This region is characterized by very poor-quality, well-drained soils of mostly Miocene sediments, both continental and maritime, with occasional quaternary deposits. The sandy, clay-like soil is poor in organic matter and rocky in the main, the pre-litoral uplands consisting of Triassic, Cretaceous and oceanic deposits, while coastal mountains are mostly jagged Cretaceous limestone. A largely Mediterranean climate prevails although the Penedès enjoys a wide variety of micro-climates, due to the proximity of the coast and a varied terrain ranging from sea level to over 2,600 feet. Coastal areas are hot and dry, while upland vineyards are much more prone to frosts, with some areas recording annual rainfall of up to 35 inches.