The C horizon is below the A and B horizons of most soils. It consists of materials that were little altered by the soil-forming processes, though the materials may be modified by weathering. Below the C horizon in some soils is an R horizon of consolidated bedrock, such as limestone, shale, or sandstone.
Ultrabooks Guide. If you want one of the most portable computers on the market, consider getting an Ultrabook, a new kind of super-thin, ultra-light laptop that wakes from sleep quickly and offers a compelling Windows 8 experience.
If you mainly want a laptop, a proper Ultrabook is still your best bet. But if you want the option of using your device in tablet mode, both the Surface Pro 3 and the Lenovo Yoga 3 Pro are good choices. And what of the MacBook Air, which I keep comparing to Dell's new machine?