For the previous week I was attending the
North American Paleontological Convention, held this year in Ann Arbor, Michigan by the University of Michigan. While
walking and wandering on the campus, it became clear that many of the
buildings include fossiliferous rock, so I began to look
for interesting examples.
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Like that. That's interesting. (coin in all examples with coins is a US
quarter)
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I cannot claim to be comprehensive; I was only on the central campus,
and didn't have time to go everywhere. (Obviously, that wasn't what I was there to do! Also, the hot muggy weather all week did
not encourage being out and about.) Just about everything I saw can be
attributed to Indiana Limestone. We briefly covered the topic of Indiana
Limestone/Salem Limestone several years ago in
this post, and just about anything you could want to find about the use of this building
stone can be found
here. While there are many, many surfaces of Indiana Limestone throughout the
campus, in most cases the fossils are itty-bitty shreds; maybe you can tell
something came from a bryozoan, or there's an obvious crinoid columnal, but
that's about it.
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Well, and there's sometimes these burrow-looking things, observed near
entry stairs on the southwest side of the Literature Science and the
Arts building.
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A couple of places, though, had coarser fossils. One of the best is actually
one of the campus's most prominent landmarks, the Burton Memorial Tower near
the north end of the campus. There are some coarser blocks here near and below
head height, particularly on the north side of the building.
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This is more like it.
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Even better!
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Shell fragments and maybe a little bit of a nautiloid near the
quarter?
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The outline of a large D-shaped shell.
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Abundant fragments, and if you look closely, a tiny coiled shell near
the center right margin.
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Going south across campus, the School of Kinesiology building is just the
other side of N University Avenue. If you go to the southernmost wall, there
are several more coarsely grained stones around the doors. The surfaces are
smoother, so the fossils are not quite as distinct, but there are some nice
examples.
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A typical stone at the south entrance. It's not highly polished (there
are more polished surfaces in the Rogel Ballroom in the Michigan Union,
for example), but it's certainly not as rough as the Burton Tower
stones.
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A very obvious section through a fairly extravagant bryozoan.
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If you continue going south, across S University Avenue you will run into the
law quad. Where the Lawyer's Club building meets the John P. Cook Dormitory,
there are some worn stones in the ground with fairly coarse fossils.
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Crinoid columnals are an important part of this balanced foundation.
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If instead you go southeast, to the physics building, you'll find a passage
between two buildings. Crossing through and looking back, you'll see panels on
either side that are heavily weathered, revealing trace fossils.
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These surfaces are crumbling, so take care not to damage them!
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Somehow the block on the other side is the same way. Maybe they were
selected and arranged for effect.
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As you go toward the south end of campus, you'll come across a ringer near the
T-intersection of Monroe and Tappan. There, near the red brick Lorch Hall, is
a freestanding portal of whitish stone. When I saw it, I decided this was
clearly something that needed a closer look. Was this the remnant of a
building that formerly stood here? Would there be an explanatory plaque? There
was no such information, but it turned out that several large white spots were
actually large horn corals.
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Mysterious isolated columns...
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Large white spots...
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Turn out to be large horn corals.
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A universe of horn coral galaxies.
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Looking up a column, over my head, and trusting I'll get the photo.
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Further research showed that this was in fact the portal of the Bank of
Michigan/First National Bank/Michigan Mutual Life Insurance building of
Detroit, formerly at the corner of Jefferson Avenue and Griswold Street. This
was built in 1836 and was the oldest stone building in Detroit before it was
demolished. Photos (1,
2,
3) and good
line drawings
exist of the original use, and it is unmistakable. (Note this comment in the
third link: "It is built of shell limestone, and the stories show many
beautiful petrifactions; in older times the building was oiled yearly, and
they were very noticable". Noticeable white spots in the stone in the photo
may represent other examples of large corals.) The portal was obtained in the
1930s by Emil Lorch of the College of Architecture as part of
his vision for a sort of outdoor museum of architectural pieces
to inspire the students. When installed on campus, there was originally
more context (plus friends)
(see also
this
for more), but now it's just kind of an odd island. If you do come across it,
it's certainly worth a moment to stop and contemplate the fossils and history.
Is it also Indiana Limestone? I initially thought so, but on further reflection
decided against it. The corals were much larger than anything I'd seen in
building stone of this rock before. Furthermore, the groundmass looked less
like skeletal fragments, more along the lines of an
oolite. Finally, the provenance suggests otherwise: Indiana Limestone wasn't really
a widespread building stone until about the last quarter of the 19th century.
This is much more likely to be something local to the Detroit area; a local
geologist/paleontologist would probably know exactly what this is.
After all that walking, maybe you'd like a snack and some levity. Head over to
the Michigan Union. While getting something to eat, have a look at the
flooring in the stairwell going from the ground floor to the first floor
inside the north side of the building:
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Wowee! (Or not.)
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Looks like a lot of shells, right? That's what I thought. Then I looked really
close, and it turned out the "fossils" were made up of dots; this is a printed
surface!
Finally, I would be remiss if I didn't mention you can see fossils on campus
that are *intended* to be seen, in the University of Michigan Museum of Natural History.
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Including mastodons!
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...and this sacrum, which may reappear as a friendly titanosaur in the
near future...
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(For our Minnesota readers: While researching this post, I found this
extinct page
about the geology of St. Paul buildings. The photos are gone, but the text
remains.)
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