258 



SCIENCE. 



[Vol. IV., No. 84. 



ferred to in the address by the chair. The general 

 impression made by the address seemed to be that 

 the problems presented were not only important ones, 

 but too much so to admit of much discussion here, 

 and that they can be solved only by a large amount 

 of observation and field-work. 



The ten papers presented during the first day's ses- 

 sion, with one exception, related to the geology of 

 the dominion. 



The paper of Mr. Gilpin upon gold-mining in Nova 

 Scotia, that of Mr. Brown upon the apatite deposits 

 of Quebec, and that of Mr. Merritt upon the locali- 

 ties and output of economic minerals in Canada, 

 were more or less statistical, and, although important 

 in themselves, did not admit of much discussion. 



A short paper by Mr. Frank Adams of the Geologi- 

 cal survey of Canada, upon the occurrence of Nor- 

 wegian ' apatitbringer' in Canada, and its associated 

 minerals, although upon a subject mineralogical 

 rather than geological, was a valuable contribution in 

 itself, and drew forth an interesting discussion by 

 Dr. G. U. Williams of Johns Hopkins University. 

 Kecent studies of optical anomalies seen in many 

 minerals seem to show that not a few substances have 

 different crystalline forms at different temperatures. 

 One of these, pyroxene, has a tendency to pass into 

 hornblende when the temperature is lowered. Na- 

 ture may accomplish the same thing by pressure. 

 Such changes have been observed by Dr. Williams in 

 certain rocks in Maryland and New York, where 

 schistose structure and these changes appear to be 

 co-extensive. 



Mr. Honeyman's paper upon the geology of Halifax 

 Harbor was strongly dissented from by Dr. Selwyn, 

 supported by Professor Hitchcock, who insisted that 

 the rocks at that locality were lower Cambrian, and 

 not archean as stated, except perhaps in isolated 

 masses. 



The coal-fields of the dominion were treated of 

 directly and indirectly by Mr. Bailey of the Canadian 

 survey on the Acadian basin in American geology, 

 Mr. Gilpin on the distinctive features of the Nova 

 Scotian coal-field, and by Mr. Budden on the coals of 

 Canada. 



The Acadian basin borders upon and includes the 

 Gulf of St. Lawrence, New Brunswick, Nova Scotia, 

 Newfoundland, and Prince Edward Island, dipping 

 on all sides toward the gulf. Within this great basin, 

 the most important coal-fields are those of Cumber- 

 land, Pictou, and Cape Breton. The beds are more 

 or less folded; the axes of the folds are east-west; 

 and, except where they have been complicated with 

 older strata, there are no serious faults. Differences 

 between districts within this great basin are probably 

 due to local influences in the original basin, rather 

 than to isolation. Attention was called by Dr. Sel- 

 wyn to the contrast between this broken region and 

 the less-disturbed country adjoining it to the west 

 and north-west, which he considered was due to the 

 limiting of the disturbances by the great St. Law- 

 rence and Champlain fault. This fault is supposed 

 to follow up the St. Lawrence River from somewhere 

 in the gulf, to Quebec, where it leaves the stream, 



and swings more strongly to the south, and passes 

 down Lake Champlain to somewhere in the vicinity 

 of the Hudson River. To the east of this great fault, 

 the rocks are metamorphosed, folded and broken, 

 while to the west they are but slightly disturbed, and 

 dip at low angles. Besides the coal-fields occurring 

 in the St. Lawrence basin, the two other localities 

 within the dominion producing coal were referred 

 to ; one extending from the 97th parallel to the base 

 of the Rocky Mountains, the other on Vancouver's 

 Island. Of the three fields,, the first is in the carbon- 

 iferous, while the last two belong to the secondary or 

 tertiary formations. But little is known as yet of 

 the coal of north-west British Columbia, while that 

 of Vancouver's Island is said to be the best on the 

 west coast. 



Mr. Panton's contribution upon the Silurian strata 

 of Red River Valley, Manitoba, was of local interest, 

 and referred to a structure that is not indicated upon 

 the new geological map of the dominion, for want of 

 sufficient information. The same material is already 

 in the hands of the Canadian survey, and will appear 

 in due time. 



The principal discussion of the first day's meeting 

 was called forth by Professor Claypole's paper upon 

 the crumpling of the earth's crust as shown by a sec- 

 tion across Huntingdon, Juniata, and Perry counties 

 in Pennsylvania, a distance of sixty-five miles. The 

 speaker showed that the folding of the strata along 

 this line, and especially of those in Cumberland val- 

 ley, has caused a shortening from an original length 

 of about one hundred miles to the present sixty-five 

 miles. Although Professor Claypole's method of 

 obtaining the original length of this line was a mathe- 

 matical one, and though the folding of the Cumber- 

 land-valley strata is a series of overturns, such an ex- 

 tensive contraction of the earth's crust was more than 

 the section was prepared to accept without question. 

 Doubt was expressed in regard to the trustworthiness 

 of the data; while another member, in endeavoring 

 to solve this very problem, basing his estimates upon 

 Professor Lesley's maps, had computed a contraction 

 of eighteen miles over a part of the section where 

 Professor Claypole had made out thirty-two. It was 

 also suggested that the thinning of the beds by 

 crushing in the folded parts had been left out of 

 account. 



It was replied to these objections, that the data 

 were as trustworthy as it was possible to obtain ; that 

 absolute accuracy was not claimed for the figures, 

 for in such a case it was impossible; and that, at the 

 least estimate, the eighteen miles remained to be 

 accounted for over one part of the section line. The 

 possible thinning of the beds had been left out of 

 account, because, if such a thing had taken place in 

 this instance, it was more than counterbalanced by 

 the tangential pressure that caused the folding. 



The 29th was devoted to the discussion of phe- 

 nomena relating to, and supposed to be the results of, 

 glacial action. Professor Lewis spoke upon the mar- 

 ginal kames of Pennsylvania as distinguished from 

 the moraine ; and Dr. Newberry followed with a short 

 lecture upon the last phases in the evolution of the 



