T.S. Hunt on the Crystalline Limestones of N. America. 197 
anriferons rocks of the great Appalachian chain. Gold, associated 
with talcose slates, serpentine, chromic and titaniferous iran ores, 
is traceable along their outcrop from Canada to Georgia. Gold- 
bearing veins have also been found in the slates which in Eastern 
Canada, form the base of the Upper Silurian. I remark that in 
a somewhat chloritic and very silicious magnesian limestone, 
id 
analysis. Ihave also found titanium in some of the very fer- 
Tuginons slates, which by their alteration become chloritic schists 
holding magnetic and specular iron, ilmenite and rutile. 
ntine is found as an imbedded mineral in the Laurentian 
its associated talcose slates and chromic iron, appear to be con- 
the so-called serpentine rocks of northern New York, are hydrous 
Silicates of alumina, iron, and potash, containing very little lime 
or magnesia; they are the dysyntribite of Shepard. 
As the northwestern limit of the metamorphic belt in Eastern 
nada runs southwesterly into Vermont, the undulations of the 
Strata, which are nearly N. and S., escape from it to the north- 
Ward, Proceeding E. S. E. however, from the unaltered Tren- 
ton limestones of the Yamaska, we cross the overlying slates, 
Saidstones and dolomites, and entering the metamorphic region 
nd the serpentines, talcose, chloritic and micaceous schist, with 
seiss and quartzite, very much disturbed, and repeated by undu- 
tons. On reaching the valley of Lake Memphramagog, we 
ome upon the third class of crystalline limestones, which are 
Upper Silurian. ‘This limestone formation has a continuous out- 
top from the Connecticut valley, by the lake just mentioned and 
the upper part of the St. Francis river, to the Chaudiére, and is 
thence traceable by intervals as far as Gaspé, where it 1s Clear 
“thconformable with the Lower Silurian. It holds the character- 
‘Sie fossils of the Niagara group, but for some distance from the 
line of Vermont, is so much altered as to be white and crystalline, 
and to contain abundance of brownish mica, the fossils being often 
ed 
teristic Favosites gothlandica, and various species of Porites 
Na Cyathophyllum, have been identified. These fossils in a 
Smilar condition are also found at Georgeville on Lake Memphra- 
th og Following the section in a S. E. direction, to Canaan on 
oe Connecticut river, we meet with calcareo-micaceous schists, 
are gradually replaced by mica slates with quartzose beds. 
