Complex sentence: The fortunes of Furness changed dramatically in 1840s and 1850s, when William Schneider found iron ore deposits at Dalton-in-Furness, these deposits were spread throughout the Dalton area in Askam, Lindal & Roose as well as Dalton.
Split into simpler sentences: The fortunes of Furness changed dramatically in 1840s and 1850s, when William Schneider found iron ore deposits at Dalton-in-Furness. These deposits were spread throughout the Dalton area in Askam, Lindal and Roose as well as Dalton.