This material was from a stratum of whitish aspect, about 18 inches in thickness, found in the bluffs facing the Missouri River about 7½ miles north of Omaha. It has the same general characteristics as the volcanic dust which has been found in quantity along the Republican, in southern Nebraska, also in Knox, Cumming and Seward Counties in the same State. This statement is made on the authority of J. S. Diller of the United States Geological survey, who has examined samples from all these localities microscopically. This differs in being stained with oxide of iron, and the sharp angular grains are coated with carbonate of lime. Like the rest it contains with the finely pulverized glass, a few rounded grains of quartz and angular grains of feldspar less than.02 of a millimeter in diameter. The dust is such as is carried through the air from volcanoes. The sand grains and occasional diatoms indicate its deposition in still water.
Proceedings of the Iowa Academy of Sciences
©1890 Iowa Academy of Science, Inc.
Todd, J. E.
"Exhibition of Volcanic Dust from Omaha, Nebraska,"
Proceedings of the Iowa Academy of Science, 1(Pt. 2), 16-16.
Available at: https://scholarworks.uni.edu/pias/vol1/iss2/6