CONTENTS. Xi 



Page. 



Chapter XII.— The Trias 3.51 



The Connecticut River sandstone 351 



General section of Triassic rocks 354 



The Sugar Loaf arkose, or the feldsi)athic sandstone and conglomerate 354 



Contact and distribution 355 



The Mount Toby conglomerate, or the slate and quartzito conglomerate 358 



Contact aud distriluition 358 



The outcrops of crystalline rocks in the midst of the Mount Toby conglomerate . . . 361 



Action of ice in the Trias 363 



The Longmeado w sandstone 364 



Fragments of white trap without augite in the sandstone above the Holyoke sheet. 365 

 Disturbances iu the sandstones and inclusions of trap fragments just below the 



posterior sheet 367 



The boundary of the sandstone 368 



The Granby tuff, or the diabase-tuflf 3G9 



The Chicopee shale, or the calcareous shale 370 



The continuation of the State-line fault in a crnshed band at the Holyoke dam and the 



secondary minerals found in the fissures 370 



The diabase 372 



The formation of the basin and the distribution of the sediments by strong tidal currents.. 372 



The possible connection of the foot tracks with the trap sheets 379 



Artesian wells 380 



Pseudomorphs of calcite and dolomite after hopper-shaped cubes of salt 389 



The use of the Triassic sandstone as a building stone 391 



Paleontology 394 



Plants 394 



Insects 398 



Fishes 398 



Ichnology 400 



Recent progress in Ichnology, by C. H. Hitchcock 400 



Reptiles 405 



Chapter XIII. — The Triassic eruptive rocks 407 



Historical 407 



The three epochs of eruptive activity ; general account 410 



Diabase dikes and stocks in the gneiss east of the Trias 411 



A microscopical diabase dike from Pelham, and olivine and glass-bearing dikes from 



Monson 416 



The bedded or contemporaneous eruptives 418 



The Deerfield sheet -tlS 



Contact on the sandstone below; the underroUlng of the crust and the alteration of 

 the diabase by heated waters to a pitchstone-breocia and a diopside-plagioclase 



rock 419 



General character '124 



Greenfield quarry exposures and contacts 424 



Petrographical description *32 



Diabase-pitchstone *32 



