[3][4] However, as a stage in the Pennsylvania-Permian marine embayment of Kansas (Midcontinent Basin), the unit extends only limited distances into Oklahoma, Colorado, Nebraska, Missouri, and Iowa.

[5] The Haskell Limestone's outcrop extends from northeast Oklahoma through Douglas County, Kansas, continuing into the adjoining corners of Nebraska, Missouri, and Iowa.

[5] Proceeding west from Independence, Missouri, the Oregon Trail kept a distance south from the incised bluffs nearer the Kansas River.

[6] In 1855, Shawnee chief and Methodist minister Charles Blue Jacket, received authority to create a crossing by cutting ramps into the limestone and soils of the banks, greatly speeding transport across the river.

[7] An outcrop of the Haskell Limestone (pictured above) occurs on the bridge right-of-way of Douglas County Highway 1057 a half mile south of the E 1900 Road exit of the K-10 between Lawrence and Eudora.