Yorba Linda / Santa Ana Canyon field trip, Part 4

Okay, I know I said that my last post was the end of the Santa Ana Canyon/Yorba Linda irrigation posts. But I didn't expect reader Glenn Frank would overlay the 1908 map Doug McIntosh provided onto modern maps and satellite photos. These images are so cool, I had to share them. But I can stop any time I want. Really.
The detail image above shows specifically the area we were hiking in on July 25th. Interestingly, the Cajon Canal appears on the map exactly where we saw openings into an underground canal. Now I want to go back and see what else we can find.
Glenn writes, "I took some... maps and messed around with overlaying Doug's map on them. I think this is a pretty good match based on the county line, the drastic horseshoe curve and the rail line (which I think must have been moved in the area of Green River Golf Course when the Prado Dam project went in place) because the rail line matches pretty well until that point. ...I used Macromedia Fireworks."
In case you missed the rest of this series (and your mouse finger is too weary to scroll backward), here are links to the previous three installments: Part 1, Part 2, Part 3.