From OREGON we have intelligence to the 25th of October. The rainy season had set in, but not with much severity. The Oregon Spectator states that emigrants from the Cascade Mountains were arriving every day, though quite a number were still on the way. It is feared that they will suffer severely, especially from falling snow, though the government was doing all in its power for their relief. Quite a number of them intend to winter on the Columbia, between the Cascades and Dalles, as they find excellent food for their cattle in that section. The amount of wheat grown in the territory during the past season is estimated at 800,000 bushels. MEXICO. We have intelligence from the City of Mexico to November 13th. The question of the Presidency, it is conceded, is definitely settled in favor of Arista. The financial condition of the Republic still engages the attention of Congress, which body is yet occupied in arranging the interior and foreign debt. General Thomas Reguena died on the 13th ultimo, at Guadalajara, and General Manuel Romero on the 31st, at San Louis Potosi. General Joaquin Rea, living at a village called Minerva, was, about the same time, murdered by one Felipe Delgado, and a band of scoundrels under his command. The _Siglo_ announces positively that the Mexican Government has concluded two contracts with Colonel Ramsey, for the transportation of foreign mails through the Republic. The Mexican Government will receive $20 for every 100 pounds of correspondence and 20 cents for every 100 pounds of newspapers. By another contract there is to be communication between New Orleans and Vera Cruz twice a month, between New York and Vera Cruz, by the way of Havana, twice a month, and between a Mexican port and San Francisco, once a month. It appears that at its session of the 18th of July last, the Mexican Geographical and Statistical Society elected Daniel Webster a corresponding member. The _Monitor Republicane_ learns by letters from New Grenada, that the Jesuits have been expelled from that country. The Congress of that Republic confirmed the decree of the Government with great unanimity. GREAT BRITAIN.