Part 17

_Boundaries._--The boundary line between Bolivia and Brazil has its origin in the limits between the Spanish and Portuguese colonies determined by the treaties of Madrid and San Ildefonso (1750 and 1777), which were modified by the treaties of 1867 and 1903. Beginning at the outlet of Bahia Negra into the Paraguay river, lat. 28 deg. 08' 35" S., the line ascends the latter to a point on the west bank 9 kilometres below Fort Coimbra, thence inland 4 kilometres to a point in lat. 19 deg. 45' 36" S. and long. 58 deg. 04' 12.7" W., whence it follows an irregular course N. and E. of N. to Lakes Mandiore, Gaiba or Gahiba, and Uberaba, then up the San Matias river and N. along the Sierra Ricardo Franco to the headwaters of the Rio Verde, a tributary of the Guapore. This part of the boundary was turned inland from the Paraguay to include, within Brazilian jurisdiction, Fort Coimbra, Corumba and other settlements on the west bank, and was modified in 1903 by the recession of about 1158 sq. m. to Bolivia to provide better commercial facilities on the Paraguay. The line follows the Verde, Guapore, Mamore and Madeira rivers down to the mouth of the Abuna, in about lat. 9 deg. 44' S., as determined by the treaty of 1903. This is a part of the original colonial frontier, which extended down the Madeira to a point midway between the Beni and the Amazon, and then ran due W. to the Javary. The treaty of 1867 changed this starting-point to the mouth of the Beni, in lat. 10 deg. 20' S., and designated a straight line to the source of the Javary as the frontier, which gave to Brazil a large area of territory; but when the valuable rubber forests of the upper Purus became known the Brazilians invaded them and demanded another modification of the boundary line. This was finally settled in 1903 by the treaty of Petropolis, which provided that the line should ascend the Abuna river to lat. 10 deg. 20' S., thence along that parallel W. to the Rapirran river which is followed to its principal source, thence due W. to the Ituxy river which is followed W. to its source, thence to the source of Bahia Creek which is followed to the Acre or Aquiry river, thence up the latter to its source, whence if east of the 69th meridian it runs direct to the 11th parallel which will form the boundary line to the Peruvian frontier. This frontier gave about 60,000 sq. m. of territory to Brazil, for which the latter gave an indemnity of L2,000,000 and about 1158 sq. m. of territory on the Matto Grosso frontier. The boundary with Paraguay is unsettled, but an unratified treaty of the 23rd of November 1894 provides that the line shall start from a point on the Paraguay river 3 m. north of Fort Olimpo and run south-west in a straight line to an intersection with the Pilcomayo in long. 61 deg. 28' W., where it unites with the Argentine boundary. The boundary with Chile was greatly modified by the results of the war of 1879-83, as determined by the treaties of 1884, 1886 and 1895, Bolivia losing her department of the littoral on the Pacific and all access to the coast except by the grace of the conqueror. Provisions were made in 1895 for the cession of the port of Mejillones del Norte and a right of way across the province of Tarapaca, but Peru protested, and negotiations followed for the cession of Cobija, in the province of Antofagasta. These negotiations proved fruitless, and in 1904 Bolivia accepted a pecuniary indemnity in lieu of territory. The new boundary line starts from the summit of the Sapaleri (or Zapalegui), where the Argentine, Bolivian and Chilean boundaries converge, and runs west to Licancaur, thence north to the most southern source of Lake Ascotan which it follows to and across this lake in the direction of the Oyahua volcano, and thence in a straight line to the Tua volcano, on the frontier of the province of Tarapaca. From this point the line follows the summits of the Cordillera Silillica north to the Cerro Paquiza, on the Tacna frontier, and to the Nevado Pomarape, near the frontier of Peru. Thence it continues north to an intersection with the Desaguadero, in about 16 deg. 45' S. lat., follows that river to the Winamarca lagoon and Lake Titicaca, and crosses the latter diagonally to Huaicho on the north shore. From this point the line crosses the Cordillera Real through the valley of the San Juan del Oro to Suches Lake, follows the Cololo and Apolobamba ranges to the headwaters of the Sina river, and thence down that stream to the Inambari. Thence the line either follows the latter to its confluence with the Madre de Dios, or the water-parting between that river and the Tambopata or Pando, to the valley of the Madre de Dios, from which point it runs due north to 12 deg. 40' S. lat., and north-west to the new Brazilian frontier. The N.W. angle on the map represents the Bolivian claim until the settlement of 1909, which gave the territory to Peru.

