Today I’m returning to my Pictures At An Exhibition. In case
you haven’t read part 1, here’s the link http://davidsamateurpalaeo.blogspot.com/2015/03/pictures-at-exhibition-part-1.html
This time we’ve moved on to the late Silurian, specifically
in Chicago in Cook County Illinois about 425 million years ago. It’s only
fitting that the paintings depict one of the few faunas known from the area of
the museum itself, and the very brief Silurian period is well-represented in
the Field Museum’s fossils. Indeed, the fossil collection began with mostly
local geology from this period, and until 1990 there was a hall of Paleozoic
fossils and dioramas in the museum. As
of now, they still have a corner in the Evolving Planet exhibit. Above the
fossils of the Chicago region and a diorama of a Silurian reef is Charles
Knight’s depiction of the city to which he dedicated this work of art.
Like the previous Ordovician mural, this depicts a
coastline, with both land and sea depicted and no animals seen swimming. However, as the Ordovician mural, marine
animals are nevertheless present. In this case, it’s the coral reefs. Despite
the massive extinction event that began the Silurian and the three minor
extinctions that followed, the last two during the Ludlow epoch, corals still
prevailed. In these extinctions, the
temperature dropped, and with it the sea level. This is depicted in the mural
as the reefs protrude from the surface, exposed to the air.
This may be the most colorful of the Paleozoic murals-the
corals are maroon and white, with drifts of algae and seaweed adding green to
the bright blue ocean. My knowledge of corals is limited, so I cannot comment
on which species are being represented. The
background has rock formations, sea, and a cloudy sky, with a peninsula on the
horizon, much like the Ordovician mural. The geological evidence does suggest that Chicago was a tropical bay
with a coral reef, so this depiction is still accurate.
It is interesting that in the Paleozoic murals, the coast is
depicted and not marine ecosystems. It’s not a question of knowledge-by 1930
the fossils of the Midwest marine faunas were well-known and catalogued. It’s not
a question of ability-Knight repeatedly depicted these faunas in other murals
for New York and National Geographic. It
might have been time constraints-on the other hand, he had the time to depict
the sea creatures of the Ordovician and the coral reefs of the Silurian. It
could simply be a creative choice-there are no underwater scenes at all in this
series, and he wanted thematic continuity to match stylistic and palette
continuity.
One more note- the Silurian seen here represents the Thorton
Quarry Reef site, dating to the Niagara formation in the late Silurian. This quarry has provided a great deal of
stone for the local area, and so local collectors have found thousands of
specimens from this region, including the aforementioned collection in the Field
Museum. For more on the reef, the
Milwaukee Public Museum has a website on it: https://www.mpm.edu/content/collections/learn/reef/thornton-front.html
I apologize for the short essay-it comes down to my
ignorance of the subject matter.
