1. LIMESTONES Calcite (calcium carbonate) dominates Fine-grained –Chalk (cliffs of Dover, England) Medium-grained –Oolitic limestones Coarse-grained –Coquina (broken shells loosely cemented) –Fossiliferous limestones

2. CHERT Microcrystalline silica (microquartz = silicon dioxide) Many varieties: –Flint = gray due to organic matter –Jasper = reddish due to iron oxides –agate = banded structures Scots Bay Formation at Ross Creek

3. EVAPORITES Precipitated crystals from –oceans –lakes –rivers Halite (sodium chloride) Gypsum (hydrated calcium sulfate) Death Valley, California

4. COAL Compressed, heated thick accumulations of organic matter With little detrital sediment to form much ash Environment: vegetation in a lush swamp Well-known from Carboniferous Period of Nova Scotia

5. Coalfields of Nova Scotia

6. FOSSIL FUELS Alteration of partly decayed and buried organic matter. Coalsolid rock Petroleumliquid in pore Natural gasgas (mostly methane) spaces Coal is mostly from terrestrial plant matter, but petroleum and natural gas come mostly from marine animals, plants and micro-organisms