238 PRINCIPLES OF STRATIGRAPHY 



coast by the southeast trades, as the South Equatorial current, and 

 in part becomes a compensating current to replace the eastward- 

 flowing waters of the great South Pacific West-wind drift. This 

 finally turns northward as the Peruvian current, with an average 

 velocity of 15 nautical miles per day, which velocity is greatly 

 increased as it nears and finally joins the South Equatorial stream, 

 which has the eiTect of an aspirator. Cold waters well up between 

 the Peruvian current and the South American coast, and these were 

 formerly regarded as Antarctic waters flowing northward. 



The Equatorial Counter current crosses the entire Pacific from 

 west to east, being especially strong during the northern summer, 

 when it occupies the zone between 5° and 10° north latitude, 

 though in winter it shrinks to a narrow band between 5° and 7°. 

 With the varying season the strength of the current fluctuates. 

 Thus in winter it is from 5 to 8 nautical miles per day, while in 

 summer it rises to 9 or 12 nautical miles. 



The Indian Ocean. The currents of this ocean are subject to 

 semiannual variation induced by the alternate dominance of the 

 winter or summer monsoons. During the winter or northeast mon- 

 soons the currents correspond in a measure to those of the Atlantic 

 and Pacific. Two westward-flowing currents separated by an east- 

 ward-flowing counter current occur. The South Equatorial is the 

 most pronounced, its boundaries being between 10° and 2y° south 

 latitude, while the counter current lies between 2° and 5° south 

 latitude. This latter has a strength of 20 to 60 nautical miles per 

 day. During the northern summer, when the southwest monsoon 

 prevails, the southern westward-flowing current is broadened to 

 near 5° south latitude, the counter current as such has disap- 

 peared, while the movement of the waters north of the equator is 

 eastward. 



Against Madagascar the impinging South Equatorial current 

 divides, a large part passing southward as the Mozambique cur- 

 rent, and later becoming the Agulhas stream, which bathes the coast 

 of Cape Colony in South Africa outside of the continental shelf, 

 where velocities ranging from 50 to no nautical miles per day 

 have been noted. South of the Cape of Good Hope the Agulhas 

 current meets the southern continuation of the cold West-wind drift 

 of the South Atlantic, which causes it to splinter into numerous 

 fingers, the spaces between which are taken by the cold fingers of 

 the eastward-flowing stream. In addition to carrying ofif the waters 

 of the South Equatorial current, the Agulhas stream further acts in 

 a compensatory manner to supply the water carried eastward by 

 the strong west winds of the southern latitudes. This south Indian 



