St. Jofseph. ëapt. 24. The Pony Expresa, with Gulilbrniu nrtvices to the 12th iut., arrived here last night. fan Francitcn, Sipt. V2lh, 3:40 P. M. - The Pony Express, with Si. Louis chites to August 31st, arrived at Curson Yalley tliis morning. The tent h anniversaiy of tho admisión of California into the Union was celebrated by the pioneer in San Francisco by a partial suspens-on of business. A procession, nn oration, ncd a grand ball in tbe evening wcre had. At the Kepiiblican primary elcction? in San Francit-co on the Sth, ten out cf the twelvu district docided agamst. making a partisan nornination for locul offieere, and in favor of :in alliancc with the People'a Party in the muuici pal elcction. The Breckinridge State Convention ia in sei-sion at Sacramento. An electoral ticket wil] undoubtedly bo nomited, as inany of that party bi.'l;eve the State can be carritd for BrucklDtidge. Tbe Mariposa gold inine, on Col. FrotnontV grant, are reported to yield injinensely since tho complelion of his txtensive quartz milis. 'J lst week' yield was at the rate of nenrly 2000 per day. Sufficient census returns have been made to the Marshal to lorm a baeií for ontimutiiig the population ot California at 500,000. A fire at Sonora on the lO'.h destroyed $8 000 worth of property. Advices from Oregon to the 6th. Extravagant runiors prevailed respec ting the gilver mines in different parts of the Caseudy Mountains. The Portland Aetw, give the most encouraging reports irorn the Rock Creek gold minea. It representa the range to pay from five to ten dollars per day to tlie man. Iron ore hus been discovered iu tbe Caecade Mountaine.