• Stratigraphic frameworks and palaeogeographic reconstructions dominate across eras, integrating sedimentary cycles, faunal succession, and layered stratigraphy to decode past environments [4], [7], [8], [9], [10], [12], [16].

• Igneous rock genesis and tectonophysics provide a unifying lens to interpret rock formation, evolution, and volcanism across 1890s-1910s literature, exemplified by The Natural History of Igneous Rocks, Igneous Rocks and their Origin, The Later Stages of the Evolution of the Igneous Rocks, and the ancient volcanoes of Great Britain [1], [3], [11], [20].

• Economic geology and ore-genesis studies anchor practical resource exploration, linking metal distributions to geochemical processes, illustrated by platinum sources, quicksilver deposits, and applied geology themes in early 20th-century literature [14], [17], [19].

• Regional geology and environmental applications drive state and regional mapping, sedimentology, and resource context, from Connecticut's geology manual to US clay deposits and Carboniferous sequences [2], [7], [10], [13].