Sandstone: Rock for Crack Climbing. Sandstone is a sedimentary rock, a rock type that encompasses a wide variety of characteristics and is deposited directly on the earthâs surface. Roughly 75% of the earthâs land surface is covered with some type of sedimentary rock. Sedimentary rocks like sandstone form when minute rock particles, often from granite, are deposited by wind and water on earth surfaces.
8. 1  Other Causes. 2  Diabetes causes arms or hands and feet to fall asleep even when one is awake and relaxed. 3  Hand surgery and arthritis damage or irritate the nerves.
Sleep attacks â falling asleep suddenly and without warning â are also common in people with narcolepsy. They may occur at any time. The length of time a sleep attack lasts will vary from person to person. Some people will only have microsleeps lasting a few seconds, whereas others may fall asleep for several minutes.