Stories in Stone (16 page)

Named for the great naturalist Louis Agassiz, Lake Agassiz lasted for over five thousand years and eventually grew to cover
580,000 square miles, about the size of Alaska.
²⁶
Four outlets drained the lake, which reached a maximum depth of 2,500 feet.
One drainage carried water north to the Arctic
Ocean, one east out the St.
Lawrence valley to the Atlantic, one northeast through Hudson Bay, and one south to what later
became known as the Mississippi River valley—the River Warren.
They did not drain at the same time.

For 99 percent of its life, Warren flowed at an average of 1.6 million cubic feet per second, or about three times the flow
of the modern-day Mississippi River at its mouth and thirteen hundred times the flow of the Minnesota River near Morton.
But
then some environmental change triggered a flood of epic proportions.
For days and maybe weeks, the river ripped at up to
sixty miles per hour down the valley, a grayish-brown, roaring, churning soup of mud, debris, plants, boulders, and animals.
Total estimated volume would have about equaled the combined average annual flow of the ten largest rivers on Earth.

Geologists don’t know how many of these megafloods scoured the Minnesota River valley.
The last one hit 12,900 years ago and
all of Lake Agassiz drained in a cataclysmic flood 8,400 years ago.
Geologists do know, however, that without the River Warren
floods and the river’s constant, high-volume flow out of Lake Agassiz, the Morton Gneiss may never have been revealed.
Instead,
tens to hundreds of feet of glacially deposited sediments would still be covering the rock and one of the planet’s longest
geologic stories could not be told.

I find it compelling that the last chapter of the Morton story is also the final global geologic event to hit the planet.
From deep time to modern time, the Morton Gneiss has been present.
It existed when life evolved on Earth, when modern-style
plate tectonics began to operate, and survived the ice age.
As one geologist says of the Morton, “It’s got it all.” Plus it
is a damned gorgeous rock.

5

T
HE
C
LAM
T
HAT
C
HANGED
THE
W
ORLD
—
FLORIDA
C
OQUINA

And under Anastasia’s verdant sky,

I saw St.
Mark’s grim bastions, piles of stone.

Planting their deep foundations in the sea,

And speaking to the eye a thousand things,

Of Spain, a thousand heavy histories.

—Ralph Waldo Emerson, “St.
Augustine”

H
ARDLY ANYONE THINKS that clams changed the world.
Most are benign bivalves toiling away in the sand or resting quietly in
the sea.
If we do consider them, we are usually thinking about food, though perhaps the most famous mollusk in the world is
the one that supports Venus in Botticelli’s
The Birth of Venus
.
Botticelli depicts the Roman goddess of beauty and love using the shell as a mode of transport as she arrives on land, blown
there by the winds.
Although unrealistic as a way to travel, Botticelli’s shell does fit the classic image of a clam, something
trod underfoot.

Thus some may find it odd that a bivalve, and one much smaller than the one that carried the lovely Venus, was seminal to
the early colonization history of North America.
Carolina governor James Moore was the first to discover the power of the
clam when he lay siege to the Spanish colonial town of St.
Augustine, in 1702.

Ambitious and greedy, Moore had arrived in Charles Town (later shortened to Charleston) in 1700 to govern the southernmost
of England’s American colonies.
Founded in 1670, Charles Town had suffered smallpox, an earthquake, fire, and the yellow fever,
but was a thriving town of four thousand when Moore arrived.
¹
He recognized, however, that in order for Carolina to survive and prosper, the English had to defeat Spain’s strongest North
American colonial outpost, St.
Augustine, in what is now Florida.
In addition, he worried about the growing strength of France,
which had established Louisiana in 1699 and had recently allied itself with Spain.

A French-Spanish partnership had developed because of the death of Spanish monarch Charles II in November 1700.
The childless
Charles had named his great-nephew Philip of Anjou as his successor.
Philip was also Louis XIV’s grandson, and Philip’s ascension
would unite Spain and France and pose a significant threat to England.
To counter Philip’s claim to the Spanish throne, England’s
William III allied with Holy Roman Emperor Leopold I to support Leopold’s son as heir to the Spanish crown.

