
English Mid-Upper Jurassic Limestone
Mid-Upper Jurassic limestones formed in the later part of the Jurassic (around 175-144 million years ago). The most commonly used varieties are Portland Limestone and Bath Stone both of which are oolitic with occasional shell fragments. The lower Jurassic limestones are generally made up of older limestone fragments which have been re-deposited and therefore tend to be courser in texture and less durable