1 74 •^^- ^- Winchen en a gi-eat 'Primordm! Ouartzytc 
rrtburitkins. Prof. Emmons regarded these quartzose rocks as 
distinct, and the Red sandsrock as the Potsdam sandstone. But 
there never has been given any good reason for separating them, 
and it seems now that the work of Mr. Walcott has indissohibly 
united them as one and the same formation. Barrande and 
BilHngs called attention first to the primordial character of the 
fbssils contained in the Red sandstone at Georgia, Vermont, and 
from that time to this there has been a steadv increase in that 
faima, until now it is regarded as the chief member of the prim- 
ordial in America. 
If the "red sandrock," and the granular quartz," constituting 
a mass of hard quartzyte which has a thickness of over a 
thousand feet, be followed westwardly, it is found to rise on the 
west side of lake Champlain, and, with a short spur extending 
into Canada, sweeps along the northern and northwestern borders 
of the Adirondack mountains, affording large outcrops on the 
Racket river, and important quarries at Potsdam, in St. Law- 
rence county. Here it has been described by Dr. Emmons and 
named "Potsdam sandstone." His description is so exact and 60 
important that it should be given wide publication.' 
I shall not enter upon its geological relations, any further than to state 
that in Potsdam, and other towns in which it appears, it uniformly rests 
on the primary strata ; and in no part of the country is there any rock 
which interposes itself between it and the primary, so that it appears here 
as the oldest representative of the transition series. The identification of 
this rock Avith the sandstones along the south border of lake Ontario 
will be a matter of some difficulty. It is geologically below the transition 
linaestone, and never in the northern district alternates with it, but always 
holds the relation of an inferior rock. So much is known of its position, 
but still some doubt remains as to its general relation and to its name and 
place in the series of rocks. Some call it the old red sandstone ; others 
regard it as equivalent to the new, or saliferous rock of Eaton. But our 
business is to describe the rock as it is, and speak of its economical ap- 
plications, leaving some doubtful jioints to be cleared up by future ob- 
servations. 
This rock is a true sandstone, of a red, yellowish-red, gray and grayish 
white colors. It is made up of grains of sand and held together without 
cement [sic]. Intermixed with the siliceous grains are finer particles of 
yellowish feldspar, which do not essentially change the character of the 
sandstone, but they show the probable source from which the materials 
forming it were originally derived, viz. some of the varieties of granite. 
' Annual report of the geological survey of New York for 1S37, p. 214. 
