Geoscience Reference
In-Depth Information
acter that in many cases it can still be traced to the original Irish county
where their ancestors lived nearly two hundred years ago.
It is here, in the small town of Trepassey, on the southern part of the
peninsula, that Simon Poulton and I warm our frozen bodies with hot
cups of coffee and a delicious chicken soup made by Paula Carew, a
short, bubbly dynamo of a woman and proprietor of “First Venture,” a
Trepassey eating tradition. We were too long and too late in the field
today. Paula floats over to our table and asks in a rich Irish brogue if we
would like to follow our coffee with something stronger, perhaps a beer
or maybe a whiskey? We nod emphatically to both. We are part of a
field trip organized by Guy Narbonne of Queens College, Ontario, and
Jim Gehling from the South Australian Museum in Adelaide. Guy and
Jim are both world experts on a fascinating group of marine organisms
that first appear in the fossil record around 580 million years ago. El-
kanah Billings, a prominent Canadian paleontologist, was the first to
describe a member of this group in 1871. In fact, he found a fossil type
called
Aspidella terranovica
in open view in black shales outcropping onto
Duckworth Street, in downtown St. John's. You can still see them there
today. Billing also noted that these fossils were from sedimentary strata
deposited before the appearance of abundant animals in the Cambrian
Period, a topic we will come to later.
Fossils from this time period came to prominence much later, how-
ever, when Reg Sprigg in 1946 stumbled across some strange fossil
forms he interpreted as ancient jellyish-like animals from the Ediacaran
Hills of the Flinders Ranges in South Australia. These late-Precambrian
fossils, and many others of similar age, have become collectively known
as the Ediacaran Fauna. Taken together, these fauna represent a wide
range of very different types of organisms, but they also share some
common attributes (
ig. 10.2)
. They are mostly in the centimeter to tens
of centimeter size range, lived on the seafloor either lying down or
standing on some kind of a stalk, were mostly immobile, exhibited com-
plex but semiregular morphologies, and with a few exceptions, cannot
be easily assigned to any modern or ancient animal group. Therefore,
Sprigg's first impression of ancient fossil jellyfish was probably incor-
rect, leaving the question open as to what indeed the Ediacaran Fauna
represent.
