There are three principal exposures of the Lime Creek Formation in the area between Mason City and Charles City, northern Iowa. By a considerable margin, the most extensive site is the quarry of the former Rockford Brick and Tile Company, only 1 mi (1.6 km) west of town in Floyd County (NW¼Sec. 16, T.95N., R.18W.). The Juniper Hill State Preserve is 0.5 mi(0.8 km) to the northwest. Bird Hill is located just a fe miles farther west at a road cut on an east-west county right-of-way in eastern Cerro Gordo County (NE½Sec.24, T.95N., R.19W.). The stratigraphic section known historically as Hackberry Grove, now called Claybanks Forest, lies just south of the Winnebago River (near center NE½Sec.34, T.96N., R.19W.). The Winnebago River was originally called Lime Creek (hence the name Lime Creek Formation). A location map (Fig. 1) has been prepared from the general highway and transportation maps of Cerro Gordo and Floyd counties. Topographic sheets for the Mason City Southeast and Rockford 7½-minute Quadrangles cover the area.

The Rockford Brick and Tile property lies adjacent to County Road B47, west of Rockford. The kilns have been inactive for several years, and permission to visit the grounds must be secured from the present owner, Allied Construction Company, 1211 South Main Street, Charles City, Iowa 50616. Bird Hill is also situated on County Road B47, with a large parking area on the north side of the road. The site has recently been designateda State Preserve. At Hackberry Grove, the Claybanks