There it lay as long as the lake existed, and would be lying now, but that in New England a tilting movement of the land tipped the north end of the lake up and the water all ran out. Then the stream began to flow over its own delta and in time of freshet tore a channel down through the old delta carrying the pebble still further down, until it came to the level stretch which represented the old lake’s bottom and there it dropped the pebble in its bed. And there it was found and picked up to become the pebble which told the above story of its life, and to repeat it as often as anyone will look at it with a seeing eye. The second pebble is quite a different one. It was picked up in a gravel bank along a railroad cut, just at the foot of Mt. Toby in Massachussetts, and the writer has used it many times to test his students, to see if they could read the story which it tells. It consists of two sorts of rock, the one, angular fragments of a hornblende schist, the other, a fine-grained granite filling all the spaces between the fragments of schist, even in cracks less than a quarter of an inch wide. The schist is the older rock and in its first appearance represents a deposit of mud (clay and sand) on the floor of the ocean, well out from the shore, and somewhere off to the east of Mt. Toby, perhaps ten miles, perhaps more, from the place where it was found. This was back in early Palæozoic times, millions of years ago. This deposit was buried by further layers of sediment on the sea bottom and cemented into a shale. Then during a mountain making period the region was folded, and the sediments were altered by the combined pressure and heat, our layer of rock becoming a hornblende schist. After that happened considerable time must have passed, but just how much is not indicated by the pebble, before another period of disturbance took place, during which this deep seated schist was faulted, and shattered to fragments along the line of breaking. This accounts for the angular fragments. Then into the fissure thus formed was pressed a molten magma, which while liquid enough to flow and be squeezed into every opening could not have been very hot; for not even the corners of the schist fragments are melted or altered, so as to appear any different from the mass of the schist. The molten magma cooled rather slowly, making a fine-grained granite. This must all have taken place far below the surface, or the magma would have cooled into a felsite or dense lava.