While they are in the Southern part of the Pennines, the Pennines are divided into a series of distinct geographical areas based either on the geology of the area and/or the natural boundaries provided by the major river valleys. The above-mentioned hills are considered to be in the 'Dark Peak' (i.e. consisting of millstone grit), while to the South is the 'White Peak' (consisting of magnesian limestone). The 'South Pennines' are generally considered to be the area South of Airedale/Ribblesdale and North of the Etherow and Don valleys.
Ah, ok - thanks. Yes, I was aware of the Dark Peak and White Peak for the areas further south.
I did once (in the year 2000, with my last-ever journey on a first-gen DMU being the transport there) do the southern part of the Pennine Way. I went as far as Horton, before turning westwards over Ingleborough and Whernside and eventually to the Lake District, and can see that the hills did divide into these areas. The "South Pennines" area definitely seemed lower and less wild, compared to both the Dark Peak to the south of it, and the Dales to the north - and an entire day's worth of walking, from Lothersdale (had to look it up, it's been a while) to Malham appeared to be completely over lowland country.