XVU PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



that over the vast area of the coal field of South Wales not a seam 

 had been discovered without an underclay abounding in Stigmaria, 

 it was impossible to avoid the inference that there must be some 

 essential and necessary connexion between the existence of Stigmaria 

 and the production of the coal. He thought there were reasonable 

 grounds for supposing that in some way or other the Stigmaria 

 Jicoides was the plant to which may be mainly ascribed the vast 

 stores of fossil fuel. 



In 1842 he communicated another important paper, "On the 

 Coal-fields of Pennsylvania and Nova Scotia*," in which he described 

 some interesting particulars connected with the extent and character 

 of the carboniferous deposits of Pennsylvania ; he also pointed out 

 the extension to the coal-fields of America of those facts bearing on 

 the origin of coal which I have alluded to in noticing his former 

 paper on the coal-seams of South Wales. The presence of the 

 underclay, or Stigmaria fire-clay as it is sometimes called, was almost 

 universal. The second portion of this paper refers to the coal-fields 

 of Nova Scotia, which he also examined in the autumn of 1841. 

 Here also he observes, that under every bed of coal which he had 

 examined, amounting to more than twelve, he had detected the 

 Stigmaria fire-clay, and he was informed by Mr. Poole, the super- 

 intendent of the Albion Mines, that similar strata occupy the same 

 position in the coal-field of Cape Breton. 



In the same year Mr. Logan communicated another paper to this 

 Society, in which he described the phsenomena accompanying the 

 packing of ice in the river St. Lawrence. In the same paper he 

 has described a remarkable landslip which took place in the valley 

 of the St. Lawrence in 1840, and has also given an account of the 

 occurrence of marine shells on Montreal Mountain, where they are 

 found on a sort of raised beach, 430 feet above Montreal Harbour, 

 or about 460 feet above the Atlantic. 



Since that period, with the exception of two papers on the fossil 

 tracks in the Potsdam sandstone and on the stratigraphical relations 

 of that rock, Mr. Logan's communications to this Society have 

 ceased. Appointed in 1842 to superintend the geological survey 

 of Canada his whole time and energies have ever since been devoted 

 to that important work. We have watched his progress with in- 

 terest, and now witness the result. And in congratulating him upon 

 it we must not forget that before this period no systematic exa- 

 mination of the geology of Canada had been undertaken. Up to 

 that time some partial attempts only had been made by a few 

 enlightened individuals to form a commission with the view to 

 examine the country, both geologically and mineralogically ; but it 

 was only in 1841 that the Chambers allotted a sum of ^1200, or 

 30,000 francs, for the geological examination of the province, and 

 Sir William Logan was appointed to carry out the work with Mr. 

 Alexander Murray as an assistant. The examination having been 

 thus commenced, it was continued under the government of Lord 

 Metcalfe by a second vote of 40,000 francs per annum, for five 

 * Proceedings of the Geol. Soc. of London, vol. iii. p. 707. 



