Graptolites ➚ are always interesting fossils to find. In some dark shales and slates they are abundant and very distinctive.
Monograptidae are the 'simplest' form of the graptolites with all the thecae in a single line or curve. They were one of the last major groupings of graptolites to emerge in the early Silurian before the whole class became extinct in the Devonian ➚ period.
The tiny colony of zooids (each zooid lives in its own 'bump' or theca) filter food from the sea water passing over them.
Monograptus lobiferus lived in the Llandovery Series of the Silurian period. They were quite small graptolites, each theca is about 1mm long.