The Middle-Jurassic oolitic limestone series which forms the bulk of the Cotswolds hills contains the best-known of the county's rocks on account of its extensive use throughout the area as a building stone. All from churches to humble cottages have been imbued with a mellow, warm character from the golden yellow colour of the stone - to which many ‘honey-pot’ Cotswold towns owe their modern popularity and prosperity. The series is divided into the Inferior and Great Oolite Groups. The Inferior Oolite, capping the main north-west facing escarpment, comprises up to 100m of mainly oolitic limestones including the Cheltenham freestone - quarried most extensively at Leckhampton and used widely in the distinctive Regency architecture of Cheltenham. The Great Oolite, forming much of the rather barren Cotswold plateau, encompasses a variety of oolitic, shelly, sandy or marly limestone beds, many of which are used for building purposes such as dry-stone walling and roof tiles.