These are the only blue-stained copper L-shaped bookends we know. Decorated with a gold abstract butterfly, these midnight blue bookends are striking to see. Relatively large, each bookend is 6.5 inches tall, 6 inches wide, and is marked with an S within a C, the mark of Carl Sorensen. His shop was active in Philadelphia in 1914, which confirms these as early American Arts and Crafts productions.
There is a website which claims that Craftsman Studios of California used a trademark of S within a C on some of their bookends, but no evidence is offered. Until we see some evidence, we will attribute this shopmark to Carl Sorenson.