And so we wander farther and farther into the gloomy depths, adding ever new specimens to our pre-historic menagerie, including the rare find of a bird that looks uncommonly like the penguin.

Mind, by the way, that you do not fall into that round hole in the floor.

It is enormously deep; and more than forty cave-bears have left their skeletons at the bottom, amongst which your skeleton would be a little out of place.
Next day let us move off eastwards to the Little Pyrenees to see another cave, Niaux, high up in a valley scarred nearly up to the top by former glaciers.

This cave is about a mile deep; and it will take you half a mile of awkward groping amongst boulders and stalactites, not to mention a choke in one part of the passage such as must puzzle a fat man, before the cavern becomes spacious, and you find yourself in the vast underground cathedral that pre-historic man has chosen for his picture-gallery.

This was a later stock, that had in the meantime learnt how to draw to perfection.