84 TAYLOE'S GEOLOGICAL RECONNOISSANCE. 



Minus del Rey. The locality is about nine miles up the Palenque river. It 

 contains some ancient Spanish excavations, the working of whicli, for some years 

 subsequent to the revolution, was either abandoned or was limited to the occasional 

 operations of a few Creoles and half-breeds; adventurers who prosecuted their 

 researches without responsibility or license from the temporary government. 



The ancient or original mining works, if they can be considered entitled to this 

 appellation, consisted of excavations from the surface downwards, in the vertical 

 seams of auriferous quartz. These operations appear to have proceeded no further 

 than open cuttings or trenches, 20 or 30 feet deep, and some occasional washing 

 of the sand and gravel of the small streams which cross the principal gold vein. 



We found at the Rio del Rey mine four or five Indian miners, who were engaged 

 in extracting the gold from one of the princioal veins there. Even under the 

 primitive and very inefficient system there employed, the result was considered to be 

 amply remunerative to the adventurers. The vein, so worked, is from two to three 

 feet thick, inclosed in a dyke many 3'ards thick, of white and occasionally mottled 

 unctuous clay, which appears to be well adapted to the making of porcelain, and the 

 finest description of potter3^ Although occurrring in so soft a matrix, the walls of 

 this quartz vein are remarkably well defined. They present, in their smooth, 

 polished, and striated surfaces, the usual evidence of a considerable vertical 

 movement in gangue, or in the cubical area of the vein. We may remark that this 

 feature characterises most metalliferous veins of contemporaneous origin, and is even 

 very frequently seen in highly inclined beds of coal. 



As reganls ulterior practical operations, in excavating these metalliferous veins on 

 the Isthmus, much will depend upon the nature of the formations which are now 

 exhibited in the form of soft clay dykes. At present, no excavations have proceeded 

 to a depth low enough to show any perceptible change in the soft clay beds. This 

 matter, therefore, must await the future operations of the miner. 



Should it appear that these argillaceous beds result from rocks which have been 

 disintegrated by the influence of atmospheric agency, and that they exist below in a 

 more solid form, the cost of excavation, now so insignificant, will be much enhanced, 

 and the process of blasting may eventually be necessary. Of this we have at present 

 no evidence. 



The native miners remark, with perfect propriety, that mundic or sulphuret of 

 iron, and the accompanying black magnetic sand, are highly favorable indications of 

 gold in the quartz veins. 



The writer examined more than a dozen localities where gold veins occur. All of 

 these veins can be advantageously mined from the water level of the rivers, and 

 from the ravines ; in which cases there will be many hundred feet of breast, or 

 perpendicular and cubical area, rendered available, without the necessity of resorting 

 to any description of machinery, either for the purpose of drainage or hoisting. 



