Very strange. The stippling and the labels for the Park boundary are quite wrong, showing it in the middle of the river. Another mystery, then: if USGS amended the map after 1975, why did they put the boundary in the wrong place, when it is correct farther upstream?
As far as correction goes, the stippling is very dirty; pink, blues, brown, black. The only way to completely clean it up would be to remove it and then put down the contours and river line. Unfortunately, I need to replace the contours right away; otherwise I lose their placement. So the stippling cannot be completely removed. The incorrect boundary labels are gone, as is the center line, but I left the county names.
The pencil with various sizes worked well in cleaning up; either with background color or the mode set on clear.
The biggest problem has been replacing the river water on the stippled half, which comes off easily enough. I thought that I could use the Define Brush tool, but something very strange happens here. It worked the first time I tried it. Then I did something, and when I used the brush, it was invisible until I had done 15 or so clicks in one place. On the other hand, the default brushes worked fine. However, odd things happened to the mode; it would change from normal to threshhold (?), and not lay down the pattern properly. I will keep experimenting. Too bad, because the idea was attractive of just painting the water (one color only, though) with a brush and getting a nice random scatter of pixels. The closest so far is dry brush. But I dont trust any of them as this point.
Later: But success. Defined a brush on still another map; one color light blue. And with the brush mode at dissolve, painted the river with no trouble. Strange software; so far it has rewarded persistence; knock, knock. No joke.