The ruins of Clonmacnois form by far the most interesting architectural remains on the Shannon. Their situation is unique--on a sandy knoll overlooking the winding river, as it flows in great reaches among marshy meadows of apparently illimitable extent. Thousands of acres of them on both banks of the Shannon are spread before one's gaze when standing at the base of any of the ruined shrines of this ancient seat of piety and learning. The ecclesiastics of ancient Ireland seem to have been gifted with an extraordinary amount of appreciation for the beautiful and unique in nature. The wilder and the more beautiful a place was, the more it seems to have attracted them. Cashel's solitary Rock, Glendaloch's gloomy vale, and this barren sandhill overlooking the most peculiar scenery in all the island, were the places in which they reared their most cherished fanes and most beautiful buildings. The situation of Clonmacnois cannot be said to be beautiful, but it is strange and weird to the last degree--more strange and weird, perhaps, than any other place in Ireland. The best and most agreeable way to reach Clonmacnois is from Athlone. It is twelve English miles from Athlone by road, and ten by river. By river is not only the cheapest way but the most interesting. Sails can be used on this part of the Shannon almost as well as on Loch Ree, for the banks are so low that every breeze that blows can be fully utilised; and the river is so crooked, that no matter from what quarter the wind comes it can sometimes fill the sail. The Shannon here is no tiny stream like the Liffey, but a wide river, never less than from 150 to 200 yards in breadth, and generally deep enough to float a small ocean steamer. The current is, however, not rapid.