11. The underlying rocks are a Carboniferous Limestone along with some Millstone Grit to the east. 12. The geology of Oldham is represented by the Millstone Grit and Coal Measures series of rocks. 13. It is constructed of sandstone with Millstone Grit dressings and is built directly on the bedrock. 14. The Millstone Grit outcrops at the Cow and Calf Rocks near Ilkley form a rolling dissected plateau. 15. These were followed by dark marine shales, siltstones, and coarse sandstones of the Millstone Grit . 16. A major problem was the change in the rock type which ranged from soft earth to Millstone Grit . 17. The Millstone Grit Group comprises the Pendleton, Silsden, Samlesbury, Hebden, Marsden and Rossendale formations. 18. This suggests that early pastoral farming on millstone grit soil flourished in areas where lime was most easily available. 19. Many of the Millstone Grit boulders at the site are perched on pedestals of limestone up to 30cm high. 20. Parts of these sites were formerly quarried or gleaned for millstone grit but have now reverted to woodland and scrub.
