15. _Byron, Ogle County._—In 1873 (Geol. Surv. Illinois, vol. V, p. 110), James Shaw reported that a tooth identified as that of a mastodon had been found, in 1858, in a tributary of Stillman’s Run, somewhere in the region about Byron. The locality is low and marshy. The tooth is described as having been a ponderous grinder, weighing 7.5 pounds, and to have been covered with a black and shining enamel. A large mastodon tooth, just out of the water, might attain such a weight. The statement regarding the enamel confirms the identification. Shaw reported further that a large leg-bone, supposed to belong to a mastodon, had been found 2 or 3 miles above Byron, along the bank of Rock River, 5 feet below the surface and about 15 feet above ordinary water-level. It was sent to the State Museum at Springfield. This may have belonged to one of the elephants. _Harper, Ogle County._—In Netta C. Anderson’s list, on page 15, is a report from Miss Abba Eager, of Forreston, concerning a tooth of a mastodon found on the farm of Mr. Gross, in Forreston Township, about a mile south of Harper, in the bed of a small stream. Another tooth had been found there a short time before. Byron is on Rock River, and the tooth was probably in alluvial deposits laid down after the recession of the Wisconsin ice. Harper is near the western border of the county and Illinoian drift covers the country. All that can be said in the case of the teeth found is that the possessors lived after the Illinoian stage. 16. _Urbana, Champaign County._—In the collection of the Illinois State University the writer saw a lower right last molar of a mastodon, found June 1, 1911, at Crystal Lake park, 1.5 miles northeast of the university. _Pesotum, Champaign County._—In 1909, Mr. Rufus M. Bagg (Univ. Ill. Bull., vol. VI, No. 17, p. 49) recorded the fact that a mastodon tooth with some bones had been found near Pesotum, on the farm of Mr. Pfeffer, at a depth of 3.5 feet, in digging a ditch. Inasmuch as this whole region is covered by Wisconsin drift, the animal could not have lived there before the ice which deposited the Champaign moraine had withdrawn. It probably lived there long after the ice had retreated, possibly about the time when the megalonyx, whose claw alone is left as a memorial of his former existence, lived in that region. 17. _Edgar County._—In 1870 (Geol. Surv. Illinois, vol. IV, p. 266), Frank H. Bradley, in describing the topography of Edgar County, stated that a nearly perfect skeleton of a mastodon had been found in one of the sloughs of the prairie region which prevails in the western part of the county. It was said that after having been exhibited over that region it was sold to some museum in Philadelphia, but the writer has been unable to obtain further information.