Upvote:2
The script used by the writer is mostly a form of Spencerian script, with some capital letters slightly altered. If you look at Plate 2 (p. 73 of the scan) of this textbook, you will find all the letters used, albeit not in alphabetical order, but by form elements used in the letters.
Lesson XIII on page 30ff. (p.56 of the scan) contains detailed instructions on how to write what are called "Capital Stem letters". Fig. 42 compares the Letters S, L, and G. After the "stem", the initial up-and-down stroke, there follows a large oval loop to the left for S, but a small loop near the bottom line for the L. Additionally, only the L connects with an uninterupted stroke to the next letter.
The disputed name is J. F. McLone, not McSone.
For differences to the textbook, the writer tends to interchange curls to the left and long upstrokes for the initial movement. The B in "Bailey" is written as two strokes, the first beginning at the bottom, but as one stroke beginning at the top in "Boyd". Contrary to the taught form, the C in "Colby" begins at the bottom. Thus the L on "Lowell" begining at the top, but at the bottom in "McLone" is explainable. If you look at the S in "Simons", if you imagined a long upstroke being used instead of the upper curl, the difference to a L would still be pronounced in the way the stroke ends, with the large loop to the left.
BTW, I am in the middle of developing a script font based on this textbook. McLone (left) and McSone (right) in the current version would look like this (superscript is not implemented at this point):