

* 



THE 



AMERICAN 



JOURNAL OF SCIENCE, &c 



Art. I. o 



Fort Winnebago } Mich 

 of the U. S. army. 



>/ 



5 



Fort Winnebago is situated 43|° N. lat. and 12° W. Ion. from 

 Washington. The general character of the country is secondary ; 

 and the soil within the section this survey contemplates, varies be- 

 tween calcareous, argillaceous and siliceous. The most striking fea- 

 tures are the various combinations of water, marsh and upland, 

 which, perhaps, render this particular spot as interesting to the geol- 

 ogist, as any equal portion of a country but partially explored. 



Here is a summit level from whose sources the waters of the St. 

 Lawrence and Mississippi flow to the extremes of our republic. 

 This summit level is called the Winnebago Portage, and is a marsh 

 of one mile and a quarter in breadth, between the Wisconsin and 

 Fox river, over which at times of high water, boats freighted with 

 from twenty to forty tons, pass without interruption ; and at ordinary 

 stages of water, this, although the principal, is very far from an in- 



Port Winnebago, M. T., May 20, 1835. 



* To Prof. Silliman. — Sir — Having been assured that a brief geological sur- 

 vey of this section of U. S. Territory, would interest scientific men generally, and 

 be considered worthy, perhaps, of the medium which your valuable Journal 

 affords, I am induced to throw into form, some observations I have made during 

 my residence here. - 



The observations, I must add, do not profess to be purely geological, but of a 

 mixed nature, so as to embrace the most prominent objects of interest which sur- 

 round us. The accompanying map, is the result of observation and not of ad- 

 measurement, consequently it cannot be rigidly accurate. It has been submitted 

 to the examination of several gentlemen well qualified to judge, but no material 



errors have been pointed out. I submit it, Sir, although with diffidence, to be dis- 

 posed of at your pleasure. Yours, &c. D. Rugoles. 



Vol. XXX.— No. 1. 1 



