66 STRIATION AND EMBOSSMENT. 



may expect to find some evidence of drift action. If the whole of New England were 

 denuded of soil, we doubt not that at least one half of its surface would be found covered 

 with strue, or smoothed, or with its prominences rounded. And AVC have often wondered 

 why the numerous examples of these markings, which show themselves on the present 

 surface, do not more forcibly arrest the attention of intelligent men and and excite inquiry 

 as to the cause. 



We have spoken of three forms of this phenomenon. The first is Striation. In this 

 case after the surface of the rock has been ground down it is scratched, as if an enor- 

 mous rasp had been firmly pressed upon it and steadily drawn forward ; for the grooves or 

 stride are usually approximately parallel, although a second application of the same 

 force may have produced a second set of stripe which cross the others at a moderate 

 angle without obliterating them. It is more usual to find one set upon one part of a 

 ledge, and another set upon the other part. 



When the rock is very hard, or the drift materials very firm, the surface is only 

 smoothed, but not striated. This we call planishing. 



When the ledges were uneven with projecting points, the drift agency wore off the 

 angles and rounded the salient parts, so that the surface presents protuberances like the 

 bosses on a shield. This we call embossment. Where the protuberances are small and 

 near together, they have been called by French geologists Roches montonnes curled or 

 frizzled rocks. 



Of these different kinds of markings, striation is probably the most instructive. For 

 by it we are able to determine accurately the direction taken by the drift agency. To this 

 point, therefore, we have given a great deal of attention, and are able to furnish a full list 

 of the courses of the striae in different parts of Vermont. We have shown the same 

 thing also upon the Map of Surface Geology. Such observations and such a map were 

 commenced by Prof. Adams and continued by Prof. Thompson. The folloAving Tabular 

 View of the Drift and Glacier Striae in Vermont (prepared by C. H. Hitchcock) will 

 show to whom we are indebted and who is responsible for the observations. The map 

 teaches the same thing as the table, but more impressively through the eye. This map, 

 however, shows other striae besides those of drift, which we refer to ancient glaciers ; 

 though some geologists look upon the common drift striae as the result of glaciers. But 

 in another place we shall point out certain differences which in our opinion indicate a 

 diversity in the causes. 



A TABULAR VIEW 



OF ALL THE DRIFT AND GLACIER STRI^ THAT HAVE BEEN OBSERVED IN 



VERMONT, 



BY THE DIFFERENT GEOLOGISTS AND THEIR ASSISTANTS.. 



Where the same strife have been observed by different persons, the name of the first observer only is 

 recorded : and this is the case with most of those recorded by the earlier geologists, although their 

 observations have been confirmed subsequently. These observations are recorded in the order of the sections 

 beginning at South Vernon, crossing the State to Pownal, then returning from Bennington across the 

 State to Brattleboro, and so on zigzag towards the north part of the State. We have made no allowance 



