During the
Pleistocene, massive runoff spilled from the
Sierra Nevada into a chain of inland seas. The system of interconnected lakes stretched from
Mono Lake to
Death Valley and included Searles Lake. Deep beneath Searles Lake, calcium-rich groundwater and alkaline lake water combined to grow tufa formations. Similar (modern) formations can be found today at Mono Lake to the north. Known as tufa pinnacles, these strange shapes formed underwater 10,000 to 100,000 years ago. The pinnacles did not all form at the same time. They are divided by age and elevation into three groups. The groups are dubbed the northern, middle, and southern groups because they formed during the three ice ages. The northern group is the youngest at 11,000 to 25,000 years old. These are the best examples of what are known as tufa towers. The northern group also include shapes called tombstones, ridges, and cones. The small middle group claims only 100 spires, but boasts the tallest "tower", rising . The southern group includes 200 tufa formations aged 32,000 to 100,000 years old. People have historically given names to the strange forms. These ancient spires were once dubbed "Cathedral City". Geologically, the pinnacles are classified into four general shapes.
Towers are taller than they are wide and rise .
Tombstones are stubby and squat and rise . Most tombstones are in the northernmost tufa formations.
Ridges are massive toothy tufa ruins. Trona has three ridges, one in the northern tufa cluster and two in the middle group. One ridge is long and wide and tall.
Cones are less than tall. Dumpy and mounded, cone shapes lie scattered throughout the Trona Pinnacles. ==In media==