Haystack Rock the U.S. The tallest and probably best known Haystack Rock due to its proximity to Portland is in Tillamook County located off Pacific City and near Cape Kiwanda. It stands above the sea and is the fourth tallest sea stack or off-shore monolith in the world. Haystack Rock in Cannon Beach is accompanied by several smaller rocks known as The Needles. The other Oregon coastal Haystack Rock stands above sea level in Coos County near Bandon. Composed of basalt, Haystack Rock was formed by lava flows emanating from the Blue Mountains and Columbia basin about 15-16 million years ago. The
Chinchillas (lava dome) part of a caldera system in the Pozuelos basin. Chinchillas (lava dome) Chinchillas is a lava dome complex in the northern Puna of the Andes, in the Sierra de Rinconada. The complex is constructed on an Ordovician basement called the Acoite Formation. In addition to the dacitic lava dome on the southern end of the complex it also contains small volume massive pyroclastic flows and ash-and-block flows. The complex has a volume of . The complex was formed 13±1 mya over a fault zone. Hydrothermal Ag-Pb-Zn deposits found there in breccia were mined occasionally. According to Coira "et al." (1996)