This fork of an Irish map with a borehole combines a geographic view with a stratigraphic cross-section. The map uses D3’s `geoPath` and `geoMercator` projections to render the country, with zooming enabled via `zoom()`. Clicking a borehole opens a modal containing an SVG diagram of subsurface layers (topsoil, peat, till, and sandstone) beneath a water table. Hovering over each colored rectangle or water line displays a tooltip with depth information. The geological visualization is built with D3’s `select` and SVG shapes, styled with Bootstrap and CSS.