GEOGRAPHICAL RECONNAISSANCE ALONG THE SEVENTY-THIRD MERIDIAN BY ISAIAH BOWMAN Director of the American Geographical Society colophon PUBLISHED FOR THE AMERICAN GEOGRAPHICAL SOCIETY OF NEW YORK BY HENRY HOLT AND COMPANY 1916 Copyright, 1918 BY HENRY HOLT AND COMPANY THE QUINN & BODEN CO. PRESS RAHWAY, N.J.   TO C. G. B.  ...

T HE geographic work of the Yale Peruvian Expedition of 1911 was essentially a reconnaissance of the Peruvian Andes along the 73rd meridian. The route led from the tropical plains of the lower Urubamba southward over lofty snow-covered passes to the desert coast at Camaná. The strong climatic and topographic contrasts and the varied human life which the region contains are of geographic interest chiefly because they present so many and such clear cases of environmental control within short dista

L ET four Peruvians begin this book by telling what manner of country they live in. Their ideas are provincial and they have a fondness for exaggerated description: but, for all that, they will reveal much that is true because they will at least reveal themselves. Their opinions reflect both the spirit of the toiler on the land and the outlook of the merchant in the town in relation to geography and national problems. Their names do not matter; let them stand for the four human regions of Peru,

A MONG the scientifically unexplored regions of Peru there is no other so alluring to the geographer as the vast forested realm on the eastern border of the Andes. Thus it happened that within two weeks of our arrival at Cuzco we followed the northern trail to the great canyon of the Urubamba ( Fig. 8 ), the gateway to the eastern valleys and the lowland plains of the Amazon. It is here that the adventurous river, reënforced by hundreds of mountain-born tributaries, finally cuts its defiant way

T HE white limestone cliffs at Pongo de Mainique are a boundary between two great geographic provinces ( Fig. 17 ). Down valley are the vast river plains, drained by broad meandering rivers; up valley are the rugged spurs of the eastern Andes and their encanyoned streams ( Fig. 18 ). There are outliers of the Andes still farther toward the northeast where hangs the inevitable haze of the tropical horizon, but the country beyond them differs in no important respect from that immediately below the

T HE people of a tropical forest live under conditions not unlike those of the desert. The Sahara contains 2,000,000 persons within its borders, a density of one-half to the square mile. This is almost precisely the density of population of a tract of equivalent size in the lowland forests of South America. Like the oases groups in the desert of aridity are the scattered groups along the river margins of the forest. The desert trails run from spring to spring or along a valley floor where there

T HE lofty mountain zones of Peru, the high bordering valleys, and the belts of rolling plateau between are occupied by tribes of shepherds. In that cold, inhospitable region at the top of the country are the highest permanent habitations in the world—17,100 feet (5,210 m.)—the loftiest pastures, the greatest degree of adaptation to combined altitude and frost. It is here only a step from Greenland to Arcady. Nevertheless it is Greenland that has the people. Why do they shun Arcady? To the trave

Fig . 41—Regional diagram of the eastern aspect of the Cordillera Vilcapampa. See also 17 of which this is an enlarged section. On the northeastern border of the Peruvian Andes long mountain spurs trail down from the regions of snow to the forested plains of the Amazon. Here are the greatest contrasts in the physical and human geography of the Andean Cordillera. So striking is the fact that every serious student of Peru finds himself compelled to cross and recross this natural frontier. The thre

H UMAN character as a spontaneous development has always been a great factor in shaping historical events, but it is a striking fact that in the world of our day its influence is exerted chiefly in the lowest and highest types of humanity. The savage with his fetishes, his taboos, and his inherent childlikeness and suspicion needs only whim or a slight religious pretext to change his conduct. Likewise the really educated and the thoughtful act from motives often wholly unrelated to economic cond

T O the wayfarer from the bleak mountains the warm green valleys of the coastal desert of Peru seem like the climax of scenic beauty. The streams are intrenched from 2,000 to 4,000 feet, and the valley walls in some places drop 500 feet by sheer descents from one level to another. The cultivated fields on the valley floors look like sunken gardens and now and then one may catch the distant glint of sunlight on water. The broad white path that winds through vineyards and cotton-fields, follows th

The noble proportions of the Peruvian Andes and their position in tropical latitudes have given them climatic conditions of great diversity. Moreover, their great breadth and continuously lofty summits have distributed the various climatic types over spaces sufficiently ample to affect large and important groups of people. When we add to this the fact that the topographic types developed on a large scale are distributed at varying elevations, and that upon them depend to a large degree the chief

