34 GUIDE TO LOCALITIES. 



north line of Holyoke, to see the trap at Larrabee's quarry, where 

 mud has been kneaded into the trap at the surface ; and to look at 

 the tuff beds. Then cross the whole Triassic series to the top of 

 Mount Tom, seeing remarkable intruded dikes and sills ; the sur- 

 face of the trap sheet where ejected fragments have fallen on the 

 lava sheet while it was moving ; an excellent exposure of the great 

 fault which cuts through the Mount Tom range ; and the largest 

 Brontozoum tracks in situ. The ascent of the mountain will be 

 made by electrics, and the view is in many respects the finest in the 

 valley. From the top of the mountain one can ride by electrics to 

 Holyoke or Springfield. 



Literature. 



See papers especially by B. K. Emerson; the one referred to above 

 being Diabase pitchstone and mud enclosures of the Triassic trap of Xew 

 England. (Geol. Soc. Am., Bull., vol. 8, pp. 59-86.) 



SURFACE DEPOSITS. 



In the Greenfield excursion described above, the drive will 

 take one across the filled-up northern lobe of Hadley lake ; and 

 at the northwest corner opportunity will be given to see where an 

 arm of the glacial sheet projected into the lake, preventing the fill- 

 ing of a portion near the shore. One can study also a fine dis- 

 sected delta thrust into this depression after the ice had melted 

 away. 



From the lookout on the trap ridge east of Greenfield, one can 

 follow the lake beach southward and see the excavation made in it 

 by the Green river, and the broad well-terraced depression cut by 

 the Deerfield river. To the east across the Connecticut will be 

 seen the front of the broad sand-plain of the delta of Miller's river, 

 which extends six miles eastward. In Turner's Falls the river has 

 worn fine terraces in these beds, exposing the clays, and has cut 

 back a postglacial rock gorge and made a good waterfall. At 

 Lily pond is also an excellent specimen of an abandoned waterfall 

 and canon, where the Connecticut has worn round a sandstone 

 ridge and forsaken its old course. 



At Northampton drumlins are developed well on both sides of 

 the valley. The shore deposits of Hadley lake are shown well and 

 the Champlain clays exposed at the asylum, and exhibit complex 

 contortions from the stranding of glacial icebergs. The ox-bows, 

 meadows, and new islands of the Connecticut are seen to ad- 



