[Illustration: uncaptioned]
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.
[Illustration: _Plate 4_]
_Sphenopteris_ ⅗×
_Linopteris_ ⅗×
_Neuropteris_ ½×
_Odontopteris_ ⅗×
_Cycopteris_ ½×
_Alethopteris_ ⅗×
_Alethopteris_ ⅗×
_Odontopteris_ ½×
_Alethopteris_ ⅗×