The Stone Forest area was a shallow sea some 270 million years ago. Extensive deposits of
sandstone overlain by
limestone accumulated in this basin during the
Permian period of geologic time. Uplift of this region occurred subsequent to deposition. Later, exposure to wind and running water shaped these limestone pillars. These formations extend as far as the eye can see, looking like a vast forest of stone, hence the name "The Stone Forest". The Major and Minor Stone Forests are developed in the nearly pure limestone of the Permian Makou Formation. The Naigu Stone Forest, 9 km northeast of the Major Stone Forest, is developed in
dolomite and
dolomitic limestone of the Permian Qixia Formation. Both formations are of Lower Permian age. They aggregate 505 m in thickness and consist of shallow water (platform) massive limestone and dolomite, bio-clastic limestone,
calcarenite and
calcilutite. The Maokou Formation at Stone Forest appears to have been heavily altered
diagenetically, and macroscopic fossil remains are seldom seen. Under the microscope, single whole or fractured
fusulinid foraminifera are seen, commonly in biomicrite, biopelmicrite to biopelmicrosparite limestones. At least one zone of
chert nodules occurs in the limestone. Unlike in the dolomitic Qixia Formation, dolomite in the Maokou Formation seldom ranges above 3%. The strata are part of a gentle (2-6 degree) westward
dipping monocline. Conjugate
shear joints (NE-SW and NE-SE) are well developed and these fractures provided the main passageways for surface and underground water in the pre-karst development stage. The distribution, density and orientation of the fractures controlled the depth, size and orientation of the karst topography. Sandstones and shales of the Liangshan Formation that lies below the carbonate rock formations serve as a
permeability barrier and force the local groundwater to flow from west to east. ==Flora==