530 



CENOZOIC TIME. 



The Transportation was sometimes across, and sometimes in accord- 

 ance with, the slopes of the surface. — The facts stated above, respect- 

 ing lines of stones crossing valleys and hills without deviation from a 

 right line, are examples of a very general fact with regard to the Drift. 

 At the same time, the trains often follow the directions of the grander 

 slopes of the surface, and especially the courses of the larger valleys. 



On the other hand, bowlders were sometimes carried up slopes, to a 

 height of a thousand feet or more. Thus, limestone bowlders from 

 Canaan, Conn., were carried southeastward, up to Goshen, 1,000 feet: 

 and fossiliferous bowlders from the region north of Mt. Katahdin were 

 left on that mountain, at a height of 4,385 feet above the sea, or more 

 than 3,000 feet above the low country to the north. 



II. Attendant Phenomena — Groovings or Scratches. 



1. Evidences of Abrasion. — Besides the transportation of stones 

 and earth, there was the abrasion of rocks, which left nearly the 

 whole rocky surface of the country, within Drift regions, scratched or 

 grooved and polished. Figure 940 represents a slab of limestone thus 

 scratched and planed off. In addition, the stones and large bowlders 



Fig. 940. 



Drift groovings, or scratches, from Western New York. 



of the Drift are often scored, like the rocks they abraded. The bot- 

 toms of valleys are commonly scratched, showing that the deposition 

 of most of the stratified, as well as un stratified Drift, took place after 

 the era of greatest abrasion. 



The bare ledges have not often retained the scratches, unless they consisted of slate, 

 compact limestone, or a hard kind of gneiss. But these, and even softer rocks, are gen- 

 erally found to be grooved wherever the soil has been recently removed. 



The groovings are long, straight, parallel lines, often like the lines of a music-score, 

 or broad planings, ploughings, and gougings of the surface. The scratches generally 



