1898  But let him disembark and go inland and he will find the ground covered with what are locally known as "niggerheads," which consist of columns of decayed coarse grass peculiar to this region. They are formed by the annual growths of grasses decaying and falling down, while year after year the roots of the growing grasses bind this together into an almost solid column, which stands upon a bed of mud.
1938  Unless the train stopped near a creek, we had to scoop up water from the ditch or between the "niggerheads."
1958  They poled up the Klondike for two miles, left their boat in a backwater, shouldered their packs, and began to trudge through the wet mosses and black muck and the great clumps of grass "niggerheads" that marked the mouth of Rabbit.
2bn. such mounds of grass collectively.
1909  By muskeg hollow and nigger-head it wandered endlessly. . . .
1953  When he emerged from the niggerhead twenty minutes later, he was soaking wet and plastered with mud, but he had two tender young mallards in his sack.