U.S. scouts discovered the Mexican position at a key ford along the San Gabriel River on January 7, 1847. Approaching from the south, Stockton and Kearny planned a crossing for the next day. The U.S. forces were formed into a hollow square with the artillery and baggage in the center. Kearny ordered the artillery unlimbered to cover the crossing, but Stockton countered the order and began to move across the river. The crossing proved to be especially difficult because Flores was in a good position to contest the crossing from the high banks across the river, and the ford had patches of quicksand at the bottom of the knee deep water.