Cheryl Kimball's Nature Talks: Rocks figure prominently in any NH outdoor-lover's lifeBy CHERYL KIMBALL October 12. 2018 9:21PM
The format I use to save my Nature Talks columns on my computer includes a word or two identifying what a particular column is about. Since I first started writing this column in March 2014, no column is saved with the identifying word “rocks.” I know I have talked about rocks randomly amidst other topics in the past, but rocks have been on my mind these days. They are not wildlife, I know, but rocks are nature too.
A couple of weeks ago I checked the mail and while walking back into the driveway between two stone pillars — a dirt driveway that could probably use a fresh supply of dirt — I looked down and saw a stone around two inches by one inch embedded in the gravel. There are lots of stones packed into the gravel from 25 years of driving over them. But this one is dark gray, almost black, with a thin white layer running the width of it, making the rock resemble an Oreo cookie.
This stone particularly caught my eye because I have a stone very similar to it in a dish on my dresser that also holds beach glass and various shells including a beautiful long-vacant delicate sea urchin shell. And that got me thinking — how is there a stone in my driveway that is so similar to the stone I found on the beach? While my friends in the Midwest may think otherwise, the beach is a long way away, perhaps 40 miles, from my driveway. Although 40 miles isn’t far at all in the geological scheme of things, coastal habitat and the habitat of my woodsy home environment would seem like it should be quite different from one another. But of course glaciers can move rocks a long way.
My interest in geology has been minor. I recall as a teenager going to a mica mine in the Ossipee area. My memory pictures it as a very cool (both in temperature and in wow-factor) expanse of sparkling rocks and shards of mica leading steeply down to an ominous-looking basin of water. In a Google search of “mica mine in Ossipee,” I learned that the mine is now (if mindat.org is up to date) called the Ham and Weeks Educational and Recreational Area operated by the Maine Mineralogical and Geological Society (MMSG), is actually in Wakefield, and was, in fact, originally just called The Mica Mine. An aerial view on the site shows it exactly how I remember it.
Despite my limited interest in geology, rocks figure prominently in my life. Granite is, of course, present on the farm — granite posts still stand that once flanked gates to pastures and granite slabs lay in the woods with the drill marks from where those posts were obtained.
As most who have tried to pound a fence post in New Hampshire know, it doesn’t take much pounding to get to a rock. One attempt at fence building or one pass around a “field” with a bush mower makes it easy to figure out where the massive stone walls on our property came from. There is a long stone wall along the roadway; a beautifully crafted tall and straight stone wall enclosing a quarter-acre cemetery plot a couple hundred yards behind the barn; low stone walls around original perimeters of property lines; and seemingly random stone walls in the 90ish-acres of our property, remnants of when New Hampshire was 80 percent open and 20 percent tree-covered, the opposite of today. Back in the 1850s all that land was dotted with sheep — not trees — and those walls helped keep those sheep contained.
My dogs have enjoyed the large boulders dotting our woods, using them as vantage points for scouring the area for rodents. The rodents themselves use the large rocks as dining tables, hammering open acorns on the hard surface and leaving the shells behind. Fox and other smaller mammals like to use rocks in the trail as bathrooms, leaving their scat on an impermeable surface where it might be better noticed and where scent may last longer since rock does not absorb much.
Glacial erratics are a clear sign of geological activity. Defined on Britannica.com as an “erratic, glacier-transported rock fragment that differs from the local bedrock,” these sometimes car-sized boulders stuck “in the middle of the woods” were transported by a glacier, left behind when the glacier melted, and differ from the size and type of rock (the rock’s “lithology”) around them since they came from somewhere else.
A relatively small erratic in our woods sits beside a trail I frequently walk. A bonsai-like tree has been growing for several years out of a crack in the top of the erratic and is one of several things that I have enjoyed keeping track of in the quarter-century I have wandered through these woods.
Cheryl Kimball is a freelance writer who lives north of Rochester. Email her at email@example.com.