But it was nothing like the atmosphere we know today.

This was a witches' brew of carbon dioxide, methane and steam

laced with poisonous hydrogen sulphide.

There was no sign of the gas we humans depend upon, oxygen.

This lethal mix was to endure for something like two billion years

until primitive life began to transform the atmosphere.

The sea here is full of life,

but these creatures aren't what I've come for.

It's these curious lumps I'm interested in.

They're important because every single plant and animal,

in fact, every single person on the planet,

owes their existence to them.

These bizarre blobs

Look Like boulders washed up on the foreshore but they're not.

They're actually alive.

These lumps are one of the earliest forms of life on Earth.

They're called stromatolites.