Cambrian vs Graptolite - What's the difference?
cambrian | graptolite |
(geology) of a geologic period within the Paleozoic era; comprises lower, middle and Furongian epochs from about 542 to 490 million years ago
of, or relating to Wales
Any of a group of extinct aquatic colonial invertebrates, of the class Graptolithina , from the Cambrian and Carboniferous periods
*2004 , (Richard Fortey), The Earth , Folio Society 2011, p. 70:
*:The samples were black shale, and on the shales were some ancient fossils called graptolites .