The term "basal grannle" refers to a geologic rock formation found in certain regions. It is composed of fine-grained sediments, typically silt or clay, that have settled at the bottom of a body of water over millions of years. While "basal grannle" is the commonly used term, there are several synonyms that can be used interchangeably to describe this geological feature. Some alternative terms include "bottom sediments", "subaqueous deposits", "underwater detritus" or "submerged granular accumulation". These synonyms help geologists and researchers communicate effectively when discussing the various types and characteristics of sedimentary rocks formed at the base of lakes, rivers, or oceans.