76 The Taconic — Mar ecu. 
Walcott) and the Lower Potsdam (Middle Cambrian or 
Georgia formation of Walcott), and the fault is "purely hypo- 
thetical." On p. 18, another section is figured, with 'the admis- 
sion that "the precise position of the fault (the Great Fault in 
Rensselaer county) is somewhat uncertain ;" and to increase 
the incertitude Mr. Ford put it in the bed of a creek — an invis- 
ible fault. Finally the geological sketch map at p. 17, shows 
a perfect concordance of his so-called Lorraine shales and so- 
called Lower Potsdam group. A simple bending or slight 
curl of the whole mass of the Georgia slates and Phillipsburgh 
and Pointe-Ldvis group has been taken by Messrs. Ford and 
Walcott as a great fault. 
The Georgia formation. — No. 5 referred to the Georgia 
slates or Middle division of what Mr. Walcott calls Cambrian, 
is rather confused in the text, in the geological map and in the 
section. On the geological map the Georgia formation is com- 
posed of three groups, two with the same number i, two dif- 
ferent colors and a geographical distribution completely distinct. 
On the section we have only a single number i, which refers 
to the Quartzites, and the No. i [red sandrock] is not repre- 
sented. Mr. Walcott after carrying on the map the red sandrock 
as far as the latitude of Shoreham and parallel thereto his No. 5, 
makes it disappear under his Calciferous-Chazy-Trenton, and 
even under his Hudson group. 
However leaving Mr. Walcott to explain his numerous con- 
tradictions and confusions with regard to the equivalency of 
his No. I being "the sandy deposit of the shore line" and his 
No. 5 the "off-shore" accumulation of finer sediment, I shall 
say, that his No 5 is formed of 14,000 feet or more of strata,- 
containing Taconic fossils, at over 100 localities within the 
typical Taconic area — among them the original locality with 
special fossils (the primordial fauna) described and figured by 
Dr. Emmons, as far back as 1S44. As to his saying that "ifc 
was 3i fortunate happening that the upper Taconic fossils proved 
to be of pre-Potsdam age and not a scientific induction based on. 
on accurate observation and comparisons;" and that Mr. 
Barrande was misled into crediting him (Emmons) with a dis- 
covery that was based on errors of field observations, it is- 
sufficient for me to have quoted those remarks. No answer is 
