Complex sentence: The highest concentration of valleys is on the eastern edge of the Long Mynd, near Church Stretton, the geography of the valleys has many of the larger ones, adjacent to each other, running North West to South East.
Split into simpler sentences: The highest concentration of valleys is on the eastern edge of the Long Mynd, near Church Stretton. The geography of the valleys has many of the larger ones adjacent to each other, running North West to South East.