OF NORTH AMERICA. 
83 
clay, very tenacious, and sometimes containing sand pouches Avith pebbles and grains of gold ; 
the gold is never in the clay, vidiich is here from 25 to 60 feet thick. Below this is the drift 
proper, formed of sand and pebbles varying in size according to the position of the drift on the 
sides of the hills, or at the bottom of the ravines; there is also a little clay mixed with the sand, 
and much oxyd of iron, giving a reddish color to the whole deposit. It is in this part of the 
Californian Quaternary that the gold is found either in lumps, grains, or dust, and the richest 
part of the drift is that next to the eruptive rocks that lie beneath. This is easily explained by the 
great density of the gold, causing it to descend to the lovA^er part of the deposit, and further, the 
easy decomposition of the sienite gives to the tAvo or three first feet of these rocks, the appearance 
and consistence of a soft stone penetrated hy golden lumps and grains. 
The geological period for the gold of the Sierra Nevada Avas probably the end of the Tertiary, 
or the beginning of tbe Quaternary. It has been thought until noAV that the gold did not exist 
until the Quaternary epoch; and Murchison in his Siluria (edition of 1854) says, page 446 : «What 
«then Avas probably the geological period when these rich auriferous impregnations of the Uralian 
«rocks took place? We cannot believe that it occurred shortly after the Permian era, nor even 
«Avhen any of the Secondary rocks were forming; since no golden debris is found even in any of 
«the older Tertiary grits and sands which occur on the Siberian flank of the chain. If, then, the 
emammoth drift be the oldest mass of detritus in which gold occurs abundantly, non only in the Ural but in 
«many parts of the world, AA'e are led to believe that this noble metal, though for the most part formed 
«in ancient crystalline rocks, or in the igneous rocks Avhich penetrated them, was only abundantly 
(limparted to them at a comparatively recent period; — i. e. a short lime (in geological language) 
abefore the epoch when the very poAverful and general denudations took place which destroyed 
«the large extinct mammalia. » 
But my friend Prof. Ehenezer Emmons in his last valuable Geological Report of the Midland- Counties 
of North Carolina , New York, 1856, says, page 130, 131 and 135: «The second geological position 
«in AAdiich I find gold, is in layers or beds in the rock vAutli which it is contemporaneous. If this vicAV 
«is correct, gold is a sediment; and belongs, as I shall shoAV, to the Paleozoic period.;) — 
((These ancient auriferous deposits may be distinguished from veins by the absence of walls ; there 
«is really no line of demarcation between the auriferous layers and the adjacent ones.;; — «I am 
((not able, at this time, to stale hoAV Avidely gold is disseminated in the Paleozoic rocks ; but from 
((indications derived from a fcAV facts, it appears probable that it may be widely diffused or con- 
((tained in most of the rocks in North Carolina which belong to the Taconic system. » — ((One of 
((the most interesting instances of the occurrence of gold in the consolidated sediments, is at a place 
((Called Sion, tAA'clve miles from Troy, in Montgomery County. It is both interesting and important, 
((because here the fact, that gold is a sediment, is attested by the presence of fossils. This loca- 
(dity has been already described, and the geological position of the rocks stated. The series con- 
((sist of sandstones and chert, which rest upon a thick mass of brecciated conglomerate, which in 
((its turn overlies talcose slate. Those part of the rock which contain gold are brown and of a 
((loose texture from the presence of the oxyd of iron, which undoubtedly originated from the 
((Sulphuret of iron, which is sometimes visible in the rock. There is no doubt respecting the beds 
((from Avhich gold is derived. » 
