Although these two brothers did not graduate from U of M, they both attended law school there in 1871-1872.
A search for "Sedgwick" turns up several other instances of that name.
If any of your ancestors are listed, you'll find some helpful explanatory material here:
- p. iii - preface, followed by table of contents
- p. 597 - see footnote at the bottom of the page
- p. 967 - key to italic abbreviations