Urban Ecology: Stones or Rocks?
A Rock in the City
My big rock, was in fact a scaled up version of a
|The Newark rock. Photo: Victoria Marshall|
creek pebble, but the water in which the lonely Ironbound boulder was shaped was the water released by a mile-high mass of ice as it melted. Such meltwater streams were huge, and they could carry rocks half the size of a first-generation suburban tract house. Those streams tumbled the big and the small rocks that had been dislodged and trapped as the ice ground across the surface of northern North America some 20,000 years ago. And this one was a good sized, but not a gigantic representative of glacial grinding followed by years of tumbling down the huge glacially fed precursor of the Passaic River. The Passaic River is now a pretty respectable stream. But when the glaciers were melting, it would have been much larger, and been joined to a sibship of other massive streams coursing toward the then distant Atlantic coast. As the glaciers were exhausted by their own melting, the massive streams shrank and left deposits of mixed, smoothed sediments, pebbles, cobbles, and boulders.
Stones in the Country
|Art Deco switching station lower left, old stone barn upper center. Bing.com|
Seeing Rocks and Seeing Stones
So there are two contrasts in these stories. Rocks versus stones, and who sees rocks and who sees stones. Rocks are generally considered those things out there in, on, and of the ground that are found where the volcanoes, rivers, glaciers, faults, uplift, and erosion left them. They may have smooth or sharp edges depending on how long and how effectively water and wind have worked them, or whether the work has been dome by freezing and thawing of water in almost imperceptible cracks.
Here’s the big difference. Stones may be found, but more likely worked, and them moved and arranged by people for their purposes. That’s different from rocks, that just are, though they may be used pretty much as they are found sometimes. Field walls are more likely an example of “use as found,” of course, since they don’t have to be weather-tight. So the difference between stones and rocks says something about origin of the mineral conglomeration, the source of the energy shaping them, and whether there is purpose embodied in the shape.
|The A. Hoen Lithography and Printing factory. S. Pickett|