It is, therefore, in the arctic and antarctic regions where we ought to find the most marked and decided evidence of warm inter-glacial periods. And doubtless such evidence would be abundantly forthcoming had these regions not been subjected to such intense denudation since the glacial epoch, and were so large a portion of the land not still buried beneath an icy covering, and therefore beyond the geologist’s reach. Only on islands and such outlying places as are not shrouded in snow and ice can we hope to meet with any trace of the warm periods of the glacial epoch: and we may now proceed to consider what relics of these warm periods have actually been discovered in arctic regions. _Evidence of Warm Periods in Arctic Regions._—The fact that stumps, &c., of full-grown trees have been found in places where at present nothing is to be met with but fields of snow and ice, and where the mean annual temperature scarcely rises above the zero of the Fahrenheit thermometer, is good evidence to show that the climate of the arctic regions was once much warmer than now. The remains of an ancient forest were discovered by Captain McClure, in Banks’s Land, in latitude 74° 48′. He found a great accumulation of trees, from the sea-level to an elevation of upwards of 300 feet. “I entered a ravine,” says Captain McClure, “some miles inland, and found the north side of it, for a depth of 40 feet from the surface, composed of one mass of wood similar to what I had before seen.”[132] In the ravine he observed a tree protruding about 8 feet, and 3 feet in circumference. And he further states that, “_From the perfect state of the bark_, and the position of the trees so far from the sea, there can be but little doubt that they grew originally in the country.” A cone of one of these fir-trees was brought home, and was found to belong apparently to the genus _Abies_, resembling _A. (Pinus) alba_. In Prince Patrick’s Island, in latitude 76° 12′ N., longitude 122° W., near the head of Walker Inlet, and a considerable distance in the interior in one of the ravines, a tree protruding about 10 feet from a bank was discovered by Lieutenant Mecham. It proved to be 4 feet in circumference. In its neighbourhood several others were seen, all of them similar to some he had found at Cape Manning; each of them measured 4 feet round and 30 feet in length. The carpenter stated that the trees resembled larch. Lieutenant Mecham, from their appearance and position, concluded that they must have grown in the country.[133] Trees under similar conditions were also found by Lieutenant Pim on Prince Patrick’s Island, and by Captain Parry on Melville Island, all considerably above the present sea-level and at a distance from the shore. On the coast of New Siberia, Lieutenant Anjou found a cliff of clay containing stems of trees still capable of being used for fuel.