This is Mazon Monday post #137. What's your favorite Mazon Creek fossil? Tell us at email:[email protected]. Thanks!
-----------------------------------------------------
The Mazon Creek area is a well known fossil collecting locality. It's considered a lagerstatte, with soft-bodied fossil preservation of exquisite quality. It can be very challenging to collect, as public areas are rare and the ones that exist are covered by thick plant growth. ESCONI tries to make it easier for collectors with our two field trips to the Braceville spoil pile each year. A few club members generously provide fossil material at those events. Pit 11 is a State Park near Braceville. Fossil collecting is allowed from March 1st to September 30th. Despite the overgrown nature of the area, there are still notable fossils found there each year.
Back in the heyday of collecting Mazon Creek fossils, many sites were easily accessible and people came from all over to collect the abundant fossils. These people included amateurs, paleontologists, students, and those people just eager to find something interesting. College geology clubs were one of the groups that included all of these types. The Geological Society of Marietta College in Marietta, OH was one of these groups.
ESCONI member Ralph Jewell found this guide for a trip that the Geological Society of Marietta College took to Pit 11 in 1978. It's very good and does a excellent job explaining what was known about Mazon Creek in the late 1970's. There are some nice hand draw fossils and tips about concretion shape. The resource list includes interesting and useful papers and books about Mazon Creek plants, animals, and the geological setting of the region.
Unfortunately, we don't know if they had a good trip, as there isn't anything recorded. They had high hopes and planned to return the fossil material back to Marietta. It couldn't have been too notable as there isn't a fossil species called the Dennis Monster!
Pit Eleven
Pit Eleven is located about 500 miles by interstates and a few wiggly roads from Marietta College. The locality is about three miles south of Braidwood, Illinois, or one mile east of Godley. noted for its several night spots. Pit Eleven is today an abandoned Godley is open pit or strip mine where bituminous coal was mined from 1945 to 1974 by the Peabody Coal Company. Bedrock exposures are no longer present, and the region we will visit consists of elongate steep waste dumps with intervening narrow and deep clear water lakes. Bass and beaver occupy some of the lakes. The Commonwealth Edison Company has constructed the Braidwood Nuclear Station on this site. The company laveled some of the concretion-rich hills and weeds and trees have been planted. Some of the former collecting sites are no longer accessible. The mine is shown on the 1973 Essex, Illinois 7% minute topographic quadrangle, and had a north-south length of 4k miles and an east-west width of 14 miles. Most of our collections will be made in Will County, but the southern half of the mine is in Kankakee County.
The stratigraphic terms applicable to the rocks of the mine are as follows:
Paleozoic Era
---Pennsylvanian Period Kewanee Group
------Desmoinesian Epoch
---------Carbondale Formation
------------Francis Creek Shale Member
---------------Colchester Coal Member (Number 2)The newest deposits in this northeastern region of Illinois are Pleistocene sediments. These consist of glacial tills with large boulder-sized glacial erratics (granite, gneiss, schist, limestone, and other rocks), glacial outwash plain gravels and sands with cross bedding, and some wind deposited loesses.
Below the thin veneer of uncemented Pleistocene deposits are Pennsylvanian sedimentary rocks. The disconformity or erosional unconformity separating the two moments of time represents the Permian, all of the Mesozoic Era, and most of the Cenozoic Era. No doubt some sediments accumulated during the 300,000,000 year interval represented by the erosional surface, but they were later removed by erosion.
The one to three foot black Colchester or Number 2 bituminous coal is located at the base of some of the high walls along the west margin of the coal mine. (Most, if not all, of the walls have been removed.)
Above the coal are 30 to 40 feet of gray siltstones and some sandstones that are a part of the Francis Creek Shale Member. The specific
environment of deposition of the siltstones and sandstones is still in doubt, but they are a part of a large deltaic deposit whose source area was to the northeast. The predominantly fine grained silty sediments with marine animals are interpreted to represent deposition in an interdistributary bay.
