ONCOLITES (COLLECTION OF FOUR SPECIMENS) - 330 million years old - Northumberland
« backCOLLECTION OF CARBONIFEROUS ONCOLITES
Cut and polished to reveal the internal structure
330 million years old
(Carboniferous period)
Spittal, near Berwick-upon-Tweed, Northumberland
Near spherical nodules known as ‘oncolites’ from an algal band in the Carboniferous Limestone.
Oncolites are spherical structures formed by the growth of cyanobacteria (also known as blue-green algae). They are very similar to stromatolites but instead of being dome-shaped, they form spherical nodules. They usually form around a nucleus such as a fragment of shell.
The price is for all four – one large and three small.
Click on a picture for a larger image
Size: 7 x 5.5 x 3 centimetres approx. (large nodule)
Weight: 214 grams (all four nodules)
Price for all four:
