Part 2

Fossiliferous concretions may be found in a number of the strip mines in the area, although probably most have come from the Northern Illinois Coal Corporation mine between the towns of Braidwood and Wilmington.

In earlier years good collections were made from the spoil heaps of underground mines. Especially notable are the mine dumps of the Wilmington Star No. 7 mine, 2¼ miles west of Coal City, and Skinner No. 2 mine, two miles northeast of Braidwood.

In the vicinity of Morris on the northwest edge of the Mazon Creek area, fossil ferns have been found along the north side of the Illinois River and in the banks of the Illinois-Michigan Canal. About a mile north in an area of strip mining, fossil-bearing concretions have been found in shale and irregular sandstone layers.

_Sphenophyllum_ ⅗× _Lepidostrobophyllum_ ⅗× _Annularia_ ⅗× _Sphenophyllum_ 1× _Lycopodites_ ⅗× _Cordaites_ ⅗× _Asterophyllites_ ⅓×

Fossils in concretions also have been collected from a shaly limestone at the south end of the Kankakee River bridge along the Grundy and Will county line.

Bureau County

Some 40 miles downstream from Morris on the Illinois River, plant fossils have been discovered in waste from the Spring Valley Coal Co. mine 1. They also are found in black shale below the LaSalle Limestone in a small gully in the southwest part of town, but at neither place are they plentiful.

Knox County

A notable number and variety of well preserved plant fossils have been produced from a locality along Court Creek in East Galesburg. The Rock Island (No. 1) Coal is mined in the area and the fossils appear to have come from the shale overlying it.

Fossil plants also have been found in shales above the Colchester (No. 2) Coal in the vicinity of DeLong and with the Herrin (No. 6) Coal in mines southeast of Victoria.

Mercer and Warren Counties

In northern Warren and southern Mercer Counties the sandstone underlying the Rock Island (No. 1) Coal is termed the “Stigmarian” sandstone because of numerous siliceous casts found in the bed. Many of the fossils have been collected from an old mine dump and from ravines along the Edwards River northeast of Aledo.

A number of representatives of _Sphenophyllum_, _Neuropteris_, and _Annularia_ have been collected from ironstone concretions occurring in shale that overlies the Colchester (No. 2) Coal about three miles southwest of Alexis. They were found in a gully about a third of a mile southeast of Center School.

_Pecopteris_ 1× _Ptychocarpus_ ⅗× _Pecopteris_ ⅗× _Mariopteris_ ⅗× _Asterotheca_ ⅗× _Spiropteris_ ⅗× _Pecopteris_ ⅗×

In the same general area but about three miles due south of Alexis, fossil plants also may be found in the clay pits of the Hydraulic-Press Brick Company and the Northwestern Clay Manufacturing Company.

Fulton County

Although there are numerous isolated occurrences of plant fossils throughout the extensive strip mines and outcrops in Fulton County, no exceptionally good collecting localities have been discovered.

Fern and cordaitean leaves have been collected along Mill Creek about a mile northeast of Pleasantview where the fossils occur in the shale overlying the Babylon Coal. In the same general area, impressions and casts of _Stigmaria_, _Lepidodendron_, and _Cordaites_ have been found in the Babylon Sandstone.

Three miles north of Pleasantview, a quarter of a mile northwest of Union School, several species of leaves have been collected from the Browning Sandstone where it is exposed in a roadcut.

Farther east, there is a fairly good locality in the stream bluff of Kerton Creek about 3¼ miles north and a quarter of a mile west of Bluff City. There the plants are found about 18 feet below a coal bed.

Numerous fern impressions also are found in shale beds above the Herrin (No. 6) Coal along the Middle Branch of Copperas Creek, six miles west of Glasford. Other specimens may be found in these beds elsewhere in the area.

McDonough County

In some of the small underground mines near Colchester, the shale overlying the Colchester (No. 2) Coal contains ironstone concretions similar to those from northeastern Illinois. More than 50 species of plant fossils have been reported, but they were collected many years ago from spoil heaps at the mines. Beds of the same age crop out widely in other localities in western Illinois and may contain plant fossils.

