Complex sentence: Rising steepy behind the village is Yr Eifl and its neighbouring hills, where there is a granite quarry, "Trefor granite quarry" or the "Yr Eifl quarry" opened in 1850.
Split into simpler sentences: Rising steepy behind the village is Yr Eifl and its neighbouring hills. A granite quarry, "Trefor granite quarry" or the "Yr Eifl quarry" opened there in 1850.