In Morocco, substantial limestone deposits from the Devonian period encase the remains of many aquatic animals from the Age of Fishes.  Most commonly seen in the layers of sediment that have amassed to form fossil beds are trilobites, ammonites, and gastropods.  All of these creatures had shells, which persisted and became fossils long after their flesh decayed.

This process of fossilization is less common than it might seem, in light of the vast collections in museums and universities.  These are indeed many fossils of a myriad of species from many periods of history around the world, but compared to the actual number of animals that have lived throughout the earth’s life span, the number of fossils that form from their remains is very low, making fossilization a comparatively rare event.

Animals most likely to be fossilized are those that are low in the food chain as these animals tend to be more plentiful than those higher up.  Morocco’s fossils are primarily of this type of animal.  It is also unsurprising that trilobites, ammonites and gastropods all probably spent part of their lives in the sand near the ocean floor.  Upon their deaths, their positioning near the sediment made them good candidates for this fossilization.

For fossilization to happen, once the animal dies, it must be quickly buried under layers of sediment or rock.  If not, it will likely be scavenged by other animals in the area.  If buried, however, the animal may fossilize.  Its soft tissues and flesh will usually decay completely, but hard parts like shell and bone remain, and over time, various minerals may seep into these remnants and become part of their structure.  Basically, the shells or bones become rock.

Millions of years later, a paleontologist may see something that looks unusual protruding from a layer of rock deposits, and the excavation begins to identify and study it.  For a fossil to be discovered, some of the rock that lies over it must be removed by natural or accidental processes for the bones or shells to be exposed.

         The fossils of Morocco lie in what was, during their time period, a seabed which was eventually buried under layers of sediment that became rock or marble.  Now, they are exposed in a marble quarry to be recovered, studied and admired.  By the very nature of life and death, no two pieces of Moroccan marble will EVER contain exactly the same types of fossils.  Each one is unique, just as a photograph is unique.  Each fossil is a frozen record of the death of a group of organisms, never again to be repeated.