|A portrait of Owen, found on p. 206 of Owen (1852).|
David Dale Owen (1807–1860) was one of the most significant American geologists of the pre-Civil War period. Owen was a son of reformer Robert Owen. Robert had come to the United States with his family in the 1820s to implement a utopian community at New Harmony, Indiana. The experiment didn’t take, but the Owens remained there for many years, and New Harmony became an early scientific center in the US. In his relatively brief life David racked up a surprising tally of state and territorial surveys, working in Arkansas, Indiana, Iowa, Kentucky, Minnesota, Tennessee, and Wisconsin. For his work in Minnesota, Wisconsin, Iowa, and points west, he assembled an all-star cast, including Joseph Granville Norwood (eventually of the Illinois and Missouri geological surveys), collectors and paleontologists John Evans and Fielding Bradford Meek, Owen’s brother Richard (not to be confused with namer-of-dinosaurs and noted grouch Sir Richard Owen of the UK), geologist and archeologist Charles Whittlesey, future Gettysburg hero G. K. Warren, and Benjamin Franklin Shumard. Shumard (1820–1869), although most frequently associated with St. Louis, was another geologist in the mold of Owen who covered a number of areas. After the Upper Mississippi work, he went on to Oregon, Missouri, and Texas, where his work as the head of the state geological survey was ended by the Civil War. Finally, for vertebrate fossil identification, Owen had Joseph Leidy, who contributed one of the first long discussions of Badlands fossils to Owen’s 1852 tome on the expeditions.
With such a large group, and a large area to cover, Owen delegated. For 1848, he focused on the Red River, Norwood got the St. Louis and Mississippi rivers and Lake Superior, Shumard got the Minnesota River, and others went to southern Minnesota. In the end, Shumard ended up covering the area of immediate interest to this blog, although work was complicated by his struggles with pleurisy that left him laid up at various times. The various sub-parties had the typical run of difficulties, including illness, hunger, getting lost, storms while on the water, and one dramatic incident where a rifle accidentally discharged in the direction of Owen and another member of his party, resulting in both being peppered with metal fragments when the bullet struck the brass mountings of another rifle. The actual report (Owen 1852) is somewhat less picturesque than either Featherstonhaugh’s or Nicollet’s efforts, but what is lost in the picturesque is more than made up for in the geology. In addition, both Owen brothers were no slouches as artists, and Owen (1852) is profusely illustrated throughout. There is even a geological map, which you can see alone in all its glory here. (We also get some figures of specimens from the North Shore that the authors tentatively considered fossils of seaweeds, which turns out to be a double error. The objects aren’t fossils, and the “fucoids” they were compared to were burrows. For reasons which are unclear to me, 19th century geologists apparently thought that seaweeds made really great fossils and burrows did not. The prehistoric seas of their imaginations must have been positively choked with seaweeds.)
For our purposes, Owen (1852) is the first attempt to deal in a systematic way with the rocks of what becomes the Twin Cities metro area. We get the first detailed division of the local rocks into distinct formations, even if the names were for the most part not particularly exciting and gave way to other names. The basic column was divided into three formations and a kind of sub-formation: the Lower Sandstone (Formation 1), the Lower Magnesian Limestone (Formation 2), the St. Peter’s Sandstone (Formation 2c), and the St. Peter’s Shell Limestone (Formation 3a), which was differentiated from a younger Upper Magnesian Limestone (the rest of Formation 3; note that at this time, with the Ordovician not yet having been defined, these rocks are described as Silurian). The Lower Sandstone has gone on to be divided into the various Precambrian and Cambrian units better seen in areas peripheral to the core Twin Cities, such as the St. Croix River valley. Some of the modern units can be recognized in Owen’s descriptions. We'll probably be hearing more about them sometime this summer; for the moment, there is the important recognition of fossils in the Cambrian rocks. Granted, they’re pretty low-diversity faunas of inarticulate brachiopods, snails and snail-like mollusks, trilobites, and trace fossils. Owen thought that these were the oldest known fossils at least regionally and perhaps in the world.
The Lower Magnesian Limestone (minus the St. Peter’s Sandstone) is the Prairie du Chien Group. Two divisions are even recognized, which would eventually give way to the Oneota Dolomite and Shakopee Formation (“magnesian limestone” being just another way to say “dolomite”). The St. Peter’s Sandstone had already been named by Owen, back in 1847. It is of course the St. Peter Sandstone with an extra possessive. It was no more cemented or fossiliferous in the late 1840s than it is today. It is topped by the “St. Peter’s Shell Limestone”, which is basically the Platteville Formation. The potential “hydraulic limestone” sounds like a reference to the clay-rich Hidden Falls Member. Again, like Nicollet and Conrad before them, Owen’s group did not describe any of the fossils from the “St. Peter’s Shell Limestone”, although they did describe other taxa, including the extraordinarily variable trilobite Dikelocephalus minnesotensis from Cambrian rocks at Stillwater. At least some of the material from the survey went to the Smithsonian, which is a good thing because for both Owen and Shumard collections had a tendency to disappear, although apparently for different reasons. Owen seems to have preferred to hoard his fossils in New Harmony (see here for a few comments), while Shumard, historically, may be one of the most snakebit geologists to date, having lost his Texas collections to the turmoil of the Civil War and collections in St. Louis (Academy of Science) and Columbia (University of Missouri) to 19th century fires.
This closes our short series on early Minnesota geology. The subject wouldn't be taken up in earnest again until the 1870s, by which time Minnesota would be an established state and the principle figures of the early surveys would be dead.
Hendrickson, W. B. 1945. David Dale Owen’s geological survey of Minnesota. Minnesota History 26(3):222–233.
Owen, D. D. 1847. Preliminary report of the geological survey of Wisconsin and Iowa. Pages 160–174 in U.S. General Land Office Report 1847. Washington, D.C. 30th Congress, 1st session, Senate Executive Document 2, Congressional Serial Set Volume 504.
Owen, D. D. 1852. Report of a geological survey of Wisconsin, Iowa, and Minnesota; and incidentally of a portion of Nebraska Territory. Lippincott, Grambo & Co., Philadelphia, Pennsylvania. Available at http://archive.org/details/mobot31753000174885 (plates not included), https://archive.org/details/reportofgeologi00owen (full plates) or http://books.google.com/books?id=Y_ZYAAAAYAAJ.