In addition to marine animale, some of the concretions at Pit Eleven will have fresh water animals, and many will have plants that probably occupied swamps or floodplains, And so, at one locality we find a mixing of organisms from different environments. To account for this odd assortment, Johnson and Richardson (1970) and Richardson and Johnson (1971) proposed the stoza surge hypothesis. During storms, marine waters would be driven by the winds in a shoreward direction. The marine waters with animals would move across brackish and fresh water environments and perhaps a floodplain. Animals from different ecological sites would then be mixed together. The mixing occurred several times as the lower part of the Francis Creek Shale Member was accumulating. Some of the siltstones accumulated very rapidly as a nine foot trunk of a coal age tree was found in an erect position on one of the former walls. The trunk would not have remained vertically oriented for a long time as decay would have destroyed it.
Circular to flattened ironstone concretions with siderite (iron carbonate) are abundant near the base of the Francis Creek Shale Member. These concretions are usually gray within the gray siltstone, but their surfaces change to reddish-brown after being exposed to the atmosphere. Some of the one to eight inch long concretions have small pyrite cubes scattered near their centers. A few have patches or bands of pyrite or marcasite. Internal fractures of other concretions are filled with dark gray to black sphalerite.
Practically all the animals in the member are found in concretions with very few occurring in the surrounding rock. The animals served as a nuclei for concretion growth, and although the definite chemical requirements for the development of iron carbonate around an animal is unknown, it is obvious that the concretions started to form very rap idly after the animals died. See Tom Rymer for more specific details, also Woodland and Stenstrom (1978). Soft bodied forms without hard skeletons would include many worms, Tully monsters, blobs, and jellyfish. These soft animals would normally be expected to decompose rather quickly, but their remains within the concretions are spectacularly well preserved. Many occur as light gray stains near the centers of the concretions. Very few animal fossils have black carbon residues.
Drying and decomposition affected many animals after they were rapidly entombed in the new, relatively firm concretions. Worms, holo thurians (sea cucumbers), and other soft bodied animals lost fluids, and developed cracked "skins." Many of the cracks are now filled with white kaolin clay.
Occasionally, a detailed three dimensional internal mold of an animal that had not been crushed is found within a concretion, but all
the soft parts have vanished. These animals completely decomposed after the concretions were formed. Some of these elongate cavities within the concretions are sometimes filled with white soft kaolin.
Approximately 90% of the concretions from Pit Eleven are barren of fossils, 5% will have plants, and the remaining 5% will constitute the mission of this trip. The 5% group of concretions we will search for has a fantastic collection of animals that includes over 300 species. Many of these are soft bodied forms that have never been discovered elsewhere. The most plentiful species are marine animals whose state of preservation has been compared to that of the Cambrian Burgess Shale fauna of British Columbia.
The following Pennsylvanian animals have been found at Pit Eleven:
Coelenterata, Scyphozoa, jellyfish Coelenterata, class uncertain, perhaps Scyphozoa, jellyfish with 8 tentacles
Coelenterata, class uncertain, perhaps Scyphozoa, blobs
Coelenterata, Hydrozoa, hydroids and a hydra
Coelenterata?, class uncertain, perhaps Hydrozoa, Wye animals
Brachiopoda, Inarticulata
Mollusca, Amphineura (Polyplacophora), chitons
Mollusca, Cephalopoda, Nautiloidea
Mollusca, Cephalopoda, Anmonoidea, goniatites
Mollusca, Cephalopoda, Coleoidea
Mollusca, Pelecypoda, clams
Mollusca, Gastropoda, snails
Priapulida
Nematoda
Chaetognatha
Nemertina
Echiura
Annelida, Polychaeta
Arthropoda, Crustacea, Branchiopoda, branchiopods
Arthropoda, Crustacea, Cirripedia, barnacle
Arthropoda, Crustacea, shrimp
Arthropoda, Crustacea, Isopoda
Arthropoda, Crustacea, Phyllocarida
Arthropoda, Crustacea, Ostracoda
Arthropoda, Trilobitomorpha, Arthropleurida
Arthropoda, Arthropoda, Chelicerata, Xiphosuza, horseshoe crabs
Arthropoda, Chelicerata, Eurypterida
Arthropoda, Chelicerata, Arachnida, Scorpionida
Arthropoda, Chelicerata, Arachnida, Araneida, spiders
Arthropoda, Chelicerata, Arachnida - Architarbida, Arthrocomartida, Trigonotarbida, Ricinuleida, etc.
