. ' REVIEWS 87 



article dealing with the western portion of the state. With regard to 

 the crustal movements which such features involve, he states : 



"The earth's superficial or crustal portion is sensitive to unequal loading, 

 or differential pressures, and it appears that northeastern North America 

 was depressed by the weight of the long persistent ice sheets of the recent 

 glacial time. With the removal of the weight by the melting of the ice body, 

 the land rose. The amount of Post-Glacial land uplift, and the area affected 

 seem to have been proportionate to the calculated thickness and extent of 

 the latest ice sheet." 



The article is accompanied by a map representing the approximate 

 amount of post-Glacial uplift as shown by isobases. 



IV. "A Report of the Geological Work within the Rochester Ver- 

 mont Quadrangle," by W. G. Foye. — Rochester quadrangle lies within 

 the heart of the Green Mountains, midway between the Champlain and 

 Connecticut valleys. The structure is rather complex, with the bed 

 rock chiefly pre- Cambrian. 



V. "The Terranes of Northfield, Vermont," by Charles H. 

 Richardson and Samuel H. Camp. — The geology of Northfield is 

 intricate. The terranes consist of a series of highly crumpled, folded, 

 and faulted metamorphic rocks, dipping at high angles and cut by 

 intrusive masses. The discovery of Ordovician fossils in the Northfield 

 slate quarries and in the limestone and quartzose marbles, has made 

 possible the accurate stratigraphic correlation of these beds and con- 

 stitutes the most important result of the work. 



VI. "The Terranes of Roxbury, Vermont," by Charles H. Richard- 

 son. — The work here was very similar to that at Northfield, important 

 graptoHte faunas being found forming the basis for the correlation of 

 the beds of the area. The origin of the verd-antique marble, which is 

 of commercial importance, is carefully studied. 



XL ''Eruptive Rocks at Cuttingsville, Vermont," by J. W. Eggleston. 

 • — The general character of the main body of the igneous rock mass 

 indicates that it is a composite stock. The order of eruption found was 

 from the more basic essexite through the syenites to the more acid 

 nordmarkite. In the complementary dikes the order was reversed, 

 tinguaite dikes antedating the camptonite dikes. 



Other chapters are: VII. "Progress in Copper Mining and MilHng," 

 by E. C. Jacobs; VIII. "Progress in Talc Production," by E. C. 

 Jacobs; IX. "The Lime Industry in Vermont," by E. C. Jacobs; 

 X. "Additional Corrections to the List of Altitudes in Vermont," 

 XIL "Provisional Report of the Areal and Structural Geology of the 

 West Flank of the Green Mountain Range," by N. C. Dale; XIII. 



