Tufa outcroppings from Lake Winnemucca north of Nixon, Nevada.  Lake Winnemucca is now reduced down to a desert playa w/ ancient lakeshore levels noticeable on the surrounding mountainsides, part of the Pleistocene-era Lake Lahontan.  Tufas are a form of limestone, specifically created from the precipitation of carbonate minerals from temperate water bodies, according to Wikipedia --> https://en.wikipedia.org/wiki/Tufa

These formations are abundant in this region of Nevada & have a circular top that almost resemble a massive horn coral head or even a stromatolite.  An up close analysis reveals they consist of intricate sharp-bladed crystals of calcite variety thinolite, a type of glendonite (calcite pseudomorphs after ikaite).  These tufas indicate the former location of Lake Winnemucca which today you can see its dried form to the north.