Arthropoda, Myriapoda, Diplopoda, millipedes
Arthropoda, Myriapoda, Chilopoda, centipedes
Arthropoda, Insecta
Arthropoda, class uncertain, Genus Cyclus
Echinodermata, Crinoidea
Echinodermata, Rolothuroidea, sea cucumbers
Chordata?, Hemichordata?, H animals (perhaps Coelenterata, Hydrozoa)
Chordata, Vertebrata, Pisces, Agnatha, Cyclostomata, lampreys
Chordata, Vertebrata, Pisces, Placodermi
Chordata, Vertebrata, Pisces, Chondrichthyes, sharks
Chordata, Vertebrata, Pisces, Osteichthyes, bony fish
Chordata, Vertebrata?, Pisces?, large coprolites
Chordata, Vertebrata, Tetrapoda, Amphibia, salamander-like
phylum uncertain, Tully monster (perhaps Mollusca, Gastropoda) other animals of uncertain taxonomic positionThe following Pennsylvanian marine animals are common elsewhere in Illinois and surrounding states, but are absent from the Pit Eleven concretions: Protozoa (including fusulinids), sponges, horn and colonial corals, bryozoa, articulate brachiopods, and conodonts.
The true jellyfishes (Johnson and Richardson, 1968) are not common, so do not be dismayed if the entire group of students leaves the mine without a single specimen. The typical jellyfish you might find is in the Genus Octomedusa. This form has a float that is about of an inch across, and will bear eight (8) tentacles. The mouth consists of two crossed lines.
The most common animal fossils you will whack into are merely known as the "blobs." They are perhaps jellyfish-like forms in the Phylum Coelenterata, but they do not possess tentacles that extend laterally from their bodies, and very few distinctive features or parts can be gleaned from the majority of specimens. Blobs can be divided into two groups known as (1) blobs without character, and (2) blobs with character. Group 1 includes the blah blobs that are round to oval stains. Two or more may be within one concretion. Group 2 includes the pretty blobs, and it is doubtful if there are two specimens that are identical. The blobs with character can be divided into two parts or sections, and many have "wrinkles" and elongate "lobes." A few have U-shaped tentacles. Some are monsters and attain lengths of about six inches. Most of the big round and flattened concretions will have these nifty blobs. Instead of recognizing the two categories of blobs as listed above, Nadasdy (1976) divided the blobs into four types: circular, elliptical, acorn, and contorted. Some workers at the Field Museum in Chicago divide the blobbies into six categories:
disc ( blob without character), multiple discs, tongues, trapezoids, juvenile
blob (= blob with character), and blob (= blob with the most character) (Eugene Richardson, pers. comm., 1976).Do you need some $$? If so, sell D.D.S. your attractive blobs the going sub wholesale rate is 26¢ per blob, or 28¢ if two blobs in one concretion appear to be mating. Marietta College already has over 2,000 blobs, but because we want to become the chief blob repository in southeastern Ohio, we need more and more. Many people open the blob concretions and then leave them lying on the ground. Do not pass a pile of broken concretions without looking for a few weird objects that others do not want. These forms will be classified eventually,
at least to the genus and species level, so they should be collected. Foster (1978a) will no doubt name the species in the future. Blobs are ONLY known from Pit Eleven.
Look at the article by Nitecki and Solem (1973) for the Wye animals that are probably coelenterates.
The rare chitons (over 100 specimens are known) are about three inches long and have skeletons consisting of eight arched plates. Some of the Pit Eleven specimens show the teeth or radula.
Pelecypods representing several genera are common on a few of the waste piles. Both bilaterally symmetrical clams and asymmetrical pectens should be discovered. Quite often both of the opened valves of the symmetrical types are found together, and some concretions have six or more specimens (Richardson, 1956). Some unusual concretions have trails made by crawling clams.
Gastropods have been collected, but are rare. Most are small bellerophontoids represented by external molds.
More than a dozen polychaete worms have been reported, but most have not been described in the published literature. See Thompson and Johnson (1977), Thompson (19787). Many are essentially complete with setal bundles and chitinous jaws or teeth called scolecodonts. Many will be brown and not black like the lab specimens you saw. In addition to the worms with legs and teeth, some will be legless and tooth less.
