Visitors to the Maquoketa River gorge below Monticello in Jones County have been impressed with its rocky walls of the Niagaran formation which rise in places 100 to 125 feet above the stream. Overlying this rock formation are drift and loess. Crags, turrets, and chimney rocks, similar to the rugged features of the valleys of the driftless area, appear here and there. In fact, the characteristics of this gorge are so nearly like those of the valleys of the driftless area that in the report of the Geology of Jones County the gorge is considered to be pre-glacial in age.
Proceedings of the Iowa Academy of Science
©1917 Iowa Academy of Science, Inc.
Leighton, M. M.
Proceedings of the Iowa Academy of Science, 24(1), 83-85.
Available at: https://scholarworks.uni.edu/pias/vol24/iss1/13