156 DISCOVERY REPORTS 



upwelling would be brought into being either by a counter-current or an eddy, the 

 existence of which is rendered Ukely by the evidence of set and drift which was erratic 

 in this neighbourhood, a current of 24 miles a day setting directly towards the shore 

 (north-east by north) between Sts. WS 689 and 690. The influence of these conditions 

 on the fauna and flora are discussed on p. 220, the possible influence of the rocks 

 on upwelling on pp. 205 and 207. 



Although pronounced upwelling brought cold water to the surface within 1 5 miles of 

 Punta Aguja, yet over the next 189 miles the temperature rose no more than 2-2° C. 

 Thus immense breadth is a conspicuous feature of the northern part of the Peru Coastal 

 Current. The warm-water wedge seems to be recognizable though relatively less warm ; 

 its western margin (the isotherm of 20° C.) ragged, irregular, and ill-defined off Punta 

 Aguja leaves the area investigated. The eastern, shoreward margin of the wedge, 

 swerving outwards from the shore, is found at a distance of 50 miles off the Guafiape 

 Islands, 140 miles off the Lobos Islands and 180 miles off Punta Aguja (Fig. 16). 



5-2° S: CAPO BLANCO AND SANTA ELENA 



Here the current leaves the coast on its entry into the tract leading to the westerly 

 flowing South Equatorial Current. We are concerned with its point of convergence 

 with the warm waters off Ecuador. Although the hydrology of the complex region 

 outside the Peru Current is beyond this enquiry, the following notes derived from Schott's 

 valuable paper (1931) will assist in the interpretation of conditions near the coast. 



Cool water of moderately high salinity ( >35 %o) is brought into the region from the 

 south by a chain of processes constituting the Peru Coastal Current, and it is drawn off 

 to the westward in the wake of the South Equatorial Current. North of this the 

 Equatorial Counter-current flows eastwards in the opposite direction, and brings warm 

 water of low salinity (< 33 °/oo) irito the region from the west. The characteristics of 

 these two currents are very different, and the coasts adjoining them differ from one 

 another correspondingly. The warm counter-current, whose salinity has been lowered 

 by tropical showers, flows against Ecuador, and the country has luxuriant forests 

 drenched by rains. The Peru Current has acquired its higher salinity through the 

 drying action of the south-east trades and the Peruvian coast along which they blow 

 is a desert region. Similarly the Cocos Islands in the path of the counter-current have 

 tropical scenery, whereas the Galapagos Islands in the South Equatorial Current has a 

 much more scanty vegetation.^ But it is not clear from Schott's account whether the 

 relation of current to climate in the one is the same as that in the other. In the first 



1 The appearance of the Galapagos vegetation varies. Darwin (1845) remarks that "Nothing could be 

 less inviting than the first appearance. A broken field of black basaltic lava thrown into the most rugged 

 waves, and crossed by great fissures, is everywhere covered by a stunted sunburnt brushwood which shows 

 little signs of life." Agassiz (1891), on the other hand, writes: "Arriving as we did at the Galapagos at the 

 beginning of a remarkably early rainy season, I could not help contrasting the green appearance of the slopes 

 of the islands, covered as they were by a comparatively thick growth of bushes, shrubs, and trees, with the 

 description given of them by Darwin who represents them in the height of the dry season as the supreme 

 expression of desolation and barrenness." The climate of the islands must depend upon the position of the 

 convergence between the counter-current and the South Equatorial Current. 



