The Palaeobotanical Garden is Mata's outdoor fossil showcase, with petrified trunks set in a public garden rather than sealed away behind glass. It makes the town's ancient-forest story easy to grasp: these stone logs were once living trees in a landscape far older than the present pampas.
Go after the museum if you can. The garden is simple, but the sequence from labels and cases to open-air fossil trunks makes Mata feel less like a one-room curiosity and more like a place with a theme running through it.