_Sphenopteris_ ⅗× _Linopteris_ ⅗× _Neuropteris_ ½× _Odontopteris_ ⅗× _Cycopteris_ ½× _Alethopteris_ ⅗× _Alethopteris_ ⅗× _Odontopteris_ ½× _Alethopteris_ ⅗×

Vermilion County

In outcrops about three miles below Georgetown on the Little Vermilion River, a number of fossil plant species and one insect species have been collected from shales overlying the Herrin (No. 6) Coal, locally called the Grape Creek Coal. The fossils occur in concretions much like those from Mazon Creek.

An occasional stem replacement or impression is found in the concretionary shale above the No. 7 Coal in the strip mine area west of Hillery. In fact, isolated fragmentary plant specimens are fairly common in the Danville mining area, but no especially productive localities have come to light.

Other Northern Illinois Localities

In addition to the counties listed above, a number of others have produced plant fossils. For example, there are records of plant fossils found southeast of Franklin in Morgan County, at Neelys in Peoria County, and at a number of places in the southern and western parts of Rock Island County. Local exploration is certain to turn up numerous other collecting places at present unknown.

_Codonotheca_ ⅗× _Calamostachys_ 1× _Pachytesta_ ⅗× _Codonospermum_ ⅗× _Cordaicorpus_ ⅗× _Samaropsis_ ½× _Whittleseya_ 1× _Trigonocorpus_ ¼× _Holcospermum_ ⅗× _Neuropterocarpus_ ⅗× _Lepidostrobus_ ⅗× _Carpolithes_ ⅗×

Southern Illinois

Lawrence County

Near the Lawrence-Richland county line, not far from the towns of Berryville and Calhoun, there is an area rich in the fossil petrifactions called “coal balls” in which cellular structures of stems and roots generally are well preserved.

Saline, Pope, and Johnson Counties

Saline County has more recorded plant fossil localities than any other southern Illinois county. Fossil plant collecting localities are isolated but numerous in the area southwest of Harrisburg. Mine dumps, such as in the area five or six miles northwest of Eddyville, and many outcrops are available throughout the region. The fossils probably are associated with the Murphysboro, Delwood, Willis, Reynoldsburg, and Battery Rock Coals.

One especially good collecting area is on the south tributary of the East Branch Cedar Creek about 6½ miles south of Stonefort. The fossils are found in six feet of shale overlying the Battery Rock Coal horizon.

Perry and Jackson Counties

Near DuQuoin and Murphysboro, a variety of well preserved plant fossils has been collected from shales overlying both the Herrin (No. 6) Coal and the Murphysboro Coal. Nearly all have come from shaft mines that are not easily accessible to the collector.

One currently good outcrop locality for collecting plant fossils from the shale above the Murphysboro Coal is just southeast of Murphysboro.

Other Southern Illinois Localities

Other collecting localities have been recorded west of McLeansboro in Hamilton County, northwest of Mt. Vernon in Jefferson County, near Grayville in White County, and in the Friendsville area of Wabash County. There is no doubt that careful search will turn up many more.

Almost anywhere in the large coal producing areas of southern Illinois plant fossils can be found either in spoil heaps or in outcrops along stream, road, and railroad cuts. The thick Pennsylvanian sandstones that crop out in a belt extending through Gallatin, Saline, Williamson, and Jackson Counties generally contain compressions or replacements of trunks or other woody plant parts.

SUGGESTIONS FOR COLLECTING PENNSYLVANIAN PLANTS

Where to Look for Plant Fossils

Pennsylvanian plants are most commonly found in shales directly overlying coal beds. The shales are believed to be of nonmarine origin like the coals and may contain fossils either in ironstone concretions or on the bedding planes. The shale layers as well as the concretions should be examined. Where the bed directly overlying the coal consists of black slaty shale or limestone containing marine fossils, plant remains are rarely abundant or well preserved.

