384 Memorias de la Sociedad Científica 



as desired. Althougli every variety shows fine graduations o£ 

 color and banding, we remark principally: Orange-onyx oftke 

 most wonderful kind produced at the deposits o£ "Pozo de 

 Calvo" and "Las Víboras;" amber-onyx o£ fineyellow colour, 

 found in "Las Víboras;" Eose-banded-onyx, remai-kable for 

 delicacy o£ tonas and curiously stiñped; Jasper-onyxor black 

 onyx, banded white and black, with variegated figures; Agate- 

 onyx, and many kinds o£ clouded onyx, white, red and some- 

 times green like onyx coming £rom Puebla and Oaxaca quar- 

 ries. 



The structure o£ onyx marble is holocrystalline, common- 

 ly fibrous or columnar, rarely-granular and scaly; semi-trans- 

 lucent, increasing by transparency the intensity o£ colour. The 

 composition is absolutely similar to that o£ so called onyx 

 marble £rom other countries, i. e. carbonate o£ lime (more than 

 90 p3 ) with very little sulphate o£ lime and carbonate o£ iron 

 and other impurities. 



Hardness 3 Weight o£ cubic meter — . 2.71 tons. 



Specific gravity. 2.71 „ ,, „ £oot 78.5kilos=1731bs. 



I have already indicated that the topographical condi- 

 tions, and position o£ these deposits give plenty of £acilities £or 

 working, and allouring£orthe establishment o£a plant o£ ma- 

 chinery of any capacity desired. In a very dry country as this. 

 is, we fix first on the question o£ water supply. Water, is not 

 very deep in the valleys near the deposits, also at the £oot o£ 

 the mountains, where we made the necessary investigations to 

 assure the existence o£ an underground level not £ar £rom 50 

 to 60 f eet in depth. Fuel would -be transported from the rail- 

 way either at Peralta or Noria Station. Good workmen are 

 plenty in the small towns and Jimulco, The customary wages 

 being one dollar silver per day. At Jimulco provisions etc. can 

 always be obtained and implements can be brought £rom To- 

 rreón on the Central R. R. £our hours travel £rom Jimulco. 

 As is well known, the Central R. R. is connected at El Paso ' 



