Most small-molecule neurotransmitters are stored in small vesicles that range from 40 to 60 nm in diameter and, in electron micrographs, appear to have clear centers. The vesicles that store neuropeptides are larger, ranging from 90 to 250 nm in diameter.
The world's largest concentration of natural sandstone arches. 1  Hike the 1.5 mile trail leading to the base of Delicate Arch to experience one of the most breathtaking vistas in the world. 2  Your family will love the short trails in the Windows Section that lead right up to several massive arches.
Established in 1926. The sandstone arch that is called Natural Bridge has stood for millenniums. The arch is 78 feet long, 65 feet high, 12 feet thick and 20 feet wide. Some geologists believe that the stunning natural sandstone arch is at least a million years old. There are other natural archways in the area, but none have gained the prominence of Natural Bridge.