Beneath the coals there generally is an underclay that is interpreted as the material in which the coal forest grew. The underclay is in turn underlain by a sandstone, and both are believed to be mostly nonmarine. Stigmarian axes and “roots” are common in many of the underclays. Plant fossils are common in the sandstone but generally are poorly preserved, except in the local shaly lenses.

The best place to look for plant fossils in northern Illinois, except for the strip mines of the Mazon Creek area, is probably in the spoil heaps from shaft mines. The Colchester (No. 2) Coal has been extensively mined by the longwall method. This technique causes the mine roof to settle when the coal is removed, and the haulage ways are kept open by removing the roof shale. Inasmuch as the roof shale is the Francis Creek Formation of the Mazon Creek area, it may contain abundant plant-bearing concretions. The shale is not everywhere fossiliferous, however, and in many spoil heaps fossils are rare.

Collecting Equipment

The collector of plant fossils should have the following tools and equipment:

① Hammer—a bricklayer’s hammer will work well. ② One or two chisels, preferably one large and one small. ③ Knapsack or basket in which to carry specimens. ④ Newspapers and a roll of tissue paper for protecting fragile specimens. ⑤ Pencil and paper for labeling specimens and making notes about the collecting locality from which the fossils came. Much of the value of a particular fossil lies in knowing precisely where it was found and the layer of rock it came from.

Rules of Courtesy

When entering a collecting area every collector should observe several rules carefully:

① For your own protection get permission to enter and collect on any private property. Such action also will help to assure your welcome if you wish to come back again.

② Leave the gates exactly as you find them, open or closed. Do not climb fences that may break or sag under your weight; crawl under or go around.

③ Don’t litter, even though far from any house or other buildings. Do not disturb the owner’s equipment, stock, or planted areas.

Handling Specimens

The most successful way to split an ironstone concretion is to set it on edge, long axis horizontal, on any fairly large rock and strike the upper edge with the hammer. If the concretion is one that developed around a fossil nucleus, it generally will split along the plane of weakness, revealing the fossil. Sometimes one side of the concretion will break off in the middle, in which case the remainder should be tapped firmly but gently on the upper edge until the fossil is completely uncovered. Pieces of the broken half should be glued together neatly with waterproof cement so that the entire specimen can be retained.

Fossils embedded in shale may be recovered by the same method or by repeatedly tapping a chisel inserted along the bedding plane. If the fossil is exposed, the matrix can be chiseled away by slow, painstaking effort.

The usual method of wrapping plant-bearing nodules is to place the end of a sheet of newspaper between the two halves of the nodule, fold the paper over the nodule, and roll it up in the sheet.

When several localities are visited in one collecting trip, the fossils from each should be kept separate; cloth bags are convenient for this purpose. Notes about the locality should be put in the same bag as fossils from that locality so that there is no possibility of confusion.

Some fossils are so fragile or porous that they should be covered with a hardening protective coat of crude gum arabic solution. (Refined gum arabic will not serve.) This may be applied with a fine brush in successive layers, or sturdier fossils may be dipped in it.

When a fossil is so delicate that the surface tension of the gum arabic solution causes the fossil to “spread,” celluloid (not plastic) dissolved in acetone should be substituted. Before this solution is used, the specimen must be completely dry or the coating will become cloudy or opaque.

If the specimen is pyritized, it should be sprayed with lacquer or shellac to prevent disintegration. If these protective sprays are used they must be applied to dry specimens during dry weather or the coating will remain sticky.

REFERENCES

AN INTRODUCTION TO PALEOBOTANY. C. A. Arnold. McGraw-Hill Book Co., New York, 1947, 433 p.

GRUNDY AND WILL COUNTIES. Frank H. Bradley. In Worthen et al., Geology and Paleontology, Geological Survey of Illinois, vol. IV, 1870, p. 190-225.

PALMLIKE PLANTS FROM THE DOLORES FORMATION (TRIASSIC), SOUTHWESTERN COLORADO. Roland W. Brown. United States Geological Survey Professional Paper 274-H, 1956, p. 205-209.

