OF NORTH AMERICA. 
61 
the red sandstones, and also the true country of the red American Indian, the buffaloes and the 
antelopes. 
Silurian formation. — The Strata containing- the organic remains of the first living forms that 
inhabited our planet, so well described by Murcbison under tbe name of Silurian formation , occupy 
a vast extent of the North American Continent. Their position is of the first importance among 
the Sedimentary rocks, partly owing to their wide geographical distribution , and partly to the thick- 
ness of their strata. The Silurian formation is divided, as in Europe, into three principal groups. 
The Lower group embraces tbe primordial fauna of Barrande , and is characterized by Trilobites of 
peculiar forms. Lingula, Obolus and Orbiculaj it is known in the State of New York as Potsdam sand- 
stone, and in Wisconsin and Minnesota is called the Lower Sandstone of the Upper Mississippi smd iMcer 
Magnesian Limestone. The Middle group is formed by a mass of limestones and blue marls contain- 
ing numerous fossils, as: Trilobites, Orthoceras, Orthis, Spirifer, liellerophon, Corals and Crinoides. It 
is called in America Trenton group and Blue limestone, and is much developed near Trenton falls and 
in the vicinity of the town of Cincinnati. The Upper group consists principally of a grayish-white 
limestone containing numerous fossils, as: Pentamerus, Spirifer, Terebratula, Leptcena, Ifijpanlhocriniles , 
Caryocrinus, Favosites, Cyathophyllum and Catenipora. The Upper Silurian forms the celebrated falls 
of tbe Niagara river, and has therefore been named Niagara group. 
The Silurian strata occupy especially the eastern or Atlantic region; they form the north coast 
of Labrador and the whole extent of the Hudson’s bay, ns well as a great number of islands and 
coasts in the Arctic regions. The numerous expeditions, by land and water, sent out to discover 
the celebrated North-West Passage, have brought back stones and fossils proving that the Silurian 
strata, especially of tbe Upper group , are very much developed there; and Parry, Franklin, Ross, 
Richardson, Back, Rae, Mac Clure and others, have shown that the Silurian forms part of the coasts 
of Winipeg, Athabasca, Great Slave and Great Bear lakes, of Victoria land and the peninsular of 
Melville. 
In the gulf of Si Lawrence we find some small islands, called Mingan islands, olf the coast of 
Labrador, formed of the Silurian formation; it is also in Newfoundland near the straits of Belle 
Isle; the island of Anticosti is wholly Silurian, and it appears also at Port Daniel near the bay of 
Chaleurs. 
In Nova Scotia the Silurian is not much developed, it is only met with at Arisaig and behind 
Windsor and Kentsville, where it forms only a narrow band. In the provinces of New Brunswick 
and Lower Canada and the States of Maine and Vermont, large tracts are occupied by Silurian strata; 
beginning at Cape Gaspe, the Siltirian extends over nearly the whole of the country from Eastport, 
Bangor, Kammouraska and Quebec; it ascends the valley of the St Lawrence and enters the val- 
leys of the Ottawa, of Lake Champlain and of Lake Mempbremagog. 
The Silurian forms an immense band extending from the falls of St Anthony on the Upper Mis- 
sissippi to the northeastern corner of the State of Alabama, crossing the States of Minnesota, Iowa, 
Wisconsin, Michigan, the province of. Upper Canada, and lastly the States of New York, New Jer- 
sey, Pennsylvania, Virginia, North and South Carolina, Georgia and Alabama. This Silurian band 
forms consequently a part of tbe coasts of Lakes Michigan and Huron, includes the whole of Lake 
Ontario, and constitutes several of the long parallel chains of the Alleghany mountains. 
