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  February 5, 2001

Earthly Matters Slabs in Babbidge Library Recall
Ancient Waves on Sands of Time

When I go to the beach, I run to the water, dive into the waves, and swim out to the nearest sand bar.

I also do this in February - in my imagination - in Homer Babbidge Library. There, in the north entrance, at the top of the stairway, perfectly centered in the foyer, is a large bluish-gray slab of sandstone. It formed on a beach not unlike those gracing the Atlantic shores today.

Sometimes, while walking into the library on an errand, I pause on my favorite slab and imagine the waves of some ancient sea. Once, a colleague asked me what I was doing. "Just thinking," I replied. Left unspoken was my trip to a beach, somewhere, sometime in prehistory.

Most of the building materials in the library's foyer - benches, walls, railings - are made of synthetic rock. But the "bluestone" floor of the foyer is authentic, composed of beautiful slabs of quarried rock. Most are faintly striped with small ridges and hollows spaced several inches apart. Each ridge is a ripple, one of thousands that formed as the sand was being moved parallel to shore by a "longshore current," like those forming coastal barrier islands today. Each trough is the hydraulic hollow from which the ripple obtained its sand.

Although the details of this former environment remain unknown, the asymmetric profile of the ripples and their spacing relative to the sand texture - a clean, fine-to-medium sand - suggest a firm, smooth bottom, a steady current less than a mile per hour, and a depth about waist-deep.

Sharks - ancient marine creatures - would have been part of this ancient scene about 300 million years ago, during the Devonian, when shallow seas repeatedly invaded the eastern side of what is now North America.

I traced the source of the stone to a quarry on Bear Mountain, about 50 miles west of Binghamton, N.Y. The consulting geologist in charge confirmed my interpretations about the stone, which is being sold under the trade name "Elk Brook Bluestone."

The short version of this story told in stone is: "É ancient continent disintegrates into sand, gets washed onto the coastal plain by large rivers, is re-worked into a broad beach, is deeply buried, converted to rock, and returned to the earth's surface by erosion. It is then quarried for use, hauled nearly a thousand miles to the east, and placed in the center of campus for aesthetic considerations - and, perhaps, for at least one geologist to delight in."

There is an old saying that we must take time from our busy lives to "stop and smell the roses." I agree. I also take the time to dive into the past.

Robert Thorson