64 



Result — By the measured offset and azimuth, from this station, given 

 at the beginning of this article XI. the most northern cupola on the 

 top of the ticket-office of the rail road depot, is in — 



Latitude •- - - - 42° 29' 42".5 N. 



Longitude, west of Greenwich. - - 6h. 02m. 35.8s. 



Equal, in arc, to - - - 90° 38' 57" W. 



Dunleith is at the north-western terminus of the Illinois Central 

 Rail Road, on the east bank of the Mississippi river, and occupies the 

 site of the old Indian village o^ Sinipi. Extensive earth works, con- 

 sisting of mounds thrown up in oval forms by the tribe which formerly 

 resided here, still exist at Dunleith, in a state of perfect preservation. 

 We had no time to devote to them that minute exploration which 

 would no doubt show their contents to be similar to those of the numer- 

 ous Indian mounds examined by Professor J. A. Lapham, of Mil- 

 waukee, and described in his valuable memoir, published in the year 

 1855, by the Smithsonian Institution, under the title of "The Anti- 

 quities OF Wisconsin. " 



The position oC Sinipi (now Dunleith), is laid down on the map of 

 Nicollet, in latitude 42° 36' north, and in longitude, west of the meri- 

 dian of Greenwich, 6/t. 02/n. 38.6s. = 90° 39' 39"- Nicollet did 

 not, however, make any astronomical observations at this or any 

 other point on the Mississippi, between the " Head of the Upper Rapids, 

 below Port Biron and Parkhurst,"and "Prairie du Chien. We infer 

 from his report, that the extensive reach of the Mississippi, from lati- 

 tude 41° 36' 08" to latitude 43° 03' 06", was laid down on his map, 

 from the surveys made under the direction of the (general Land Office 

 of the United States, checked by his observations made at the two ex- 

 treme points above mentioned. (See his table of Geographical posi- 

 tions, page 123 of Senate Doc. No. 237, of the 26th Congress, 2d 

 Session.) Nicollet's longitude, thus derived, agrees very closely with 

 ours; but in latitude he is 6' 18" = 7^ miles north of us. Dubuque 

 is placed equally out of position, in latitude, on his map; but it appears 

 to be very correct in longitude. 



In the last map issued from the War Department of the "Territory 

 of the United States, from the Mississippi to the Pacific Ocean," these 

 cities arc laid down correctly in longitude, but they are placed four 

 minutes, = 4^^^ miles too far north in latitude. 



The boundary line between the State of Illinois on the north, and 

 the State of Wisconsin on the south, is defined to be along the parallel 

 of 42° 30' of latitude. 



