This appears to be Henry Corwith Dangler's drawing in ink and pencil for his bookplate design for his clients, ca. 1910-13 for an Italian villa, Villino San Nicolo, at 1115 East Illinois Road, Lake Forest for Alfred and Clarisse Hamill, Alfred being Dangler's fist cousin, the son of his mother's sister.  At the bottom of the plate are the initials: "H. C. D."  A small, bookplate scaled halftone print was created and is found in  the Hamills' copy of at least one book in the Lake Forest College library collection. 

Arthur E. Hamill was a Chicago and Lake Forest investment banker and president of the Newberry Library Board of Trustees from 1929 to 1953. He was born in Chicago in 1883 and graduated from Yale University in 1905. He resided in Lake Forest, Illinois. His business career began at the Northern Trust Company, though he ended it at Goldman, Sachs, and Company. He was  president of the Lake Forest Public Library, a trustee of the Presbyterian Hospital, and vice-president of the Chicago Art Institute. His wife, Clarice, was an illustrator and book designer.

Alfred's cousin, Henry Corwith Dangler, was the Ecole des Beaux-Arts trained architect of the Hamills' home, ca. 1910-13. David Adler later recast the home's facade and added to the structure and dependencies, after Dangler died in 1916. See the article on the Hamill house, Villino San Nicolo, later Centaurs under Adler's 1920s renovations, in David Adler, Architect: The Elements of Style ed. Martha Thorne (New Haven: Yale U. P., and the AIC), 2002).  A north entry elevation Dangler's earlier plan is reproduced, as well.