Ann Arbor, Michigan                                   Published by the University...

The Interlobate Lake District has a conspicuous system of moraines, making up a most irregular land surface. Steep knolls 100 to 200 feet in height are closely associated with basins, which are often deep, and some of which are occupied by lakes. Small, undrained depressions occur everywhere, producing thousands of acres of swamp and marsh land. The Clay Morainic Belt occupies the region from just below Portage Lake to Ypsilanti. It is composed of glacial till plains and clay moraines extending

Didelphis virginiana virginiana. Virginia Opossum.—This species is rare in the county. One was taken by my father, Jessup S. Wood, in 1845, in Lodi Township. We have later records for Ann Arbor, Dexter, Manchester, Saline, and Scio Township. The last recorded specimen was taken by some boys in November, 1921, just south of the Oakland County line. February 5, 1912, a trapper took a specimen near Ann Arbor on a night when the temperature was about 10° F. below zero. Scalopus aquaticus machrinus.

The mammals included in this list have been reported as occurring in Washtenaw County, but I can find no specimens with authentic data nor descriptions satisfactory for identification, and consider the records doubtful. Rattus rattus rattus. Black Rat.—Covert [6] states that the species is "very rare. I have but one specimen, which was caught at the Michigan Central R. R. Depot." [6] Covert, A. B., in History of Washtenaw County, pp. 193-194, 1881. Mustela allegheniensis. Least Weasel.—Covert sa