Kieselguhr, 91 chemical composition of, 92 of the Isle of Skye, 42 Kimeridge clay brick-earth, 26 Labradorite felspar, chemical composition, 34 Lacustrine brick-earth: that laid down or deposited in lakes brick-earths--Chapter II., 17–21 brick-earths, formation of, 17, 18 Lime, builder’s, 52 in bricks, 52 in manufacture of fire-bricks, 53 Limestone, a flux, 54 Limonite, under blow-pipe, 73 Lincolnshire brick-earths, 21 Loam: sandy clay London stock bricks, 97, 140 Magnesian limestones, chemical composition of, 90 limestone (see Dolomite) Magnesite, 55 behaviour in the kiln, 56 Californian, 56 in Greece, 56 Styrian, 56 under blow-pipe, 74 Malachite, 67 Malm bricks, 53, 86 Manganese, under blow-pipe, 74 Marcasite, 46, 47 behaviour in the kiln, 48 weathering of, 47, 48 Marine brick-earths: those laid down or deposited on the sea-floor Marine brick-earths, not so variable in character as river, lacustrine, or estuarine, 23 brick-earths--Chapter III., 22–27 brick-earths, origin of, 23 Marl: clay containing much lime. Mica, 43 behaviour in the kiln, 44 micro-structure of, 130 under blow-pipe, 73 Microscopes, 121 Microscopes, use of, 59 useful in analysing earths, 30 Micro structure as a means of determining fusibility of minerals and brick-earths, 43 of bricks, 118, 128 Minerals, their behaviour in the kiln (see Kaolin, Felspar, Quartz, Flint, Mica, Iron, Calcite, Aragonite, Selenite, Dolomite, Salt, etc.). behaviour under the blow-pipe (see Quartz, Felspar, Mica, Calcite, etc.). Mississippi, sediments of the Delta of, 7 Mortar and Scum, 112 Muscovite mica, 43 mica, under blow-pipe, 73 Musk-sheep remains, found in brick-earth, 2, 3 Natrolite, 68 Newcastle-on-Tyne fire-clays, 80 Newton Abbot, clays near, 20 Northamptonshire brick-earths, 21 Oligoclase felspar, chemical composition, 34 felspar, under blow-pipe, 73 Origin of fluviatile brick-earths--Chapter I., 1–16 Orthoclase, 69 felspar, chemical composition, 34 felspar, under blow-pipe, 73 Overburden: the material for the most part useless, overlying the good brick-earth, sand, limestone, or other rock for which the pit or quarry was exploited, and which, in the majority of cases, has to be removed to obtain the material sought for. Oxford clay, 24, 25, 33 Oxidising flame, 65 Paving bricks, tests, 148 Peterborough bricks, 24 clays, 51 Plants, fossil, 21, 26 Platinum wire, 60, 63, 66 Plesiosaurus, fossil reptile, 26 Porcelain earths, 30 Pottery clays, chemical composition, 82 Power of transport of sediment by rivers, 8 Pumice for brickmaking, 93 Pyrite, 46 behaviour in the kiln, 48 under blow-pipe, 74 Pyrometers, 99, 100