Conglomerate, in geology, a sedimentary rock composed of rounded rock fragments cemented together by a finer-grained material such as sand or clay. The fragments, which are commonly quartz or limestone but can be almost any type of rock, originally may have accumulated on beaches or in beds of streams.
Climate, the average condition of the weather in an area for a period of years.
Folks in Montana usually expect snow or rain to fall from the sky, not ash. But the 1980 eruption of Mount St. Helens in Washington flung ash across state lines. What is this gritty, gray stuff?