A Crack in the Edge of the World (52 page)

AMMONITE
A slow-swimming creature of the warm and deep Mesozoic oceans, which propelled itself backward by flexing its muscular tentacles and was supported in the sea by a coiled chambered flotation cell, and which resembled in shape the horn of the Egyptian ram-headed god, Ammon. These attractively coiled fossils are found today in great abundance in limestone and shale of the Cretaceous and Jurassic.

ANDESITE
An extruded volcanic rock with a very high silica content and which seems to be involved in highly explosive volcanoes. It contrasts with its much-lower-silica-content colleague-rock basalt, which tends to be found in the more gently oozing volcanoes of the world.

BORE
A riverine tsunami, usually caused by unusually high flood-tides colliding with the estuarine outflow from a powerful stream. Bores can also be caused by earthquakes that strike near major rivers. The word probably has the same Old Norse root as the modern word
billow
.

BRACHIOPOD
A common bivalved marine creature, found through almost all periods of the geological time scale, from the Lower Cambrian onward. One of their species—
Lingula
, which can still be seen in modern oceans—has remained evolutionarily unchanged for more than 500 million years. The creatures—often, because of their similarity in shape, known as
lamp-shells
—are fixed to the seabed by a muscular foot, and they waft extendable feeding devices through the passing seawater currents, trawling for nutrients.

CABLE
As a unit of maritime measurement amounting to a tenth of a nautical mile, or about 600 feet. (A nautical mile, defined as one minute of arc of longitude measured along the equator, is 6,082 feet; a speed of one nautical mile per hour is known as one knot.)

CLINKER
From the Dutch word
klinker
, from the ringing sound it makes when hit with a hammer, the incombustible residue of a volcanic eruption—a mixture of lava, bedrock, and other debris that often chokes a volcanic crater.

CONESTOGA WAGON
The large covered wagons with which the earliest westbound settlers traveled across the American plains were built in Conestoga, Pennsylvania, a town named after a local Iroquois tribe. These clumsy vehicles had a postilion—a nicety not found in the smaller and swifter wagons that came to be known as
prairie schooners
—and which most emigrant expeditions favored before the coming of the railways (and which led to the demise of that most sweetly named craft of whiffletree-making).

CRATON
The name given to those immense tracts of the earth's surface that have remained tectonically stable and seismically inactive for uncountable millions of years. These areas—like much of north central Canada—are composed invariably of ancient shield rock.

CWM
A Welsh word for a mountain valley, still much used in mountaineering vernacular: the Western Cwm on Mount Everest, for example. Its equivalents in France, Germany, and Scotland are the words
cirque, Kar
, and
corrie;
despite the limitations of Welsh, only
cwm
appears to have found wide international acceptance among the climbing fraternity.

DIP
The angle between a geological structure and the horizontal: Sedimentary rock layers are said to be steeply dipping, for example, if they are tilted close to vertical. See also
strike
.

GABBRO
Basaltic magma (q.v.
andesite
) that cools slowly, in a pluton (q.v.) and that in consequence assumes a more crystalline appearance and structure than fine-grained basalts themselves

GAIA AND THE GAIA HYPOTHESIS
James Lovelock, a British space scientist now regarded variously as either a visionary or a harmlessly misguided eccentric, first came up with the idea in the 1960s that the earth might be a living entity, a single, highly complex enclosed system. His belief, in essence, held then—and still holds now, after four decades of experimentation and observation—that the Gaia (the word formed is from the Greek word for “mother earth”) is a complex entity that involves the earth's biosphere, atmosphere, oceans, and soil, “the totality constituting a feedback or cybernetic system which seeks an optimal physical and chemical environment for life on this planet.” Through Gaia, says Lovelock, the earth sustains a kind of homeostasis, the maintenance of the relatively constant conditions that exist upon its surfaces.

GNEISS
A coarse-grained metamorphic rock, marked by foliations of alternately dark- and light-colored mineral bands. Even more foliated rocks that readily split into slatelike slabs are generally called
schists:
the two types of rock are frequently found together.

