Saturday, October 29, 2011


The exhibiting of fossil vertebrates at Dinosaur is somewhat unusual in that in our main display the 1500+ in-situ bones are supported by the conglomeratic sandstone in which they were buried. Although a few areas are friable from increased clay content, much of the sandstone is both hard and strong, which allows bones weighing up to several hundred pounds to be safely exposed in bas-relief.

However, delicate items, even if still in small pieces of rock, present a different challenge. These are displayed in cases and require other support so that they are held securely and in the right place both relative to lighting and explanatory text. These supports are built on site by the exhibit fabricators and installers. Each is built to match the specific size and shape of the fossil it holds.

The fabricators start with a collection of brass rods of varying width, length, and shape.

In most cases, four arms are needed, so short pieces of brass rod are cut and laid across one another at right angles. These are placed on a heat resistant ceramic slab.

Next, a rod is placed vertically and supported upright with a clamp. A small dab of flux is placed at the point where all three rods contact.

Now you can see clear why a ceramic base is needed. A small butane torch and solder is used to firmly join all the pieces together.

The arms that hold the specimen are cut to the correct length and bent to fit around the edges of the fossil. Areas that will directly contact the specimen are cushioned with soft white material or a rubber sleeve.

Once properly formed, the ends are rounded off on a small belt sander.

Then the frame is put in a vise and spray painted a neutral color.

The frame is then attached to the inside of the case……

… and the specimen is placed in it. The small arms are adjusted as needed so that the fossil is firmly held. In this example, the fossil is part of a three dimensionally preserved piece of conifer branch from rocks the same age as the Carnegie Quarry but found a short distance away from it.

Another example is this cast of a fossil conifer cone held further forward in the case than the conifer branch.

Virtually all the smaller fossils exhibited at both the Quarry Visitor Center and Quarry Exhibit Hall are on mounts such as these. Such delicate mounts require skill and patience and, if done well, are not really noticed by the viewer. So next time you wander the hall of a museum take a moment to look beyond the specimen and notice how the object is supported and positioned. Its an important, if often overlooked, part of the exhibit.

Photos: NPS

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