For those who know how to read it, a country churchyard is a veritable textbook of geology

Someone once described the goldenrod that seems ubiquitous this autumn as “quill pens signing summer’s eviction notice.”  Whether it was the blooming of goldenrod or some other harbinger of summer’s end that inspired the autumnal imagery of his classic, melancholy “Elegy Written in a Country Churchyard,” English poet Thomas Gray wandered through a rural cemetery “Far from the madding crowd’s ignoble strife” and in the evocative silence brooded over the lives of the souls interred there.

From their names and fleeting scraps of information carved on their tombstones, Gray inferred details of their triumphs and tragedies, their loves and losses, and their aspirations and failures, now marveling at the longevity of some or mourning the brevity of the lives of others. He read more into the moss-encrusted stones than most observers would — or would care to.

But it is a little-known fact that, to generations of geology professors, country cemeteries have frequently served as outdoor laboratories for the demonstration of many aspects of the cycles of weathering and erosion.

These are points that can, of course, be easily made using a textbook with its graphs and photographs.  But geology — perhaps more so than any of the other natural sciences except for biology — is best taught as a field science.

This is a fact that I can personally attest to from memorable courses I have taken at Acadia National Park, the Grand Canyon, Mammoth Cave, and other venues in which the complexities of the effects of mineral content, climate, exposure, and age on the weather-erosion cycle are clearly displayed.

And in a number of those courses, the professors packed students into vans and shuttled us off to old country cemeteries in which whatever geologic principle being taught was clearly and sometimes dramatically displayed.

The idea for this article came to me on a hot day in late August during a visit to the Town of Rose Cemetery in western New York in which some of my mother’s ancestors are buried. The cemetery sits on the slope of a drumlin, a glacially-deposited hill that is one of hundreds scattered across much of western New York and the Northeast. 

Drumlins and related glacially-formed hills called kames have frequently served as the locations of cemeteries, partially because their elevation above the surrounding landscape has symbolic meanings, but also because their composition of an unconsolidated mixture of soils and rocks makes them well-drained — ideal for burials.

One thinks of the high and windy hill that is the site of the Grover’s Corners cemetery in the melancholy third act of Thornton Wilder’s classic play “Our Town.”

Perhaps it is partly the inevitable association of cemeteries with Halloween that evokes their solemn atmosphere, and in this one even on a bright late-summer day there was a particular monument that has always saddened our family.

It stands a little over five feet tall and is carved from white Vermont marble, a very ancient rock formed during the Ordovician Period, some 450 million years ago, during the event known as the Taconian Orogeny.

The ancient ocean known as the Iapetus that lay off what is now the east coast of the United States was beginning to close as the process known as plate tectonics brought small land masses into collision with it, pushing up mountains and forming marble through metamorphism of pre-existing limestone.

Next to the monument, a bronze receptacle holds a flag, indicating that two of the dead memorialized here — my mother’s great uncles — died in the Civil War. The young men were inspired by the powerful words of  “The Battle Hymn of the Republic” — “As [Jesus] died to make men holy/Let us die to make men free.”

Their tombstone records that one of them named James Otto starved to death and was buried in Andersonville, the infamous Confederate prison in Georgia; the other, his brother Guilford, is actually interred here.  He and a fellow soldier were murdered by a Pennsylvania farmer with pro-slavery sympathies when they were sent to him purchase horses for the troops.

The memorial must have been splendid when it was erected around 1865. Today, the graven inscriptions recording the young men’s sacrifices have become difficult to read. In a decade or two, the inscription will be obliterated and it will stand as do so many other old marble headstones and monuments, their honored dead anonymous.

Marble is a very hard, dense rock that resists the absorption of water from rain or melting snow and therefore does not easily break down due to freezing and subsequent thawing in the process known as physical weathering; however, marble is composed of calcium carbonate, and as any high school chemistry student knows, calcium carbonate dissolves in acid.

Falling rain and fog pick up minute amounts of carbon dioxide from the atmosphere, producing a mild solution of carbonic acid. Ordinarily, carbonic acid of this strength is harmless to plants and animals but over many years it will slowly but relentlessly dissolve any calcium carbonate surface in a process known as chemical weathering.

Consequently, given that the monument was erected in Rose Cemetery over 150 years ago, it is surprising that the inscriptions are legible at all. But their saving grace has been the fact that the monument is situated on an open slope facing south, which means they are exposed to sunlight virtually all day when the sun is not obscured by clouds.

This results in the constant warming and drying of the surface, preventing its rapid dissolution and largely preventing growth of lichens and moss — the same factor that causes them to grow mainly on the north side of trees. They secrete small amounts of natural acids that in a damper, more sheltered environment can wreak havoc on organic or mineral surfaces — such as marble headstones.

Farther up the slope is another monument marking the graves of some other ancestors — in this case, my mother’s great-grandparents, whose surname was Briggs.

It was carved from gray granite, an igneous rock brought perhaps from New Hampshire or Maine and formed during the Devonian Period, in an event known as the Acadian Orogeny, some 380 million years ago; at that time, an ancient landmass known as Avalon — which would eventually become Europe — was subducting under North America and creating massive amounts of igneous rock through explosive volcanic action.

