Mactromya are an extinct genus of bivalves which lived during the Jurassic period, around 200 million years ago. They were marine dwelling fauna which lived in. This particular species is known as mactromya cardioides, often characterised by the smooth surface of their shells. They were found in Blockley quarry many years ago, located in Moreton, Gloucestershire. These B grade specimens vary between sizes, and are optional to choose from, unlike the A grade specimens, they will show damage to the shells and are not as uniform, however, their economical price makes them much more suitable for use in educational establishments.