AMERICAN GEOLOGY DECADE OF 1860-1869. 519 



group of the New York .survey, and with the Caradoc formation of 

 England. 



The possibility that the Laurentian system might not be a single 

 unit was here again recognized b} 7 Logan in a supplementary note: 



If, on- exploration to the eastward of the Trembling Mountain, it should be further 

 ascertained that the two inferior limestone bands of the Greenville series disappear 

 on reaching the margin of the anorthosite, it may be considered as conclusive evi- 

 dence of the existence in the Laurentian system of two immense sedimentary forma- 

 tions, the one superimposed unconformably on the other, with probably a great 

 difference in time between them; and it will be an interesting subject of inquiry 

 whether the intrusive rocks which have been found intersecting the lower division 

 give any clue to events which may have happened in the interval. 



Logan was born of Scottish parentage at Montreal in 1798, but his 

 father shortly returning to Scotland, he received his early training, 

 which was classical, in the High School and University of Edinburgh. 

 He showed no disposition toward scientific pursuits 

 sketch of Logan. until chance led him to the keeping of accounts in 

 the establishment of an uncle, who was interested in 

 mining and copper smelting operations in Wales. Here he was 

 attracted by the phenomena of the coal seams and devoted a large 

 share of his spare time to their study. 



In 1838 the death of his uncle caused him to give up his position in 

 Wales, and in 1840 he returned to Canada. His first geological paper 

 was on the character of the beds of clay immediately below the coal 

 seams of South Wales. This was communicated to the Geological 

 Society of London in 1840. In this he announced . the invariable 

 presence under the coal seams of beds of fire clay carrying Stigmaria. 

 This he regarded as proving the origin of coal through plant growth 

 in place — an opinion which was very generally accepted at that time. 



When Logan began his geological work in Canada a large portion 

 of the country was a wilderness, without roads, and there were no 

 maps. Of the topography of the Gaspe district it is written: 



Little was known of the region beside the coast line; of the geology, practically 

 nothing. Settlements were few, confined almost exclusively to the coast, and made 

 up chiefly of fishermen. There were no roads through the interior, most of which 

 was, and indeed still is, a wilderness, inhabited by bears and other wild beasts, or at 

 best only penetrated in certain regions by a few Indians or lumbermen. The courses 

 of most of the streams were unknown and the mountains untraversed. 



Living the life of a savage, sleeping on the beach in a blanket sack, with my feet 

 to the fire, seldom taking my clothes off, eating salt pork and ship's biscuit, occasion- 

 ally tormented by mosquitoes. 



« Prof. N. S. Shaler, in a paper before the Boston Society of Natural History, 

 December 18, 1861, antagonized that view and argued that from the base of the 

 level of the Canadian channel to the summit at the southwestern point of the island 

 the beds were entirely Upper Silurian and synchronous with the Clinton and Niagara, 

 of New York and elsewhere, though the fossils themselves might not be absolutely 

 identified. 



