1868.] MEETING OF THE AMERICAN ASSOCIATION. 305 



seems to have been sinking, during the past glacial period, while 

 the eastern sea-coast was rising, — the line of rest being near the 

 middle of Lake Ontario. 



On the Ripton Sea-beaches; by Prof. E. Hungerpord. — 

 This paper described a series of terraces, situated at a height of 

 2.196 feet above the sea, on the west flank of the Green 

 Mountains, on the pass from Ripton to Hancock. They consist 

 of a modified drift, overlying the true boulder drift of the region, 

 and arranged in this presant form by the action of waves and 

 currents. As the configuration of the country would not allow 

 the accumulation of a large body of fresh water at this point, these 

 deposits are regarded as strongly confirming other evidence that 

 this area has suffered a depression of at least 2,000 feet since the 

 glacial epoch. The author regards the following as the successive 

 geological events by which the drift phenomena have been produced : 



1. The formation of a continental glacier, to whose partial 

 movements, always limited to a comparatively narrow belt upon 

 the southern or seaward margin, are due the erosive phenomena, 

 and the transportation of the drift over limited areas. 



2. A depression of the continent, bringing the ocean into 

 contact with the long glacial border, which on its retreat sends off 

 icebergs and ice-rafts into the ocean. To these are attributed the 

 further transportation of detritus and boulders. 



3. Emergence of the continent, the higher beaches marking 

 the earlier, and the Champlain terraces the later stages of this 

 process. 



On certain effects produced upon Fossils by weather- 

 ing; by Prof. 0. C. Marsh. — Prof. Marsh has discovered 

 that certain peculiarities observed in Ceratites nodosus, and 

 other fossil shells, especially cephalopods, and which have long 

 perplexed German geologists, are due to the action of the ele- 

 ments, the layers of the shell differing in composition, hardness, 

 and markings. In some cases the markings characteristic of two 

 distinct genera may be observed on the same specimen. 



On the Geology of Vermont ; by Prof. C. H. Hitchcock. 

 — Prof. Hitchcock exhibited a large geological map of the State, 

 showing the great progress made in determining the structure of 

 its rocks, since the publication of his final Report upou the Geology 

 of Vermont, in 1861. This is largely due to the extension 

 southward of the recent discoveries of the Canadian survey. 



On the Ichthyological Fauna of Lake Champlain; 



Vol. III. T Xo. 4 



