- Limestone (calcium carbonate CaCO3) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of CaCO3. Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life.
- San Juan County — Thumbnail History (historylink.org)
Accessible only by water or air, San Juan County is an archipelago of hundreds of islands, reefs, and rocks between mainland Washington and Vancouver Island. Around 20 islands are inhabited. The largest three – Orcas, San Juan, and Lopez – contain most of the land area and nearly all the population. Only in 1872, later than any other area in the 48 contiguous states, did the San Juan Islands become an undisputed part of the United States following the “Pig War” boundary dispute with Great Britain. San Juan County was created the next year…