and Point Levi Fossils. 221 
actually investigating the rocks of that part of Vermont. De- 
siring to know the results of his latest researches in regard to the 
stratigraphical relations of these rocks, I withheld the final pub- 
lication till the Meeting of the American Association for the 
dvancement of Science, in Springfield, and there showed to 
Sir William my descriptions as they now stand in the Report, 
and I then received his authority for the addition of the note 
which was appended. 
This in a few words is a simple history of the matter relating 
to the publication of these species. I made no remarks or com- 
parisons with the primordial fauna of Barrande in Bohemia, 
knowing that these features would be at once recognized by 
every paleontologist; while their reference to the genus Olenus 
showed my appreciation of the nature of the fossils. 
I received a copy of the communication of Mr. Barrande, from 
Sir William Logan in September, a few days before setting out 
for my field duties in Wisconsin. Since my return to Albany, 
constant and pressing occupation has left me no time to consider 
areply to a question of so much importance. 
Later discoveries in the limestones associated with the shales 
at Quebec leave no longer a doubt, if any could have been enter- 
show a remarkable agreement between the trilobites of ‘this 
stoup and those of the Potsdam sandstone, in the occurrence of 
Sw Species of Dikellocephalus and one of Menocephalus ; while the 
°ccurrence of many others is in agreement or not incompatible 
with the fauna of the Potsdam and Calciferous sandstones. The 
Parative values of the Trilobitie faune of this group and of 
me Primordial zone of Europe, as established by Barrande, is 
_ “Ser shown in a tabular form which I here append. 
Jour. Sci.—Szconp Seems, Vou. XXXI, No. 92—Mancs, 1861. 
29 
