The Twowells Tongue in the Dakota Sandstone of southern San Juan Basin shows different types of sandstone layers that formed in various marine environments. The sandstone layers vary in thickness and sediment composition, indicating changing conditions during deposition. The layers include very silty, horizontally bedded, bioturbated structureless, and cross-bedded sandstone. These different types of sandstone suggest a complex history of deposition, with some areas experiencing erosion or non-deposition. The findings show that the Twowells Tongue was formed under different energy conditions, resembling deposits found in both nearshore and offshore marine environments.