St Ninian’s Cave, near Physgill, in the parish of Glasserton, Wigtownshire, is situated a little to the west of the wooded valley which terminates in the creek known as Portcastle. It is simply a triangular fissure in the rock, some ten or twelve feet wide at the entrance, and about fifteen feet in height, narrowing inwards until, at a distance of about twenty-five feet from the entrance, the sides of the fissure come gradually together. A rudely-built wall has been constructed across the mouth of the cave, of which the lower part still remains. On the occasion of a visit to the cave by the late Dean Stanley of Westminster, a small cross was discovered carved on a projecting part of the rock, and three others were subsequently made visible by the partial removal of the debris from the face of the rock. The form of these crosses is peculiar. They are equal-limbed crosses, formed by four arcs of circles intersecting the circumference of a circumscribing circle. Similar equal-limbed crosses, but bearing the hook-like curve at the right-hand corner of the upper limb, which constitutes the _chrisma_ or monogram—the combined _Chi_ and _rho_ of the Greek word _Christos_—are found upon early Christian monuments at Kirkmadrine and Whithorn in the same county, but nowhere else in Scotland. These monuments bear inscriptions commemorative of certain ‘holy and distinguished priests’—Viventius, Mavorius, and Florentius. Their names are so different from those of the priesthood of the Columban Church, that they may be regarded as followers if not as contemporaries of St Ninian. But none of the crosses in Ninian’s Cave present this peculiarly ancient characteristic of the _chrisma_, and these crosses may therefore be of a much later date than Ninian’s time. They are not confined to the rock-face, but have also been carved upon several of the loose stones found on the floor of the cave.