Ross: The Dunesland Heritage of Illinois 



13 



sented only by the club mosses, not now known from the Dunesland 

 but occurring in a few localities in Illinois. The rush trees are now 

 represented only by the horsetails or scouring rushes, which belong 

 to the genus Equisetion. Horsetails are widespread and abundant; 

 they can be found along the railroad right-of-way through the Dunes- 

 land and are a diminutive reminder of ancient trees that once grew 

 in the Pennsylvanian forest of the area. Most of the animals in this 

 forest, including large amphibians, reptiles, and many kinds of in- 

 sects, were different from those living now. Practically all of the 



Fig. 10. — Cockroaches. Left, a fossil 

 cockroach from Pennsylvanian times; 

 right, a present-day cockroach, abun- 

 dant today In Illinois woods. 



insects known from these forests have long been extinct, but the 

 native Illinois cockroaches of today are remarkably similar in ex- 

 ternal appearance to those found fossilized in the Pennsylvanian 

 coal forests, fig. 10. 



There is little direct evidence in Illinois concerning its terrestrial 

 conditions from the Pennsylvanian period almost to the present. 

 Fossil evidence from other areas, however, gives abundant evidence 

 that during the Mesozoic Era many modern groups of living things 

 evolved. Among the plants were the conifers and broadleaved or 

 angiospermous trees. The Mesozoic is most famous for the dinosaurs 

 that evolved, flourished, and became extinct during this era. Toward 

 the latter part of the Mesozoic Era and certainly by the end of its 

 last period, the Cretaceous, many groups well known to us today had 

 already evolved, including primitive birds, primitive mammals, most 

 of our groups of fishes, freshwater mussels, and a large assortment 

 of modern insects. 



Fossilized pollen from localities in Minnesota indicates that 

 during the latter part of the Cretaceous Period the area that is now 

 Illinois was probably covered by one of the first modern forests. The 



