Difficulty of identifying this specimen is not due to its condition, which is not bad, but to the inherent difficulty of differentiating Masticophis flagellum from M. fuliginosus. M. flagellum ranges in color from bright brick red to olive brown, whereas M. fuliginosus ranges in color from olive brown to nearly black. This snake is one of the brown ones. The ranges of the two species overlap in the U.S. only in a narrow little area of extreme southern San Diego County: right where I found this snake. I've seen a couple of very black examples of M. fuliginosus within 1-2 km of the location where I found this specimen, but I can't identify this specimen based on range, or color. I shared photos with herpetologists at USGS, but haven't gotten a definite reply from them yet.