Fossils in New York State are found almost exclusively in such sedimentary rocks as limestone (made of the mineral calcite), shale (fine grained rocks originally composed of mud and silt), sandstone (made of sand-sized particles, commonly of the minerals quartz and feldspar), and dolostone (made of the mineral dolomite, a calcium magnesium carbonate), in that order of abundance . They rarely occur in conglomerate (coarse-grained rocks made of pebbles and coarser fragments, arkose (a sandstone dominated by grains of feldspar [a potassium, sodium, or calcium silicate often derived from granite]), breccia (conglomerates made of angular fragments), and graywacke (sands tones rich in tin y rock fragments). Fossils are rare in metamorphic rocks (rocks changed by heat and pressure), such as those that compose the Taconic Range of eastern New York, and are absent in almost all igneous rocks.
The best fossil collecting areas are in exposures of sedimentary rocks along stream and river banks and along some sea and lake shores. Natural cliffs, field exposures, and artificial excavations, such as highway and railroad cuts and quarry sites, often offer excellent collecting. Before starting in an area, obtain permission from the owners of private property. Collecting is not permitted on state and federal land (parks, watersheds,