In its most common geologic application, alcove refers to a recess or niche in a cave or in the walls of complexly formed canyonland. This is one of many such terms with its origins in architectural expression. In a cave, an alcove may have the appearance of vaulting, as might alcoves in churches and cathedrals, and typically it would be adjacent to a wider chamber and likely permit no passage except back into that chamber where the principal action ensues. In canyonlands, an alcove may appear as a simple opening in a rock wall, adjacent to the ground or, higher up, to the open air, perhaps providing shelter from the elements, or a respite otherwise. The like can be seen in Canyon de Chelly and Alcove Canyon in Arizona, in Utah’s Alcove Canyon, and at Alcove Mountain in the Flathead region of Montana. In a May 31, 1805, journal entry, Meriwether Lewis noted the sculpted, light-colored rock along the upper Missouri and, while reﬂecting the inclination of many other observers of the era to form their solace by envisioning landscape as evidence of God’s handiwork, waxed rhetorical: “We see the remains of or ruins of eligant buildings; some collumns standing and almost entire with their pedestals and capitals . . . nitches and alcoves of various forms and sizes are seen at different heights as we pass . . . so perfect indeed are those walls that I should have thought that nature had attempted here to rival the human art of masonry had I not recollected that she had ﬁrst begun her work.” A less common application of the term is to ﬁngers of still water that parallel a river and connect to it. These provide refuge for aquatic creatures, in this case from the turmoil of quicker currents in the prime chamber of their existence. Fish—salmon, trout, shiner, and sucker, among other species—seek out the rich supply of food here, especially during the scouring of high runoff periods. The relative quiet of such alcoves may also be favored by ﬁsh as breeding and rearing regions. The term extends to niches in the walls of oceanic environments as well, where creatures—sometimes mythical in their aspect— abide in the yet deeper dark.