GRABEN
When two faults—not strike-strike-slip faults, like the San Andreas, but the more common vertical or near-vertical faults—occur close by and approximately parallel with each other, and the land between them drops, then the resulting valley is known as a
graben
. If it rises, pinched upward between two fault lines, the resulting uplifted block is called a
horst
.

GRANITE
Found essentially only in continental bodies, granite is a slow-crystallizing volcanic rock, invariably cooled in a pluton, and with a substantial percentage of light-colored quartz, as well as feldspar and other minerals in large or relatively large crystalline forms.

GRAYWACKE
A hard, dark, silty sandstone that has been mildly metamorphosed by heat and pressure and is thus rather harder and more dense than other sedimentary rocks of similar constitution.

INTRUSION
The rock mass that results from the invasion of one rock by a molten version of another. Dolerites—dark, fine-grained igneous rocks—invariably form intrusions, known either as
dikes
, if they invaded vertically and cut across the bedding planes of sedimentary rocks, or
sills
, if they inserted themselves in parallel, like the igneous ham in a sedimentary sandwich. The Palisades Sill, on the New Jersey shore of the Lower Hudson River opposite Manhattan, is a classic dolerite sill.

K-T BOUNDARY EVENT
The fossil record at the end of the Cretaceous and just before the beginning of the Tertiary, 65 million years ago, becomes suddenly and inexplicably interrupted, and is marked by the extinctions of nearly three-quarters of all the then-current life-forms. There was no ready explanation for what might have happened—until the 1970s, when researchers in Italy detected an anomalous spike in the amount of the rare metal iridium found in a thin clay layer that marks the boundary between the two eras. This—together with their discoveries of soot and pressure-strained minerals in the clay—led them to deduce that one or more meteors (which produce iridium as a by-product) might have struck the earth 65 million years ago, causing a major catastrophe for all living things. Eventually a meteor crater—the smoking gun—was discovered off the coast of the Yucatán, at Chicxulub, and others were detected off western India, in the North Sea, and in the Ukraine, all from the same period. It now looks very much to believers as though a shower of enormous meteors struck the planet at the end of the Cretaceous—bringing the era to an end and causing infinitely more destruction worldwide than was occasioned by any earthquake, San Francisco's included.

NUNATAK
This Inuit word denotes a mountain peak rising through or between glaciers or land ice in an arctic environment. In Greenland, where most of the world's nunataks are to be found, the base rock is invariably basalt, extruded from the mid–Atlantic ridge volcanoes in and around Iceland.

OOLITH
An egg-shaped calcareous particle precipitated in the warm seas of the (usually) Jurassic period and which, once consolidated into rock, forms an attractive and decorative limestone.

OROGENY
A period of mountain formation in which the earth's crust is deformed by one or more of a variety of processes that include vulcanism, subduction, plate collision, folding, plate divergence, and seafloor spreading or faulting.

PLATE TECTONICS
The fundamental theory of the New Geology, first adduced in the mid-1960s by a variety of geologists and geophysicists working independently around the world. The Canadian J. Tuzo Wilson is popularly credited with first using the word
plates
in a paper in
Nature
in 1965. The theory holds that the earth's lithosphere consists of large, rigid plates that move horizontally in response to the flow of the asthenosphere beneath them, and that interactions among the plates at their borders cause most major geologic activity, including the creation of oceans, continents, mountains, volcanoes, and earthquakes.

PLUTON
Another name for a large intruded body of igneous rock, inevitably younger than the country rock into which it has been intruded.

RECUMBENT FOLD
When the folding of a body of rock becomes so severe that the apex of the fold passes the vertical and the fold bends over upon itself (as in the folding seen from California Route 14 and illustrated on page 192), the structure is known as recumbent. It illustrates the intensity of the orogeny that was involved in its creation.

STRIKE
The line, or the compass direction of this line, that marks where an inclined geological feature intersects with the earth's horizontal surface.

TERRANE
One of the key components of the New Geology, a terrane is a massive body of rock or rocks that manages to preserve its original identity more or less intact, despite having been moved a long way from where the rocks were first formed. In California and many American states to the west of the Rocky Mountains, a number of readily recognizable terranes have become accreted onto the original continent by the tectonic processes involving the Pacific and North American Plates. Thus, in the Basin and Range region, in states like Arizona and Nevada, immense blocks of very foreign rocks—each a terrane—have been carried thousands of miles east to form the spectacular mountains that so define the region.

