like R the cluster is about 5μm across] of four little bolupes - one is hidden behind the others as the point of the tetrahedron. Four spoke, and speaks, potently of meiosis and a pair of cell divisions . . . life itself.
Nuvvuagittuq on the Eastern shore of Hudson's Bay in Canada. These aren't tetrads, they are tubes about 20 microns across, and there is an outside chance that they are chemically driven crystal formation with no input from DNA. But the smart money is on them being the earliest, 3.7 billion years ago, evidence of life on Earth. They are close to the Nastapoka Islands if you want to GoogleMap their location. The local concentration of iron suggests that these creatures lived on or in close proximity to hydrothermal vents at the bottom of the sea. They were able to capture the heat and chemical energy and convert that into more of themselves. Photosynthesis, on which almost all the 'obvious' life on Earth today depends, comes waaaaay later. I'd call this pretty cool if it wasn't so smokin' hot down there back then at the dawn of time.
Some of the Nuvvuagittuq greenstone is the oldest rock we know about at 4.3 billion years old. Considering that the consensus for the age of the Earth itself is about 4.6 billion years, that is quite primordial. The rest of solid crust from those dim distant times has been rechurned: subducted into the molten interior to lose all of its layered and crystalline structure. These fossil tubes push back the origins of life; not least because we have to allow them additional time to get from tiny barely detectable - but still autonomously dividing - micron sized dots.