Flat-topped landforms, such as buttes and mesas, are the remains of giant ancient trees. Tree features can be seen in Devils Tower, for example – the large hexagonal columns are fibers of a tree that would have been 19,000 feet tall. Other tree features can be seen in buttes and mesas, such as sloped sides and flat tops that look like tree stumps after trees are cut down.
Meitner, Lise meitnerium melaleuca tree melamine melanin melanism melanoma melon meltdown melting point membrane memory (computing) memory (psychology) menagerie Mendel, Gregor Johann mendelevium Mendeleyev, Dmitri Ivanovich Mendelism menhaden menhir Ménière's disease meningitis meningococcus meniscus meniscus (biology) menopause menstrual cycle mental disability mental illness menu Mercalli scale Mercator, Gerardus merchant navy Mercury (astronomy) mercury mercury fulminate Mercury project merganser meridian merino meristem merlin MERLIN array mermaid's purse mesa mescaline Mesmer, Friedrich Anton (or Franz) mesmerism mesoglea Mesolithic meson mesophyll mesosphere Mesozoic messaging Messerschmitt, Willy (Wilhelm Emil) Messier, Charles Messier catalogue metabolism metal metal detector metal fatigue metallic bond metallic character metallic glass metallographic examination metalloid metallurgy metamorphic rock metamorphism metamorphosis (biology) metazoa Metchnikoff, Elie meteor meteor-burst communications meteorite meteorology meter methanal methane methanogenic bacteria methanoic acid methanol methionine methyl alcohol methylated spirit methyl benzene methyl orange metre (science) metric system metric ton mg MHD mho mi mica Michaelmas daisy Michelson, Albert Abraham MICR micromicrobe microbiology microchip microclimate microcomputer microfiche microform micrometer (instrument) micrometre micro-organism microphone microprocessor micropropagation micropyle microscope microsurgery microtubules microwave heating microwave radiation Mid-Atlantic Ridge midge MIDI midnight sun mid-ocean ridge midwifery mifepristone mignonette migraine migration Milankovitch hypothesis mildew mile milfoil milk milking machine milk teeth Milky Way Millennium [...] butte steep-sided, flat-topped hill, formed in horizontally layered sedimentary rocks, largely in arid areas. A large butte with a pronounced tablelike profile is a mesa. Buttes and mesas are characteristic of semi-arid areas where remnants of resistant rock layers protect softer rock underneath, as in the plateau regions of Colorado, Utah, and Arizona, USA. [...] W 74 183.85 19.1 2,900–3,000