The party was divided, the spies under Captain Quinn being sent to examine the country on the west side of the White Mountains, while the Major decided to inspect the territory to the eastward of the range.
Captain Quinn with his skilful trailers moved up the San Luis Valley until he reached the famous Mosco Pass, which was often used by the Apaches when hard pressed.

They were perfectly familiar with all its diverse and peculiar windings, and, when they once dashed in among the rocks, they felt safe against any and all pursuers.
Making their way through this pass, Captain Quinn and his scouts reached Wet Mountain Valley, where he had promised to meet and report to his superior officer..