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Two years ago, I scrambled into a six-foot-deep soil pit dug into this hillside to examine the crumbling phyllite rock just below the topsoil.

Crouching in the dirt, I could see grass roots reaching deep into the soil, and crumbling rock called phyllite that spoke of centuries of evolution and decay.

The soil is phyllite, or decomposing slate, the rock easy to crumble by hand.

“Heat and pressure squeezed these layers and recrystallized them into schist” — after intermediate periods as shale, slate and phyllite.

It takes your basic quiet marine shales, which had been resting peacefully in nice horizontal layers on the sea bed, and squeezes and cooks them into phyllite.