246 MUSK-RATS. [CHAP. XXXVIII 



least prevent it from rolling back again. We saw two of them 

 in half a minute force a ball for a distance of eighteen inches up 

 a gentle slope, and when they reached a soft part of the road, 

 one of them began to excavate a hole, and soon entirely disap 

 peared under ground, heaving up the earth till it cracked and 

 opened wide enough to allow his companion to push the ball of 

 dung into it. The round mass immediately began to sink, and 

 in a few minutes was out of sight. We saw another pair try in 

 vain to bury their treasure, for they had selected a spot where 

 the soil was too hard ; at last they gave up the attempt, and, 

 rolling it away, set out in search of a more favorable spot. 



We crossed several plowed fields on the slope of the hills which 

 descend toward the Potomac, where a singular kind of manure is 

 used, consisting of dead fish, and almost exclusively of the bony 

 pike, or gar-fish (Lepidosteus oxyurus). The hard stony scales 

 resist decomposition for several years. The fishermen told us 

 that they are greatly annoyed by constantly taking these pikes 

 in their nets with the herrings. There is so enormous an abund 

 ance of herrings in some spots in this estuary, that 50,000 have 

 sometimes been taken this season in a few hours. 



In a marsh near the inn, we observed numerous habitations 

 of the musk-rat, standing up like hay-cocks. When the small 

 size of the animal is considered, the quantity of dried grass, reeds, 

 and rushes accumulated in one of these hummocks, at least a 

 cart-load, is surprising. We waded through the water to one 

 of them, and found that it was four feet high, and nine feet in 

 diameter. When we pulled it to pieces, the smell of musk was 

 very perceptible. At the depth of about sixteen inches from the 

 top we found a cavity, or chamber, and a small gallery leading 

 from it to another chamber below, from which a second gallery 

 descended, and then went upward again to a third chamber, from 

 all which there was a perpendicular passage, leading down to below 

 the level of the water, so that the rats can dive, and, without being 

 seen again, enter their apartments, in which they breathe air. 



The unio, or fresh-water mussel, is a favorite food of these 

 rats, and they often leave the shells on the banks of the American 

 rivers, with one valve entire and the other broken. In the even- 



