The spring following this, and probably every spring for the rest of their lives, they return South to breed, performing their journey, very often, not only by water, but on foot across many miles of frozen sea. [Illustration: Fig. 4. Pack Ice (on which the Adélies winter) Two Weddell Seals are seen on a Floe] [Illustration: Fig. 5. Heavy Seas in the Autumn (Page 10)] For those birds who nest in the southernmost rookeries, such as Cape Crozier, this journey must mean for them a journey of at least four hundred miles by water, and an unknown but considerable distance on foot over ice. As I am about to describe the manners and customs of Adélie penguins at the Cape Adare rookery, I will give a short description of that spot. Cape Adare is situated in lat. 71° 14' S. long. 170° 10' E., and is a neck of land jutting out from the sheer and ice-bound foot-hills of South Victoria Land northwards for a distance of some twenty miles. For its whole length, the sides of this Cape rise sheer out of the sea, affording no foothold except at the extreme end, where a low beach has been formed, nestling against the steep side of the cliff which here rises almost perpendicularly to a height of over 1000 feet. Hurricanes frequently sweep this beach, so that snow never settles there for long, and as it is composed of basaltic material freely strewn with rounded pebbles, it forms a convenient nesting site, and it was on this spot that I made the observations set forth in the following pages. Viewed before the penguins' arrival in the spring, and after recent winds had swept the last snowfalls away, the rookery is seen to be composed of a series of undulations and mounds, or "knolls," while several sheets of ice, varying in size up to some hundreds of yards in length and one hundred yards in width, cover lower lying ground where lakes of thaw water form in the summer. Though doubtless the ridges and knolls of the rookery owe their origin mainly to geological phenomena, their contour has been much added to as, year by year, the penguins have chosen the higher eminences for their nests; because their guano, which thickly covers the higher ground, has protected this from weathering and the denuding effect of the hurricanes which pass over it at certain seasons and tend to carry away the small fragments of ground that have been split up by the frost. The shores of this beach are protected by a barrier of ice-floes which are stranded there by the sea in the autumn. These floes become welded together and form the "ice-foot" frequently referred to in these pages, and photographs showing how this is done are seen on Figs. 5, 6, 7 and 8. At the back of the rookery, nesting sites are to be seen stretching up the steep cliff to a height of over 1000 feet, some of them being almost inaccessible, so difficult is the climb which the penguins have made to reach them. [Illustration: Fig. 6. "... Throw up Masses of Ice,]