SUFICIAL GEOLOGIC MAP OF THE LADD 7.5 QUADRANGLE, LASALLE COUNTYY, ILLINOIS

The work was supported by USGS, ISGS, Nicor Inc. Ladd occupies the area between 890 07? 30? to 890 15? 00? west longitude, and 410 22? 30? to 410 30? 00? north latitude. The Ladd quadrangle surficial geologic map was made from soils map, bor-hole date, DEM files, and surficial geologic observations. The Ladd quadrangle is mostly covered by Peoria silt. The Peoria silt is a light gray to yellowish brown silty loam that was interpreted as loess and was only mapped in area that were five feet or greater. However, in the southern region and spots along creeks, there is the Wisconsin till called the Lemont formation that covers the landscape. The Lemont formation is a Yorkville member and is mostly made up of dark gray silts, clays, and some fine-grained gravel. Another Wisconsin glaciers deposit is lake sediment or bedded silts and clays called the Equality formation that formed when glacier lakes were depositing silts and clays. In a few spots on the quadrangle is the Henry formation, which is an old river channel deposit that?s made up of bedded sands and gravels were glacier streams deposited its outwash. Also new river deposits are forming in the three major creeks in these areas are depositing alluvium soil surface that is made up of silts and clays; this is called the Cahokia formation. On the LaSalle County side of Ladd quadrangle there is the Lacon formation, which is a landslide/slump or colluvium. On the west side of the quadrangle around the town of Ladd and Cherry there is disturbed soil from the mines that were dumped when clearing out the mines.