354 -^- Winchell on the laconic Question. 
yond this it is known with interruptions as far as Litchfield and 
New Haven counties, Conn., and Dutchess county, New York. 
From the Canadian border to CoUunbia county these rocks 
cover a breadth of eiglit to twenty miles. Mr. AValcott states 
that he knov/s the occurrence of fossils at over one hundred 
localities within the area of the Georgia terrane. All these 
rocks and all these fossils are older than the Potsdam, They 
lie within the area of the original Taconic, and the fossils are 
all types of the first fauna of Barrande. I consider these results 
conclusive of the right of the Taconic system to full recognition, 
A sub-Silurian is therefore well established at the present 
day. This is precisely what Dr. Emmons contemplated and 
anticipated. 
III. Was Dr. Emmons anticipated by other 
INVESTIGATORS ? 
1. Limits of the Sihiriau. In 1S39, ^^'^' -^* -^* Murchison 
published his " Silurian System," in which he gave an exposi- 
tion of a system of fossiliferous rocks underlying what is now 
known as the Devonian system. The name Silurian had been 
employed by him since 1835. It was intended to embrace all 
the known fossiliferous rocks below the Devonian, but at that 
time little was known of remains belo\v the horizon of the 
Caradoc. In 1834 Murchison had recognized the extension of 
the sedimentary series as far down as the "unfossiliferous gray- 
wacke of the Longmynd." ^ In his vSilurian System, and in 
Siluria [1854] the Longmynd and Llanberis rocks are excluded 
from the scope of the Silurian system, because destitute of fos- 
sils, so far as known in Great Britain. The Longmynd were 
characterized as "bottom rocks." But even in 1844 two sjoecies 
of Oldhamia had been described from beds in Ireland equiva- 
lent to the Longmynd of Shropshire and vSouth Wales. The 
Silurian therefore, terminated downward in the midst of the 
fossiliferous column. 
2. Position and rights of Cambrian. In 1836, the name 
Cambrian was bestowed by professor Sedgwick on a series of 
strata occuring in North Wales, believed to occupy a position 
1 Proc. Geol. Soc. London, II, 11, Jan., 1S34. 
