesne in what is now Pittsburgh. The British General Edward Braddock enlarged this road the next year in his famous march to a spectacular defeat nearby (the “Battle of Monongahela“).

We can’t fault Washington too much for his choice of a fort location. He did not have the resources to clear a large patch of forest, so the meadow would have to do. He expected to be reinforced soon, so he saw the fort as a temporary measure of protection. The rain was beyond his control that July day, and the clay-rich meadow floor ensured wet misery and ruined supplies. The French surprisingly gave good terms for surrender because they were wet, too, in those woods, and they also expected more British and colonial troops would arrive soon. They feared being surrounded, and so thought their message to Washington and his countrymen had been sufficiently made. How different our world would be if the French were not so generous here in southwestern Pennsylvania!

Additional Reference:

Thornberry-Ehrlich, T. 2009. Fort Necessity National Battlefield Geologic Resources Inventory Report. Natural Resource Report NPS/NRPC/GRD/NRR—2009/082. National Park Service, Denver, Colorado.

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