The town entered a major period of growth during the Industrial Revolution, as new mills were constructed to process cotton. The climate and weather were conducive to the industry, as was the town's nearby location to the rapidly developing industrial and mercantile centre at Manchester, dubbed 'Cottonopolis'. Only a few of these mills survive today, and none are still operational. During this period, the brothers Thomas, David and Peter Whitehead became important entrepreneurs in the town. They built a number of mills, including one of the earliest mills in the valley, at Lower Mill, and the still existing Ilex Mill. They also built substantial houses for themselves at Holly Mount, as well as large numbers of terraced houses for their workers. Other industries active in this period included quarrying and small scale coal mining, as well as an expanding commercial sector.