The river Tunuyan rises from the base of the mighty mountain of Tupungato, and at first runs south through a wide and rich valley in the Cordillera; passing eastward of the volcano of Maypú, or Peuquenes, it afterwards finds its way through the eastern chain of the Andes by a deep chasm or opening, which it seems to have burst for itself through the mountains seven or eight miles below the Portillo Pass, and nearly opposite to where the Maypú leaves the Cordillera on the western side: thence its course through the plains is north, and afterwards eastward, in the direction of the great lake Bevedero, as already stated.
It would seem as though Nature herself had expressly directed the course of these rivers, viz., the Mendoza, Desaguadero, and Tunuyan, in such a way as to facilitate to the inhabitants the means of artificially irrigating their lands, which, from the quality of the soil, and the rarity of rain, would be otherwise barren and unproductive[72]:--as it is, the quantity of lands artificially watered by ducts from the rivers Mendoza and Tunuyan is estimated at about 30,000 square leagues, and these lands, which are arid and barren when not so watered, become, under regular irrigation, uncommonly rich and fertile, yielding frequently, under a very rude and simple mode of agriculture, more than a hundred-fold. Wheat, barley, and maiz are thus grown; besides which there are extensive vineyards and orchards, and grounds covered with lucern grass for the fattening of cattle,--all regularly enclosed, and walled in with thick mud walls, called _tapiales_.
The products of the province are wine, brandy, raisins, figs, wheat, flour, hides, tallow, and soap, which last is made from a species of barilla, which abounds in most parts of it:--a considerable portion of these is exported to Chile and to the provinces of Cordova, San Luis, and Buenos Ayres. The quantities so disposed of will be best understood by the following official return of the exports for a single year:--
Account of Exports of Produce of Mendoza for other parts during the year 1827.
+------------+------------+------------+------+-------+------+------+-------+ | | | |Corn | [73] | | | | | | | |and | Dried |Hides.|Soap. |Tallow.| | Where sent.| Brandy. | Wine. |Flour.|Fruits.| | | | | +-----+------+-----+------+------+-------+------+------+-------+ | |Pipes.Loads.|Pipes.Loads.|Loads.|Loads. | No. |Loads.|Loads. | +------------+-----+------+-----+------+------+-------+------+------+-------| |Buenos Ayres| 336 | 2144 | 290| 3120 | 1098 | 520 | 670 | -- | -- | |San Luis | -- | 70 | -- | 488 | 1634 | 85 | -- | 60 | -- | |Cordova | -- | 95 | -- | 355 | 125 | 49 | -- | -- | -- | |Santa Fé | -- | 81 | -- | 172 | 469 | 39 | -- | -- | -- | |Chile | -- | 12 | -- | -- | -- | -- | 8700 | 571 | 88 | +------------+-----+------+-----+------+------+-------+------+------+-------+ | | 336 | 2402 | 290| 4135 | 4452 | 693 | 9370 | 631 | 88 | +------------+-----+------+-----+------+------+-------+------+------+-------+