The geology of the Lizard is perhaps the most spectacular aspect of this area, as parts of the peninsula are the remains of the ancient ocean floor formed almost 400 million years ago that were pushed up towards the surface, when the African plate collided with the Eurasian plate some 300 million years ago. The rocks on the Lizard complex represent a fragment or slice of continental and oceanic components that have been thrust faulted (obducted) over younger rocks.
As a result of plate collision the Lizard has two distinct areas separated by the Lizard Boundary Faultline (LBF), the Lizard Platform and the Meneage.
The Lizard Platform to the south of the fault line is the remains of the ocean floor that were pushed up to the surface resulting in dramatic cliffs with rugged foreshores and wild heathland. This area is also devoid of high landmarks as the landform is predominantly a flat surface at aproximately 120m above mean sea level. Due to the toxic nature of serpentine and resulting poor soils the area has a distinctive flora of slow growing plants. The most famous local plant is the rare Cornish Heather, (Erica Vegans), which flowers from mid summer till October, forming beautiful swathes of colour on the cliffs and heathlands.
In contrast to this, the Meneage (Cornish for "Land of The Monks"), the area north of the fault line that arcs around the peninsula, has been eroded into deep wooded valleys resulting in a place of lush rolling hills, fertile farmland, valleys and ancient woodland including the Helford River and Gillan Creek.
The western edge of the Lizard boundary fault is exposed in the cliffside at Polurrian Cove close to Trenance Farm. Each time you walk down to Polurrian Cove you walk over the local geological fault line. The eastern edge of the boundary fault line meets the coastline at Porthallow.