Statistics for occurrence #1 of “Black Rivers” in chapter 58 of Admiral David D. Porter, The Naval History of the Civil War.:

... river, where the guerillas still carried on their operations on a small scale. Very little occurred that could embellish the pages of history. The Red River region was revisited, the Washita and Black Rivers patrolled, and every precaution taken to guard those inland waters. At this time the Confederate ram Webb succeeded in making her way past all the vessels of the fleet and reached a point twenty-...
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