The inclusion of Meghalaya in Peninsular India is primarily justified by its geological continuity and structural characteristics, despite its geographical separation by the Ganga-Brahmaputra alluvial plains. Geologically, the Meghalaya Plateau (also known as the Shillong Plateau) is considered an eastward extension of the Peninsular Block. It is composed of ancient crystalline rocks, including granites, gneisses, and schists, which are characteristic of the Peninsular Shield. The plateau was uplifted during the Himalayan orogeny but is fundamentally a part of the stable Indian Craton, separated from the main Peninsular block by the Malda Fault and the subsequent subsidence that formed the Bengal Basin. This geological linkage, evident in the rock types and tectonic history, firmly places Meghalaya within the broader Peninsular Indian framework.

Regarding its vegetation, Meghalaya is renowned for its rich biodiversity, largely due to its unique physiography and extremely high rainfall, particularly in areas like Cherrapunji and Mawsynram, which receive some of the highest rainfall in the world. The dominant vegetation types include:

• Tropical Evergreen and Semi-Evergreen Forests: These dense forests thrive in the high rainfall zones, characterized by tall trees, multiple canopy layers, and a rich undergrowth of ferns, mosses, and epiphytes. Species like Sal, Teak, and various bamboo species are common.
• Subtropical Broadleaf Forests: Found at higher altitudes, these forests exhibit a mix of evergreen and deciduous species, adapted to cooler temperatures.
• Grasslands and Shrublands: In areas with less dense forest cover or where shifting cultivation has occurred, grasslands and scrub vegetation are prevalent.
• Sacred Groves: Many indigenous communities maintain sacred groves, which are patches of pristine forest preserved for religious and cultural reasons, acting as biodiversity hotspots.

In terms of soil types, the high rainfall and specific geological composition of Meghalaya lead to distinct soil characteristics:

• Lateritic Soils: These are widespread, especially in areas of high rainfall and undulating topography. Formed by intense leaching of soluble minerals, lateritic soils are rich in iron and aluminum oxides, giving them a reddish-brown color. They are generally acidic and often deficient in organic matter and essential nutrients due to the heavy leaching.
• Red and Yellow Soils: Derived from the weathering of ancient crystalline igneous and metamorphic rocks, these soils are also acidic and tend to be deficient in nitrogen, phosphorus, and humus. The color varies from red to yellow depending on the hydration state of iron oxides.
• Alluvial Soils: Found in the narrow river valleys and floodplains, these soils are relatively fertile, deposited by the numerous rivers and streams flowing through the plateau. However, they are less extensive compared to the lateritic and red soils.
• Forest Soils: In undisturbed forest areas, the soils tend to be rich in organic matter dueishing to the decomposition of leaf litter and other plant material, contributing to their fertility.