R. S. Tarr — Central Massachusetts Moraine. 141 



Aet. XY1IL: — The Central Massachusetts Moraine •* by 

 Ralph S. TARR.f 



Upon the plains of the Central States the ice of the last 

 glacial period has registered, with distinctness, the various halts 

 m its recession. The record of the ice retreat in this region 

 has been worked out in admirable detail by the glacialists in 

 charge of this work. Rapid retreats, temporary halts and 

 slight readvances are here indicated by the glacial deposits. 



The disappearance of the ice from New England must have 

 been marked by very nearly the same history, but the detailed 

 record of this retreat has not yet been studied. This is due in 

 part to the fact that until recently no systematic studies of the 

 glacial deposits of New England have been undertaken, but 

 chiefly to the fact that the record left by the ice, as it melted 

 away, is obscure. This obscurity is the result of the topo- 

 graphic diversity of the region. Upon a plain a slight moraine 

 becomes a marked topographic feature, but amid the hilly dis- 

 trict of New England its importance is masked by the more 

 striking undulations and reliefs. In addition to this the very 

 fact of the diversified topography has made the minor moraines 

 actually less distinct and hence more difficult to study than 

 would have been the case on a level country. The ice margin 

 must have conformed in a measure to the topography, and 

 hence the deposits must have varied in distribution with the 

 variations in altitude and relief. Not only was their distribu- 

 tion so influenced but also their character. The rapid water 

 currents rendered possible in a hilly country swept away por- 

 tions and modified others. 



For several years. Prof. N. S. Shaler has been conducting 

 detailed studies of the glacial deposits of Massachusetts and the 

 neighboring states and eventually, if his plans are carried out, 

 the record of the ice retreat in this region will be definitely 

 known. As an assistant in this work during several summers 

 it was my fortune to find and trace out, in part, a distinct 

 morainal band in Central Massachusetts, marking a temporary 

 halt in the recession of the glacier, and it is this that I shall 

 briefly describe. 



On the islands off the southern coast of New England a well 

 defined terminal moraine has long; been known and well de- 

 * Published by permission of the Director of the United States Geological Survey. 

 f I am indebted to Prof. J. D. Dana and Mr. Warren Uphani for valuable sug- 

 gestions which have aided in the preparation of this paper as well as to Prof. N. 

 S. Shaler, under whose direction the field work, upon which these results are 

 based, was done. 



