DISPERSION OF FRESH-WATER FISHES. 85 



down in its course, the Oatka falls over a ledge of 

 rock, forming a considerable waterfall at Rock 

 Glen. Still lower down its waters disappear in the 

 ground, sinking into some limestone cavern or 

 gravel-bed, from which they reappear, after some six 

 miles, in the large springs at Caledonia. Either 

 of these barriers might well discourage a quiet- 

 loving fish ; while the trout and its active associates 

 have sometime passed them, else we should not 

 find them in the upper waters in which they alone 

 form the fish-fauna. This problem is a simple 

 one; a boy could work it out, and the obvious 

 solution seems to be satisfactory. 



Since those days I have been a fisherman in 

 many waters, — not an angler exactly, but one who 

 fishes for fish, and to whose net nothing large or 

 small ever comes amiss ; and wherever I go, I find 

 cases like this. 



We do not know all the fishes of America yet, 

 nor all those well that we know by sight; still this 

 knowledge will come with time and patience, and 

 to procure it is a comparatively easy task. It is 

 also easy to ascertain the more common inhabi- 

 tants of any given stream. It is difficult, however, 

 to obtain negative results which are really results. 

 You cannot often say that a species does not live 

 in a certain stream. You can only affirm that you 

 have not yet found it there, and you can rarely fish 

 in any stream so long that you can find nothing 

 that you have not taken before. Still more difficult 

 is it to gather the results of scattered observations 

 into general statements regarding the distribution 

 of fishes. The facts may be so few as to be 



