DIP AND STRIKE. 315 



Milton, northwest corner, N. 53 E., 12 S.E., C. H. H. 



Georgia, Lake shore, 20 E., C. H. H. 



Ram Island, N. 45 E., 30 S.E., (?) C. H. H. 



Welden's Island, N. 40 E., 6 E., C. H. H. 



Potter's Island, N. 40 E., 6 E., C. H. H. 



Butler's Island, 60 E., C. H. H. 



Knight's Island, 30-50 N.E., C. H. H. 



St. Alban's Point, 5 E., C. H. H. 



St. Alhau's Bay, N. 10 E., 30-50 E., E. H., etc. 



St. Albans, northwest part, About 25 E., C. H. H. 



Colchester, west part, N. and S. 70 E., C. B. A. 



Swanton, south part of Hog Island, N. 35 E., 46 W., C. B. A. 



Swanton Falls, N. 50 E., 75 E., C. H. H. 



Swanton, west of Falls, N. 10 W., 70 E., C. H. H. 



This table embraces all the slates of this group. The mean strike of all the observations is N. 23E. 

 Deducting from this 10, the allowance for the variation of the magnetic needle, and the mean strike then 

 will be N. 13 E. The strike of the formation as projected on the map is N. 7 E. The difference between 

 them is six degrees. There is perhaps more reason to expect discrepancy here than in the other groups, 

 because the observations were less accurate, and there are more local disturbances. 



The preceding table gives the position of the strata of shales and slates. The limestone beds were so 

 uniformly in the upper part of the formation, that we have thought it best to give their position separately. 



Localty. Strike. Dip. Observtr. 



West Haven, east part, N. 30 E., 42 E., E. H., jr. 



Orwell, village, 5 E., C. H. H. 



Orwell, south of do., N. 60 E., 30 S.E., C. H. H. 



Shoreham, north part, N. 10 E., 15 E., C. H. H. 



Addison, Cobble Hill, N. 50 E., 55 S.E., C. H. H. 



Addison, Cobble Hill, N. 20 E., 12 E., C. H. H. and A. D. H. 



Addison, Snake Mountain, N. and S., 30 E., C. H. H. and A. D. H. 



Addison, top of do., 5 E., E. H., etc. 



Milton, northwest corner, East of north, About 10 E., C. H. H. 



St. Alban's Bay, N. 10 E., 30-50 E., E. H., etc. 



Swanton, Rich's quarry, N. 45 E., 25 S.E., C. H. H. 



Georgia, N. 30 E., 23 E., Z. T. 



Highgate, middle part, Dip east, C. H. H. 



Highgate, north of Springs, 62 W., E. H. and C. H. H. 



Highgate, do., 36 E., C. H. H. 



Highgate, do., N. 65 E., 30 S.E., C. H. H. 



Highgate, east of Springs, 20 E., C. H. H. 



These limestones all dip to the east. 



The general dip of the slates is to the east. Variations to the north and northeast are caused by a cor- 

 responding change in the direction of the formation. Only one westerly dip is recorded, that is on Hog 

 Island in Swanton. There is an anticlinal in the slate in this town, caused by the folding of the strata. 

 It disappears to the south, unless it be an inverted anticlinal, but is exhibited better to the north, in 

 Canada. Upon the same anticlinal Utica slate was found in North Hero, dipping to the west. This is the 

 great anticlinal separating the eastern and western basins of Palaeozoic rocks from each other in Canada. 



Upon the islands in Lake Champlain there are many small disturbances. It is generally the case that 

 the outer cliffs dip much more than the interior parts of the islands. Knight's Island is an example. The 

 cliffs on the west side of the island dip 50 E., but in the south side, and not far from the highly inclined 

 strata, the dip is 30 E. There seems to have been some force, perhaps from causes now operating, like 



