An extensive deposit of reddish brown and white stone, called Potsdam or Lake Superior sandstone, outcrops along the eastern shore of the Keweenaw Peninsula. George Craig, Senior, first identified the rock’s potential commercial value in the late 1860s or early 1870s, according to different reports. Despite the quality of the sandstone, Craig was unable to develop the necessary capital to open and operate a successful quarry. In 1883, John Henry Jacobs, for whom the village of Jacobsville is named, obtained a lease on the Craig property and began quarrying operations as Furst, Jacobs and Company. Jacobs’ other regional business interests included Wolf & Company Quarry in Marquette, later called the Marquette Brownstone Company. Jacobs’ father-in-law, Peter Wolf, marketed the attractive Keweenaw stone, which came to be known as Jacobsville sandstone, in Chicago. The stone was a desirable building material and was used extensively in residential and commercial buildings throughout the United States. Jacobs maintained a financial interest in the Keweenaw quarrying industry until 1902. At one time there were four quarries operating at Portage Entry. By 1899, Furst, Jacobs & Co., which bought out a number of small operations through the years, and Portage Red Stone Company merged and reorganized as the Portage Entry Quarries Company. By 1919, the best beds of stone that could be economically removed were depleted, and large scale quarrying operations ceased at Jacobsville. During the days of peak production, the sandstone quarries at Portage Entry were the third largest industry in the Copper Country.