[Illustration: Map of Bolivia]

_Physiography._--Roughly calculated, two-fifths of the total area of Bolivia is comprised within the Andean cordilleras which cross its south-west corner and project east toward the Brazilian highlands in the form of a great obtuse angle. The Cordilleras, divided into two great parallel chains, with flanking ranges and spurs to the east, reach their greatest breadth at this point and form the _massif_ of the Andean system. It is made up of a number of parallel ranges enclosing great elevated plateaus broken by transverse ranges and deep ravines. North-east of Lake Titicaca there is a confused mass or knot (the Nudo de Apolobamba) of lofty intersecting ridges which include some of the highest peaks in South America. Below this mountainous area the ranges open out and enclose extensive plateaus. The western range, the Cordillera Occidental, a part of the boundary between Bolivia and the northern provinces of Chile, closely follows the coast outline and forms the western rampart of the great Bolivian tableland or _alta-planicie_, which extends from the Vilcanota knot in Peru, south to the Serrania de Lipez on the Argentine frontier, is 500 m. long, and about 80 m. broad, and contains about 40,000 sq. m. The northern part of this plateau is commonly called the _puna_; the southern part, the "desert of Lipez," in character and appearance is part of the great Puna de Atacama. This plateau has an average elevation of about 12,650 ft. near Lake Titicaca, but descends about 1000 ft. toward its southern extremity. It is a great lacustrine basin where once existed an inland sea having an outlet to the east through the La Paz gorge. The plateau is bleak and inhospitable in the north, barren and arid toward the south, containing great saline depressions covered with water in the rainy season, and broken by ridges and peaks, the highest being the Cerro de Tahua, 17,454 ft. Overlooking the plateau from the west are the snow-clad peaks of Pomarape (20,505 ft.), Parinacota (20,918 ft.), Sajama (21,047), Huallatiri (21,654), Lirima (19,128), and the three volcanic peaks, Oyahua (19,226), San Pedro y Pablo (19,423) and Licancaur (19,685). The eastern rampart of this great plateau is formed by the Cordillera Oriental, which extends north-west into Peru under the name of Carabaya, and south to the frontier in broken ranges, one of which trends south-east in the vicinity of Sucre. The main part of this great range, known as the Cordillera Real, and one of the most imposing mountain masses of the world, extends from the Peruvian border south-east to the 18th parallel and exhibits a series of snow-crowned peaks, notably the triple-crested Illampu or Sorata (21,490 ft.), Illimani (Conway, 21,204), Cacaaca (20,571) and Chachacomani (21,434). Of the ranges extending south from the Cordillera Real and branching out between the 18th and 19th parallels, the more prominent are the Frailes which forms the eastern rampart of the great central plateau and which is celebrated for its mineral deposits, the Chichas which runs south from the vicinity of Potosi to the Argentine frontier, and the Livichuco which turns south-east and forms the watershed between the Cachimayo and Pilcomayo. The more prominent peaks in and between these ranges are the Asanaque (16,857), Michaga (17,389), Cuzco (17,930), Potosi (15,381), Chorolque (18,480) and Tuluma (15,584). At the southern extremity of the great plateau is the transverse Serrania de Lipez, the culminating crest of which stands 16,404 ft. above sea-level. The eastern rampart of the Bolivian highlands comprises two distinct chains--the Sierra de Cochabamba on the north-east and the Sierra de Misiones on the east. Between these and the Cordillera Oriental is an apparently confused mass of broken, intersecting ranges, which on closer examination are found to conform more or less closely to the two outside ranges. These have been deeply cut by rivers, especially on the north-east, where the rainfall is heavier. The region enclosed by these ranges is extremely rugged in character, but it is esteemed highly for its fertile valleys and its fine climate, and is called the "Bolivian Switzerland." Lying wholly within the tropics, these mountain masses form one of the most interesting as well as one of the most imposing and difficult regions of the world. At their feet and in their lower valleys the heat is intense and the vegetation is tropical. Above these are cool, temperate slopes and valleys, and high above these, bleak, wind-swept passes and snow-clad peaks. West of the Cordillera Oriental, where special conditions prevail, a great desert plateau stretches entirely across one corner of the republic. Apart from the Andean system there is a group of low, broken, gneiss ranges stretching along the east side of Bolivia among the upper affluents of the Mamore and Guapore, which appear to belong to the older Brazilian orographic system, from which they have been separated by the erosive action of water. They are known as the Sierras de Chiquitos, and are geologically interesting because of their proximity to the eastern projection of the Andes. Their culminating point is Cerro Cochii, 3894 ft. above sea-level, but for the most part they are but little more than ranges of low wooded hills, having in general a north-west and south-east direction between the 15th and 19th parallels.

