# The Incas of Peru/Chapter 13

CHAPTER XIII
THE COAST VALLEYS
The coast of Peru was a late conquest of the Incas. It contained distinct civilisations, that to the north, especially, presenting historical and philological problems as yet unsolved. Its physical aspects are unique and extremely interesting. They demand attention before considering the little that is known of the ancient people inhabiting this wonderful region in ages long past.
A strip of land, averaging a width of from 20 to 60 miles, extends from 4° to 20° S. or upwards of 1500 miles between the maritime cordillera and the Pacific Ocean. It has been upraised from the sea at no very remote period. The same shells as exist in the present ocean are mingled with the remains of man. Corn-cobs and cotton twine were found by Darwin at a height of 85 feet above the sea. This upheaval must have taken place at a time not only when man was occupying the land, but when there already existed an agricultural community raising maize and cotton crops.
The Peruvian coast is practically a rainless region, and the reason for this phenomenon attracted the attention of most of the early writers. ​Acosta is very hazy on the subject. Cieza de Leon comes nearer the true cause, which is of course due to the height of the Andes. For the south-east trade-wind blows obliquely across the Atlantic Ocean until it reaches the coast of Brazil, heavily laden with moisture. It continues to carry this moisture across the continent, depositing it as it proceeds, and filling the tributaries and sources of the Amazon and La Plata. Eventually this trade-wind reaches the snow-capped mountains of the Andes, and the last particle of moisture is wrung from it that the very low temperature can extract. Meeting with no evaporating surface and with no temperature colder than that to which it was subjected on the mountain tops, the trade wind reaches the Pacific Ocean before it again becomes charged with fresh moisture. The last drop it has to spare is deposited as snow on the tops of the mountains. It reaches the coast region as a perfectly dry wind.
Yet the coast atmosphere is not absolutely dry. There is intense heat and a clear sky from November to April, but in May the scene changes. A thin mist arises which increases in density until October, rising in the morning and dispersing at about 3 P.M. It becomes fine drizzling rain called garua. This garua extends from the seashore to near the mountains, where rain commences, the line between the garua and the rain region being distinctly marked. There are even estates where one half the land is watered by garuas, the other half by rain. But the prevailing aspect ​of the coast is a rainless desert traversed, at intervals, by fertile valleys.
The climate of the coast is modified and made warmer by another agency. Not only is the constantly prevailing wind from the south, there is also a cold current always flowing with a temperature several degrees lower than that of the surrounding ocean. It is believed by some to be derived from the Antarctic regions, by others that it is formed by cold water in the depths rising to the surface. Be this how it may, the Humboldt current, as it has been called since 1802, profoundly affects the climate of the Peruvian coast, which is cooler and drier than any other tropical region.
Although the greater part of the coast region consists of desert or of arid and stony ranges of hills, it is watered by rivers which cross the desert at intervals and form fertile valleys of varying width. The deserts between the river valleys vary in extent, the largest being upwards of seventy miles across. On their western margin steep cliffs rise from the sea, above which is the desert plateau, apparently quite bare of vegetation. The surface is generally hard, but on some of the deserts there are great accumulations of drifting sea sand. This sand forms isolated hillocks, called medanos, in the shape of a crescent, beautifully symmetrical, with sharp ridges, and their convex sides turned towards the trade-wind. Any stone or dead mule forms a nucleus for them; but they are constantly shifting, and a strong wind causes ​an immense cloud of sand, rising to a hundred feet and whirling in all directions. When at rest the medanos vary in height from eight to twenty feet, with a sharp crest, the inner side perpendicular and the outer with a steep slope. Scattered over the arid wilderness they form intricate labyrinths, and many a benighted traveller has lost his way among them and perished with his mule, after wandering for days. Such unfortunates form nuclei for new medanos. At early dawn there are musical sounds in the desert. They are caused by the eddying of grains of sand in the heated atmosphere on the sharp crests of the medanos.
Apparently the coast deserts of Peru are destitute of all vegetation. As far as the eye can reach there is a desolate waste. Yet two or three kinds of plants do exist. The smaller medanos are capped with snowy white patches, contrasting with the greyish white which is the colour of the sand. This whiteness is caused by innumerable short cylindrical spikes of an amaranth. Its stems originate in the ground beneath the medano, ramify through it, and go on growing so as to maintain their heads just above the mass of sand. The two other herbs of the desert are species of yuca which form edible roots, but maintain a subterranean existence for years, only producing leafy stems in the rare seasons when moisture penetrates to their roots. Near the foot of the mountains are the tall branched cacti. When the mists set in, the lomas, or chains of ​hillocks, near the coast undergo a complete change. As if by a stroke of magic blooming vegetation overspreads the ground, which is covered with pasture and wild flowers, chiefly compositæ and crucifers. But this only lasts for a short time. Generally the deserts present a desolate aspect, with no sign of vegetation or of a living creature. In the very loftiest regions of the air the majestic condor may perhaps be seen floating lazily, the only appearance of life.
