NATURAL SCIENCES OP PHILADELPHIA. 107 



indicated during at least twenty years in elementary treatises. Again, although 

 a citizen of Pennsylvania — a State one of whose most remarkable evidences of 

 wealth is the fact that she is the holder of the great anthracite basin and of n, 

 portion of the chief bituminous measures — although a resident of Philadelphia, 

 whose principal domestic export is coal, it is assumed that 1 could overlook the 

 fact that there are vast deposits of coal in North America. It ought, perhaps, to 

 be said in this connection, that the author has wholly misunderstood my observa- 

 tions with respect to tlie comparative quantities of vegetable product in the car- 

 boniferous period and that in which we live. Considering that we do not know 

 the extent of the area of growth in the carboniferous period, nor the length ot 

 time consumed in forming the deposits of vegetable matter which make the coal 

 beds ; and taking into view solidity as well as size, and the multiplication of indi- 

 vidual growths, it is certainly not going very far to say that it is not " patent to 

 all " that the total quantity of vegetable growth upon the earth during a given 

 space of time was greater in the carboniferous than in the present period. I 

 made no affirmative assertion ; and in the absence of conclusive i^roof, I have 

 none to make now. It is enough to indicate the irrelevance of the reasoning 

 employed by the author upon pages 174 and 1*75. 



With respect to the scientific criticism which has occasioned these remarks, 

 it gives me no concern. It, or its equivalent, will be judged by proper persons. 

 It has been in the handsof many whose minds have been disciplined in the best 

 methods of inquiry ; and from no quarter had I reason to suspect the existence 

 of dissent until the appearance of the book before us. It is to be hoped that 

 on both sides of the Atlantic there will be cultivated a mutaal confidence, which 

 shall prevent misconception of motives ; and that hereafter the vigilance which 

 is indispensable to preserve the pursuits of philosophy from unconscious bias, 

 shall not be misconstrued as the intrusion of an unfriendly spirit. Felix quern 

 faciunt aliena pericida cautum. In conclusion, I beg to renew the expression of 

 my regret, that any accident should have made me the occasion of pain to a 

 gentleman so deserving of our consideration and friendly esteem as was the 

 author of "The Testimony of the Rocks." It cannot but enhance the appro- 

 priateness of such an expression at this meeting, that beside yourself and your 

 colleague, the other Vice President, who usually preside over the deliberations 

 of the Academy, I see here to night its venerable President, and several other 

 learned members, whose names are familiar to cultivators of the natural sciences 

 in Great Britain. 



31ay 12th. 

 Vice President Bridges in the Chair. 



Communicatious were received, for publication in the Proceedings, 

 entitled, as follows : 



Notes Explanatory of a Map and Section illustrating the Geological 

 structure of the country bordering on the Missouri River, from the 

 mouth of Platte River to Fort Benton, in lat. 47" 30' N. long., 110^ 

 30' W., by F. V. Hayden, M. D. 



On the Larva of Thyreus Abbottii, by J. P. Kirtland, M. D. 



Which as usual were referred to Committees. 



Mr. Harris observed, in relation to the specimens of cotton-wood and chips 

 cut by beavers, presented this evening, that they had been obtained by him 

 from the Missouri River, between Fort Union, at the mouth of the Yellowstone, 

 and Fort Clark, at the Mandan Village. He added, that in returning from a 

 trip up the Missouri to the mouth of the Yellowstone, in company with the late 

 J. J. Audubon and party, in the month of September, 1843, our Mackinaw boat 

 was moored for the night on the right bank of the river, under shelter of timber 

 on the bank, which was here about twenty feet above the water at its then 



1857.] 



