42S Hidden — Mineral Research in Llano County r , Texas. 



were met with and always indicated the presence near-by of 

 the rare-earth minerals. Some of the fluorite contained small 

 thin veins of a very dark mineral, which was deep indigo- 

 pnrple by transmitted light, and this may, perhaps, betoken 

 the occurrence of a basic fluoride of the yttrium or cerium 

 earths at this mine and in the region generally. 



In a period of four months there was taken out of the hill 

 enough of the yttrium ores to suffice for the Company's needs 

 for the balance of the year, and the mine was therefore closed 

 for the season. 



In the following winter (1903-4) the work was again 

 resumed at Barringer-fiill, and about a dozen workmen were 

 kept constantly employed for a period of six months. The 

 scheme of development laid down by the writer in 1902, was 

 carried forward with much energy. Considerable " dead-work " 

 was done in the line of removing "topping" and bringing up 

 the "fall" from the river-side of the hill. New cuts were 

 opened, and the whole top of the hill was blasted away. All 

 the work done at the mine thus far has been of the character 

 of open quarry work, with hand-drilling and the use of powder 

 and dynamite. The mine has been proved to have a deep- 

 seated origin and is only one of a series of so-called u blow- 

 outs " in a region that is entirely granitic. Deep work at this 

 locality may be expected to bring to light new combinations 

 of the rare earths and of uranium and of thorium, as well as 

 great quantities of the species for which the hill is already 

 famous. All the old species will probably be found in a purer 

 state and perhaps in their normal condition as when first crys- 

 tallized. This last mentioned condition is what we are eagerly 

 seeking for in order to clear up the formulae of many of the 

 species. 



During last winter's work all the old minerals, excepting 

 rowlandite, were again found and more than one thousand 

 230imds of very pure gadolinite. The seventy-three pound 

 group of crystals (of gadolinite), found in March, 1903, was 

 the greatest "find" of record in this mineral; but just one 

 year later, a mass of roughly crystallized gadolinite was found, 

 partly imbedded in the bed-rock at the northeast corner of the 

 hill, that measured thirty-six inches long, eleven inches thick 

 at the widest part, and weighed a little over two hundred 

 pounds. It was apparently free from alteration, had specific 

 gravity of 4*28 (taken on a very pure fragment), had a bright 

 green chatoyancy at certain angles, and was like glass in its 

 broad obsidian-like conchoidal fracture. 



Upwards of a pound of very pure nivenite and not exceed- 

 ing an ounce of mackintoshite, were picked out of the many 

 boxes of mixed cyrtolite, fergusonite and thoro-gummite. 



