It is common knowledge that the coastal State's right to continental shelf areas emanates from the fundamental conception that "the land dominates the sea". It is, however, by way of the "coastal opening" - the indirect basis of title to shelf areas - that such right manifests itself as the "natural prolongation" into and under the sea of the landmass of the coastal State. Over some 15 years of legal usage natural prolongation assumed a still more abstract character leaving today no trace of its origin as a concept deeply rooted in natural science. The principle of distance was sequentially introduced as the complementary carrier of entitlement to shelf areas. Yet, in case of a wide continental shelf (margin) extending uninterrupted beyond 200 nm from the shoreline, natural prolongation is still considered as the sole carrier of entitlement though in a somewhat figurative sense. It is the role of natural prolongation in relation to the wide shelf and its delimitation between neighbouring States which is the principal subject of the present paper.