390 



STKIKE AND DIP. 



Section in Fairfax. 



The most satisfactory cases of foliation in these conglomerates may be seen between the village of Fair- 

 fax, and Fairfax Falls, in ledges upon the banks of La Moille Kiver, which in high water are covered by 



the river. The rock is a green sandstone, showing the grains of sand in its com- 

 position chiefly after the surface has been smoothed by abrasion and slight decom- 

 position of the cementing substance. Divisional planes, b b, in Fig. 259, cross 

 the ledge regularly, separated by narrow layers, and are inclined 77 E. The 

 strike of these planes varies very little from that of certain marks a a, running 

 through the ledge nearly at right angles to the former, being inclined 11 N. W. 

 The latter markings are rather obscure, and may be seen to the best advantage, 

 by observing them from a stand point at some distance from them. The 

 marks a a, are generally about a foot apart. When carefully examined, they appear to be thin layers of 

 schist, an eight of an inch wide, being composed of finer laminae, which are inclined at a different angle from 

 that of any other planes in the ledge. These marks may be compared to a section of a thin plate of fibrous 

 gypsum. No. & in the Cabinet shows some of these markings. Had this ledge been upon one of the 

 islands of Lake Champlain, where two sorts of planes abound upon the same exposure, we should have 

 pronounced it a clear example of planes of cleavage intersecting those of stratification, the latter being 

 almost obliterated. 



A question of much importance is naturally suggested by these observations. In the western part of 

 Vermont, where metamorphism has not changed the aspect of the rocks so much as in the central and 

 eastern parts, the marks of strata are nearly obliterated. Now why should not the marks of stratification be 

 entirely obliterated in the more thoroughly metamorphosed regions, so that the observations recorded of 

 various dips and strikes of the strata are those of foliation ? We confess that our confidence in the truth- 

 fulness of our observed marks of stratification have been somewhat shaken by these examples of foliation. 

 If some additional planes could be discovered elsewhere in the metamorphic rocks, to correspond with marks 

 of strata, it would confirm this view. And it would probably reduce the very great thickness, which we 

 have felt compelled to ascribe to the strata of the different species of metamorphic rocks. 



STRIKE AND DIP OF THE STRATA. 



The following observations have been made respecting the strike and dip of the strata of these talcose 

 conglomerates : 



Locality. 



Wallingford, Calico rocks, 

 Chittenden, west part, 

 Lincoln, west part, 

 Lincoln, west part, 

 Starksboro, 



Starksboro, north part, 

 Starksboro, northeast corner, 

 Hinesburgh, southeast part, 

 Hinesburgh, east part, 

 Hinesburgh, east part, 

 Hinesburgh, east part, 

 Hinesburgh, east part, 

 Richmond, northwest corner, 

 Jericho, southeast corner, 

 Jericho, west part, 

 Jericho, east part, 

 Jericho, center, 



Jericho Corners, a mile northwest, 

 Jericho Corners, 



Observer. 

 A. D. H. 

 C. H. H. 

 C. H. H. 

 C. H. H. 



C. B. A. and C. H. II. 

 C. B. A. 

 C. B. A. 



C. B. A. and C. H. H. 

 C. B. A. 

 A. D. H. 

 C. H. H. 



C. H. H. and A. D. H. 

 C. H. H. 

 C. H. H. 

 C. B. A. 

 Z. T. 

 Z. T. 

 A. D. H. 

 Z. T. 