An echiuran worm (Jones and Thompson, 1977) can quite often be recognized as the one to two inch elongate body will be shortened and have wrinkles that are at right angles to its long dimension. Many will also have about a dozen elongate fecal pellets (small coprolites) in their bodies. Additional worms were described by Schram (1973).
Over a dozen species of shrimp have been collected. You should find some with feelers, legs, and body segments. Some shrimp with thick chitinous exoskeletons will be preserved as orange-brown fossils. The chitin will be cracked into small pieces. See the articles in Fieldiana Geology by Fred Schram for the shrimp info. Some of the shrimp are only partial skeletons. Many of these represent molted skeletons that were broken. Keep in mind that even a piece of a shrimp fossil would be extremely rare at other localities, so you should keep the parts found at Pit Eleven.
The Class Arthropleurida is represented by a genus that attains a length of five feet, and somewhat resembles a rather huge trilobite. So if you should stumble over a six foot elongated concretion, make sure you open it. Unfortunately, this rare and interesting animal is so far only represented by small pieces of the exoskeleton found in the concretions (Richardson, 1956, 1959; Langford, 1963).
The arachnids are represented by several orders of animals that are difficult to distinguish unless certain diagnostic features are pre served. The orders Architarbida, Arthrocomartida, Trigonotarbida, Ricinuleida, and a few others are commonly called the "spiders", al though the only true spiders are in the order Araneida. They have two chelicerae, two pedipalps, and eight. walking legs. The body is divided into two parts, the head and abdomen. Most of the Pennsylvanian arachnids have segmented abdomens which is clearly revealed on most specimens. Some of the true spiders were also segmented during this moment of time. A well preserved, but rare Ricinulid can be identified if the cucullus (covering of the chelicerae) is present. Additional data on arachnids may be found in Petrunkevitch (1946), Stormex (1955), and Langford (1963).
Millipedes and centipedes resemble worms, but are arthropods that have jointed legs. One centipede from the Pit somewhat resembles the living type occasionally found in kitchen cupboards.
Although holothurian sclerites are common in many marine deposits, the only locality in North America where essentially complete animals can be found is at Pit Eleven. The holothurians or sea cucumbers you will find are placed in the Genus Achistrua because this is the form genus for the microscopic sclerites that are so abundant in the animals skin. The sclerites look like fish hooks and bear a circular opening at one end and a curved, pointed part on the opposite end. The flattened, wiggly animals are one to about eight inches long. Most will be brown to orange brown and will have a large number of desiccation cracks that are filled with white kaolin. A few specimens reveal mouth parts and mud filled intestines.
All of the four common fish classes (Agnatha, Placodermi, Chondrichthyes, Osteichthyes) have been found in the concretions, but they are rare. The Agnatha are represented by the only fossil lampreys (obviously also the oldest). The specimens studied by Bardack and Zangerl (1968) greatly resemble the living lampreys from the Great Lakes, but are much smaller. Many of the external as well as internal parts are well preserved. The small Osteichthyes or bony fishes reveal fins, scales, eyes, plus some internal parts. Some of the baby or lar val Osteichthyes fish will have two black eyes and two or four gill bars that extend laterally from their bodies (azdack, 1974). Many coprolites are probably from the fishes.
Perhaps the most fascinating beast found at Pit Eleven is the marine "Tully monster", a form more scientifically identified as Tullimonstrum gregarium Richardson. The common name has been used in the Chicago area since the animal was discovered by Mr. Tully in 1958.
Tullimonstrum may represent the only member of a new phylum, or it might eventually be placed in one of the worm phyla. Recently, the animal has been assigned to the Phylum Mollusca, Class Gastropoda, and more specifically to the heteropods (Foster, 1978b). The bilaterally symmetrical Tullimonstrum has a length up to about 13 inches,
and the soft body is divided into a head, trunk, and tail region. The unsegmented head bears a long, anteriorly projecting flexible probosis that is sometimes found bent posteriorly along the side of the head. A slot near the anterior part of the proboscis has four pairs of small triangular teeth, which might be part of a radula. The posterior part of the head has a thin hard bar that projects laterally from each side of the body. The distal ends of the bar are expanded into circular balls, which were perhaps sensory devices (eyes). The trunk, or central part of the body, has 13 segments. The tail has two later ally projecting very thin fins that were the major propelling mechanisms (Johnson and Richardson, 1969).
