GENERAL INTRODUCTION. 
JO 
the mighty Continental sea, previous to Paleozoic time. Its stern 
Archaean shores were washed by the waves of countless ages before 
the undermost strata of the Lower Silurian were deposited upon 
them, entombing and preserving many of the Trilobites, Brachio- 
pods, and other curious inhabitants of that vast ocean. This Lower 
Silurian zone marked the shore line, so to speak, of the ancient 
island, and consists of Potsdam sandstone and the lime rocks of 
the Trenton period. Though broken and interrupted, enough of 
it still remains to afford us tantalizing glimpses of the life of the 
time, torn pages of fragmentary chapters that constitute but a half- 
told story to excite our imagination and regret. 
The old Archaean centre, which we call the Adirondacks, is made 
up mainly of gneiss, and includes areas of syenite, hypersthenite, 
granite, iron ore, and other metamorphic rocks. The soil, therefore, 
except that resulting from decomposed vegetation, is largely sili- 
cious sand. 
3 .— TOPOGRAPHY. 
The topography of the region is diversified, and in some respects 
peculiar. The mountains and short ranges of high hills have no 
regular trend, and conform to no definite axis. They are in no 
sense a chain of mountains, and have no backbone at all ; but, on 
the contrary, consist of more or less irregular groups, isolated 
peaks, short ranges, and “ hog-backs,” scattered over the entire 
area — the highest to the eastward. They slope in all possible direc- 
tions, according to the position and courses of the valleys and river 
beds adjacent. Like the grand old Lawrentian Hills of Canada, 
and other Archaean mountains, they are bold and rugged, with 
well-defined and often much broken outlines. Nearly thirty peaks 
exceed four thousand feet (1,219.20 metres) in height, several are 
about five thousand (1,524 metres), and one, Mt. Marcy, attains an 
