Proceedings of the Academy. 193 



long time before the 'beaver will be exterminated. The otter will be retained longer. 

 The deer will soon be exterminated. The last wild turkey was killed in '4G, at which 

 date a llock was killed in Kacine. 



5. On the climatic Relations of the Flora of Wisconsin, By 

 Hon. J. G. Knapp, of Madison, 



6. On the Results of Recent Investigations in the Lead Re- 

 gions of Wisconsin. By J, Murrish, State Commissioner. 



In entering upon the survey of the lead district, he found that, while there were con" 

 flicting opinions among miners in reference to the origin and nature of the fissures in 

 connection with which ore deposits were found, they were nevertheless all agreed on 

 this point, that there is a strong tendency in these fissures to an east and west direction. 



They also recognized the fact that these so-called east and west fissures were occasion- 

 ally intersected by another set of fissures at right angles, thereby presenting the famil- 

 iar feature of mineral strata noticed in all mining regions, 



In ex.nminiuing into these facts to satisfy himself in reference to their correctnese, he 

 had noticed, in looking over the various mines which had been opened, that, while the. 

 difl'erent mineral ranges and mining centers were separated from each other by a space 

 of barren ground, there was nevertheless a grouping of t ese ranges or mining centers 

 on the east and west direction. 



Further observation proves that they were confined to certain belts of land having an 

 east and west bearing. For instance, if we commence in town six, with what mining 

 there is done in the town of Fernimore, in Grant county, and extend east wilh a stiip of 

 land three or four miles wide through a large portion of that county and the whole of 

 Iowa county to Blue Mounds, in Dane county, we shall include in that strip all the 

 mines of ^''ennimore, Wingville, Dodgeville, Ridgt-way, Porter's Grove and Blue 

 Mounds, giving us a belt of land through town six for a distance of over fifty miles. 



If we extend our observations south from this belt to Mineral Point, we shall find our- 

 selves on tlie center of a parallel belt, extending east and west from that place. If from 

 thence to Platteville, in Grant county, on the third. If from taence to Hazel Green, we 

 shall find ourselves on the fourth, alT having about the same eastern and western exten- 

 sion. The lead district thus naturally divides itself into four distinct belts, conforming 

 evidently tn underlying causes, that have given origin to these peculiar phenomena. 



But, striking as the evidences of the action of underlying physical forces along these 

 and west belts are, he was disposed, nevertheless, to regard them as subordinate to a 

 stronger line of forces that have acted in a north and south direction, across which these 

 belts are found at right angles. If, for example, we draw two lines from the eastern and 

 •western boundaries of the lead district, north and south, through the Mississippi valley, 

 we shall include with our own lead district the lead districts of Iowa and Illinois, also 

 the lead and iron mines of Missouri. 



On the north, from what little we know along this line, we have a series of undulations 

 or anticlinal lims, along which large deposits of iron are found. Among the most noted 

 is the Penokee Iron Range, in town forty-four. These undulations of the strata, in their 

 bearin2 and extension, resemble very much the mineral belts of the lead districts, and 

 are collateral evidences, if nothing more, of an underlying north and south line of phy 

 sical forces of great extent. 



7. On the Laws which Govern the Configuration of Comets, 

 By Hon. J. Y. Smith, of Madison, 



This paper gave: 



1st, A statement of some general facts concerning the constitution and form of comet- 

 ary bodies. 



2d, A brief outline of the theory of Prof. Peirce, of Cambridge, concerning the forma- 

 tion of the tails or trains of comets, viz: That a power of repulsion in the comet itself 

 first throws oft' matter from the general mass as it approaches the sun, and that the sun 

 exerts a rejielling power upon the matter thus thrown off', driving it past the nucleus into 

 space and thus forming the train, so far as elongation is concerned— the curve being pro- 

 duced by the particles thrown into a wider orbit falling behind those pursuing a nar- 

 rower one. 



3d. Three objections are brought against this theory, so far as the elongation is con- 

 cerned: First, that the laws which are supposed to produce the phenomenon of elonga- 

 tion are assumed, there being no positive evidence that any such power of repulsion ex- 

 ists, either in a comet in respect to its own matter, or in the sun in respect to the mate- 

 rial of a comet. Secondly, if the existence of these forces be admitted, still it is not 

 shown why they should take efi'ect upon one portion only of the cometic matter and not 

 upon the whole of i', nor what is to limit their ettect upon those portions uoon which 

 their power is exerted; and thirdly, that it ignores the existence and efficiency of well 

 known laws which must inevitably produce the phenomena in question, viz., tlio laws of 

 gravitation, acceleration and momentum acting upon extremely attenuated matter 

 movin<r in a highly eccentric orbit. 



The theory advanced by Mr. Smith is, in substance, as follows: Cometary matter at 

 repose in space or but slightly acted on by solar attraction, (the latter being the condi- 

 tion of most comets at their aphelia,) possessing fluidity and gravity, however slight the 