The popular conception of Bolivia is that of an extremely rugged mountainous country, although fully three-fifths of it, including the Chiquitos region, is composed of low alluvial plains, great swamps and flooded bottomlands, and gently undulating forest regions. In the extreme south are the Bolivian Chaco and the llanos (open grassy plains) of Manzo, while above these in eastern Chuquisaca and southern Santa Cruz are extensive swamps and low-lying plains, subject to periodical inundations and of little value for agricultural and pastoral purposes. There are considerable areas in this part of Bolivia, however, which lie above the floods and afford rich grazing lands. The great drawback to this region is defective drainage; the streams have too sluggish a current to carry off the water in the rainy season. Between the Chiquitos sierras and the Andes are the Llanos de Chiquitos, which have a higher general elevation and a more diversified surface. North of this elevation, which formed the southern shore of the ancient Mojos Lake, are the llanos of Guarayos and Mojos, occupying an extensive region traversed by the Guapore, San Miguel, Guapay, Mamore, Yacuma, Beni and Madre de Dios rivers and their numerous tributaries. It was once covered by the great Mojos Lake, and still contains large undrained areas, like that of Lake Rojoagua (or Roguaguado). It contains rich agricultural districts and extensive open plains where cattle-raising has been successfully followed since the days of the Jesuit missions in that region. The lower slopes of the Andes, especially toward the north-west, where the country is traversed by the Beni and Madre de Dios, are covered with heavy forests. This is one of the richest districts of Bolivia and is capable of sustaining a large population.

The river-systems of Bolivia fall naturally into three distinct regions--the Amazon, La Plata and Central Plateau. The first includes the rivers flowing directly and indirectly into the Madeira, one of the great tributaries of the Amazon, together with some small tributaries of the Acre and Purus in the north, all of which form a drainage basin covering more than one-half of the republic. The two principal rivers of this system are the Mamore and Beni, which unite in lat. 10 deg. 20' S. to form the Madeira. The Mamore, the upper part of which is called the Chimore, rises on the north-east slopes of the Sierra de Cochabamba a little south of the 17th parallel, and follows a northerly serpentine course to its confluence with the Beni, the greater part of which course is between the 65th and 66th meridians. The river has a length of about 600 m., fully three-fourths of which, from Chimore (925 ft. above sea level) to the rapids near its mouth, passes across a level plain and is navigable. The principal Bolivian tributary of the Mamore, the Guapay or Grande, which is larger and longer than the former above their confluence and should be considered the main stream, rises in the Cordillera Oriental east of Lake Pampa Aullaguas, and flows east to the north extremity of the Sierra de Misiones, where it emerges upon the Bolivian lowlands. Turning to the north in a magnificent curve, it passes around the south-east extremity of the Sierra de Cochabamba, skirts the Llanos de Chiquitos, and, turning to the north-west, unites with the Mamore at Junta de los Rios in about 15 deg. 20' S. lat. and 64 deg. 40' W. long. It has a tortuous course of over 700 m., which is described as not navigable. The principal tributaries of the Guapay are the Mizque, Piray or Sara and Yapacani, the last rising on the east slopes of the Cordillera Real, flowing east by Cochabamba to the sierras of that name where it breaks through with a great bend to the north. The other large Bolivian tributaries of the Mamore, all rising on the north-east flanks of the Andes, are the Chapare, Secure, Manique or Apere and Yacuma, the last draining a region of lakes and swamps north of the Sierra Chamaya. The Beni and its great affluent, the Madre de Dios, though of smaller volume and extent than the Mamore, are of much greater economic importance, owing to their navigability, the fertility of the region they drain, and the great forests along their banks. North of the Beni, the Abuna flows into the Madeira. Several of its south tributaries belong to Bolivia. The Guapore, or Itenez, an affluent of the Mamore, is the third large river of this Bolivian drainage basin, but it rises in Brazil, on the south slopes of the Sierra dos Parecis, where it flows in a great bend to the south and then west of north to the Bolivian frontier in 14 deg. S. lat. From this point to its junction with the Mamore, a little north of the 12th parallel, it flows in a northwesterly direction and forms the boundary line between the two republics. Its Brazilian tributaries are comparatively unimportant, but from Bolivia it receives the Baures and the San Miguel, both rising in the Sierras de Chiquitos and flowing north-west across the llanos to the Guapore. The Baures has one large tributary, the Blanco, and the Itonama (San Miguel) has its origin in Lake Conception, lying among the west ranges of the Chiquitos mountains 952 ft. above sea-level.

