180 J. D. Dana on the Green Mountain Quartztte. 
the Hudson river and the Stockbridge limestone being regarded 
as in part the Hudson river shales folded and partially meta- 
morphic. 
Professor Emmons in his Geological Report (1842), treating 
of his Taconic system, reversed the order, putting the Stock- 
bridge limestone over the quartzite; but the Taconic slates, 
lying to the west, with some limestone strata associated with 
these slates, conformably below both, and making all older than 
the Potsdam, or the basal rock of the New York series. The fact 
are called, in th ti 
that of 1843 the slates all the way to the Hudson river are 
? 
Black slate of Bald Mountain, the newest of the series; 2 
this order is made consistent with the easterly dip throughout, 
by supposing, in order, “to assist us in maintaining these 
views, that the “superior members,” or newer rocks, were 
removed by abrasion to the eastward before they were upturned, 
and were “thus limited in an easterly direction ;” and, bes ve 
the upper strata were probably “scantily extended east ant 
west,” “the whole system having been formed in a trougt 
The quartzite is still made conformable to the limestone, W ile 
the black slate is at the other end of the series conformable 
also. In his American Geology, published in 1855, this ordet 
is in the main sustained, the quartzite and associated slates 
being overlaid conformably by the Stockbridge limestone, this 
e “talcose lates to 
essor Emmons made out rightly the relations of the 
quartzite to the Stockbridge limestone, the argument pre. 
in 1 and since, for the pre-Silurian age of the bg 
would have been without any foundation worthy of note. 
