Sai Kung's geological wonders are mostly clustered on its eastern flanks, but Lai Chi Chong is uniquely on the western side. Accessible by ferry from Ma Liu Shui or on foot by an easy hiking trail from Hoi Ha, the coastline has a lot of colourful volcanic sedimentary rock formations extending about 500m from the pier. Over 140 million years ago, this area was a volcanic lake where ash settled and mixed with silt and organic matter.
I opted to walk to this small coastal village. From Sai Kung's town centre, take minibus 7 bound for Hoi Ha, which is a marine reserve. Get off at Pak Sha O near the end of the line and follow the paved path to Lai Chi Chong, which takes under an hour heading downhill.
The village was small and had no shops. Continue down towards the coast, past the wetlands, and you will see the pier.