The monument stands over five feet tall and its rectangular base holds a massive sphere, an unusual design in this relatively modest graveyard. But although it, too, is over 100 years old, from its appearance one might think it had been placed there last week.

The sphere and the sides of the monument were highly polished and on a sunny day the reflection from the sphere can be blinding. Granite’s two major constituents are visible crystals of feldspar and quartz, both of which are capable of appearing in a spectrum of colors, though varying shades of pink and gray are most common.

The important fact is that neither of these minerals is easily susceptible to chemical weathering and given the extreme hardness and density of the stone and its openness to sunlight, even after a century the monument looks as fresh as if it had been erected very recently.

Almost all of the older headstones and monuments in the Rose Cemetery are carved from either marble or granite and their presence tells another story. Neither of these stones is found locally near the Rose Cemetery; they must have been imported from out of state and their inscriptions carved painstakingly by hand — which bespeaks the affluence of many of the cemetery’s silent residents and their families.

Contrast this one with many of the mossy pioneer cemeteries scattered throughout the Helderbergs in which many of the headstones of the hard-working people buried there were carved either from the native limestone or the local somewhat porous sandstone — both dating from the Devonian Period — and observe how the names of the deceased and their memorial inscriptions have largely vanished.

However, the High Point Cemetery above Altamont on Old West Road with its elegant entrance gate and meticulously-constructed stone wall is another example of a southerly-facing country graveyard in which both marble and limestone monuments a century or more old are still well-preserved.

Many of these stones are carved from marble but they face the southwest, and the view across Old West Road to a wide field is unobstructed by trees; consequently, the stones are dried and warmed from sunrise to sunset on days when the sky is not mostly overcast.

Many of the headstones are on a gentle slope and apparently were never set into concrete bases, and as a result they show the tilting common among monuments in older cemeteries caused by the slow, steady downward movement of the ground known as soil creep.

Frequently, in older cemeteries, this can cause the stones to topple, but High Point Cemetery is obviously lovingly maintained, its grass trimmed and even its very old headstones mostly upright. 

However, a collection of toppled, heavily-weathered markers in the shaded rear of the cemetery has been set aside against the old stone wall, their inscriptions mostly vanished along with record of the deceased they were intended to memorialize.

And, in a few cases, small, closely-spaced, rough-cut markers without inscriptions — harvested, perhaps, from tilled fields or pulled from stone walls — tell sad stories of deceased infants.

Shade can help to speed the forces of weathering and erosion in a humid, changeable climate such as ours — and a prime example is the venerable old cemetery near Reidsville.

With its ancient, very tall balsams and spruces, the cemetery is situated behind an evocative, slightly rusted cast-iron fence — the stereotypical locale for a Gothic ghost story. In the late 1800s and early 1900s, Reidsville was a village with a population of over a thousand.

Largely due to the quarrying activities that supplied the attractive sandstone known as Helderberg bluestone to many localities in the Albany area, the village grew, at one time boasting a hotel, a popular tavern, two churches, two retail stores, and a blacksmith shop — traces of which have largely disappeared.

The quality of the granite and marble stone monuments in the cemetery is once again evidence of the relative affluence of its occupants. Yet, although the majority of the headstones face east and could therefore be expected to get drying sunlight at least in the morning, the immense trees cast much of the cemetery into shadow and their thick boughs steadily drip moisture from rain and melting snow.

Some of the trees show the growth of the lichen commonly known as “Old Man’s Beard,” which resembles Spanish moss and flourishes in very humid boreal forests, especially those near great bodies of water such as the Acadian Coast of Maine and Canada. The damp, pitted ground surrounding many of the old headstones is deep with mosses, which do not flourish in sunlight.

As a result, even some once-stately granite monuments show evidence of heavy chemical weathering and are stained by dark lichens.  The contrast between them and some equally old, much-less-weathered stones in the more open rear sections of the cemetery is sharp.

And especially on a gloomy autumn day, the scene epitomizes Thomas Gray’s lines:

“Beneath those rugged elms, 

   that yew-tree’s shade

Where heaves the turf

   in many a mould’ring heap’

Each in his narrow cell

   forever laid,

The rude forefathers

   of the hamlet sleep.”

(In Gray’s time, the word “rude” had nothing to do with manners but rather denoted “unsophisticated.”)

In recent decades, upright stone grave markers have largely gone out of fashion due to the great expense of preparing them and in many newer areas of cemeteries they are prohibited, replaced by bronze markers which lie flat upon the ground.

An alloy of copper and other metals, bronze tends to resist chemical dissolution although after decades of exposure to moisture it may weather to a dull shade of green like a copper penny. But being at ground level, if not carefully maintained, these markers can soon be covered by grasses and weeds, hiding their inscriptions as surely as if they had been dissolved away.

A walk through a cemetery, especially one with familiar names on the memorials, may bespeak many aspects of the history of a town and its inhabitants along with many other profound thoughts that cemeteries are supposed to bring.

But a close examination of its location, the composition of its monuments and their condition reveals much about its geologic history as well: accounts of continental collisions, ancient rock changing through metamorphism, new rock forming from violent volcanic eruptions, and the much more recent passage of the great ice sheets. In all — a veritable textbook of geology.