It does not require a very careful observer to see that in these two streams the fishes are not quite the same. The streams themselves are similar enough. In each the waters are clear and fed by springs. Each flows over gravel and clay, through alluvial meadows, in many windings, and with elms and alders "in all its elbows." In both streams we were sure of finding trout,[64] and in one of them the trout are still abundant. In both we used to catch the brook chub,[65] or, as we called it, the "horned dace"; and in both were large schools of shiners[66] and of suckers.[67] But in every deep hole, and especially in the millponds along the East Coy Creek, the horned pout[68] swarmed on the mucky bottoms. In every eddy, or in the deep hole worn out at the root of the elm-trees, could be seen the sunfish,[69] strutting in green and scarlet, with spread fins keeping intruders away from its nest. But in the Oatka Creek were found neither horned pout nor sunfish, nor have I ever heard that either has been taken there. Then besides these nobler fishes, worthy of a place on every schoolboy's string, we knew by sight, if not by name, numerous smaller fishes, darters[70] and minnows,[71] which crept about in the gravel on the bottom of the East Coy, but which we never recognized in the Oatka. There must be a reason for differences like these, in the streams themselves or in the nature of the fishes. The sunfish and the horned pout are home-loving fishes to a greater extent than the others which I have mentioned; still, where no obstacles prevent, they are sure to move about. There must be, then, in the Oatka some sort of barrier, or strainer, which keeping these species back permits others more adventurous to pass; and a wider knowledge of the geography of the region showed that such is the case. Farther 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 some time 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. =Generalizations as to Dispersion.=--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.