Memorial Hospital of Martinsville and Henry County made a big donation today to the paleontology department, in the form of a cast-cutting saw. Cast-cutting saws are used at hospitals to remove plaster casts around broken bones; we use ours to remove plaster field jackets.

Our old saw died more than a year ago, and that has slowed down our lab work. The new saw is a major improvement over our old one (besides the fact that the old one was broken) and should greatly improve our workflow.

I’d like to thank Skip Phillips and Jeff Fulcher from Memorial Hospital (below), who arranged this donation and delivered the saw to us this afternoon. We’ve already opened our first jacket; more on that later this week.

Last Friday Roanoke College held their 5th annual Darwin Day celebration, in honor of Charles Darwin’s birthday (which was actually on February 12). Thanks to the efforts of DorothyBelle Poli this has become a big event at the college, and includes lectures, videos, scavenger hunts, and all kinds of additional activities. Each of the last two years, VMNH has participated by setting up a small paleontology exhibit in the student center.

This year I used the Carmel Church exhibit that we put together for display in Virginia’s General Assembly Building two weeks ago. This includes more than 30 individual specimens representing a broad range of species found at the quarry, as well as some stories about individual whales.

This has proven to be a popular exhibit, and I’m looking at the possibility of casting the included specimens and making a more refined and comprehensive version for traveling displays.

I’d like to thank DB Poli for inviting us to participate, and Tim Dooley and Shana Melanaphy for helping to set up and take down the exhibit.

I spent last Friday afternoon in Richmond on a tour of the Science Museum of Virginia (SMV). SMV is located in a converted train station, and as a result has an available exhibit space several times larger than what we have at VMNH. The exhibits focus on an impressive array of interactives, but there are very few specimens (particularly natural history specimens).

Below: Interactive extinction exhibit at the Science Museum of Virginia.

SMV is an excellent example of a science center. Science centers tend to serve as public education and outreach institutions. They generally have relatively small collections holdings (if any), and those are oriented toward exhibits rather than research. They are staffed primarily by educators, with few if any active research scientists. The primary audiences of science centers are school-age children and their families and teachers.

I’ve also recently visited several museums located on college campuses, including the Joseph Moore Museum at Earlham College and the Museum of Earth Sciences at Radford University. It used to be relatively common for small colleges to maintain museums, but they have fallen out of favor in recent decades, and those that still exist often function only as small teaching collections. The museums at Earlham and Radford are exceptions, in that they still maintain exhibits and conduct a variety of student-led programs. Radford’s museum is remarkable among small college museums in that it was only founded five years ago; it may be the youngest college museum in the US by several decades.

Below: Mineral display at Radford’s Museum of Earth Sciences.

It’s a shame that campus museums have become so rare, because they fill an important niche for science and education students at small institutions (and I’m already on record concerning the value of a small college experience in training scientists). These museums serve as training grounds for students that aspire to work in museum-related fields, or that may end up working closely with museums, as well as exposing non-science majors to scientific ideas.

Finally, we have research museums such as VMNH. Many of these museums are operated by federal, state, or local governments. VMNH, for example, is a Virginia state agency. Some, such as the Florida Museum of Natural History, are departments within research universities, which are also often state-government supported. A few, such as the Carnegie Museum, are stand-alone institutions operated, in most cases, by private foundations.

Research museums may have a variety of origins and associations, but they all share a common feature: a permanent collection of research specimens. The primary function of these museums is to preserve the specimens and associated information that constitute the data that form the basis of natural science. Generally these institutions have a written collections policy that describes the scope of the collection, how specimens are acquired, and how they are made available for study. The collections supersede any particular staff member; the curators are primarily there to support and maintain the collections, not the other way around.

Below: A collections storage room at the Virginia Museum of Natural History.

Specimens in a research collection are selected for their scientific value. Many of these specimens may be visually appealing, but that’s not the reason they’re acquired. In fact, the majority of a research museum’s collections are rarely if ever viewed by anyone except specialists who incorporate the data from those specimens into their research. In this respect, research museums stand apart from science centers and teaching museums.

Why, then, are all these disparate institutions called museums? There is one point that they all tend to share: exhibits. Even though the primary function of a research museum is maintaining collections, exhibits are a critical supporting part of that mission. To extend an analogy that a friend once suggested to me, why does a football stadium or a theatre have seats? Why do we even have art galleries? All the players, actors, or artists require is a field, stage, or easel. The seats in a stadium or theatre are for everyone else – those who aren’t athletes or actors. The theatre, art gallery, and playing field are venues for non-specialists to experience these activities. Likewise, museums are the stages that scientists use to present their work to others. The vast majority of scientific research is funded, in one way or another, by the public. We have an obligation to make the fruits of our scientific endeavors available to as many people as we can, and particularly those who pay for them.

