Xenolith at Skinburness

 We found this rock on the beach at Skinburness. It is Criffel granite. You can just see Criffel under the cloud across the water.

Criffel granite is an igneous intrusion. The hot magma welled up under the surface but never broke through. Granites can take up 1 million years to solidify so they grow big crystals. However, the grey lump is not a crystal. As the magma came up, it pushed into rock that was already there. They call this "country rock". Sometimes bits break off and fall into the magma. The rock solidifies around the intruder. The intruder is called a xenolith.