The Southern mines centered around the San Joaquin River city of Stockton. The dividing line between the Northern mines is usually considered to be the ridge between the Consummes and the North Fork of the Mokelumne River. But as the Consummes is itself a tributary of the Mokelumne and both rivers empty into the delta region where the Sacramento and San Joaquin Rivers meet, the true boundary was often a personal judgment of the individual miner. But that still left the extent of the Southern mines, in the early days of mining and in terms of territory, population and gold production, to be roughly equal to those of the Northern mines, but the available gold in the south, except for the quartz veins, was exhausted much more rapidly than in the north.
While there were many rich sites along the Consumnes there were few well-known points of interest except for Indian Diggings, although Michigan Bar, Newtown and Grizzly Flat are worth mentioning. Michigan Bar sat along the river in the lower foothills, similar to Mississippi Bar on the lower American River, but it was quickly mined out. Newtown was eight or ten miles southeast of Placerville on the North Fork of the Consumnes and, along with Grizzly Flat, eight or ten more miles to the southeast, had a certain amount of both hydraulic and quartz mining. The town of Grizzly Flat was small and the quality of gold found there was poor since it was mixed with too much silver and other base metals.
But Indian Diggings, 25 miles southeast of Placerville was a brisk and lively place with several hundred miners working there almost all the time and up to five or six hundred at its peak and was the northern most point of what was called the great limestone belt that ran south some 40 miles to the neighborhood of Columbia and Sonora. In some places the limestone had turned to marble while in others it rose in ridges through the slate. It was filled with numerous fissures and caves, and though the caves were not extensive several had stalactites and stalagmites of great beauty.
At Slug Gulch near Indian Diggings, a shaft was sunk through the limestone into what was supposed to be a layer of boulders and pay dirt. But, seemingly by accident, a mining ditch was turned into the shaft and the water allowed to run for several days without any accumulation of water in the shaft. Whether some ancient buried gravel riverbed soaked up that water or, like the River Alph, “it sank through caverns measureless to man, down to a sunless sea” was never made known.