THE DRIFT-DEPOSITS OF THE NORTHWEST. 287 



announced the transportation by ice of a large piece of conglomerate 

 4x6x8 feet a distance of 260 yards in one night. It was deposited 

 in the sands on the shores of a little bay on the Mersey Firth. 



A similar account is published in the American Journal of Science 

 and Arts, 1822, as occurring at Salisbury, Connecticut. 



After the year 1820, exact observations were stimulated in this 

 country by the publication of the American Journal of Science and 

 Arts, which from time to time called attention to the various phe- 

 nomena of the drift. The earliest investigations of note were made 

 by De Saussure, Pallas, and De Luc, on the Continent of Europe, and 

 by Sir James Hall in Scotland. These observers coincided in the 

 opinion that the existence of the " travelled rocks " must be explained 

 by the occurrence of devastating currents of water, or d'ebdcles, from 

 the north, which transported them from their original places. This 

 theory was advocated, sometimes with slight modifications, by the re- 

 vered Dr. Edward Hitchcock, of Massachusetts; by Dr. Benjamin 

 Silliman, of Connecticut ; by Dr. Hildreth, of Ohio ; Lapham, of Wis- 

 consin ; J. N. Nicollet, of Minnesota ; and by Von Buch, Studer, 

 Buckland, and De la Beche, of Europe. Von Buch, seeing that one 

 debacle, proposed by De Saussure, would not account for all the phe- 

 nomena, supposed there were several. De la Beche believed this vast 

 inundation from the north was the immediate result of a sudden up- 

 heaval of the polar regions, turning the waters of the Arctic Ocean 

 southward with great violence. This cause was also accepted by Prof. 

 Buckland and Dr. Silliman. This theory is the same as that known as 

 diluvion. Hence the groovmgs on the rocks were first known as di- 

 luvial marks. 



Contemporary with the debacle theory was that of Chabrier, who 

 believed the bowlders came from the atmosphere. This theory seems 

 not to have met with very much countenance, and soon ceased to be 

 regarded. 



In 1828 Peter Dobson, of Connecticut, proposed the germ of what 

 became an important and long-lived theory, viz., that floating ice, in 

 the form of vast sheets, carried great quantities of gravel and stones, 

 and distributed them wherever they were stranded. This suggestion, 

 aided by the quick indorsement of Sir R. I. Murchison, grew into that 

 known as the iceberg theory, which survives to the present day. This 

 last necessitates the submergence of the continent beneath the quiet 

 waters of the ocean, and here diverges from the debdcle theory which 

 requires turbulent waters. The iceberg theory received many prom- 

 inent and able advocates. Among them may be named Sir Charles 

 Lyell, Sir Roderick I. Murchison, Peter Dobson, John L. Hays, C. T. 

 Jackson, Sedgwick, of England; W. C. Redfield, of New England; 

 Prof. Mather, of Ohio ; Dawson, of Canada ; and a great many others. 



Before, however, the iceberg theory had grown into prominence, 

 Mr. De Kay, of New York, proposed another, which at least has the 



