Young Man in Chair Nibbling Nails, Late 19th C. Graphite Drawing

Just a nice small graphite drawing, late 19th century or so, surely pulled at some point from a sketchbook, as I found a few others clearly by the same artist along with it. Perhaps he's pondering his future, or the cast of the light, but I like that the looks a bit as if nibbling at his nails! I like his rolled pant cuffs too. 

6 3/8" x 4 1/2" and in very good condition, paper not brittle.