One of the party, De Rossier, became insane on March 1st, and Frémont says: "Hunger and fatigue joined to weakness of body and fear of perishing in the mountains had crazed him. The times were severe when stout men lost their minds from extremity of suffering, when horses died, when mules and horses ready to die of starvation were killed for food, yet there was no murmuring or hesitation." Sutter's Fort, on the Sacramento, was then the most important American establishment in California; the fort itself was an adobe structure defended by twelve pieces of artillery. Sutter had a large force in his employ engaged in farming his extensive wheat-fields, in milling operations, in blacksmith- and other work-shops. One might have thought that Frémont would have delayed long in the delightful climate and conditions that obtained at Sutter's, but such was not the nature of the man. The entire party were reunited at Sutter's Fort on March 8th, and under Frémont's well-directed efforts, in the short space of fourteen days the starving band was reorganized, remounted, and equipped fully for instant march. The return journey was to be through the pass at the head of the San Joaquin River, discovered by Walker, whose name was affixed to it by Frémont. Crossing the Sierra Nevada the party struck the Spanish trail, which was then followed by all wagon-trains or mounted parties travelling to and fro between Los Angeles and Santa Fé. The region over which they passed was desolate in the extreme, the road rough and rocky, grass scanty and poor, while water was found only in holes and at long distances, In pointing to it, Frémont's Spanish guide well states: "There are the great plains; there is found neither water nor grass--nothing; every animal which goes upon them dies."