386 



AMAZONIA AND LA PLATA. 



active during- tLe pliocene epoch, towards tlie close of the glacial period. Along 

 the coast the prevailing formations are trachj^tes and tuffas. In its eastern section 

 Port Deseado is accessible to vessels of heavy draught, and at high water — 16 to 

 20 feet — ships of average size are able to penetrate to the head of the inlet. 

 But the navigation is impeded by the strong currents and by the adverse winds, 

 which prevail especially in the winter months. 



Two other small watercourses, which also appear to traverse the Patagonian 

 plains in parallel valleys, have been differently named by different explorers. 



Fig. 157. — Lake Argentino accoeding to Moeeno. 

 Scale 1 ; 2.000.000. 



49 



50" 



:^':' 



•^//' 



^ Ï 



X^ 



^^wi 



7^' 



f(«y 



4 V«S»-- 



X 4 \x 



'^/mi^ 



Indo 



Afo/7tanâLi 



49' 



vVeol cF breenwich 72° 



== 30 Miles. 



But the term Salado, applied to the southern stream, shows that it is not copious 

 enough to maintain its current fresh — at least, in its lower course. 



Farther south follows the Santa Cruz, Avhich is relatively a copious river, 

 thanks to the wide extent of its upper basin, and to the heavier rainfall in this 

 contracted part of South Patagonia. About its head affluents four considerable 

 lakes stretch along the eastern foot of the Andes, a distance of about 120 miles. 



