Here's a second 1855 reference: to a "Shananigan ditch" dug in gold mining country in California in 1855. "On the first day of June, 1855, the defendants constructed two ditches, called respectively Rasin and Shenanagan Ditches, draining the waters of Todd's Valley Ravine, about one-half mile above the head of plaintiffs' ditch, and thereby diverting and depriving the plaintiffs of the waters ... More @Wikipedia
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