UTICA SLATE. 



303 



Addison, Cobble Hill, 

 Cliarlotte, northwest part, 

 Shelburne, southwest part, 

 Shelburne, Nash's Point, 

 Appletree Point, Burlington, 

 North Ferrisburgh, 

 Colchester Point, 

 Hog Island, near do., 

 Rock Dunder, 

 Juniper Island, 

 Grand Isle, east part, 

 Grand Isle, east part, 

 South Hero, Kibbe's Point, 

 Isle La Motte, east side, 

 North Hero, 

 North Hero, Carrying Place, 



N. 10 E., 

 N. 5 E., 



N. 70 E., 

 N.40E, 



N. 45 E., 

 N. 25 E., 



N.42E., 

 N. 35 E., 

 N.65E., 

 N. 38 E., 



60 E., 

 58 E., 

 45 E., 

 41 E., 

 85 E., 

 50 E., 

 50 E., 

 90 E., 

 73 E., 

 70 E., 

 30 N. E., 

 30 S. E., 

 56 E., 

 60 E., etc., 

 74 E., 

 30 E., 



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

 C. H. H. 

 C. H. H. 

 C. H. H. 



C. H. H. andE.H.Jr. 

 C. H. H. 



C.H.H. andE.H.Jr. 

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

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

 C. H. H. 

 C. H. H. 

 C. H. H. 

 C. H. H. 

 C. H. H. 

 C. H. H. 

 C. H. H. 



FIG. 217. 



Section on Yew Island showing planes of cleavage and of stratification. 



The angles between the dip of the cleavage planes and of the strata, in all these cases, will average about 

 thirty-five or forty degrees ; the limits of variation are from fifteen to ninety degrees. 



Fig. 217 represents the manner in which these two kinds of planes occur upon Hog Island, a small island 

 off Colchester Point. The name is rather an unpleasant one, and we would therefore propose for it a new 

 name, first suggested by Profs. Adams and Thomp- 

 son, in their note books namely, Tew Island, so 

 called from the great number of yew trees found upon 

 The cleavage planes are the most conspicuous of " 



it. 



the two sets, and very greatly resemble the true 



planes of bedding ; but the alternations of different 



materials in the strata, though faint, yet satisfy the observer that they are the true dip. a, a, represent the 



planes of stratification, and b, b, those of cleavage. 



This is one variety of cleavage. Another is given in Fig. 218, representing a case at Kibbe's Point, 



in South Hero, where the angle between the two kinds of divisional 

 planes is a trifle less than fifty degrees, the previous figure showing 

 a difference of 88. 



In all these cases the strata seams are readily distinguished by 

 their gentle irregularities ; while the cleavage planes are always as 

 true as if the hand of man had drawn them with rule and compass. 

 The strata here dip from four to eight degrees easterly, while the 



FIG. S13. 



Section at Kibbe's Point, in South Hero. 



cleavage planes dip fifty-eight degrees in the same direction. 



STRIKE AND DIP OF THE STRATA. 



Locality. 



West Haven, west of post-office, 

 Shoreham, west part, 

 Shorehain, Lake Shore, 

 Bridport, southwest part, 

 Bridport, west part, 

 Bridport, northeast corner, 

 Addison, west part, 

 Addison, Snake Mountain, 

 Addison, Snake Mountain, 

 Addison, Lake Shore, 



Strike. 



N. 30 E., 

 N. 10 E., 

 N. 24 E., 

 N.66E., 

 N. 35 E., 

 N.25E., 

 N.45E., 

 East of north, 

 East of north, 

 N.45E., 



Dip. 



50 E., 

 45 E., 

 16 E., 



9W., 



25 N.W., 

 38 E., 

 15 E., 

 12 N.W., 



Observer. 



C. H. H. and E. H., jr. 



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



C. H. H. 



C. H. H. 



C. H. H. 



E. H., etc. 



C. H. H. 



C. B. A. 



E. H., etc. 



C. H. H. 



