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have in them but few species of fishes ; es- lakes in central New York was south- 

 pecially is this true of the upper Missouri, ward at the close of the glacial epoch. It 

 and these are such species as we find in is said that in times of high water one 

 the Black Hills. It is thus evident that may pass in a skiff from the head waters 

 the fishes of this region migrated there, of the Mississippi to the Red River of the 

 and only such fishes as were able or will- North. With such facts before us we can 

 ing to live in the muddy, alkaline streams easily understand why the fishes of two 

 of the great plains could have ever rivers whose sources are near each other 

 reached the Black Hills. The minnows should be most nearly alike nearest the 

 and suckers are ever preyed upon by sun- divide. If the two rivers were formed 

 fishes, bass and the like, and to escape about the same time, as no doubt were 

 them evidently sought retreat in the al- the James and the Ohio, they would nat- 

 kaline water, which was too much dislik- urally have several species in common, 

 ed by their enemies for them to follow. In other words, the two fish faunas will 

 Once there and accustomed to such water resemble each other throughout their 

 they would migrate farther up stream un- whole extent. In the case of the Mis- 

 til they reached the clear, cool streams of souri and the Columbia, the former is 

 the Black Hills. If we compare the fishes much the older stream, and while their 

 of two rivers whose mouths are near each sources have fishes common to both 

 other, as the Ohio and the Missouri, those streams, in the lower parts of the rivers 

 fishes found near the mouths will be the the fish faunas are entirely different. The 

 same species and the two river faunas upper Missouri river and its tributaries 

 will differ most as you go toward their are for the most part inhabited by Rocky 

 sources. On the other hand, if you select Mountain fishes, practically the same 

 two rivers whose sources are near each fauna as we find in the Columbia, but few 

 other, as the James and tributaries of the species characteristic of the Mississippi 

 Ohio, then the fish faunas will differ most valley have been able to even cross' the 

 as you go towards their mouths. The great plains and none have ever passed 

 same is true of the Missouri and the Co- the Rocky Mountain divide, 

 lumbia. In such cases it often happens In the study of the geographical distri- 

 that during high water some fishes are bution of our fresh water fishes, we are 

 able to pass from the head waters of one able to make a few generalizations as fol- 

 river basin to the other, just as we see lows: Two rivers in the same latitude, 

 the trout from the Columbia at the pres- and belonging to the same great drainage 

 ent time colonizing the upper Yellow- basin, and draining similar areas, will 

 stone through the Two Ocean Pass, have similar fish faunas. Thus we find a 

 Near the head waters of many mountain great similarity in the fishes of the Wash- 

 streams there is usually a pass, which ita and the Tennessee rivers, a much 

 contains a strip of meadow land where greater similarity than we do in the fishes 

 the small streams from mountains unite, o f the Washita and the Cedar rivers. If 

 forming the sources of two great rivers the stream is a large one, the fishes near 

 flowing in opposite directions. This is its source will be much unlike those near 

 the case both at the Two Ocean Pass, its mouth. The fishes of Minnesota dif- 

 the source of the Missouri and the Co- f e r greatly from those of Louisiana, 

 lumbia, and at the point where the Cana- though the drainage of these two States 

 dian Pacific Railroad crosses the^ divide, i s i n the Mississippi river basin. Lime- 

 forming the source of the Frazier and stone streams have in them more species 

 Saskatchewan rivers. of fishes than do sandstone. All things 

 Many mountain streams whose sources being equal, the larger of two or more 

 are at present in no way connected may streams will contain the most species of 

 have been so at no very remote period, fishes. There are few, if any, rivers as 

 All of our streams which have their rich in species as the Mississippi river 

 sources within the glaciated area were no and its tributaries. It drains one slope 

 doubt connected as the ice receded. The of each of our two great mountain sys- 

 drainage of Lake Champlain and the terns, besides an immense area of wood- 



