Original sentence: Described in Samuel Lewis's A Topographical Dictionary of England (1848) as situated on "on a gentle declivity", Ashton-under-Lyne lies on undulating ground by the Pennines, reaching a maximum elevation of around  above sea level
Edited sentence: Described in Samuel Lewis's A Topographical Dictionary of England (1848) as situated on "on a gentle declivity", Ashton-under-Lyne lies on undulating ground by the Pennines, reaching a maximum elevation of about  above sea level