Blue Lias
![Lower Lias sequence exposed at Nash Point, Glamorgan, Wales.](/Images/godic/202501/01/Lower_Lias_Nash_Point_Glamorgan5813.JPG")
![Lytes Cary, Somerset, built of Blue Lias with Ham stone dressings around the windows](/Images/godic/202501/01/Lytes_Cary_2009_South_front,_bay_window5813.JPG")
![Scelidosaurus](/Images/godic/202501/01/Scelidosaurus25813.jpg")
![Scelidosaurus](/Images/godic/202501/01/Scelidosaurus_skull5813.jpg")
The Blue Lias is a geologic formation in southern, eastern and western England and parts of South Wales, part of the Lias Group. The Blue Lias consists of a sequence of limestone and shale layers, laid down in latest Triassic and early Jurassic times, between 195 and 200 million years ago. The Blue Lias is famous for its fossils, especially ammonites.