The plants are very plentiful on many hillsides and like the animals form the nuclei of the siderite concretions. Black carbonized Neuropteris leaves and fronds, Alethopteris fronds, Lepidodendron and Sigillaria bark fragments, Calamites 1 leaf whorls (called Annularia), Sphenophyllum, and other plants can be found. Quite often some of the concretions associated with the plant concretions will have worms. To identify some of the plants see Langford, (1958, 1963), Janssen (1957), and Darrah (1969).
By examining an unopened concretion can you tell what kind of an organism is inside? The answer is usually no, but there are some exceptions. A larger, round, flattened concretion quite often has a blob with character, and a large round flattened concretion with some projections may contain a holothurian. A very large elongate flattened concretion with a curved beak-like part on one end will likely have a Tully monster, and a crudely triangle shaped one may have an arched shrimp. See the pretty drawings.
The following items are recommended for concretion work at Pit Eleven:
hat
sunglasses
raincoat
coat gloves
boots
other garments of your own selection, such as undies and socks geologic hammer and Bandaids
two large, sturdy collecting bags or buckets
wide rubber bands
newspapers
pliers
canteen or small thermos (for water ONLY!)
sleeping bag and small pillowWith the necessary equipment on or near your body, select a ravine or hillside (there used to be several hundred of these to pick from) and casually examine the concretions. A few concretions will probably be opened by physical weathering processes. If you see some animals or plants on the broken concretion surfaces then the chances are good
that some of the unopened concretions next to them will have fossils. Many of the hard concretions with small fossils will probably be in tact, so if you want a good fauna or flora, several hundred rocks will have to be opened. Always pick up a large concretion (over five inches long). The bag or bucket should be partially filled with concretions and these can be carried to a large hard glacial erratic. The abundant erratics have been mixed with the Pennsylvanian rocks in the mine dumps. sit adjacent to the erratic, pour the 20 or more concretions on the ground, and start breaking them. Most will be somewhat flattened parallel to the original bedding planes; so hold the flat sides with a finger and thumb (or pliers) and tap the edges. Some concretions will open with one light rap with the hammer, but many have a high iron content and will challenge your arm Muscles. DO NOT allow the hammer to slip and come into violent contact with a thumb. This is a definite NO NO. Thumb smashing is one of the best ways of stimulating a person to retire from concretion work. D. Stone, an obvious expert in the sport, opened thousands of the Pit Eleven concretions without a mishap. If about 40 unproductive concretions have been opened at a given site, then you should consider moving on. Keep in mind that about 90% of these rocks from the mine will be barren of animals and plants. On some waste piles 50% will have fossils, and on other piles less than 18 will have fossils. Most fossil-bearing concretions will split lengthwise parallel to the flattened animal or plant, but if only a portion of the fossil is exposed, you may wish to open more of the concretion when you have access to glue at Marietta College. The partially or completely opened concretions should be placed together and secured with sturdy rubber bands or wrapped in newspapers. Don't throw a concretion away just because you can't decide whether the "thing" in the center is inorganic or organic. Keep in mind that most of the animal fossils are quite exotic and many have NEVER been found elsewhere in the world. Even an ugly fossil may be quite valuable because of its rarity. Some of the concretions opened by weathering processes will have a thin white calcium carbonate coating over the fossil. DO NOT throw these away as they can be easily cleaned by using acid. Many of the better MC specimens had white coatings on them at one time.
If an unusual animal is discovered you should consider sending it to Dr. Eugene S. Richardson, Jr., Field Museum of Natural History, Chicago, Illinois 60605. Gene knows who is working on the various groups of new critters. Who knows, fame might come your way with animals eventually named Hagerleakia ryneri, Fairfieldodus sinardae, Supposerbeakelia creeli, Davidsandsovonenciasexensis. Or how about Bowareoglyptus forake, the Dennis monster.
SELECTED REFERENCES:
Bardack, D., 1974, A. Larval Fish from the Pennsylvanian of Illinois: Journal of Paleontology, p. 988-933.
