43 



THE POPULAR SCIENCE MONTHLY. 



marsh abounds in stumps ; a great number of large size, some of them 

 three feet in diameter, have been seen by the writer at the verge of 

 low water, and we have found them many rods from the shore where 

 the water was ten feet deep. 1 This area was certainly a portion of 

 the original swamp when the land was sufficiently elevated to lift it 

 above the level of the sea. 



It is not necessary to further illustrate the present subsidence of 

 this coast, but evidence of the extent of the movement will be of 

 interest. 



SFACH 



VHIGH WATEF! 





Fig. 1. Section through the Dtker Meadows. 

 Horizontal scale, four inches to the mile ; vertical scale, twenty feet to the inch. 



Iu constructing the Erie Basin at Brooklyn in New York Harbor, 

 Mr. George B. Brainerd, engineer, found the following sei-ies of depos- 

 its, the water being ten feet deep at low tide: Three and a half feet 

 of mud, sand, etc. ; ten feet compact peaty meadow. This gives 

 twenty-three and a half feet of depression since the bottom of that 

 meadow was the surface, and covered with vegetation at the level of 

 the sea. 



In 1867 John Nadir, Esq., United States Engineer at Fort Hamil- 

 ton, carefully examined, by boring, the underlying formation around 

 Fort Lafayette. The earth was penetrated to a depth of 53 feet at 

 points between 800 and 1,000 feet from the shore, where the water at 

 low tide was ten feet deep. The deposits passed through were as fol- 

 lows : twenty feet coarse sand and gravel, with few broken shells ; 

 three feet decayed meadow, with shells and, Diatomaceaa ; seventeen 

 feet gravel and sand, with broken shells; thirteen feet mud, quite 

 compact, which appears to have been a marsh with scanty vegetation, 

 and shells. 2 This indicates a subsidence of the coast of at least sixty- 

 three feet, or, in other words, the land of the coast was that number 

 of feet higher than it now is, when the subsidence began. But there 

 is reason to conclude that the elevation was much greater than sixty- 

 three feet. If we take a step backward in the order of events, we find 

 that, immediately previous to the elevation mentioned, there occurred 

 a great depression of the coast. Possibly the highest hills of the 



1 " Cedar-swamps, buried beneath the meadows on the New Jersey coast, have yielded 

 logs six feet in diameter, and some with 1,000 rings of growth." Prof. Cook's Report. 



2 The shells were identified by Mr. A. R. Young, of Brooklyn, as follows: Nassa 

 obxoleta, Anomia ephippium, Mya arenaria, Crepidula fornicata, Solen ensis, and Mytilus 

 edulis. 