The south-east drainage basin, which is smaller and economically less important than that of the Madeira, discharges into the Paraguay and extends from the Sierras de Chiquitos south to the Argentine frontier, and from the Cordillera Oriental east to the Paraguay. It possesses only one large river in Bolivia, the Pilcomayo, which rises on the east slopes of the Cordillera Oriental opposite the south end of Lake Pampa Aullaguas and flows east and south-east through the sierra region to the Bolivian Chaco. It flows through a nearly level country with so sluggish a current that its channels are greatly obstructed. Nothing definite is known of its tributaries in the Chaco, but in the sierra region it possesses a number of small tributaries, the largest of which are the Cachimayo, Mataca and Pilaya or Camblaya, the latter formed by the Cotagaita and San Juan. The Bermejo, which is an Argentine river, receives one large tributary from the Bolivian uplands, the Tarija or Rio Grande, which drains a small district south-east of the Santa Victoria sierra. The Bolivian tributaries of the upper Paraguay are small and unimportant. The Otuquis, the most southern of the group, is formed by the San Rafael and Tucabaca, which drain both slopes of the Cerro Cochii range; but is lost in some great marshes 50 m. from the Paraguay. Another considerable stream of this region, which is lost in the great marshy districts of the Bolivian plain, is the Parapiti, which rises on the eastern slopes of the Sierra de Misiones and flows north-east through a low plain for about 150 m. until lost.

The third drainage basin is that of the great central plateau, or _alta-planicie_. This is one of the most elevated lacustrine basins in the world, and though it once drained eastward, now has no surface outlet. Lake Titicaca receives the waters of several short streams from the neighbouring heights and discharges through the Desaguadero, a sluggish river flowing south for 184 m. with a gradually diminishing depth to Lake Pampa Aullaguas or Poopo. The Desaguadero is navigable for small craft, and has two or three small tributaries from the west. Two small streams empty into Lake Pampa Aullaguas, which has a small outlet in the Lacahahuira flowing west for 60 m. to the Cienegas de (salt-swamps of) Coipasa. The drainage of this extensive district seems to be wholly absorbed by the dry soil of the desert and by evaporation. In the extreme south the Rio Grande de Lipez is absorbed in the same way.