Bardack, D. and Richardson, E.S., Jr., 1977, New Agnathous Fishes from the Pennsylvanian of Illinois: Fieldiana Geology, vol. 33, no. 26, p. 489-530.
Bardack, D. and Zangeri, R., 1968, First Fossil Lamprey: A Record from the Pennsylvanian of Illinois: Science, p. 1265-1267.*Not really valid according to the ICAN.
Carpenter, F.M., 1943, Carboniferous Insects from the vicinity of Mazon Creek, Illinois, in Coal Age Fossils from Mazon Creek, Illinois: Illinois State Mus. Sci. Papers, vol. 3, p. 1-24.
Darrah, W.C., 1969, A Critical review of the Upper Pennsylvanian Floras of Eastern United States with notes on the Mazon Creek Flora of Illinois, 220 p. (see this book for revisions in plant names)
Foster, M.W., 1978a, the Coelenterates of the Pennsylvanian Essex Fauna in Illinois (abs.): Abstracts with Programs, North-Central Section of the GSA 12th Ann. Meeting, p. 253.
Foster, M.W., 1978b, Tullimonstrum Gregarium: A Pennsylvanian Hetero pod-like Gastropod (abs.): Abstracts with Programs, North-Central Section of the GSA, 12th Ann. Meeting, P. 253-254.
Gillespie, W.H., and others, 1966, Plant Fossils of West Virginia: W. Va. Geol. Survey Ed. Series, 131 p.
Gregory, J.T., 1950, Tetrapods of the Pennsylvanian Nodules from Mazon Creek, Illinois: Amer. J. Sci., p. 833-873.
Janssen, R.E., 1957, Leaves and Stems from Fossil Forests: Illinois State Museum, Sci. Series, vol. 1, 190 p.
Johnson, R. G., and Richardson, E.S., Jr., 1966, A Remarkable Pennsylvanian Fauna from the Mazon Creek Area, Illinois: J. of Geology, p. 626-631.
Johnson, R. G., and Richardson, E.S., Jr., 1968, Pennsylvanian Invertebrates of the Mazon Creek Area, Illinois The Essex Fauna and Medusae: Fieldiana: Geology, vol. 12, no. 7, p. 109-115.
Johnson, R. G., and Richardson, E.S., Jr., 1969, Pennsylvanian Inverteb rates of the Mazon Creek Area, Illinois: the Morphology and Affinities of Tullimonstrum: Fieldiana: Geology, vol. 12, no. 8, p. 119-149.
Johnson, R. G. and Richardson, B.S., J., 1970, Fauna of the Francis Creek Shale in the Wilmington area: Illinois State Geological Survey Guidebook Series No. 8, p. 53-60.
Jones, D. and Thompson, I., 1977, Echiura from the Pennsylvanian Essex Fauna of northern Illinois: Lethala, vol. 12, p. 317-325.
Kjellesvig-Waering, E.N., 1948, The Mazon Creek Eurypterid. A Revision of the Genus Iepidoderma, in Coal Age Fossils from Mazon Creek, Illinois: Illinois State Mus. Sci. Papers, vol. 3, p. 1-64.
Kjellesvig-Waering, E.N., 1963, Pennsylvanian Invertebrates of the Mazon Creek Area, Illinois. Eurypterida: Fieldiana: Geology, vol. 12, no. 6, p. 85-106.
Langford, G., 1958, The Wilmington Coal Flora from a Pennsylvanian Deposit in Will County, Ill., 360 p. (see Darrah, 1969, for revisions)
Langford, G., 1963, The Wilmington Coal Fauna and additions to the Wilmington Coal Flora from a Pennsylvanian Deposit in Will County, Illinois, 280 p.
Nadasdy, G.S., 1976, Preliminary Investigation of the Blobs, Essex Fauna from Pit Eleven: Proceedings of the Peoria Academy of Science, vol. 9, p. 11-22.
Nitecki, M.H. and Richardson, E.S., Jr., 1972, A New Hydrozoan from the Pennsylvanian of Illinois: Fieldiana Geology, vol. 30, no. 1, p. 1-7
Nitecki, M.H. and Schram, F.R., 1975, Hydra from the Illinois Pennsylvanian: Journal of Paleontology, p. 549-551.
