Notable landforms, such as the Cheyenne Mountain on the city's southwest, were formed of Precambrian Pikes Peak granite uplifted in the Ancestral Rocky Mountains. Formation of the city's hills—including the Mesa, Institute Heights, and Knob Hill—created valleys for the Camp, Cheyenne, and Fountain creeks which enter the city on the west; Monument Creek from the north; and Cottonwood & Sand creeks (east). Bluffs formed with American Lower Eocene coal deposits of the Colorado Springs lignite field. Eponymic mineral springs, which flowed in 1912 from aquifers under the elevated landforms, included Horn's Mineral Springs at 1210 Lincoln, Monument Springs on Monument Creek's west bank in Monument Valley Park, and Jimmy's Camp Springs. There were also other springs located at that time on Bijou, Kiowa, 7th, and Cucharra streets and West Cheyenne Road.