TACONIC BOOKS. 439 



stone, or a new number in No. 6, still higher than No. 3. He says : "Of this limestone 

 it is necessary to remark, that it resembles so nearly another limestone, or one which I 

 no\v suppose belongs to a different period, that it is exceedingly difficult to distinguish 

 them. The one I now speak of certainly occupied the position which I have given it, 

 above the gray sandstone ; but there is another in the primary of the Taconic range 

 further east in the slates of which the range passing through Pownal in Vermont, and 

 Williamstown, Pittsficld and Richmond in Massachusetts, are examples which resem- 

 bles it so strongly that I have at times been disposed to consider the two as one and the 

 same rock." 



A limestone very closely resembling the Stockbridge limestone, enters Canada from 

 Vermont at Highgatc. It is obviously of the age of the Trenton limestone. It was from 

 this rock which has nothing to do with the Taconic system that the Canada Survey pro- 

 nounced the Stockbridge limestone, from its prolongation into Canada, to be the altered 

 Trenton limestone. (See American Journal of Science and Art, New Series, Vols. IX, p. 

 19 ; XVIII, p. 195, 196, II. Series.) The true Stockbridge limestone extends no further 

 north than Milton, in Vermont. 



The granular quartz is chiefly developed in Vermont in a great range of mountains, some 

 of which are 3000 ft. high. It forms at times the western part of the Green Mountains lying 

 east of the Stockbridge limestone. A smaller portion of the quartz in Rutland County 

 forms an independent range of hills by itself, entirely distinct from the preceding. The 

 numerous interstratifications of quartz rock and limestone, as well as the spurs of quartz 

 rock in Pittsford and vicinity, are very singular, and we will not attempt to surmise a 

 Taconic view of them. The granular quartz terminates in Starksboro, corresponding 

 throughout its whole extent with the quartz rock as described in this Report. It lies at 

 the east side of the system, and rests upon the hypozoic gneiss of the Green Mountains. 

 Divisional planes resembling strata are present in a large part of the formation, insomuch 

 that its true dip is not always a matter of certainty. 



GENERAL POSITION OF THE TACONIC ROCKS. 



As a general fact, the strata of the Taconic rocks dip to the east, from 20 to 45. This 

 is true respecting the whole belt from Canada to Alabama. Particularizing the formations 

 in Vermont, we may say, that the invariable dip of the black slate, Taconic slate, roofing 

 slate and sparry limestone, is to the east. The inference would be, therefore, without the 

 supposition of dislocations, that in proceeding eastwardly from the Hudson River group, 

 we ascend one formation in coming to the black slates, two formations in coming to the 

 Taconic slate, and so on, not only to the top of the sparry limestone, but to the top of the 

 granular quartz, and not unfrequently the very gneiss (Laurentian) itself. There must, 

 then, be some explanation of this fact. Why should the new rocks dip beneath the 

 older ones ? 



The greater part of the magnesian slate dips to the east. But in its eastern portion we 

 discover a beautiful exhibition of the true position of at least two of the members. Mt. 

 Eolus is a pile of nearly horizontal strata, and the layers may, therefore, be assumed to 

 be in their natural position. Here the magnesian slate caps the Stockbridge limestone ; 

 so that we may regard the relations of these two rocks to each other as settled. Conse- 



