Gryphaea Arcuata – Study Grade
• Geological Age: Jurassic period, Lower Lias, 200 to 174 million years ago.
• Location: Hook Cliff, Gloucestershire, Yorkshire, UK.
• Family: Bivalve
• Species: Gryphaea arcuata
Gryphea Arcuata are a common bivalve fossil and as such, these specimens are often used for educational purposes. These study grade samples come from Hook Cliff in Yorkshire and are roughly 4 to 5 cm in length, found in Jurassic strata, they are 200 to 174 million years old and are of a lower quality than our A Grade material, thus making them more cost effective for schools and educational bodies to purchase, showing such morphological features as growth lines and hinges, the specimens are between 4 to 5 cm in length and come supplied in a card tray with a label.
Gryphaea arcuata are an extinct species of oyster which lived during the early part of the Jurassic period, making these fossil specimens 200 to 174 million years old. Samples of them can be found through out Europe as well as many other sub species belonging to this group. They are a common find around coastal parts of the UK and are often referred to as 'Devils Toe Nails' due to their toe nail like appearance yet, unsightly coiled and twisted shape. As expected of a bivalve, the shell is made up of two unequal parts, the top and bottom, the bottom being smaller, however, in these study grade samples, the bottom half of the shell can often not be viewed or has been destroyed or missing during the fossilisation process. It has been inferred that the arcuata sub-species is roughly in the middle of the evolutionary line of gryphaea, with a moderate size and elongated shell, where as later species' shells appeared to be more wider and flat. These lowe grade quality samples will enable you to see many morphological features of the fossil such as the growth lines, with each sample being approximately 4 to 5 cm in length, they are more suited for educational use,due to their cost effective price. Supplied in a card tray with an information label.