At stake was domination of Europe and the New World.
Spain controlled Mexico, southwestern North America, Central America,
and Cuba.
France laid claim to North America from the mouth of the Mississippi River north to Canada, and England dominated
the eastern seaboard, Jamaica, and Barbados.
In May 1702 fighting began in what is known in Europe as the War of the Spanish
Succession and in America as Queen Anne’s War, after the queen who assumed the English throne following William’s death.

When Moore learned of the fighting in August 1702 he recognized its significance and suggested to his Commons House of Assembly
that “the takeing of St.
Augustine before it be Strengthened with French forses opens to us an easie and plaine way to Remove
the French (a no less dangerous Enemy in time of Peace than Warr).”
²
The Assembly approved Moore’s plans and provided two thousand pounds sterling for expenses.
His force of five hundred English
and three hundred Indians sailed south from Charles Town in fourteen boats under the command of Moore and Colonel Robert Daniel.
³

About fifty miles north of St.
Augustine, the Carolina army attacked their first Spanish outpost, a guardhouse and small village
at the north end of Santa Maria Island, at midnight on November 3, 1702.
Two additional villages on Spain’s northernmost Atlantic
Coast settlement succumbed the next day.
Moving south, by November 5 the English had destroyed the missions of San Juan del
Puerto, Santa Cruz, and Piribiriba.
Nothing now stood between eight hundred militia and St.
Augustine.
Three days later Moore
reached St.
Augustine with thirteen ships and many of his men.
Daniel had taken the rest of the soldiers south overland.

Two hundred and forty nine Spanish soldiers under the command of Governor Joseph de Zúñiga y Cerda defended St.
Augustine.
Zúñiga had recently told the town’s inhabitants of Moore’s successes to the north, warned them of attack from the sea and
from Daniel’s land force, and finally ordered everyone inside the town’s fort.
He did not inform them he had sent urgent pleas
for help to Havana because St.
Augustine was short of men and ammunition.
Nor did he tell them that the infantry consisted
partly of old men, invalids, and young boys and that the gunners “had no service record, lack discipline, and have only a
slight knowledge of the [fort’s] bronze and iron guns.” With everyone crowded into the fort the townspeople probably surmised
the situation.

Despite the lack of manpower and firepower, and a fort overcrowded with fifteen hundred people and their farm animals, Zúñiga’s
situation was not completely desperate.
Well located, St.
Augustine stretched for about one-half mile south of the fort along
the Matanzas River.
A marsh protected the land north of the fort.
East of the river a barrier island, Anastasia Island, reduced
coastal access.
At Anastasia’s north end, hard-to-navigate sandbars created a treacherous entrance across the narrow inlet
to St.
Augustine’s harbor.
The west offered the only easy route to town.

Zúñiga’s fort also provided a significant advantage against invaders.
Known as the Castillo de San Marcos, its construction
had been completed only six years earlier, and it was the tenth fort in St.
Augustine.
The previous nine had succumbed to
pirates, fire, and water.
The castillo’s layout consisted of an open, 150-foot-wide square courtyard surrounded by storage
rooms, living quarters, a jail, and a chapel.
Arrowhead-shaped bastions with 90-foot-long sides jutted out from each corner.
The white plastered stone walls were 16 feet thick at the base and rose 26 feet above a moat, which could be flooded with
seawater.
When the fort’s gates closed, the castillo was a secure island with three freshwater wells and enough food to last
several months.

What made the fort nearly perfect for Zúñiga’s situation was the stone used in the walls.
Quarried from Anastasia Island and
known as coquina (ko-
kee
-na), it looked like what you’d get if you took a mound of whole and broken shells, mixed in a dilute solution of Elmer’s
glue, and let it dry.
People liken coquina’s consistency to a Rice Krispies Treat or a granola bar with shells and shell fragments
replacing the oats.
Either way, the dominant component by far of coquina was a shell, from the clam that changed colonial
history.
These shells gave coquina a property found in no other rock.
Instead of breaking or cracking when hit by cannon shells,
the cavity-rich coquina absorbed or deflected the iron projectiles.

Aerial view of Castillo de San Marcos, St.
Augustine, Florida.

