u. S. EXPLORING EXPEDITION.jl'ruin the Heepe Uiver Reveille, loth.]A portion of the Wheeler exploring party, en route for Arizona, parsed through our streets this morning ami encamped at the Summit. This detachment is in command of Surgeon Cochrane, and proceeds from here to Belmont when* it joins the main division under i.t. G. M. Wheeler of the corps of engineers.It is expected that they will remain several davs with us, and the►geologists of the party. Messrs. Gilbert and Smith, will take a look at the Austin mines.A good many citizens will he interested to learn that the curious one-wheeled vehicle that accompanies the train is an odometer and is used to measure the distance traversed.The party here includes eight civilian assistants -topographers, geologists, etc.—Seven packers and ail escort of seventeen soldiers, with aoack train of fortv mules. The ▲ » twork tliev have before them is to survey and map the unexplored portions of southern Nevada and northern Arizona. To accomplish thi* ; the latitude and longitude of promi- : Yient points will he determined by thorough astronomical uber\ation, and the intervals surveyed hy ex-2»erienced top*»graphers. A portion