The Odd Fellows Hall was originally two separate, one-story buildings built of dressed schist slabs set in lime mortar. Schist was plentiful in the area and proved to be an excellent building material. Lime had to be shipped in from a quarry near Sonora.

This was an excellent method of construction, utilized by many of the Gold Rush era buildings that still remain in the Southern Mines. The five large iron doors are set in perfectly squared brick frames. The second story was added in 1924 and is reached by a covered outdoor stairway.

The east half of the lower story housed Kent and Grant's Mercantile. The west half housed Michael Gilbert's grocery store.

Both buildings survived the fire of 1863 which destroyed the original Odd Fellows Hall. Shortly after the fire, the Odd Fellows Grant's store and in the 1880s, they purchased Gilbert's store.

The similarly constructed Gamble Building was the only other building in Big Oak Flat to survive the fire.

Source: The Virtual California Gold Country: Highway 49 Revisited

Mining camps started as clusters of tents and other makeshift shelters. If the mine was productive, wooden buildings were erected and a town was born.

Conflagrations were a recurring curse. Often entire town were repeatedly destroyed by fire. Stonemasons, especially Italian immigrants from Liguria, began building "fire proof" banks and stores of stone or brick with iron doors and iron window shutters to protect the contents from fire.

Many of these stone buildings survive. Some of them, such as the Butte Store, are the sole reminders of a lost mining town.

Some of these buildings are:

The Independent Order of Odd Fellows (I.O.O.F.) is an altruistic fraternal organization derived from the similar English Oddfellows service organizations which came into being during the 1700s....Although in Britain the Odd Fellows tended to meet in pubs, in the U.S. the lodges often built their own facilities. Many of these are now on the U.S. National Register of Historic Places....

From Wikipedia entry for Independent Order of Odd Fellows