538 Geological Society. 
the Pacific Ocean (between 48° and 55° parallels of latitude), ex- 
plored by the Government Exploring Expedition under the command 
of Captain J. Palliser (1857-60).” By James Hector, M.D. Com- 
municated by Sir R. I. Murchison, V.P.G.S. 
This paper gave the geological results of three years’ exploration 
of the British Territories in North America along the frontier-line 
of the United States, and westward from Lake Superior to the Pacific - 
Ocean. 
- It began by showing that the central portion of North America is 
a great triangular plateau, bounded by the Rocky Mountains, 
Alleghanies, and Laurentian axis, stretching from Canada to the Arctic 
Ocean, and divided into two slopes by a watershed that nearly follows 
the political boundary-line, and throws the drainage to the Gulf of 
Mexico and the Arctic Ocean. The northern part of this plateau 
has a slope, from the Rocky Mountains to the eastern or Laurentian 
axis, of six feet in the mile, but is broken by steppes, which exhibit 
lines of ancient denudation at three different levels: the lowest is 
of freshwater origin; the next belongs to the Drift-deposits ; and the 
highest is the great Prairie-level of undenuded Cretaceous strata, 
This plateau has once been complete to the eastern axis, but is now 
incomplete along its eastern edge, the soft strata having been removed 
in the region of Lake Winipeg. 
The eastern axis sends off a spur that encircles the west shore of 
Lake Superior, and is composed of metamorphic rocks and granite 
of the Laurentian Series. To the west of this follows a belt where 
the floor of the plateau is exposed, consisting of Lower Silurian and 
Devonian rocks. On these rest Cretaceous strata, which prevail all 
the way to the Rocky Mountains, overlain here and there by de- 
tached tertiary basins. 
The Rocky Mountains are composed of Carboniferous and Devo- 
nian limestones, with massive quartzites and conglomerates, followed 
to the west by a granitic tract which occupies the bottom of the 
great valley between the Rocky and the Cascade Mountains. The 
Cascade chain is volcanic, but the volcanos are now inactive; to the 
west of it, along the Pacific coast, Cretaceous and Tertiary strata 
prevail. The description of these rocks was given with considerable 
detail, on account of their containing a lignite which for the first 
time has been determined to be of Cretaceous age. This lignite, 
which is of very superior quality, has been worked for some years 
past by the Hudson Bay Company, and is in great demand for the 
steam-navy of the Pacific station, and for the manufacture of gas. 
Extensive lignite-deposits in the Prairie were also alluded to; and, 
like those above mentioned, were considered to be of Cretaceous age ; 
but, besides these, there are also lignites of the Tertiary period. 
The general conclusion was that the existence of a supply of fuel 
in the Islands of Formosa and Japan, in Vancouver's Island, in the 
Cretaceous strata of the western shores of the Pacific, but principally 
within the British territory, and in the plains along the Saskatchewan, 
will exercise a most important influence in considering the practica- 
bility of a route to our Eastern possessions through the Canadas, 
the Prairies, and British Columbia. 
