5. Stratified gravels and sands with fossil shells of the oyster, also wood and lignite underneath the bowlder-drift.
6. Laminated sands and clays with decayed vegetation and lignite have been found; also one shark's tooth (C. angustidens).
7. The above beds seem to merge into more clayey sands, and in the deeper portions fine dark-colored plastic clay.
The period we have considered is one of immense duration, but throughout there is no evidence of sudden or violent changes. No catastrophe has "set Long Island off from the mainland." In its wonderfully complex structure it is a monument of a state of things which has passed away, but also of a series of movements of oscillation which has continued to the present time.
But it is only after long periods of time that these become obvious, and we realize how completely old landmarks have disappeared.
The tourist in Italy lingers with astonishment before the erect columns of the temple at Pozzuoli in the bay of Baiæ, and sees, at a height of twenty feet above their base, proof of their long submergence in the waters. Moore said of them:
"These lonely columns stand sublime,
Flinging their shadows from on high,
Like dials which the wizard Time
Has raised to count his ages by."
But, on our own shores, beneath the clear waters, and on the hills we cultivate, are records of similar movements, vastly greater in extent, and running with marvelous continuity through periods so vast that all the centuries which have passed since the Pozzuoli marbles were erected seem but as yesterday.
| AN AMERICAN ASTRONOMICAL ACHIEVEMENT. |
By RICHARD A. PROCTOR.
AN American astronomer, Prof. Young, of Dartmouth College, Hanover, New Hampshire, has recently achieved a victory over a problem which has for many years foiled the skill of the best European observers; and, in so doing, he may be said to have added the keystone to an arch of no small importance in the edifice of modern astronomical science. It will be in the knowledge of most of my readers that astronomers have succeeded, during the last eight years, in measuring the rate at which some of the stars travel from or toward us, employing for the purpose what is called the spectroscopic method. I do not mean here spectroscopic analysis simply, but a special application of this now familiar analysis to measure the rate at which luminous bodies are approaching us or receding from us.
