Mercoledì Nov 22

Pliocene in the Bergamo area

This room’s cabinets are dedicated to the more recent geological phenomena characterising the Pliocene epoch in the area of Bergamo. Here, we find fossilized flora and fauna developing in our region from about 5 million to 10,000 years ago. A number of cabinets are dedicated to the origins and evolution of Man, from the primates to Homo sapiens sapiens. Man’s physical and behavioural characteristics are presented alongside the major evolutionary triumphs of this species: technologies, art and spirituality. The large central cabinet contains a number of remains of Mammuthus meridionalis, the southern elephant that disappeared during the Lower Pleistocene epoch and which inhabited the region during the interglacial phases.

The “Museum you can touch” section includes the casts of the teeth of various proboscidean animals. Braille comments are also provided for the blind. The last part of this section is made up of seven cabinets which are frequently renewed, since they are dedicated to research, study and donated items.

Important fossils dating back to about one and a half million years ago have been discovered in the sediments of an ancient Pleistocene lake basin in the vicinity of the small town, Leffe, in Val Seriana. The lake, which has since disappeared, was formed by a naturally occurring dam made up of sediments deposited by the river Serio. As the lake formed, plant material accumulated, which then became lignitious coal. Extraction of this fossil fuel constituted a resource of economic value for the area roughly from the mid-nineteenth to mid-twentieth centuries. It was through mining that the fossil remains emerged of the proboscideans exhibited here. Lakes such as the lake at Leffe were most dangerous. What are termed ‘floating meadows’ formed around the banks, where the grass grew on a muddy substrate. As they attempted to reach the water itself, large herbivores would remain trapped in the mud, where they would die, leaving the fossils remains that we can admire today. The findings on display belong to specimens of various sizes and ages. The atlas vertebra belongs to an animal that had grown to a greater size than the mammoth at the entrance to the Museum. Its lower jaws were deformed under the enormous pressure exerted at the time of its fossilizing within the lake sediments. The missing parts, reconstructed in plaster during previous restoration work, are now highlighted by a different colour than that of the material of the original findings.

The six cabinets lined up to the left of the room display the fossil remains of plants, invertebrates and vertebrates discovered in the immediate vicinity of Bergamo. Study of these items enables us to arrive at a paleogeographic reconstruction of our territory between 5 and 1.8 million years ago. In the first cabinet, a reconstruction provides us with a view of the Bergamo area when the sea invaded our valleys for the last time. The next cabinets contain fossils illustrating the sea’s advance and retreat. The cabinet dedicated to plants displays yellowish sandstone exhibits containing the fossilized remains of typically Asiatic plants dating back to the Middle Pliocene epoch – indicating a mild-to-hot climate. The seeds of sequoias, to be found today only in North America, seem to indicate that the climate was mild and damp over the earliest period documented by the grey Lower Pliocene clays. The sediments also host many marine invertebrates, indicating that the Bergamo area was impacted by the advance of the sea over today’s Po valley and pre-Alpine valleys. The last cabinet houses the fossilized remains of an ancient elk, about 2 million years old. It was found in an ancient lake basin at Ranica, in Val Seriana. This indicates that the climate then cooled down.

The ‘family album’ of proboscideans – a tactile exhibition area providing an account of the evolution of these large mammals, with its casts of the chewing surfaces of enormous molars. Mammuthus meridionalis, dating back to the Lower Pleistocene epoch, is the largest and most ancient of the various proboscideans. The cast on display comes from a specimen discovered at Leffe. Mammuthus primigenius, widely known as the mammoth, dates back to the Upper Pleistocene epoch. A reconstruction dominates the Museum entrance. The exhibited cast is of a molar tooth discovered at Petosino, just a few miles from Bergamo. We note that, over a period of millions of years, the chewing surface of molars broadened out, also with various lamellate surfaces that facilitate the shredding of plant material.

Paleontologia Paleontologia Paleontologia