myddosomes

Myddosomes are a type of fossilized sedimentary structure that resemble the shape of a mushroom. They are typically found in marine environments and are formed by the accumulation of sediment around a central core, often a piece of organic material or a mineral nodule. The cap of the myddosome is composed of fine-grained sediment, while the stem is usually coarser and may contain fossils or other sedimentary structures. Myddosomes are often used by geologists to interpret ancient depositional environments and to study the processes of sediment accumulation and diagenesis. They are named after the Welsh word "mydd" which means "mushroom."