RIVERS 129 



Classification of Cotitincntal Seas or Lakes. 



A. Saline (without effluent). 



1. Deep, with pelagic, littoral, and abyssal zones. (Cas- 



pian, Dead Sea.) 



2. Shallow, with pelagic and littoral zones. (Aral, Great 



Salt Lake.) 



B. Alkaline (without effluent). 



1 . Deep. 



2. Shallow, with pelagic and littoral zones. (Albert and 



Summer Lakes, Oregon; Mono Lake, California, etc.) 



C. Fresh. 



1. Without effluent or with only temporary one. 



a. Deep, with pelagic, littoral, and abyssal zones. 



(Tanganyika.) 



b. Shallow, with pelagic and littoral zones. (Eifeler 



Maare ; Silver Lake, Oregon ; Eagle Lake, 

 California; many ponds.) 



2. With effluent. 



a. Deep, with pelagic, littoral, and abyssal zones. 



(Lake Superior, Lake Nyassa, Lake Geneva, 

 Lake Baikal.) 



b. Shallow, with j)elagic and littoral zones. (Lake 



Erie ; most of the fresh water lakes of the 

 world.) 



IV. Rivers. 



In the genetic classification of rivers we must recognize at the 

 outset that we are dealing with two distinct things, the rivers them- 

 selves and their drainage basins. Either may be simple or compli- 

 cated. A simple type of river may be conceived of as existing in 

 a complicated drainage basin (see antecedent, superimposed con- 

 sequents, and consequents on a peneplain surface) ; or the reverse 

 may be conceived of, a complicated (polygene) river existing in a 

 drainage basin of simple structure, as on a coastal plain. Consid- 

 ering rivers alone, we may class them with reference to their 

 development as simple or monogene and complicated or polygene; 

 and with reference to their relation to the structure of the region 

 as antecedent, or existing before the structure, and postcedent, 

 coming into existence after the structure. Most rivers belong to 

 the latter class. Rivers generally, by growth, capture and the acci- 



