GEOLOGY : SOUTH SHORE. 27 



able calcareous streaks and nodules. Characteristic lower Cam- 

 brian fossils have been found, but are not plentiful. 



On the south side of the cove is granite, and in this direction the 

 calcareous portions of the slate show interesting alteration. The 

 chief secondary mineral is epidote, occurring commonly as a shell 

 enclosing the more purely calcareous center of the nodule which,- 

 on the weathered surface, usually has been removed by solution, 

 leaving the epidotic shell hollow. 



To the north of Mill cove is a finely moulded frontal slope of 

 one of the deltas (Quincy plain) of lake Bouve. Between "Wey- 

 mouth Highlands and Weymouth station (one and one-half miles) 

 the railroad passes through two long cuts in the dark middle 

 Cambrian slates, with exceptionally good exposures of the fault 

 contact between the slate and granite. 



THE 1IONATIQUOT VALLEY, HAYWAED CREEK (PARADOXIDES QUARRY) 

 AND RUGGLES CREEK. 



Cambrian strata and their relations to the granite, including the 

 only known localities in the Boston Basin for middle Cambrian 

 fossils. 



Route. — Train to Weymouth station, electric car from Weymouth 

 via Hay ward creek to Quincy, and thence by train or electrics to Boston. 



Monatiquot river becomes Weymouth Fore river at the head of 

 tide water. This valley has a floor of middle Cambrian slate and 

 walls of granite, with a fault contact on the south side and an orig- 

 inal igneous contact on the north side. The fault contact is ex- 

 posed well in the railroad cut immediately east of Weymouth station. 

 West of the station, on Quincy avenue, the granite and slate are 

 separated by a diabase dike more than two hundred feet wide. 

 Crossing the valley obliquely through Shaw street and returning 

 eastward to Quincy avenue on Allen street, north of the river, the 

 igneous contact of the slate and fine granite may be observed at 

 several points ; and at one point about half way from Shaw street 

 to Quincy avenue several dikelets of fine granite penetrate the slate. 

 Paradoxides harlani has been found by Mr. T. A. Watson on the 

 north bank of the river about half a mile east of Quincy avenue, 

 and south of the river on Commercial street near Liberty street. 



Taking the electric cars on Quincy avenue, we cross Wyman 



