THE MECHANICAL INTERPRETATION OF JOINTS' 



WALTER H. BUCHER 

 University of Cincinnati 



PART I 



OUTLINE 

 The Joints on Mine Fork 

 Hartmann's Law 

 Hartmann's Law Applied to Experimental and Field Observations 



Compressive stress vertical, tensile stress horizontal 



Experimental observations 



The joints on Mine Fork, Magoffin County, Kentucky. 

 Both, compressive and tensile stresses horizontal 



Daubree's experiments on Torsion 



The joints on Crooked Creek, Adams County, Ohio 



The joints of Lake Cayuga, New York 



The joints of the Wisconsin shore of Lake Superior 



The areal study of joint systems 

 Greatest compression horizontal, least compression vertical 



Small "symmetrical faults" of Lake Cayuga, New York 



Experimental observations 



I. THE JOINTS OF MINE FORK 



In the course of field work in eastern Kentucky, in 191 7, the 

 writer observed a case of local jointing which gave him the clue 

 to the following investigation. 



On Mme Fork, a few hundred yards above the mouth of Lacy 

 Creek, in Magoffin County, close to the Morgan and Johnson 

 county lines, in a nearly vertical cliff of a strongly cross-bedded, 

 coarse-grained sandstone forming the top of the Lee Group of the 

 Pottsville series, the system of intersecting joints shown in the 

 accompanying sketch (Fig. i) is exposed along the roadside. 

 Unfortunately the commercial work in w^hich the writer was 

 engaged at that time did not permit him to spend any more time in 

 that vicinity than was necessary for a hasty surv^ey of this exposure. 



' Part I of this paper was presented, in essence, at the last meeting of Section 

 "E" of the American Association for Advancement of Science, at St. Louis, 

 December, 1919. 



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