106 



Junction of Trap and Sandstone. 



course, excepting only two passes through the ridge, which seem to 

 have been designed expressly for roads, for which purpose they are 

 used. 



This brief description will give the reader an idea of the general 

 geological aspect of Wallingford. At No. 5, the turnpike leading 

 from Hartford to New Haven passes, and at No. 6, is the bed of 

 Quinipiac River. The first rise and plain east, is what properly now 

 constitutes the river meadows. From the second rise eastward, are 

 extensive sandy plains, the materials of which seem to have been 

 originally primitive. At No. 7, is the town, commanding a view of 

 the plains, meadows and highlands to the westward, at No. 12, runs 

 Muddy River, and at No. 10, lies Paug Pond. 



The dyke of trap which emerges from beneath the sandstone near 

 Mr. Hill's Manufactory, with its course across the stream, is repre- 

 sented by fig. 2. 



Fig. 2. 



Surface view. 



a, road. &, aqueduct, c, stream. <Z d, strata cropping out in high banks. 



Its first appearance is on the east side of the way ; about eight 

 feet in width, extending down to the bank of the pond, where it sud- 

 denly turns south, running down stream about three feet, when it 

 again turns east, and cuts across the valley and bed of the stream into 

 the opposite bank. At the corner of the dam, where it makes its 

 turn, the dyke is not more than three feet in width, and where it en- 

 ters the opposite bank, it is scarcely one foot ; although in the inter- 

 mediate space it is five or six feet wide. There is a mass branch- 

 ing out from the main dyke extending down the bed of the stream, 



