the mills produced 12 million board feet (28,000 m³) of lumber. That total had risen to about 91,000,000 board feet (215,000 m³) in 1869, and 960,000,000 board feet (2,270,000 m³) in 1899. During the peak of this activity, at least 13 sawmills were operating on the falls. The sawmills also supported related industries such as mills that planed and smoothed the lumber; factories that built sashes, doors, and windows; and manufacturers of shingles and wooden buckets. The flour milling industry, dating back to the Fort Snelling government mill, later eclipsed the lumber industry in the value of its finished product. Flour production stood at in 1860, rising to in 1869. Cadwallader C. Washburn's imposing mill, built in 1866, was six stories high and promoted as the largest mill west of Buffalo, New York. Other prominent industries at the falls included foundries, machine shops, and textile mills. During this time, St. Anthony, on the east side, was separate from Minneapolis, on the west side. As a result of inferior management of the water power, St. Anthony found its manufacturing district declining. Some people and organizations started to talk about merging the two cities. A citizens' committee recommended merging the two cities in 1866, but a vote on this issue was rejected in 1867. Minneapolis incorporated as a city in 1867. The two cities found themselves competing with St. Paul, which had a larger population, the head of navigation of the Mississippi River, and more access to railroads. In 1886 Richard Warren Sears started a mail-order watch business in Minneapolis, calling it "R.W. Sears Watch Company," before relocating the business to Chicago and later founding Sears, Roebuck and Co., more commonly known as Sears. Threatened collapse of St. Anthony Falls The two cities were later pushed toward merger by a disaster that nearly wiped out the falls. The geological formation of the area consisted of a hard, thin layer of limestone overlaying a soft sandstone formation. As the sandstone eroded away, large blocks of limestone would fall off causing the falls to progress upstream. The expansion of milling and industry at the falls accelerated the process of erosion. If the fragile limestone cap ever eroded away completely, the falls would turn into a rapids that would no longer provide water power. The Eastman tunnel was a tailrace tunnel being excavated in the sandstone from below the falls, under Hennepin Island, under the