THIXOTROPIC
The property of certain solid or nearly solid substances to become fluid when agitated, and then to resume their solid or semisolid state when the agitation ends. Thixotropic reactions in areas of landfill—the marina in San Francisco, Battery Park City in Manhattan—can lead to disastrous consequences in the event of earthquakes: The land turns to liquid under the influence of the shaking, and buildings collapse in great numbers.

UMBO
This knob on the very tip of a bivalved shell, such as a brachiopod (q.v.), represents the oldest, originating part of the shell, and its size and shape is much used in determining the precise type, species, and, thus, the relative age of fossils.

I
N A BOOK CALLED
SIXPENCE HOUSE,
A WRY AND PLEASANTLY
amusing recent account by an American named Paul Collins of his move to Britain's book-dealing village of Hay-on-Wye, the author tells of finding a long-faded copy of a volume titled
The San Francisco Calamity by Earthquake and Fire
, written by an equally long-faded writer named Charles Morris. I found a copy in my own collection—it is one of those books with a title page that tries to tell all, breathlessly. (It begins by describing the book as “A Complete and Accurate Account of the Fearful Disaster which Visited the Great City and the Pacific Coast, the Reign of Panic and Lawlessness, the Plight of 300,000 Homeless People and the World-wide Rush to Rescue Told by Eye Witnesses including Graphic and Reliable Accounts …” and so on and so on.)

Paul Collins notes that the book he bought had evidently been sent as a gift (to relatives in Winnipeg) in October 1906—meaning that the 446-page book had been written, published, bought, wrapped, and mailed no more than six months after the event that it sought to describe. It becomes amply clear to any reader, Mr. Collins among them, that in part as a consequence of this rush to publication, the book is almost entirely fiction.

The cover illustration sets the tone, dominated as it is by a lurid engraving of a skyscraper busily collapsing itself into a sea of licking flames. The building is easily recognizable as the beehive-domed Claus Spreckels Building (popularly known as the Call Building, because it housed the city's preeminant newspaper of the day). And true, it did burn, spectacularly. But far from ever collapsing, as the book's cover suggests, it survived. Moreover it still stands today, remodeled but proudly wearing its well-known beehive roof, on San Francisco's Market Street.

The jacket's fanciful design hints at the myriad other inventions within. Dubious accounts turn out to be legion, all collected and repeated by a writer whom Collins describe as one of the many local hacks all too eager “to make quick bucks off cataclysms.” One passage, which he admits he did find “viscerally affecting,” concerned a man who apparently threw himself onto the body of a woman who he claimed was his dead mother. He was supposedly smothering her face with grief-stricken kisses when a soldier noticed that what in fact he was doing was
chewing off her ears
, to get to hold of her diamond earrings. The soldier shot him—or, as Morris naturally wrote, “he put a bullet through the ghoul.”

And all, so far as one can check, total nonsense.

There are gentler and more affecting reported scenes in the book, too—a refugee walking his huge Newfoundland dog and carrying a kitten, talking to the kitten all the while. A lone woman pushing an upright piano along the road, a few inches at a time. But then there is the account of a group of soldiers watching three men who were standing on top of the roof of the Hotel Windsor, two blocks from the Call Building, which was blazing furiously. “Rather than see the crazed men fall in with the roof and be roasted alive,” Morris writes, “the military officer directed his men to shoot them, which they did in the presence of 5,000 people.”

Is there any truth to these stories—to the tale of the earrings, or of the sad lady with her pianoforte, or the assassinated men plunging from the top of a burning hotel? Almost certainly not, say today's more clinically detached historians. Official records note that a great number of dreadful and memorable things happened in San Francisco—sufficiently numerous, indeed, for one to have little need of invention. Yet many writers of the day, and some subsequently, seemingly found in the San Francisco story such a seductive combination of glitter, sin, and violence that it seemed entirely meet and proper to them to add a seasoning of fiction, to make the spicy even spicier.