STTEFACE FEATUEES. 71 



this way : — Some of the channels formed and abandoned by the 

 river, as before intimated, were never afterward re-occupied by 

 it, because the general deepening of the channel progressed con- 

 siderably in some instances before changes above or below 

 certain points, induced a change of occupancy there. There- 

 fore these previously isolated portions of the old channel have 

 remained to this day as bodies of still water, and have now a 

 position a little above the present highest floods of the river. 

 These lakes, resting upon alluvial material, show evident 

 traces of their fluvatile origin, in their general character and 

 form. Some of these fluvatile lakes, indeed, are not entirely 

 above the reach of the highest floods of the streams near 

 which they are located, and it is not impossible that a 

 part of them may yet be re-occupied by the shifting channel, 

 particularly as their location often suggests a more direct or 

 favorable course for the stream than the one it is now taking. 

 Such lakes as these are not uncommon upon the flood-plains 

 of the Mississippi and Missouri rivers, but they are not common 

 elsewhere in Iowa. They are usually well stocked with fish, 

 and also in their season, with an abundance of wild water- 

 fowl; but their vicinity is never attractive as a place of 

 residence on account of the marshy surroundings and low 

 situation. 



On the contrary, the shores of the majority of the drift- 

 lakes of northern Iowa, are some of the most delightful spots 

 for residence to be found within the limits of the State. Their 

 waters are always clear and excellent, and their borders 

 usually gravelly and clean. These lakes, resting as they 

 do in gentle undulations of the surface, have few very bold 

 features in the landscape which surrounds them, and their 

 depth, for the same reason, is usually slight. This is 

 indicated by the evident continuation of the gently curved 

 contour of that portion of the surface which is now above 

 their water-levels. 



For reasons elsewhere explained, the regions to which the 

 drift-lakes are principally confined are near the head-waters 

 of the principle streams of the State. We consequently find 



