TRANSACTIONS OF SECTION E. Giil 



changes, of which I shall treat, have profoundly modified this section of the 

 Argentine Republic, and reduced the volume of its waters. 



I am indebted to several of the Argentine railway companies for sections of 

 their lines, made from instrumental surveys. From these, and from other sources, 

 including a carefully prepared table of altitudes by the Argentine engineer, 

 A. Schneidewind, I have had plotted the sections which accompany this Address. 



Sections of the Coimtry. — Section 1 shows a part of the coast line of the 

 Southern Railway. It is practically a cross section of the east coast of the 

 province of Buenos Ayres from north to south, where tlie lowest part of 

 the Pampean beds slope into the ocean. It passes also near the head of Sam- 

 borombon Bay, which was once a great muddy estuary extending far inland, and 

 the home of countless myriads of small crabs. The land slope of this bay so 

 gradually merges into the ocean that, at a little distance, it is difficult to tell 

 where the shore line meets the water. Century by century, it now slowly 

 advances seaward. 



Section 2, from Buenos Ayres to Rosario and Tucuman, shows with what 

 regularity the country rises, from south-east to north-west, up to the outlying 

 foothills of the Andes. 



Section 3 is the first 350 kilometres of the Neuquen extension of the Southern 

 Railway, and shows in part the relation of the Colorado to the Rio Negro. 



Section 4 is the Buenos Ayres and Pacific Railway to Villa Mercedes, and 

 thence to Mendoza by the Argentine Great Western. Here we have a line almost 

 on a parallel of latitude nearly to the frontier of Chile. Again we note the 

 regular slope of the Pampa westward, until the country begins to swell into the 

 Cordova sierra. Thence to Mendoza it is broken. 



Section 5 shows the Bahia Blanca and North- Western Railway, as far as Toay, 

 and thence its proposed extension to Villa Mercedes. It traverses a district 

 the southern half of which has apparently been much troubled in former times by 

 water, wind, and .sand. From Victoria to Villa Mercedes the country assumes 

 a more uniform slope, but beyond that, to the north, it rapidly rises into the 

 barren mountainous districts of San Luis and Western Cordova. 



Section 6 is the Central Argentine Railway, Rosario to Cordova. This is of 

 interest as showing how far the uplifting of the Cordova range extended east, 

 and nearly divided the Pampean Sea into a great northern and southern section. 

 In fact, this railway is the southern border of a belt of rounded-up country, 

 extending from the Cordova sierra to within thirty to forty miles of the river 

 Parana. 



Section 7 is from Bahia Blanca north to Villa Maria (say 482 miles), thence 

 to Cordova by the Central Argentine line, thence to Tucuman by the Central 

 Northern section of the Cordova Central Railway, and thence to Jujuy by the 

 Government Railway — a total length, nearly south to north, of, say, 1,127 miles. 

 This section presents some notable features : between Bahia Blanca and Carhue it 

 crosses the extreme western slope of the Curamalal sierra; thence to Villa Maria 

 it shows an almost level .stretch of Pampa. the lowest part of which, near Trenque 

 Lauquen, is only about 300 feet above sea-level. This depression is on the parallel 

 of Samborombon Bay, down to which it gradually slopes in a distance of 300 

 miles. From Villa Maria to Dean Funes the line ascends the Cordova Mountains, 

 a marked feature of which is their bold western escarpment, overlooking the pro- 

 found hollow which separates them from the south-eastern spur of the Catamarca 

 sierras. In this depression lies the Salina Grande. From Tucuman to Jujuy, 

 near the Bolivian frontier, the country rises rapidly towards that mountain bastion 

 which is thrown so far east from the Pacific Ocean, and which is the true heart of 

 the Andes. During a ride from Jujuy to Potosil could not avoid being impres.sed 

 with this mighty swelling up of the continent ; and on several occasions, espe- 

 cially looking eastward, I was convinced that I could see the curvature of oiu' 

 globe. 



Section 8 is the Buenos Ayres Western Railway. It stretches south-west 

 across the heart of the true Pampean plain. Tbe regularity of its gentle slope is 

 remarkable. 



3 2 



