Meek and Hayden's type-section of the Cretaceous Dakota sandstone is directly across the Missouri River from Sergeant Bluff, below Sioux City. Neither this outcrop, nor the fine exposure at Sergeant Bluff, which latter is commonly considered as Iowa's best section of the formation, are complete to top or to bottom. Drill-core records have shown the Dakota sandstone to extend nearly 200 feet below the base of the exposed section named; and erosion has removed perhaps as many more feet from the top.
Proceedings of the Iowa Academy of Science
©1937 Iowa Academy of Science, Inc.
Keyes, Charles R.
"Dakota Sandstone as a Basinal Basilium,"
Proceedings of the Iowa Academy of Science, 44(1), 131-132.
Available at: https://scholarworks.uni.edu/pias/vol44/iss1/33