D. V. Nalivkin began his scientific activity as a paleontologist. Paleontologist, he remained and all his life. Even in the last years of his life he had to advise on the definition of Devonian brachiopods. However, he was characterized by an unusually broad approach to all the problems he had to study. He considered not only shells, but also the conditions under which the animals lived, the extent to which these conditions endured, the causes of their change, and their succession. All this required tracing individual stacks, layers, and hence mapping.

It is known that all objects in geology have limits both in space and time. These limits are not infinite. Their boundaries are of different character, and the types of boundaries are close for objects and phenomena changing both in time and in space.