The data in this chapter, on the weather and climate of the Peruvian Andes, were gathered under the usual difficulties that accompany the collection of records at camps scarcely ever pitched at the same elevation or with the same exposure two days in succession. Some of them, and I may add, the best, were contributed by volunteer observers at fixed stations. The observations are not confined to the field of the Yale Peruvian Expedition of 1911, but include also observations from Professor Hiram

F ROM the west coast the great Andean Cordillera appears to have little of the regularity suggested by our relief maps. Steep and high cliffs in many places form the border of the land and obstruct the view; beyond them appear distant summits rising into the zone of clouds. Where the cliffs are absent or low, one may look across a sun-baked, yellow landscape, generally broken by irregular foothills that in turn merge into the massive outer spurs and ranges of the mountain zone. The plain is inte

T HE Western or Maritime Cordillera of Peru forms part of the great volcanic field of South America which extends from Argentina to Ecuador. On the walls of the Cotahuasi Canyon ( Fig. 131 ), there are exposed over one hundred separate lava flows piled 7,000 feet deep. They overflowed a mountainous relief, completely burying a limestone range from 2,000 to 4,000 feet high. Finally, upon the surface of the lava plateau new mountains were formed, a belt of volcanoes 5,000 feet (1,520 m.) high and

T HE culminating range of the eastern Andes is the so-called Cordillera Vilcapampa. Its numerous, sharp, snow-covered peaks are visible in every summit view from the central portion of the Andean system almost to the western border of the Amazon basin. Though the range forms a water parting nearly five hundred miles long, it is crossed in several places by large streams that flow through deep canyons bordered by precipitous cliffs. The Urubamba between Torontoy and Colpani is the finest illustra

A LONG the entire coast of Peru are upraised and dissected terraces of marine origin. They extend from sea level to 1,500 feet above it, and are best displayed north of Mollendo and in the desert south of Payta. The following discussion relates to that portion of the coast between Mollendo and Camaná. At the time of the development of the coastal terraces the land was in a state of temporary equilibrium, for the terraces were cut to a mature stage as indicated by the following facts: (1) the ter

In the preceding chapter we employed geologic facts in the determination of the age of the principal topographic forms. These facts require further discussion in connection with their closest physiographic allies if we wish to show how the topography of today originated. There are many topographic details that have a fundamental relation to structure; indeed, without a somewhat detailed knowledge of geology only the broader and more general features of the landscape can be interpreted. In this c

South America is classical ground in the study of tropical snowlines. The African mountains that reach above the snowline in the equatorial belt—Ruwenzori, Kibo, and Kenia—have only been studied recently because they are remote from the sea and surrounded by bamboo jungle and heavy tropical forest. On the other hand, many of the tropical mountains of South America lie so near the west coast as to be visible from it and have been studied for over a hundred years. From the days of Humboldt (1800)

By Kai Hendriksen, Topographer The main part of the topographical outfit consisted of (1) a 4-inch theodolite, Buff and Buff, the upper part detachable, (2) an 18 x 24 inch plane-table with Johnson tripod and micro-meteralidade. These instruments were courteously loaned the expedition by the U. S. Coast and Geodetic Survey and the U. S. Geological Survey respectively. The method of survey planned was a combination of graphic triangulation and traverse with the micro-meteralidade. All directions

A few fossil collections were gathered in order that age determinations might be made. With the following identifications I have included a few fossils (I and II) collected by W. R. Rumbold and put into my hands in 1907. The Silurian is from a Bolivian locality south of La Paz but in the great belt of shales, slates, and schists which forms one of the oldest sedimentary series in the Eastern Andes of Peru as well as Bolivia. While no fossils were found in this series in Peru the rocks are provis

A , C , E , H , J , L , M , O , P , Q , R , S , T , U , V , Y Abancay, town, lat. 12° 35′, Figs. 20 , 204 . Abra Tocate, pass, between Yavero and Urubamba valleys, leaving latter at Rosalina, (Fig. 8 ).     See also Fig. 55 . Anta, town, lat. 13° 30′, Fig. 20 . Antabamba, town, lat. 14° 20′, Figs. 20 , 204 . Aplao, town, lat. 16°, Figs. 20 , 204 . Apurimac, river, Fig. 20 . Arequipa, town, lat. 16° 30′, Fig. 66 . Arica, town, northern Chile, lat. 18° 30′. Arma, river, tributary of Apurimac, lat.