Zúñiga did not know of the unique qualities of coquina.
No one did.
No one had yet attacked the fort.
And no other significant
building in the world had been made of coquina.

Moore began his siege on November 10 when Colonel Daniel arrived with his men after marching down the coast from Piribiriba.
With the Spanish holed up in the castillo, the English took all of St.
Augustine, but not before the Spaniards stampeded 160
cattle through Daniel’s men and into the dry moat.
The English set up around the perimeter of the castillo and began to dig
trenches to get closer.
They also sailed their boats across the sandbars that protected the harbor and began to fire cannons
from sea and land.
The Spanish responded by burning strategically located houses where Moore’s men could hide and shoot anyone
entering or leaving the fort.

As the siege progressed,Moore’s circle tightened.
By November 24, he had located four of his biggest guns only 750 feet from
the castillo.
At one point, a twenty-four-hour-long battle broke out with the British firing canisters, round shot, bar shot,
and broken glass.
The cannon fire could not break the walls of clamshell.

Moore’s men continued to dig their trenches closer to the fort, supplemented by erecting rows of gabions, rock-filled cages
that provided a protected shooting site for gunners.
They also burned the southern end of St.
Augustine.
By December 19 they
had advanced to within pistol shot of the castillo, and still their artillery did little damage to the massive, spongy walls.
They would get no closer.

Four Spanish man-of-war gunships arrived the day after Christmas with supplies and men from Cuba.
Moore realized the hopelessness
of his situation, burned four of his ships, abandoned four others, set fire to the remaining houses in St.
Augustine, and
retreated north on foot to Charles Town.

When the gates of the Castillo de San Marcos reopened on December 30, the Spaniards found little left of St.
Augustine.
The
English had destroyed the main church, the governor’s palace, and all farms, fields, crops, and cattle.
Only twenty houses
remained in the desolate landscape.
But St.
Augustine was still Spanish, and Spain still retained control over Florida and
its lucrative trade routes.
The English would not attempt another attack on St.
Augustine for thirty-eight years.
All that
had saved the Spanish was their castillo made of clamshells.

Joe Brehm has been a National Park Service ranger at the Castillo de San Marcos for thirteen years.
Usually he wears the typical
green and gray NPS uniform, but on weekends he may wear a custom-made red and blue wool, cotton, and linen uniform of an eighteenth-century
Spanish artilleryman.
On those days Brehm gets to perform one of the favorite parts of his job, shooting a six-pound cannon.
And it is a performance that he and his team solemnly reenact in Spanish: the soldiers’ ritually loading, lighting, and firing
cannons from atop the fort.

The six-pound cannons use three pounds of gunpowder to fire a three-inch-diameter solid iron ball one and a half miles.
The
reenactors at the castillo shoot bread wrapped in tinfoil instead of a ball.
It makes a tremendous sound, provides food for
birds in the harbor, and makes you wonder how many Spanish soldiers went deaf or ended up with hearing problems.
At maximum
firepower the castillo had seventy-seven cannons, the largest of which shot twenty-four-pound balls, three miles at six hundred
miles per hour.

“Hollywood gets it all wrong.
Movies show cannons going
boom-boom-boom-
boom-boom
all the time,” said Brehm.
⁴
“In reality, they could shoot one shot every ten minutes.
Plus, when these guys were holed up in the fort, they had to deal
with how much gunpowder they had and not waste it.” In addition to firing cannons, soldiers protected the fort by pulling
up the drawbridge that spanned the moat and connected the ravelin to the main fort.
The ravelin is the triangular outbuilding
that served as guardhouse.
It is the only part of the castillo that was never finished.

“One of the first questions most people ask after crossing the bridge,” Brehm said, is ‘Where’s the water?’ I always hate
to disappoint them and tell them that once again Hollywood is misleading us.
The moat was usually dry.” When necessary, the
castillo’s moat could be filled as the tide rose and flowed through a pipe into the forty-foot-wide, eight-foot-deep space.
After the United States acquired the castillo along with the rest of Florida in 1821, by treaty and not by battle—proving
again that the pen is mightier than the sword—engineers filled in the eastern part of the moat and built up the sea wall to
support cannons.
⁵