Yol. 52.] REV. E. HILL ON TRANSPORTED BOULDER CLAY. 307 



never could find evidence — but here the masses occasionally passed 

 in strings into the sand, and small boulders of clay occurred in the 

 sand below. Whatever might be the explanation, he could come to 

 no other conclusion than that the clay-masses were true boulders. 



Dr. Dtj Eiche Preller suggested, from the description given by 

 the Author, that the Boulder Clay wedged in between sand, as 

 shown in the first section, was probably deposited during an oscil- 

 lation of the drift-ice, the similar effect of such oscillations being 

 frequently apparent in the Alpine glacial deposits, which were, of 

 course, the product of land-ice. He had recently examined some of 

 the Boulder Clay of West Norfolk near Lynn, which was absolutely 

 different from the glacial clay of the Alps, and. in his opinion, was 

 clearly the product of drift-ice. 



Mr. Lamplugh was reminded by the section on the wall of what 

 he had seen some years ago on the flank of the Muir glacier in 

 Alaska, where a strip of ice loaded with debris overran stratified 

 gravels without disturbing them. The presence of thin strips of 

 clayey material in gravels was a common phenomenon in Glacial 

 deposits, and he saw no difficulty in accounting for them as the 

 product of the edge of an ice-sheet. The admirable descriptions 

 given by the American geologists, especially by Messrs. I. C. Russell 

 and T. C. Chamberlin, of the great glaciers of Alaska and Greenland 

 came as a revelation on many points to the students of glacial 

 geology, and deserved the closest study. 



The Author said that to suggest an ice-sheet as the cause of the 

 insignificant fragments of Boulder Clay upon the gravels was like 

 suggesting a steam-hammer as the cause where a few bits of 

 nutshell had been found. 



Q. J. G. S. No. 206. 



