Interesting BOR instructions

I picked up a well used original printing of the 1919 advance sheets for a few dollars on fleabay. It's covered with an ink stamp for a John F. McGrew. I do not find him listed as a GLO Surveyor, but I've only checked a half dozen states. Anyone who has heard of him please post or drop a note.

When looking through the book I found an old BOR section diagram with instructions for 16th corner designations. The instructions are written in red pencil and signed by A.P. Davis, 10-24-1906. I've been looking at a lot of data and found some cool stuff. Mr. Davis would eventually become Director of BOR and prepare the concept for Boulder (Hoover) Dam. He was also cofounder of the National Geographic Society among other things.

I spent so much time researching the sketch I forgot about the book...