A rather fantastic example of the classic Jurassic Arnioceras semicelatum ammonite. Ten ammonites in all are scattered through the fossil bed (now solid limestone) which is suspended in the unique custom fitted bronzed mount.
Superb quality preparation has been undertaken to show the commune grouping to its full aesthetic potential. While at the same time retaining a crisp and clear scientific aspect to each specimen ammonoid. An excellent representative display block from this 'national treasure' fossil discovering region of the northeast Yorkshire coast.
The geological periods are subdivided into aeon's, era's, periods and epoch's stages or ages, and further subdivided into zones or horizons, this fossil commune of Arnioceras semicelatum ammonites is from the lower lias horizon of the Jurassic period, a period around 180,000,000 years ago. So we can identify the age division as the Toarcian stage which spanned 174,000,000 to 183,000,000 years ago. Within this stage are as many as nineteen horizons to identify the stratigraphic time zones further and pinpoint the story of the Ammonites, the specimen featured here is intertwined in that story of northern European ammonoid development.