With exhibits serving as one of the significant public faces of research, it’s easy for the public to become misled about the function of exhibits, particularly when the term “museum” is used for a variety of institutions. It can seem to a visitor that the only reason museums exist is to have exhibits. In the case of a science center such as SMV, this is actually the case; they are an institution that exists to provide science education, primarily through exhibits. But the knowledge that’s imparted in SMV’s exhibits came from somewhere; someone had to collect and interpret the raw data that led to those discoveries. That was done in university and government research facilities…including research museums. Institutions such as VMNH don’t just provide the scientific knowledge described in our own exhibits, but also for the exhibits of science centers that don’t perform research or maintain collections. For VMNH and similar museums, we don’t acquire collections in order to supply the exhibits; rather, the exhibits exist to teach the public about the significance of our collections. The different missions of SMV and VMNH are reflected in the state government’s organization; while SMV is located within the Department of Education, VMNH is in the Department of Natural Resources. All these different types of museums may share exhibits as a common point, but they perform different, yet complimentary, roles in the advancement of science.

For the last week VMNH has had an exhibit set up in the lobby of Virginia’s General Assembly Building in Richmond. The museum’s research activities were a particular focus for the exhibit, with special emphasis on Carmel Church, which is only about 30 miles from here.

The Carmel Church part of the exhibit focused on the biodiversity of the site, and included specimens from most of the major groups we’ve found there over the years. We also highlighted several individual stories, including “Popeye’s” large flippers, “Nemo’s” broken flipper, and the shark bite marks on “Caroline’s” vertebrae.

Even though the exhibit was only up for a week, it was well received and made a lot of people (including state legislators) more aware of VMNH’s activities. The Carmel Church part of the exhibit will be on display again next Friday at Roanoke College as part of their Darwin Day celebrations.

In honor of Groundhog Day, I did a quick search through our paleontology collections looking for groundhogs. Groundhogs (Marmota monax) have been reported from four different Pleistocene sites in Virginia, so there was a chance that we would have some. A database search didn’t turn up any, but a large percentage of our collections are not yet in the database, so I went to the Pleistocene cabinets.

After a half-hour of searching, I found the tooth shown at the top of the page. Comparison with a modern groundhog (courtesy of VMNH’s archaeologist Elizabeth Moore) shows that the tooth is an almost perfect match for the right lower fourth premolar; it’s just a bit larger:

Our groundhog tooth is part of a small collection of bones labeled as coming from “Champ Cave”. It was collected some years ago, before I was with the museum and before our records were digitized, so I’m going to have to do some research to find the details on the site. I’m pretty sure the cave is located in Smyth County near the famous Pleistocene deposits in Saltville. It’s most likely early Holocene in age, although many Virginia caves include Pleistocene remains, so it could be older. We have a fair number of bones from other mammals at this site, which might help us determine the age of the deposit. The Saltville area was still experiencing near-Arctic conditions as recently as 14,000 years ago (talk about 6 more weeks of winter!), which had an effect on the faunal makeup.

Happy Groundhog Day!

Last Thursday I made yet another trip to Indiana, this time for visits to Earlham College and the Indiana State Museum. I had arranged to meet ISM’s paleontologist, Ron Richards, to spend Friday looking at Pleistocene squirrels from various Indiana sites, like the femur shown above.

(I’ve been doing a lot of teasing about my squirrel research over the last 6 months or so, which was the reason for my visits to both ISM and Earlham; I promise I will be describing it in more detail in a few weeks!)

After several hours in the collections, I had only a few minutes to run through the exhibits. Indiana State Museum has some very good paleontology displays, especially of Paleozoic fossils. They also have some great models and dioramas, such as this giant eurypterid:

This model shows a dire wolf that was trapped in a cave and preserved, along with vast numbers of other animals:

I’d like to thank Ron for making my visit to the Indiana State Museum both pleasant and productive.

A huge amount of my time over the last several weeks has been spent working on an upcoming VMNH exhibit, which will include a significant component on the Ordovician Period (the reason I’ve been doing so much collecting in Indiana and Kentucky over the last year). In addition to collecting specimens and writing text, I’ve also been working on life-sized models of some of the Ordovician critters.

This is my first completed model of the nautiloid cephalopod Isorthoceras sociale, which is preserved in vast numbers in the Maquoketa Formation outcrop at Graf, Iowa (the rock it’s sitting on is from one of the cephalopod beds at Graf). I modeled this individual in a swimming mode, making the assumption that these nautiloids bunched their tentacles together when swimming in the same way as many modern squid. I’ve also done a few with the tentacles spread out a bit, but they’re not yet completed.

The model is made from five separate resin pieces, for which I’ve made silicone molds. That way I can make a small school of Isorthoceras for the exhibit, time permitting. I’m also working on several other models; I’ll post photos of those when they’re completed.

