Margaret knew the Rhynie chert better than anyone alive.
The silicified hot spring deposits, 407 million years old, preserved in extraordinary detail the moment when life first colonized land. She had spent thousands of hours peering through microscopes at cellular structures frozen in stone—the tracheid cells of early vascular plants, the hyphae of symbiotic fungi, the cuticle patterns that revealed how organisms managed water in an environment their ancestors had never faced.
She had published monographs on its plant communities, its fungal associations, its arthropod inhabitants. Her mental map of Devonian Rhynie was precise enough to sketch the probable positions of hot spring vents, the gradients of temperature and chemistry that shaped what grew where.
But she had never seen it.
"Navigation parameters locked," ARCHIE said. "Temporal coordinates: 407 million years before present. Geographic coordinates: the Rhynie basin during the Early Devonian."
"Jennifer," Margaret said, "stay close. I don't know how I'll respond to this."
Jennifer's hand found hers. "I've got you."
The descent began.
Time peeled back in layers Margaret could feel through the synthesis.
They passed through the Mesozoic, the age of dinosaurs compressing into a blur of scaled and feathered forms. Through the Permian, with its sail-backed synapsids and the great dying. Through the Carboniferous coal swamps.
And then the Devonian opened before them.
Mar…
