Dalmahoy and Kaimes Hills
The Dalmahoy and Kaimes Hills form a prominent landscape feature in the south-west reaches of Edinburgh. They are composed of hard igneous intrusive rocks which are more resistant to weathering than the surrounding sedimentary rocks. These were formed when magma forced its way between beds of sedimentary rocks and cooled underground as a sheet (sill). The sedimentary rocks have since been removed, leaving towering cliffs of columnar jointed micro-gabbro (dolerite), a medium grained igneous rock rich in iron and magnesium. This is a type example of the ‘Dalmahoy Sill’ with similar rocks cropping out within 10km to the south and west. Many of Edinburgh’s high points are capped with these hard, igneous sills. However, this particular sheet (330 million years old) pre-dates the more prominent Midland Valley Sill that is seen at Ratho and adjacent quarries.