THE TRAP MINERALS OF NOVA SCOTIA—GILPIN. 287 
the volcanic outbursts. Above this comes a mass of compact 
dark, roughly columnar trap. 
On the north shore of the Cape of Blomidon the sandstones 
appear on the beach; as they gradually rise to the south they 
finally attain a height equal to that of the trap, which by its 
hardness has preserved them from being washed away. Similar 
indications of the conformability of the trap, amygdaloid and 
sandstone are presented at other points, although, as might be 
expected, the former frequently alternate. 
As the tides wear away the sandstones immense masses of the 
amygdaloid and trap, loosened by the rain and frost, are spread 
along the shore, and open a rich field to the mineralogist. This 
noble cliff, 400 feet in height, torn by the storms and frosts of 
winter, and mantled by trees and shrubs which vainly try to 
hide its losses, presents, with its dark walls and waving woods, a 
scene hardly to be expected in our usually tame landscapes. 
There is a strong resemblance between the Nova Scotia trap 
and that which occurs along the Atlantic coast, in strata consid- 
ered to be of Triassic age, as far as South Carolina. All being 
of one species and forming varieties of dolerite made up essen- 
tially of Labradorite and Pyroxene, with more or less disseminated 
magnetic oxide of iron, etc. No single analysis or set of analyses 
could exactly represent the composition of this great mass of 
rock. 
We may first notice the economic minerals found in the rock 
under consideration :— 
IRON ORES. 
Magnetite—This ore is frequently present in the trap, the 
amount varying in different localities, and may be detected by 
passing a magnet through the powdered rock. At certain points, 
among which may be mentioned Digby Neck, St. Mary’s Bay 
and Blomidon, it is concentrated in veins up to a few inches in 
thickness, frequently associated with amethystine quartz and 
other forms of silica. The composition of this ore, which is 
frequently of a very high grade, will appear from the following 
analysis of a sample from the North Mountain : 
