Complex sentence: It is nowadays represented by two separate administrative divisions ("comarques") which are part of the Barcelona Province: the Western Vallès, which has two capitals, Sabadell and Terrassa; and the Eastern Vallès, with Granollers as its capital.
Split into simpler sentences: It is nowadays represented by two separate administrative divisions which are part of the Barcelona Province, named. One of them is the Western Vallès, which has two capitals, Sabadell and Terrassa, whereas the second "comarca" is the Eastern Vallès, with Granollers as its capital.