Complex sentence: By the following year the Yorkshire end had been extended to Gargrave, and by 1777 the canal had joined the Aire and Calder Navigation in Leeds and on the western side it reached Wigan by 1781, replacing the earlier and unsatisfactory Douglas Navigation.
Split into simpler sentences: By the following year the Yorkshire end had been extended to Gargrave, and by 1777 the canal had joined the Aire and Calder Navigation in Leeds. On the western side it reached Wigan by 1781, replacing the earlier and unsatisfactory Douglas Navigation.