Epipaleolithic is the earlier part of the Mesolithic. Some identify it with the Mesolithic. To others it is an Upper Paleolithic transition to the Mesolithic. The exact use in any context depends on the archaeological tradition or the judgement of individual archaeologists. The issue continues. Lower, middle and upper from Haeckel to Sollas The post-Darwinian approach to the naming of periods in earth history focused at first on the lapse of time: early (Palaeo-), middle (Meso-) and late (Ceno-). This conceptualization automatically imposes a three-age subdivision to any period, which is predominant in modern archaeology: Early, Middle and Late Bronze Age; Early, Middle and Late Minoan, etc. The criterion is whether the objects in question look simple or are elaborative. If a horizon contains objects that are post-late and simpler-than-late they are sub-, as in Submycenaean. Haeckel's presentations are from a different point of view. His History of Creation of 1870 presents the ages as "Strata of the Earth's Crust", in which he prefers "upper", "mid-" and "lower" based on the order in which one encounters the layers. His analysis features an Upper and Lower Pliocene as well as an Upper and Lower Diluvial (his term for the Pleistocene). Haeckel, however, was relying heavily on Lyell. In the 1833 edition of Principles of Geology (the first) Lyell devised the terms Eocene, Miocene and Pliocene to mean periods of which the "strata" contained some (Eo-, "early"), lesser (Mio-) and greater (Plio-) numbers of "living Mollusca represented among fossil assemblages of western Europe." The Eocene was given Lower, Middle, Upper; the Miocene a Lower and Upper; and the Pliocene an Older and Newer, which scheme would indicate an equivalence between Lower and Older, and Upper and Newer. In a French version, Nouveaux Éléments de Géologie, in 1839 Lyell called the Older Pliocene the Pliocene and the Newer Pliocene the Pleistocene (Pleist-, "most"). Then in Antiquity of Man in 1863 he reverted to his previous scheme, adding "Post-Tertiary" and "Post-Pliocene". In 1873 the Fourth Edition of Antiquity of Man restores Pleistocene and identifies it with Post-Pliocene. As this work was posthumous, no more was heard from Lyell. Living or deceased, his work was immensely popular among scientists and laymen alike. "Pleistocene" caught on immediately; it is entirely possible that he restored it by popular demand. In 1880 Dawkins published The Three Pleistocene Strata containing a new manifesto for British archaeology: The continuity between