Triassic Fault of Southern Connecticut. 491 



The occurrence of pebbles of this quartz lode in the f an- 

 glomerates between the main and upper trap sheets shows 

 that by the time these fangiomerates were laid down 

 three separate events must have taken place : first, there 

 must have been movement along the fault plane ; second, 

 this fault plane must have been sealed by the formation 

 of the quartz lode; third, there must have been further 

 movement to bring the lode to the surface again. These 

 bowlders also show that during the formation of these 

 fangiomerates the Triassic did. not extend more than a 

 few feet east of the outcrop of the fault. If there were 

 any previous Triassic deposits, they must have been 

 already eroded away. 



The lowest horizon at which fangiomerates were found 

 is just below the lower basalt sheet. The bed rock of the 

 horizons below this is all concealed for considerable dis- 

 tances from the fault, so that it is impossible to tell 

 whether fangiomerates occur in them or not. They were 

 found at various horizons from below the lower basalt 

 sheet to well above the upper. In one place the upper 

 flow dies out against the fanglomerate, indicating that the 

 surface slope of the alluvial fan was probably several 

 hundred feet per mile. The bowlders are of such great 

 size and so angular that they could not have been trans- 

 ported far. Therefore, their source in the crystallines 

 must have been nearby, and the contact with the Triassic 

 rocks must have been a fault at that time, for the Newark 

 strata at that time were very thick immediately west of 

 the fault, but did not exist close to the east of it. 



The Basalt Bowlders of the Fanglomerate. 



The occurrence of huge, angular bowlders of vesicular 

 basalt in the fangiomerates tends to support the fore- 

 going conclusions. These basalt fragments do not occur 

 solely in or near the same horizons as the basalt flows as 

 Davis believed they did. They are found in between 

 them, and above them all. They might be supposed to 

 have been derived from volcanoes in the hills or moun- 

 tains east of the fault, or they may have been derived 

 from basalt flows that had spread over on the east side of 

 the fault, and then been uplifted. The bowlders are so 

 huge and angular that it is difficult to see how they could 

 have been carried far, and moreover their occurrence 



