The Taconic — Marcou. ^i 
large and so numerous trilobites of the second fauna, such as 
Ceraurus, and more especially Isotelus gigas^ fragments of 
which can be picked up by the hundred and thousand at Chazy, 
Plattsburg, isle La Motte, Grand isle and South Hero, in the 
middle of the very narrow lake Champlain, at a distance of less 
than a cannon shot. 
Mr. Dana in his paper "on the geological age of the Taconic 
system" of 1882, repeats on pp. 401 and 402 the same names of 
fossils, adding only on p. 405, five brachiopods [ Or//^/^ lynx^ O. 
pectinella^ Rhynchonella capax, Leptcena sericca and Stropho- 
mena alternata)^ a coral Petraia corniculum and a trilobite 
Illcenus crassicaiida. Besides he quotes, Orthoceras primi- 
geniufHy Maclurea ?nagna and finally Orthis testudinaria found 
by Messrs Dwight and Nelson Dale in Dutchess county. 
Adding all the species identified, and accepting them as well 
determined, a fact which for several of them admits of doubt, 
we have only twenty-one species of the second fauna, mixed in 
the four Bathyuri of the first fauna, and very likely some other 
primordial fossils not yet recorded, scattered from Middlebury 
to Poughkeepsie, contained in lenticular masses or belts of lime- 
stone — never in the slates — showing only sporadic apparitions 
of less than six per cent of the Calciferous-Chazy-Trenton 
fauna. It is the old classification revived of the Quebec group 
of Logan, to which Messrs. Dana and Walcott have added the 
Trenton — Logan having synchronized his Quebec only with the 
Calciferous and Chazy — a rather difiicult task round Quebec 
city and at Pointe Larabde where the Trenton lies in discord- 
ance of stratification over the Taconic Swanton slates. 
We have here all the j^aliEontological proofs of Mr. Dana, 
accepted by Mr. Walcott as conclusive of the identity of three 
or four thousand feet of the Phillipsburgh and Pointe L^vis 
group, with the one thousand feet of the typical Calciferous- 
Chazy-Trenton of Chazy in the western part of lake Champlain. 
This is one of the "principles" used by the adversaries of the 
Taconic system. 
Mr. Walcott did not try to recognize, as Mr. Dana and others 
did, in his No. 3, the Calciferous, Chazy, Birdseye, Black River 
and Trenton, at Fort Cassin, Snake mountain, Shoreham, Rut- 
land, Wappinger etc., nor did he signalize anywhere the Quebec 
