Show geology of the new camp by letson balliet geologically the camp of gilbert is situated near the bottom of a synclinal fold in the structures in which a secondary stress has made a sub fold the axis of which is marked by the so called rhyolite dylie dyke the pressure exerted has been very great sufficient to metamorphose the rhyolite the movement having been accompanied by great heat evidently it has cooled quickly comparable perhaps to hot glass that has been submerged in water for the fracture zone shows many shrinkage cracks and a shattering of the metamorphosed the shrinkage cracks have been filled and the shattered mass cemented together in a rhyolite breccia with a quartz quarts in which free gold is visible in places and can be readily seen in bannings pann ings further evidence of is notable in some places where calc balc spar and even quartz can be found the visible gold is found in the quartz and often fine specks of gold can be seen in association with small masses of iron the gold therefore must have been deposited simultaneously with quartz at least such a part of it as is contained with the tarle deposition the altered rhyolite contains some gold not visible until it is ground and panned but in nowise the quantity the quartz carries which cemented the shattered volcanic rhyolite into a breccia the which occurred during the period cf deposition is greater than the primary if indeed there was a primary r rne one ne for the unaltered rhyolite does not carry values in one place a dyke of chalcedony is found near the surface which changes to quartz within a few feet chemically both are a silica this dioxide the change in character is no change in analysis alteration from quartz to chalcedony is in hydrothermal hydro thermal conditions assisted probably due to a difference by sodium or some catalytic agent or possibly to a dynamic change in in any event pressure or both gold deposition predominated luring during the greater period of tile the process of erosion has covered the formation the ridges and the best away from veins may yet be found under the desert overburden the quartz and chalcedony dyke or vein stands nearly vertical in the flat not on a ridge the chalcedony does not carry values but after it changes to a quartz it does the ordinary miner and prospector calls a vein that carries no values a dyke and a dyke that carries values a vein or fledge ledge tho the mass at the last hope does not to be e a vein or dyke but appear simply deposition a of gold g old in the fractures of the mass where it makes a contact with unaltered rhyolite this formation breaks under the rhyolite and dips to the west its limits westward have not been exposed and may extend to considerable sid erable distance and undoubtedly to depth it would not be surprising P to find a true vein on the contact which would give an additional value to that property on the colorado it is a clearly defined vein with well defined walls the extends over a distance of 2 miles so far fi as my were concerned and possibly still further beyond my illy examination unless it should some time be desirable to gopher and glory hole the deposit around the original discovery of the last hope it seems that in all other cases the one thing to do is to sink shafts well into the formation below the desert overburden and crosscut cross cut for ore filled fissures that may exist in the permanent formations on the big four properties the last hope black Al mammoth ammoth storm cloud and colorado with their showings inthe in the outcrop this method of development has already been planned or started all indications are that the is permanent and will extend to depth over a large area I 1 |