Worcester County Gneiss. 



387 



gitic gneiss certainly deserves a more thorough examination than I 

 have been able to give it. 



In the western part of this gneiss range in Connecticut, beds of 

 coarse saccharine limestone' are common. But I have never been 

 able to find one of this description, in Massachusetts ; though I sus- 

 pect their existence, as in New Marlborough. 



The limited patch of gneiss marked on the map, in Buckland and 

 Shelburne, lies chiefly in the ravine through which Deerfield river 

 passes. In its most elevated parts, (as on the western slope of the 

 high land in the west part of Shelburne, and on the opposite side of 

 the river in Buckland, on the stage road between the two bridges over 

 Deerfield river,) this rock is very regular in its stratification : but at 

 the bottom of Deerfield river, at and below Shelburne Falls, it is the 

 granitic gneiss, almost destitute of stratification, and contains horn- 

 blende. The feldspar here is in small proportion ; and some of the 

 rock might properly be denominated quartz rock. 



These facts have led me to inquire, whether the greater regularity 

 of stratification in the higher parts of this deposit, might not pro- 

 ceed from the fact, that the lower parts are nearer to that igneous 

 power, which, according to the theory that I have elsewhere ex- 

 plained, has partially fused some portions of the primary rocks, and 

 entirely fused other portions ? Here the upper strata are perfectly 

 regular and continuous: but as we descend, we find the rock approx- 

 imating nearer and nearer to unstratified granite, yet retaining some 

 faint traces at least of a schistose structure. Is it reasonable to sup- 

 pose, that a little deeper excavation would disclose perfectly well 

 characterised granite ? The light which I fancy this spot throws 

 upon theory, is the most interesting circumstance connected with this 

 deposit. 



Worcester County Gneiss. 



The broad ranges of gneiss in the central parts of the State, which 

 for distinction's sake may be called the Worcester county ranges, 

 next claim attention. That range, which lies west of the mica slate 

 deposit in Worcester valley, extends across the whole of Connecti- 

 cut to Long Island Sound on the south, and probably through all the 

 western part of New Hampshire, and I know not how much farther 

 north. The most elevated point of this range in Massachusetts is 

 Wachusett Mountain, in Princeton, which rises 3000 feet above the 

 level of the ocean. This is a remarkably insulated peak, nearly 



