Tens of thousands of years ago, glaciers scraped and re-scraped the New England landscape. Soil was pushed away, and among the artifacts left behind were drumlins: mounds of glacier till, flowing in the direction of the glaciers (northwest to southeast in NE), consisting of silt, clay, and gravel. One such drumlin is the hill upon which Robbins Farm Park resides. And what is "gravel" to a glacier includes what farmers and gardeners call "rocks."
When in April we turned over the grassy sod to unearth a potential garden, we also found rocks: lots of them. Rocks are not useful to growing plants -- they are not soil, they hold no water. Carrots will grow around pebbles, twisting and branching, rather unlike the straight ones store-bought. Removal is the typical response to rocks in the garden. Rock-weeding really, as pebbles work their way upwards, again and again. Mix into a bowl some sand and some pebbles; shake it gently to see the pebbles cluster atop; the same happens in the garden, just slower.
But rocks don't have to be useless waste, even for a garden. The early farmers of New England made low fences of their rocks, giving Robert Frost's last line of his poem "Mending Wall": Good fences make good neighbors. What have we done with our rocks? The largest two we set as showpieces at the garden entry, big enough to sit on (especially if you're small). Others we hammered into holes to brace the bottoms of our posts. But one artist among us saw that they could be beautiful, and lined our two main walkways with an elegant, flat-side-up, rock border.