Triassic Fault of Southern Connecticut. 485 



unreplaced granite. In other places the transition is of 

 another type. As the fault plane is approached, a net- 

 work of small quartz veins cutting the crystallines is 

 encountered, which forms a larger and larger percentage 



Fig. 1. 



FASGL01DSBATB 

 (TRIASSIC) 



OTHER TRIASSIC 

 SEDIMENTARY ROCKS 

 (CHIEFLY SANDSTONE 

 AND SHALE.) 



EXTRUSIVE BASALT 

 (TRIASSIC) 



s 



m 



OUTCROPS OF 



?UARTZ LODE 

 PRE- 



TRIASSIC? ) 



INTRUSIVE BASALT 

 ( T RIASSI C ) 



CRYSTALLINE ROCKS 

 (PRE-TRIASSIC) 



LOr; J31A5D 3CWD 



SCALE OF MILES 



Fig. 1.— Geologic map of the region of the Great Triassic Fault between 

 Lighthouse Point and Durham, Conn. 



of the whole rock, until near the quartz lode the rock has 

 the appearance of a breccia. The fragments of crystal- 

 lines become more altered and silicified and less numer- 

 ous towards the lode. "Where the crystalline rocks 