Nitecki, M. H. and Schram, F.R., 1976, Etacystis Communis, A Fossil of uncertain affinities from the Mazon Creek fauna (Pennsylvanian of Illinois): Journal of Paleontology: p. 1157-1161
Nitecki, M.H. and Solem, A., 1973, A Problematic Organism from the Mazon Creek (Pennsylvanian) of Illinois: Journal of Paleontology. P. 903-907.
Petrunkevitch, A., 1946, Palaeozoic Arachnida of Illinois. An Inquiry into their Evolutionary Trends, in Coal Age Fossils from Mazon Creek, Illinois: Illinois State Mus., Sci. Papers, vol. 3, p. 1-76.
Raymond, P.E., 1945, Xiphosura in the Langford Collection, in Coal Age Fossils from Mazon Creek, Illinois: Illinois State Mus. Sci. Papers, vol. 3, p. 1-10.
Richardson, E.S., Jr., 1956, Pennsylvanian Invertebrates of the Mazon Creek Area, Illinois: Fieldiana: Geology, vol. 12, nos. 1-4 (insects, serpulids, clams, chitons, trilobitomorphs) p. 1-78.
Richardson, E.S., Jr., 1959, Pennsylvanian Invertebrates of the Mazon Creek Area, Illinois. Trilobitomorpha Arthropleurida, II: Fieldiana: Geology, vol. 12, no. 5, p. 79-82.
Richardson, E.S., Jr., 1966, The Tully Monster: Bull. Field Museum of Natural History, vol. 37, no. 7, p. 4-6
Richardson, E.S., Jr. and Johnson, R.G., 1971, The Mazon Creek Faunas in Proceedings of the North American Paleontological Convention 1969, Part I Extraordinary Fossils, p. 1222-1235.
Schram, F.R., 1969, Pennsylvanian Invertebrates of the Mazon Creek Area, Illinois. Some Middle Pennsylvanian Hoplocarida (Crustacea) and their Phylogenetic Significance: Fieldiana: Geology, vol. 12, no. 14, p. 235-289.
Schram, F.R., 1973, Pseudocoelomates and Menertine from the Illinois Pennsylvanian: Journal of Paleontology, p. 925-989.
Schram, F.R., 1974a, the Mazon Creek Caridoid Crustacea: Fieldiana Geology, vol. 30, no. 2, p. 9-65.
Schram, F.R., 1974b, Paleozoic Peracarida of North America: Fieldiana Geology, vol. 33, no. 6, p. 95-125.
Schram, F.R., 1976, Some notes on Pennsylvanian Crustaceans in the Illinois Basin: Fieldiana Geology, vol. 35, no. 3, p. 21-28.
Schultze, H.P., 1977, Megapleuron Zangerii, A new Dipnoan from the Pennsylvanian, Illinois: Fieldiana Geology, vol. 33, no. 21, p. 375-396.
Smith, W.H. and others, 1970, Depositional Environments in Parts of the Carbondale Formation - Western and Northern Illinois Francis Creek Shale and Associated Strata and Mazon Creek Biota: Illinois State Geol. Sur. Guidebook Series No. 8, 125 pages (Pit 11 articles on p. 28-2 49, 53-60).
Stormer, L. and others, 1955, Chelicerata with sections on Pycnogonida and Palaeoisopus: Part P, Arthropoda 2, Treatise on Invertebrate Paleontology, 181 p.
Thompson, I., 1978?, Errant Polychaetes (Phylum Annelida) from the Pennsylvanian Essex Fauna of Northern Illinois: Unpub. manuscript, M.C.
Thompson, I. and Johnson, R.G., 1977, New Fossil Polychaete from Essex, Illinois: Fieldiana Geology, vol. 33, no. 25, p. 471-487.
Woodland, B.G. and Stenstrom, R.C., 1978, The Occurrence and origin of siderite concretions in the Francis Creek Shale (Pennsylvanian) of northeastern Illinois (abs.): Abstracts with Programs, North Central Section of the GSA, 12th Ann. Meeting, p. 253-254.
Torino Hill in Pit 11 - taken spring 2022
