Ultraconglomerate is a coarse-grained sedimentary rock composed of very large clasts, often exceeding several meters in size, cemented together. This rock type is significant in sedimentology for understanding high-energy depositional environments, such as alluvial fans and glacial deposits, and the processes of sediment transport and deposition.
Source Boggs, S. (2009). “Petrology of Sedimentary Rocks.” Cambridge University Press.