FTR is a British rapid-transit bus system, currently in operation in Leeds, Luton and Swansea.irst Group has introduced the system, using Wright StreetCar articulated buses in conjunction with infrastructure upgrades by local authorities. The vehicles have been branded as the future of travel, the operators claiming that ftr is textspeak for the word future.
Limestone is a sedimentary rock, composed mainly of skeletal fragments of marine organisms such as coral, forams and molluscs. Its major materials are the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO3).
Jupiterimages/Photos.com/Getty Images. Limestone is a sedimentary rock composed of a mineral called calcite, which has the chemical formula CaCO3. Together with the dolomites, a related class of sedimentary rocks, limestone makes up some 10 to 15 percent of all sedimentary rock on our planet.he first element found in limestone is calcium; the symbol for calcium is Ca. Calcium has atomic number 20, meaning it has 20 protons in its nucleus.