Few of the Bolivian lakes are at all well known. The great lacustrine basin between the Beni and the Mamore contains several lakes and lagoons, two of them of large size. These are Lake Rogagua whose waters find their way into the Beni through Rio Negro, and the Roguaguado lagoon and marshes which cover a large area of territory near the Mamore. The latter has an elevation little, if any, above the level of the Mamore, which apparently drains this region, and its area has been estimated at about 580 sq. m. Lake Conception, in the Chiquitos mountains, belongs to this same hydrographic area. In the south-east there are several large shallow lakes whose character and size change with the season. They fill slight depressions and are caused by defective drainage. Near the Paraguay there are several of these lakes,

## partly caused by obstructed outlets, such as Bahia Negra, Caceres,

Mandiore, Gaiba and Uberaba, some of them of sufficient depth to be navigable by small craft. Above the latter are the great Xarayes swamps, sometimes described as a lake. This region, like that of the north, is subject to periodical inundations in the summer months (November-March or even May), when extensive areas of level country are flooded and traffic is possible only by the use of boats. The two principal lakes of the plateau region are Titicaca and Pampa Aullaguas or Poopo. The former lies near the north end of the great Bolivian _alta-planicie_, 12,644 ft. above sea-level, being one of the most elevated lakes of the world. It is indented with numerous bays and coves; its greatest length is 138 m., and its greatest breadth 69 m. According to a survey made by Dr M. Neveau-Lemaire (_La Geographie_, ix. p. 409, Paris, 1904), its water surface, excluding islands and peninsulas, is 1969 sq. m., and its greatest depth is 892 ft. The level of the lake rises about 5 in. in summer; the loss in winter is even greater. The lake belongs to both Bolivia and Peru, and is navigated by steamers running between Bolivian ports and the Peruvian railway port of Puno. The outlet of the lake is through the Desaguadero river. It has several islands, the largest of which bears the same name and contains highly interesting archaeological monuments of a prehistoric civilization usually attributed to the Incas. Lake Pampa Aullaguas or Poopo is about 180 m. south-east of Titicaca, and is fed principally by its outflow. It lies 505 ft. below the level of Titicaca, which gives an average fall for the Desaguadero of very nearly 21 ft. per mile. The Pampa Aullaguas has an estimated area of 386 sq. m., and has one large inhabited island. The lake is shallow and the district about it is sparsely populated. Its outlet is through the Lacahahuira river into the Coipasa swamp, and it is estimated that the outflow is much less than the inflow, showing a considerable loss by evaporation and earth absorption.

Having no sea-coast, Bolivia has no seaport except what may be granted in usufruct by Chile.

_Geology._--The eastern ranges of ihe Bolivian Andes are formed of Palaeozoic rocks with granitic and other intrusions; the Western Cordillera consists chiefly of Jurassic and Cretaceous beds, together with the lavas and ashes of the great volcanoes; while the intervening plateau is covered by freshwater and terrestrial deposits through which rise ridges of Palaeozoic rock and of a series of red sandstones and gypsiferous marls of somewhat uncertain age (probably, in part at least, Cretaceous). The Palaeozoic beds have yielded fossils of Cambrian, Ordovician, Devonian and Carboniferous age. In southern Bolivia Cambrian and Ordovician beds form the greater part of the eastern Andes, but farther north the Devonian and Carboniferous are extensively developed, especially in the north-eastern ranges. The hills, known as the Chiquitos, which rise from the plains of eastern Bolivia, are composed of ancient sedimentary rocks of unknown age. The Palaeozoic beds are directly overlaid by a series of red sandstones and gypsiferous marls, similar to the _formacion petrolifera_ of Argentina and Brazil. At the base there is frequently a conglomerate or tuff of porphyritic rocks. Marine fossils found by Gustav Steinmann in the middle of the series are said to indicate an age not earlier than the Jurassic, and Steinmann refers them to the Lower Cretaceous. It is, however, not improbable that the series may represent more than one geological system. No later marine deposits have been found either in the eastern Andes or in the plains of Bolivia, but freshwater beds of Tertiary and later date occupy a wide area. The recent deposits, which cover so large a part of the depression between the Eastern and the Western Cordillera, appear to be partly of torrential origin, like the talus-fans at the foot of mountain ranges in other dry regions; but Lakes Titicaca and Pampa Aullaguas (Poopo) were undoubtedly at one time rather more extensive than they are to-day. The volcanoes of Bolivia lie almost entirely in the Western Cordillera--the great summits of the eastern range, such as Illimani and Sorata, being formed of Palaeozoic rocks with granitic and other intrusions. The gold, silver and tin of Bolivia occur chiefly in the Palaeozoic rocks of the eastern ranges. The copper belongs mostly to the red sandstone series.