Part 4

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.