Lake Thetis is one of the few places on earth where stromatolites – aka Living Fossils are to be found. They are built by microbes called cyanobacteria which are similar to the earliest organisms that produced oxygen for subsequent life forms. They have been growing here for about 3500 years. These rocklike formations teem with micro-organisms that are invisible to the human eye but these living communities of varied residents have population densities of 3000 per square metre!

The lake has a circumference of 1.2 metres, with an easy walking path looping around it. It is said to have been separated thousands of years ago from the sea.

A walk down a gravel path

and then up a boardwalk and one reaches the lookout platform

which has good, informative sign posts.

An aborigine legend about this lake goes thus:

The stromatolites are our only doorway into the emergence of life way, way, back in cavernous time. A small piece of stromatolite is encoded with biological activity that is thousands of years old.

This community is threatened by nutrient enrichment and physical crushing, so visitors are requested to keep off these extraordinary forms.