This work entitled "Erosionada" (Erosioned), which belongs to a series he called "Fósiles" (Fossils), is part of his search for his own identity as a sculptor.

These fossils represent the sculptor's first step beyond more or less realistic representational sculpture. From the perspective of the evolution of his work, this series had no continuity, and in his trajectory, it was an exercise in the synthesis of organic form.

The material used in this series is a compound of resins and marble dust, and is also an attempt to move away from conventional materials. However, this was a path that Mateos rejected as sophisticated and unnatural.

The sculptor is looking for his own way, and this gentle sculpture of rounded volumes did not express the strength he intended. Dissatisfied and energetic from the outset in his rejection of the easy, "ready-made", as he would say, he sought new approaches, new paths.