The Hunsrück Slate (in German: Hunsrück-Schiefer) is one of the most valuable fossil records for paleontologists to examine. The slate was first excavated by paleontologists in 1997, and the investigation has not been completed yet. More than just visual echoes of a distant era, the fossils serve as valuable research material for paleontologists that also reveals interesting biological narratives about species that lived during the Devonian era which was about 400 million years ago. Much like the “Garden of the Fugitives” at Pompeii these species, forever frozen in time, continue to be the object of fascination among researchers and aficionados alike. In Visions of a Vanished World: The Extraordinary Fossils of the Hunsrück Slate, co-authors Gabriele Kühl, Christoph Bartels, Derek E.G. Briggs, and Jes Rust showcase a stunning visual compendium of photographs of species fossilized in the Hunsrück Slate and tell the story of the Slates discovery, excavation, and significance for scientists.

At about 3,750 meters thick, the Slate spans the Hunsrück region for which it is named as well the Mayen and Bingen regions in present-day Germany. During the Devonian period, however, when many of these fossils were formed, the distribution of continents was very different to how the landmasses are arranged today. The Rheic Ocean separated the southern hemisphere supercontinent Gondwana from the northern hemisphere supercontinent Laurussia, also known as the “Old Red Continent. The Hunsrück sea was located on the along the northeast to southwest coast of the Laurussia continent, which explains why most of the fossil remains found on the Slate are of marine animals; more than 260 species have fossil remains in the Hunsrück Slate.

During the first half of the 20th century, the Hunsrück Slate was subjected to mining exploitation (though not for the first time; evidence suggests that the Romans mined the Slate to build walls and roofs). In the mid-1950’s, the demand for slate declined with the rise of synthetic materials, but during the oil crisis of the 1970’s, when the cost of synthetic material increased dramatically, slate became a valuable commodity once more. It was during this second wave of slate mining in the latter half of the 20th century that fossils were discovered on the Hunsrück Slate.

One of the remarkable elements of this find is that a great deal of soft tissue was preserved in the slate. When animals in the ocean die, their soft tissue remains are usually consumed by microbes and seafloor scavengers. But in this case iron-rich muddy sediment clouds quickly enveloped these animal remains in the Hunsrück Sea, possibly due to earthquake activity and major storm systems, thus allowing the soft tissue to remain almost perfectly intact. Another curious aspect about the Hunsrück Slate is that the fossils appear golden. This is a result of a process called pyritization, when iron and sulfide reacted to make the soft tissues turn into pyrite, commonly known as “fool’s gold.” This process makes it possible to preserve tiny details of hard remains as well as the morphology of soft tissue remains

In addition to fossil images, this book also provides detailed, digital models of some of the species, thanks in part to the work of physicist Wilhelm Stürmer. Between the 1960s and the 1980s, he designed an x-ray device that was installed in a Volkswagen bus, thus providing paleontologists with portable technology to examine slate tablets during excavations. This new device laid the groundwork for x-radiographs that are used today to construct three-dimensional models of fossilized remains through computer technology.

The Hunsrück Slate contains the remains of various marine species such as sponges, clams, crustaceans, sea stars, and corals among many others, and has proved to very influential to paleontologists; the sea spider species discovered on the Slate has been the first and oldest piece of evidence that arthropods lived in the Paleozoic era. Some of the spiders had legs that reached almost 40 cm in length!

Although most of the fossils found on the Hunsrück Slate are of marine animals, there are a few plant fossils visible to suggest that land was nearby. This is just an example of how the Hunsrück Slate has played a vital role in helping us piece together the history of our planet and better understand the species that inhabited it. Discovering fossils in the Hunsrück Slate marked the start of an exciting investigation, one that continues today and may yield even more finds in the future.