446 REPOET OF NATIONAL MUSEUM, 1904. 



Concerning the variation in vein structure and the changes of the 

 contents of veins at various depths, he wrote: 



Except in those few cases where the enrichment of a vein is due to extraneous or 

 superficial causes, we may safely say that veins gain in the quantity of their metal- 

 liferous contents as we leave the surface; that is to say, the lodes increase in diameter 

 and in the compactness of their ores. 



Thus do we find one who was the best authority in the State promul- 

 gating a theory wholly erroneous and misleading. 



The question of the origin of gold received consideration, and the 

 opinion was expressed that "the gold in some igneous rocks with us 

 and elsewhere may have been brought up with the fluid masses from 

 beneath, but it may also have been imparted by the solution of 

 auriferous sedimentary rocks traversed at the period of injection." 

 While noting that dikes exerted a conspicuous influence on the dis- 

 cernible presence of gold, he believed that these did not impart the 

 metal, or if they did, only in exceptional cases, and that as a rule cer- 

 tain sedimentary rocks must be regarded as the true source of the gold 

 into which it was infused at the time of their deposition, though by what 

 means or from what source he found it impossible even to guess. 



Each of the reports was accompanied by two or more colored geog- 

 nostic maps, in which the various formations were grouped according 

 to their lithological nature rather than according to their geological age. 



In 1855 there appeared Dawson's Acadian Geology, a small octavo 

 volume of but 388 pages, but which, through successive editions, grew, 

 by 1878, to nearly 800 pages. This in all its editions was by far the 

 most important production of this most prolific writer.^ 

 Sy, s i8ss dian Tne edition of 1855 contained a colored geological 

 map of the region and purported to give in a con- 

 densed form what was known of the more general features of the 

 peninsula. A discussion of the views held, and as subsequently mod- 

 ified, can well be reserved until we come to the edition of 1878. 



A very large proportion of Dawson's geological papers related to 

 the Coal Measures of Nova Scotia and their included plant and animal 

 remains. His first publications on these subjects date back to 1843. 

 As early as 1853 he announced, in connection with 

 Nova S s"o S ti^? rk '" Lyell, the finding, at the base of an upright fossil tree 

 1853=1865. trunk . n thege Coa] MeasureSi f bones identified by 



Jeffries Wyman and Richard Owen as those of a reptile or batrachian, 

 to which the name Dendrerpeton acadian kih was applied. The finding 

 of the shell of a terrestrial mollusk was also announced at the same time. 

 Dawson also made important observations regarding the origin of the 

 various coal beds. He felt that the conditions indicated the existence 

 at one time of a long succession of oscillations between terrestrial and 



a Dawson's bibliography contains upward of 360 titles, of which at least nine 

 were books. 



