Barrande and the Taconic System — Marcou. 123 
abrupt entrance into geological science. Notwithstanding some 
good points, it has been, through its greater errors, long a hin- 
drance to progress here and abroad. It has also been a promoter 
of investigations of wide bearing and influence. But, whether 
the evil or the good has predominated, we may now hope, while 
heartily honoring professor Emmons for his earnest geological 
labors and his discoveries, that Taconic ideas may be allowed to 
be and remain part of the past. 
IS^l-lSSS." 
(See "A brief history of Taconic ideas," p. 427, Amer. Jour. Sc, 
vol. xxxvi, 1888.) A last but not least '4eap in the dark," 
which completes the dozen leaps of the adversaries of the 
Taconic system. 
The expression " long a hindrance to progress here and 
abroad" applied to the Taconic and its supporters, is simply a 
jewel, worth all the utterances of Mr. Dana. 
"Leaps ix the dakk" of the adversaries of the TAcoiq"ic. — 
An enumeration of the progress claimed by Mr. Dana and his 
associates, is so curious a reading that I take great pleasure in 
placing it under the eyes of geologists, for it is unique in the 
history of progress of our science. 
Here are a dozen of "leaps in the dark :" 
I. 1843. — W, W. Mather says: the Taconic rocks are the same 
in age as those of the Chaniplain division modified in 
character by metamorphic agency. 
II. 1847.— James Hall says: the rocks of thf! Taconic system 
are clearly Hudson River group acted upon by gradual 
metamorphism . 
III. 1847. — James Hall says: the fossils described by Dr. 
Emmons are uneqiiivocally identical with well-known 
species in the Hudson River group: Atops trilineatus 
is unquestionahhj the Calymene Beckii of the Utica 
slates. 
IV. 1859. — James Hall says: the trilobites of Georgia belong 
to the Hudson River group, adding: "It would be quite 
superfluous for me to add one word in support of the 
opinion of the most able stratigraphical geologist (W. 
E. Logan) of the American continent." Barrande did 
not think it "superfluous to add one word;" and that 
