Bibliographical Notices. 197 
which the plants forming the coal-seams originally grew. This 
generalization he subsequently verified in the coal-fields of Pennsyl- 
vania and Nova Scotia. In the latter locality he was the first 
(in 1841) to observe the traces of reptilian footprints in the Carbo- 
niferous system, a fact which has been somewhat overlooked by 
subsequent observers; but Logan’s claim is vindicated by his 
friend and life-long associate Principal Dawson, in his work on the 
air-breathers of the coal-period, published in 1863. 
After retiring from the management of the copper-works, subse- 
quent to the death of his uncle in 1838, Logan returned to Canada 
in 1840 and was engaged in the researches last mentioned on the 
coal of the United States and maritime provinces. In the course of 
his explorations he was much impressed with the great mineral 
wealth of the basin of Pennsylvania, and had some thoughts of 
establishing himself as a coal-viewer in the United States; but upon 
the determination of the provincial government of Canada to insti- 
tute a Geological Survey in 1842, he was, on the unanimous recom- 
mendation of the leading English geologists, De la Beche, Murchison, 
Sedgwick, and Buckland, appointed to undertake it, which he did in 
the spring of 1843, having for his sole assistant Mr. Alexander 
Murray, who was his constant associate during the whole time of 
his work in Canada, and subsequently directed the Survey of New- 
foundland. 'Thenceforward for more than a quarter of a century 
Logan’s life was entirely devoted to the working-out of the geo- 
logical structure of his native country. He commenced in the 
eastern district of Gaspé, on the south shore of the Saint Lawrence, 
among Carboniferous and Devonian strata, and proceeded along the 
shores of Lakes Huron and Superior, through the valley of the 
Ottawa, and along the Labrador coast, all of which, now become 
familiar places to the student of American geology, were then un- 
known to geologists, and scarcely, if at all, topographically delinea- 
ted, at any rate for more than a short distance from the shores of 
navigable waters, where hydrographic surveys had extended. This 
absence of topographical maps added enormously to the labours of 
the work ; and for several years the method of traverse-surveys by 
counting paces and compass-bearings was added to the geological 
work proper, with the result of furnishing valuable additions to the 
cartography of the province ; while the courses of streams navigable 
by canoes were plotted from similar surveys, in which the distances 
were determined by the Rochon micrometer-telescope. The value 
of the latter part of the work was specially noticed by Captain 
(afterwards Admiral) Bayfield, R.N., the Admiralty surveyor of the 
Saint Lawrence. ‘The privations and discomforts experienced in the 
earlier years of Logan’s work in Canada are abundantly evidenced 
by the numerous extracts from his journals describing incidents of 
camp life and references to a somewhat sparse dietary, in which 
spruce-partridges, porpoises, and porcupines figure largely, the last 
being spoken of as especially acceptable additions to the larder, 
while the short commons were aggravated by the persistent worries 
of mosquitoes and black flies during the greater part of the working 
