GEOLOGY AND MINERALOGY. 
treatment has, however, made it yield up its auriferous por- 
tion; and the basaltic sand of San Jose might be treated 
with advantage in the same manner. That gold does exist on 
the Isthmus is a matter of history, which is corroborated by its 
geological structure. Quartz, talcose slate, and alluvial sands, 
are here in great abundance, which elsewhere are the auriferous 
beds ; and a rigid search through the neighboring Sierra would 
no doubt display the actual position of the gold. The following 
extracts show how abundant and easily obtained it was at one 
period upon the Isthmus. 
Antonio de Herrera, in his " Description de las Indias Occi- 
dentales" speaking of Tehuantepec, says : " En todo este Obis- 
pado no hay in que no lleve oro." And in another place, refer- 
ring to the Estates of Marquesanas : " Cogese en el mucha seda 
trigo, y maiz : tiene la lengua Zapoteca : ha havido en el buenas 
minas de oro." 
Bernal Diaz, in recording the account of the expeditions of 
Gonzalo de Umbria and the gold which he brought, says : " Nei- 
ther did Diego de Ordas, who had been sent to the river Coatza- 
coalcos, return with empty hands." 
Again, in reference to the march of Sandoval : " Twenty of 
the caziques and principal personages soon made their appearance, 
bringing with them a present of gold-dust in ten small tubes, 
besides various pretty ornaments." 
At another jDlace, in the same connection : " We arrived in 
the province, and began diligently to explore the mines, accom- 
panied by a great number of Indians, who washed the gold-dust 
for us in a kind of trough, from the sand of three different rivers. 
In this way we obtained four tubes full of gold-dust, each about 
the thickness of the middle finger. Sandoval was highly de- 
lighted when we brought him these, and concluded that the 
country must contain rich gold mines." 
The expedition of Alvarado to Tehuantepec, in 1522, seems 
to have been attended with far greater success. Bernal Diaz, 
speaking of this expedition, says : " Among the more powerful 
tribes who submitted on this occasion, was that of the Tecuan- 
tepec (Tzapotecs), whose ambassadors brought with them a pres- 
ent in gold ; stating, at the same time, that they were at war with 
