446 Hohhs — Southwestern New England Region. 



the crystalline belt, but some approach to it is afforded by a 

 zone of silicified limestone or dolomite lying between Sheffield, 

 Massachusetts, and Falls Village, Connecticut. This zone of 

 silicitication has been supposed to be accounted for by fracture 

 and infiltration along a fault and has already been designated 

 the Housatonic fault."* 



Conclusions. 



As a result of the studies of these areas it may be stated that, 

 based upon the peculiarities of faults and of fault systems as 

 outlined above, an abundance of evidence has been discovered 

 to show that the area of soutwestern New England has been 

 deformed by a system of joints and faults of post-Newark age 

 superimposed upon older structures which appear to be largely 

 due to folding. The system of faults conforms in direction 

 with the system of joints and is in fact occasioned by a displace- 

 ment which has occurred along the joint planes. The evidence 

 of this can only be presented with the aid of detailed maps of 

 the several areas accompanied by full descriptions and illustra- 

 tions. The present paper can therefore be considered only as 

 a preliminary notice of a larger work to appear in a profes- 

 sional paper of the United States Geological Survey. The rela- 

 tive importance of the fold structure and the superimposed fault 

 structure it is difficult to estimate quantitatively. It appears, 

 as expected, that both have played their part, but the result of 

 the investigation has been to show that, so far as the areal dis- 

 tribution of formations and the directions and positions of their 

 mutual boundaries are concerned, the role of the system of 

 folds has been altogether subordinate to that of the system of 

 Post-Newark faults. 



Madison, Wisconsin. 



* Jour. Geol., i, pp. 793-798 (1893). 



