CONTENTS. Xiii 



Chaptek xiii. — The Triassic eruptive rocks — Continued. Page. 

 The newer series of cores and short dilves — Contiuued. 



Belchertown 481 



Granhy 482 



South Hadley 483 



The nintli core of diabase, with granitic inclusions 483 



Petrographical description 484 



The eleventh or Black Rock core 489 



Petrographical description 492 



Northampton 494 



Summary of the history of the Connecticut River sandstone 49."> 



The use of the trap as road material 5110 



Chapter XIV. — Mineral veins 502 



Chapter XV. — The Pleistocene period 508 



Literature 508 



The interval Ijetween the Triassic and the Glacial period 508 



Deposits 508 



Pre-Glaeial weathering 509 



Pre-Glacial drainage and erosion 510 



Pre-Glaoial course of the Connecticut and its tributaries 513 



Character and amount of the erosion during later Jlesozoic time as compared with that 



of the Glacial jieriod 515 



Chapter XVI. — Tho Glacial period 518 



The present rock surface and the amount of Glacial and post-Glacial material on the same. . 518 



Glacial grooves and striis 522 



Glacial notches 529 



Pseudo-glacial striaa on Devonian argillites 531 



Potholes 532 



The till 533 



Introduction 533 



The upland drift *. 535 



The line valley drift of the east side of the valley -537 



The coar.se valley drift 541 



Distribution of the coarse valley till west of the river 542 



Drumlins 543 



Moraines and bowlder trains 549 



Interglacial sands 5.50 



The upper till 558 



Remarkable bowlders 559 



Chapter XVII. — The Champlain period 562 



Glacial lakes east of the Connecticut River 562 



Introduction 562 



Ice barriers 565 



The Brimfield Lake 565 



The Monson esker 566 



The Monson drainage 567 



The eastern Palmer and Monson Lake 567 