Imagine the traveller, who has wearily toiled over many leagues of this wild and forbidding region, suddenly reaching the verge of one of the river valleys. The change is magical. He sees at his feet a broad expanse covered with perpetual verdure. Rows and clumps of palms and rows of willows show the lines of the watercourses. All round are fruit gardens, fields of maize and cotton, while woods of algaroba fringe the valley and form one of its special features.
The algaroba (Prosopis horrida) is a prickly tree rarely exceeding forty feet in height, with rugged bark and bipinnate foliage. The trunks never grow straight, soon become fairly thick, and as their roots take little hold of the friable earth, they fall over into a reclining posture, and immediately begin to send off new roots in every part of the trunk in contact with the soil. They thus assume a twisted and fantastic appearance, more like gigantic corkscrews than trees. The algaroba has racemes of small yellowish green flowers which nourish multitudes of small flies and beetles, and they in their turn supply food to flocks ​of birds, most of them songsters. The flowers are followed by pendulous pods, six to eight inches long, containing several thin seeds immersed in a mucilaginous spongy substance which is the nutritive part. The timber is very hard and durable, and also makes excellent firewood. With the algaroba there are bushes, sometimes growing into trees, of vichaya (Capparis crotonoides), a tree called zapote del perro (Colicodendrum scabridum), and an Apocynea, with bright green lanceolate leaves, and clusters of small white flowers. Near the roots of the cordillera the vegetation becomes more dense and varied.
The fertile valleys of the coast vary in extent and in the supply of water they receive. Some rivers have their sources beyond the maritime range, and the flow is abundant and perennial. Others are less well supplied. Others, with sources in the maritime cordillera, are sometimes dry, and the supply of water is precarious.
Altogether there are forty-four coast valleys along the 1400 miles of Peruvian sea-board, and, with reference to the study of the former history of the country, they may be divided into three sections. The twenty northern valleys include the territory of the Grand Chimu, whose history is still shrouded in mystery. The central twelve formed the dominions of the Chincha confederacy, ​and the southern twelve were only peopled by mitimaes in later times, though there was a scanty aboriginal fishing population.
| Valleys of the Chimu | Valleys of the Chincha confederacy | Valleys in the south |
| 1 | 1 | Tumbez | 1 | 21 | Chancay | 1 | 33 | Acari |
| 1 | 2 | Chira | 1 | 22 | Carabayllo | | 34 | Atequipa |
| 1 | 3 | Piura | 1 | 23 | Rimac | 3 | 35 | Atico Yauca |
| 1 | 4 | Motupe or Leche | 2 | 24 | Lurin | 1 | 36 | Ocoña |
| 1 | 5 | Lambayeque | 1 | 25 | Mala | 1 | 37 | Majes |
| 2 | 6 | Eten | 1 | 26 | Huarcu | | 38 | Vitor |
| 2 | 7 | Saña | 3 | 27 | Tupara | 1 | 39 | Tambopalla |
| 1 | 8 | Pacasmayu | 1 | 28 | Chincha | | 40 | Ylo |
| 1 | 9 | Chicama | 1 | 29 | Pisco | 1 | 41 | Locumba |
| 1 | 10 | Muchi | 1 | 30 | Yca | 1 | 42 | Sama |
| 2 | 11 | Viru | 1 | 31 | Rio Grande | 1 | 43 | Tacna |
| 2 | 12 | Chao | 2 | 32 | Nasca | 1 | 44 | Azapa |
| 1 | 13 | Santa |
| 2 | 14 | Nepeña |
| 1 | | Patavilca |
| 2 | 15 | Casma |
| 2 | 16 | Culebra |
| 2 | 17 | Huarmay |
| 2 | 18 | Parmunca |
| 2 | 14 | Nepeña |
| | 19 | Huaman |
| 1 | 20 | Huara |
| 2 | | Supe |
* ↑ On the island of San Lorenzo, forming the Callao anchorage.
* ↑ Von Tschudi gives the number at fifty-nine, adding fifteen to the forty-four. But he must have included ravines with watercourses almost always dry, such as Asia, the quebredas of Pescadores and Manga, Pisagua, Tacama, Mexillones, and Loa; as well as branches of main rivers, such as Macara, Quiros and Somata, tribu- taries of the Chira; Cinto and Tuquene, Ingenio, Palpa, and Chimpa, tributaries of the Rio Grande. These, with the forty-four irrigated valleys, would make fifty-nine. Von Tschudi does not give the names. 1 Sources within the region of regular annual rains. 2 Rivers with affluents within the rain region. 3 Sources outside the regular rains.