habited the coast on the South Sea, they added, and possessed great quantities of gold, both in the raw material and in ornaments." Again: "The cazique (of the Tutepecs) soon after arrived with a valuable present in gold, which he repeated almost every day, and provided the troops with abundance of provisions. When Alvarado found what a quantity of gold the inhabitants possessed, he ordered him to make him a pair of stirrups of the finest gold, and gave them a couple of his own for a pattern; and indeed those they made turned out very good."

The same writer, in describing the expedition of Alvarado to this province in the following year, says: "From this place he marched to the large township of Tecuantepec, which is inhabited by a tribe of the Tzapotecs, where he met with the kindest reception, and was presented with some gold dust."

Clavigero, in his history of Mexico, speaking of the abundance of the precious metals in this country, says: "The Mexicans found gold in the countries of the Cohuixcas, the Mixtecas, Zapotecos, and in several others. They gathered this precious metal chiefly in grains amongst the sands of the rivers, and the abovementioned people paid a certain quantity in tribute to the crown of Spain."

The auriferous localities of California are in the alluvial sands and clays, whether they be silicious, aluminous, or basaltic; in granite and primary quartz, and lastly in talcose slate. Although the Sierras of Mexico are a more easterly range, yet their geological constitution is similar to that of California ; and it is also on the eastern sides of the range that these metals have been plentifully obtained.

The Andes of South America are the great store. houses of silver for the world. The richness of the mines is almost inconceivable; but their great elevation above the sca makes the climate so cold and the

labor of mining so great, as not to be a profitable speculation, except in a few cases.

In Mexico the ores are equally rich; but at a comparatively low elevation, so that where the ore is found in quantity, it is always advantageous to work

it.

The general position of silver ores is in veins which traverse the primary and older of the secondary stratified rocks; but especially the former, as well as in the unstratified rocks, the granites and porphyries which accompany the above. the above. In the limestone the silver is generally associated with lead ore, which is then termed argentiferous galena. The same system of rocks which are metalliferous in the other districts of Mexico exist upon the Isthmus; and the limestone contains galena which is argentiferous. An explanation of the metamorphic rocks might lead to the discovery of valuable veins.

That gold exists in the Chivela Pass in considerable quantities, there can be no reasonable doubt. But its discovery is far from being of recent date. It is a well-known fact that the crown on the statue of the Virgin in the church at Chilhuitan is of pure gold, and that it came from the bed of the Rio Verde in the precise locality where the present discoveries have been made. This crown is upwards of fifty years old, and was fabricated at a time when Tehuantepec was a bustling town under the old Spanish regime. Some gold has also been found in the Almaloya; but up to this date a severe day's work has not yielded over three dollar's worth of the precious metal. It occurs in the ferruginous sands in the dry valleys and gorges, but the grains are very small, usually flattened scales, showing that, in the original rock it is laminated. Some very fair specimens have been found in fragments of talcose schist, with veins of quartz. This schist is invariably more or less decomposed, and stained with iron rust. The gold thus found in the

cellular pockets of the quartoze rock, is associated with copper pyrites, specular iron ore, hematite, &c.

Every one who has passed over the road between Almaloya and the Rio Verde, has been struck with the strong resemblance which the country bears to the metalliferous tracts of Mariposa, and this remark was often made by the California passengers long before any gold was found. The opinion prevails, however, that silver is far more abundant in that locality; and that the rock excavations, which will have to be made through the dividing ridge on the railroad line, will develope veins of incomparable richness. Galena exists almost everywhere in the Chivela Pass; and an antimonial sulphuret of silver occurs here and there with native copper.

It is impossible to say what results may follow a more systematic inspection of the gold fields of the Isthmus. It is undeniable, however, that the operation of mining will be expensive, and it is this fact which has thus far discouraged explorations.

The hills of San Martin, on the Gulf towards the west, are of a volcanic character, and contain cinnabar ore in abundance. From this mineral (the sulphuret of mercury) almost all the quicksilver of commerce is made. Its location here is a future source of riches to the Isthmus.

Petroleum abounds in this neighborhood on the banks of the Goatzacoalcos in quantities, and conveniently disposed for shipping.

With reference to the energy of the present volcanic action in the country, everything on the Isthmus bears the mark of stability, and the absence of any active volcanic force. This is a point of great importance where the stability and permanence of large buildings are concerned; and in this respect, this portion of Mexico is less liable to motions of the ground than Guatimala or Nicaragua; in which latter place several alterations of level have taken place lately.

Previous absence of upheaval and eruption through a long period of time is a priori evidence of the nonexistence of the upheaving cause; and this is the actual condition of the Isthmus of Tehuantepec.

VII.

TIMBER AND VEGETABLE PRODUCTIONS.

On all the rivers of the Isthmus are seen huge specimens of the most valuable trees of the equinoctial regions; amongst the many valuable woods, is the Encina (live oak,) which grows in great profusion.

Remote from the river margins, the limit of the periodic overflow is marked by the presence of many varieties of trees of great value, as the mahogany, the cedro, varieties of the oak, the ebony, the iron wood, the lignum-vitæ, "chico-zapote," "quiebra-hacha," or "break axe," and the "acacia." In a pecuniary point of view the value of these products is immeasurable, especially that which would result from the felling of mahogany and cedar alone. As we ascend the rivers, first appears the oak, then the pines which grow to an enormous size. Indeed, the abundance of these and other building timber of equivalent value, is such that the only limit which can be assigned to the supply they may yield is the demand for centuries to come.

Not less important in value, perhaps, is the indiarubber tree, which is found in astonishing numbers throughout the forests that skirt the tributary streams. Its value, however, is so little appreciated there, that the gum is only gathered for foot-balls, or for some medicinal purposes.

So far as the necessary purposes of construction are concerned, there will be found no lack of durable. timber on the Isthmus. Among these we may enum