Browse Map

Explore away

Explore Map Collection

Check out our basemaps

Print a Map Plus

Generate a high-quality PDF

Field Guide

Discover local flora, fauna, geology, and more

Local Flora & Fauna

Learn the ecology of your area

Local Geology

Learn the geologic formation at your feet

Get Started or Sign In

Welcome

Continue with Apple

Already have an account? Sign In

Measure

Topo

Ecoregions

Public Lands

...

BASEMAPS

Default Weather

Temperature

Smoke

...

WEATHER

Cretaceous Hills

Ecoregion in IL

Print Map

Generate High-Quality PDF

The Cretaceous Hills ecoregion is composed of unglaciated, steep to rolling hills that are characteristically underlain by unconsolidated sands, gravels, and clays of Cretaceous- and Tertiary-age. The Cretaceous Hills (72k) is lithologically distinct from other ecoregions in Illinois. Upland soils are derived from loess and, locally, from unconsolidated sediments (Schwegman, 1973, p. 28-29). In the early 19th century, forests containing upland oaks, black gum, hickories, and tuliptree, were common. Mesic prairies occurred locally on wide stream bottoms, and dry prairies were found on eastern uplands (Schwegman, 1973, p. 29). Today, steeper slopes remain mostly wooded. Elsewhere, the land has been converted to livestock farms, general farms, and cropland growing corn, wheat, hay, and soybeans. The range of the spotted dusky salamander in Illinois, listed as endangered in the state, is largely restricted to The Cretaceous Hills ecoregion (Illinois Department of Natural Resources, on-line resource “b”; Illinois Natural History Survey, on- line resource).

— EPA