F. H. Lahee — Metamoiphism and Geological Structure. 259 



two synclines and an anticline, we have adopted the latter 

 hypothesis. Following are the results : 



jine. 



Fold 

 tra- 

 versed. 



Length 



of line 



in miles. 



Number of 

 folds per 

 ten miles. 



Sum of land 



portions in 



miles. 



Number of folds per 



ten miles of 



land breadth. 



A. 



9 



19 



4-73 



16 



5-62 



B. 



13 



16 



8-12 



8-75 



14-85 



C. 



16 



13-5 



11-85 



9 



17-78 



This table indicates that the number of principal folds per 

 unit of Basin width, and, therefore, the degree of compression, 

 regularly increases southward. 



Minor folding. — Contortion of the strata was recorded at 

 the localities listed below : 



Number of 



Location on 





locality* 



map 



Type of rock 



1. 



D : 1 



Shale, sandstone, little conglomerate! 



4. 



D-E : 2-3 



Chiefly sandstone and shale 



5. 



D : 6 



Shale 



6. 



D : 7 



Shale and sandstone 



7. 



C : 7 



Shale and fine sandstone 



10. 



C : 13-14 



Shale and sandstone 



li. 



C : 15 



Shale and sandstone 



12. 



B : 16 



Shale and sandstone (inclusions) 



13. 



B : 16 



Shale and sandstone (inclusions) 



14. 



C-D : 13 



Chiefly shale and sandstone 



15. 



D : 10-11 



Chiefly shale 



16. 



E : 11 



Chiefly shale 



18. 



E : 13 



Shale 



19. 



D : 13 



Shale 



20. 



C-D : 14 



Shale and sandstone 



21. 



D : 14 



Shale 



22. 



D : 14 



Shale 



25. 



D : 15 



Shale 



26. 



D : 15 



Shale 



27. 



E : 12 



Chiefly shale 



28. 



E-F : 13 



Shale and arkose 



29. 



F : 13 



Shale, sandstone, and conglomerate 



30. 



F : 12-13 



Shale and sandstone 



33. 



H: 9 



Chiefly shale 



36. 



H : 11 



Chiefly shale 



37. 



H.12 



Chiefly shale 



38. 



H: 14 



Shale and arkose 



40. 



G : 14 



Shale, sandstone, and conglomerate 



41. 



F-G: 15 



Shale 



44. 



I : 12 



Chiefly finer rocks 



46. 



J : 10 



Chiefly sandstone and conglomerate 



48. 



I : 8 



Shale, sandstone, and conglomerate 



49. 



J : 5 



Shale and fine sandstone 



50. 



G : 6 



Shale and sandstone 



* These numbers are plotted on the map. 



f For convenience the rocks are here spoken of as shales, sandstones, or 

 conglomerates, whether or not they have been metamorphosed. 



