Reader, have you ever visited the far-famed Lakes of Killarney? If you have not, by all means go there; and if you are a geologist as well as a lover of beautiful scenery, the pleasure of the visit will be greatly enhanced.

There you have lofty and rugged mountains (some of them clothed with wood nearly to the summit), from whose sides gush limpid fountains, increasing in force as they descend, and in their onward course madly leaping down the steep cataracts, until they are at last lost in the majestic lake beneath,—the admixture and variety of the whole being beautifully harmonized and softened by the extraordinarily luxuriant foliage of thousands of plants, from the stately oak, the bushy arbutus, and dark green holly, to the humble but graceful “London Pride” (Saxifraga umbrosa), the abundance of which seldom fails to attract the notice of the most casual observer.

The mountains are formed of rocks of the “old red sandstone period,” the upper division of that group or “yellow sandstone” being generally observed at the foot of the slope, this being again overlaid conformably by the “mountain-limestone,” which extends in many a contortion over the plain.

In the rocks of the “old red sandstone” a geological eye will at once be struck by the fine examples of glacial action exhibited in the scratches and groovings of their surfaces, caused by the sharp edges of blocks and fragments of other rocks, contained in icebergs, having passed over them; such markings being, for a considerable extent, parallel, or nearly so.