The slab still needs some cleaning, but it’s already clear that the surface is covered with specimens of Inoceramus, a large pteriomorph bivalve. Here’s a closeup of part of the surface:

Inoceramus is extremely common in many Cretaceous rocks from central North America, like those that cover northern Kansas. Even though some of these specimens exceed 10 cm in length, they’re actually quite small by the standards of the group. Related species are known to have reached lengths approaching 2 meters, and are the largest known bivalves.

We don’t have large amounts of Cretaceous sedimentary rocks in Virginia, so we don’t have many specimens like this at VMNH. Thanks, Ed, for this nice addition to our collections!

Administrative duties and exhibits have kept me away from the blog for the last few weeks. I somehow found the time to take an actual non-working (mostly) vacation this week (my first one in years), and that’s given me a chance to catch my breath and focus on the blog a bit.

Just before Christmas I made a trip to Indiana to pick up a specimen (more on that in a future post), and while I was there Andy Moore took us on a visit to Oakes Quarry Park near Dayton, Ohio. Ohio has several fossiliferous quarries that have been turned into educational parks, which I think is an excellent practice that other states should consider emulating.

The Oakes Quarry Park exposes about 8 meters of the the Silurian Brassfield Formation, a fossil-rich limestone and dolostone. The quarry floor is a dolostone that is absolutely riddled with burrows:

The wall of the quarry exposes several other units, including a crinoidal limestone made up mostly of broken crinoid fragments:

There are finer-grained units that include a variety of fossils, including gastropods and nautiloid cephalopods:

There are also limestone beds that are filled with rugose and tabulate corals:

As you may have expected, the different units are not distributed at random through the quarry, but occur in a particular sequence. In the marked up image below, the blue represents the burrowed dolostone (not visible in this image), the red is the crinoidal limestone, the green are the fine-grained beds that include nautiloids, and the yellow are the coral-rich limestones:

This seems to represent a transgressive sequence, in which the water was getting deeper over time. The burrowed dolostone is probably an intertidal deposit which was actually exposed (or nearly so) at low tide. As the water got somewhat deeper, this spot became the surf zone right along the beach. The high wave energy carried broken fragments of various organisms, especially crinoids. Crinoids are delicate animals that have skeletons made up of hundreds of individual pieces that will quickly disassociate under high-energy conditions.

Above the crinoidal limestones are slightly deeper-water conditions. There is some variation here; the finer-grained beds are probably the deepest water, and may have been below normal wave base, while the coral-rich units were almost certainly above wave base (but still subtidal). The alternating occurrence of these units probably represents slight changes in local sea level. This didn’t have to be due to actual regional changes in sea level; it could easily be the result of the migration of coral reefs as they grew across the sea floor, with the water getting shallower when the reef is present because of the thickness of the reef.

There’s one more interesting piece of this story. At the top of the quarry the corals are all beveled off:

All the exposed rock around the top of the quarry is polished, and in most areas it’s covered with striations:

During the Pleistocene, glaciers covered this area, stripping away the younger sediments and grinding away the top of the coral-rich limestone. So, on a single surface, we have evidence for a tropical coral reef and a continental glacier, separated by over 430 million years.

In 1962, Bouma described and explained a sequence of sedimentary rocks which later became known as the “Bouma sequence”. The sediments he was studying were from deep-water deposits and were mostly fine-grained shales, but they included certain characteristics that would more typically be found in fluvial (river) systems, such as graded sands and cross-bedding. Bouma suggested that these deposits were formed by turbidity currents, which are basically submarine sediment flows. Sediment-water slurries are more dense that sea water, and on a shallow slope can flow across the seafloor for great distances. Check out the lab example below (direct link):

These flows leave behind a very specific sequence of sediments. Bouma labeled the unit A-E, with A at the base:

E: Fine-grained, massive bed

D: Parallel laminae

C: Cross-bedded or wavy lamina

B: Parallel, laminated beds

A: Massive, graded, relatively coarse-grained, with an erosional base

The image at the top, from the Devonian Chattanooga Shale, I believe represents a complete Bouma sequence. Here it is with the units labeled:

It’s possible that what I’ve labeled “E” actually includes unit “A” of the next sequence. Bouma sequences are often incomplete, with younger flows eroding parts of the older sequences, or with the lower units never reaching the distal part of the flow.

It turns out that turbidity currents are probably the most significant source of sedimentary deposits in offshore deeper-water environments, such as the outer continental shelf and slope, as well as in back-arc and foreland basins. As such, understanding the origins of Bouma sequences was a critical step in the interpretation of depositional settings and tectonic histories.

Below is a link to a 2010 interview with Dr. Bouma (direct link); embedding is not working for this site:

http://www.minigeology.com/embed/MTM3MzQ3NjIz?related=1