GEOGNOSY OF THE APPALACHIANS. 467 
This view of Emmons as to the Quebec rocks was adopted by 
Sir William Logan, when, a few years afterwards, he began to 
study the geology of that region. The sandstone of Sillery was 
described by him as corresponding to the Oneida or Shawangunk 
conglomerate, while the limestones and shales of the vicinity, 
which were supposed to underlie it, were regarded as the repre- 
sentatives of the Trenton, Utica, and Hudson River formations. * 
By following these rocks along the western base of the Appalach- 
ians into Vermont and Massachusetts, they were found to be a 
continuation of the Taconic system, which Sir William was thus 
led to refer to the upper half of the Champlain division, as had 
already been done by Professor Adams in 1847. As regards the 
crystalline strata of the Appalachians in this region, he, however, 
rejected the view of Emmons, and maintained that put forward by 
the Messrs. Rogers in 1841, viz., that these, instead of being older 
rocks, were but these same upper formations of the Champlain 
division in an altered condition ; a view which was maintained dur- 
ing several years in all of the publications of those connected with 
the geological survey of Canada. 
This conclusion, so far as regards the age of the unaltered fos- 
siliferous rocks from Quebec to Massachusetts, was supposed to 
be confirmed by the evidence of organic remains found in them in 
Vermont. Mr. Emmons had described as characteristic of the 
upper part of the Taconic system, two crustaceans, to which he 
gave the names of Afops trilineatus and Elliptocephalus asaphoides ; 
the other fossils noticed by him being graptolites, fucoids, and what 
were apparently the marks of annelids. In 1847 Professor James 
Hall, in the first volume of his Paleontology, declared the Atops of 
Emmons to be identical with Triarthrus (Calymene) Beckii, a char- 
acteristic fossil of the Utica slate; while the Elliptocephalus was 
referred by him to the genus Olenus, now known to belong to the 
primordial fauna of Sweden, where it is found in slates lying be- 
neath the orthoceratite limestone, and near the base of the paleo- 
zoic series. Although, as it now appears, the geological horizon of 
the Olenus slates was well known to Hisinger, this author in his 
classic work, Lethea Suecica, published in 1837, represents, by 
some unexplained error, these slates as overlying the orthoceratite 
*Geol. a eae RO T and Amer. Jour. Sci., II, ix, 12. 
t Amer. Jour. Sci., II, v, 
AMER. NATURALIST, VOL. V. 30 