CARBONIFEROUS INSECTS FROM THE VICINITY OF MAZON CREEK, ILLINOIS. F. M. Carpenter. Illinois State Museum Scientific Paper 3, pt. 1, 1943, p. 7-20.

THE LIVING CYCADS. C. J. Chamberlain. University of Chicago Press, Chicago, 1919, 172 p.

GUIDE FOR BEGINNING FOSSIL HUNTERS. Charles Collinson. Illinois State Geological Survey Educational Series 4, 1956, 36 p. (Revised 1959, 40 p.)

HISTORICAL GEOLOGY. Carl O. Dunbar. John Wiley & Sons, Inc., New York, 1949, 576 p.

COLLEGE BOTANY. Harry J. Fuller and Oswald Tippo. Henry Holt & Co., New York, 1954, 993 p.

HANDBUCH DER PALÄOBOTANIK, BD. 1: _THALLOPHYTA, BRYOPHYTA, PTERIDOPHYTA_. Max Hirmer. R. Oldenbourg, Munich and Berlin, 1927, 708 p.

SOME FOSSIL PLANT TYPES OF ILLINOIS. Raymond E. Janssen. Illinois State Museum Scientific Paper 1, 1940, 124 p.

LEAVES AND STEMS OF FOSSIL FORESTS. Raymond E. Janssen. Illinois State Museum Popular Science Series; v. 1, 1957, 190 p.

THE MAZON CREEK EURYPTERID: A REVISION OF THE GENUS _LEPIDODERMA_. Erik N. Kjellesvig-Waering. Illinois State Museum Scientific Paper 3, no. 4, 1948, p. 3-46.

PLANTS OF THE PAST. F. H. Knowlton. Princeton University Press, Princeton, N. J., 1927, 275 p.

THE WILMINGTON COAL FLORA FROM A PENNSYLVANIAN DEPOSIT IN WILL COUNTY, ILLINOIS. George Langford. Esconi Associates, Downers Grove, Ill., 1958, 360 p.

THE MAZON CREEK, ILLINOIS, SHALES AND THEIR AMPHIBIAN FAUNA. R. L. Moodie. American Journal of Science, 4th Series, v. 34, 1912, p. 277-285.

INTRODUCTION TO HISTORICAL GEOLOGY. Raymond C. Moore. McGraw-Hill Book Co., Inc., New York, 1958, 656 p.

PENNSYLVANIAN FLORA OF NORTHERN ILLINOIS. A. C. Noé. Illinois State Geological Survey Bulletin 52, 1925, 113 p.

PENNSYLVANIAN INVERTEBRATES OF THE MAZON CREEK AREA, ILLINOIS. Eugene S. Richardson, Jr. Fieldiana: Geology, v. 12, 1956, p. 1-76.

REPORT ON THE CARR AND DANIELS COLLECTIONS OF FOSSIL PLANTS FROM MAZON CREEK. Wilson N. Stewart. Illinois Academy of Science Transactions, v. 43, 1950, p. 41-45.

A RECENTLY DISCOVERED _PHLEGETHONTIA_ FROM ILLINOIS. W. D. Turnbull and Priscilla F. Turnbull. Fieldiana: Zoology, v. 37, 1955, p. 523-535.

EDUCATIONAL EXTENSION PROGRAM

The Educational Extension Section of the Illinois State Geological Survey reaches the public through a number of channels, including nontechnical publications, rock and mineral collections for Illinois schools and educational groups, lectures, exhibits, correspondence involving identification of rocks and minerals, news items for the press, and field trips.

During each year six field trips are given, in widely separated parts of the state, for teachers, students, and laymen. The general program is especially designed to assist in teaching geological sciences and to help make Illinois citizens aware of the state’s great mineral wealth.

Illinois State Geological Survey Urbana, Illinois

Morris Braidwood Peoria Colchester Danville Springfield Duquoin Murphysboro Harrisburg Marion

_Illinois State Geological Survey Educational Series 6_

Transcriber’s Notes

—Silently corrected a few typos.

—Retained publication information from the printed edition: this eBook is public-domain in the country of publication.

—In the text versions only, text in italics is delimited by _underscores_.