No. 40] GEOLOGY OF SHEPAUG TUNNEL 37 



the Berkshire schist. Finally, the rock forming Mount Tom and 

 the neighboring hills is not a true amphibolite but a hornblende 

 gneiss with a protoclastic texture, and Little Mount Tom is 

 composed of the same rock and not, as previously mapped, of 

 Brookfield diorite. 



Besides these definite changes the areal distribution of certain 

 formations has been altered considerably ; the boundaries between 

 the Brookfield diorite and the neighboring schists have been located 

 more accurately ; the diorite itself has been shown to be a composite 

 of many closely related intrusions, and the Berkshire schist to be 

 considerably older than the Hartland. 



Bibliography 



1. Observation of the Minerals Connected with the Gneiss Ranges 

 of Litchfield, Conn. J. P. Brace, Am. Jour. Sci., (i) i, 351-355- 

 1819. 



2. Sketches of a Tour in the Counties of New Haven and Litchfield 

 in Connecticut, with Notices of the Geology, Mineralogy, and 

 Scenery. B. Silliman, Am. Jour. Sci.. (i) 2, 201-235, 1820. 



3. Report on the Geology of the State of Connecticut. J. G. 

 Percival, 1842. 



4. On the Southward Ending of a Great Synclinal in the Taconic 

 Range. J. D. Dana, Am. Jour. Sci., (3) 28, 268-276, 1884. 



5. Archaean Limestone and Other Rocks in Norfolk, Connecticut. 

 J. D. Dana, Am. Jour. Sci., (3) 39, 321, 1890. 



6. The Geologic Structure of the Housatonic Valley Lying East of 

 Mount Washington. W. H. Hobbs, Jour. Geol., i, 780-802, 1893. 



7. Geology of the Green Mountains in Massachusetts. R. Pum- 

 pelly, T. N. Dale, J. E. V/olff, U. S. Geol. Surv. Mon. 23, 1894. 



8. Notes on the Geology of Southwestern New England. W. H. 

 Hobbs, Jour. Geol. 5, I75-I77, 1897. 



9. Geology of Old Hampshire County, Massachusetts. B. K. 

 Emerson, U. S. Geol. Surv. Mon. 29, 1898. 



ID. Geology of Eastern Berkshire County, Massachusetts. B. K. 

 Emerson, U. S. Geol. Surv. Bull. 159, 1899. 



11. The Geologic Structure of the Southwestern New England 

 Region. W. H. Hobbs, Am. Jour, Sci., (4) 15, 437-446, 1903. 



12. On Two New Occurrences of the "Cortland Series" of Rock5 

 within the State of Connecticut. W. H. Hobbs, Festschrift v. 

 H. Rosenbusch, 25-48, Stuttgart, 1905. 



13. Manual of the Geology of Connecticut. W. N. Rice and H. E. 

 Gregory, Conn. Geol. and Nat. Hist. Surv. Bull. 6, 1906. 



14. Preliminary Geological Map of Connecticut. H. E. Gregory and 

 H. H. Robinson, Conn. Geol. and Nat. Hist. Surv. Bull. 7, 1907. 



15. Structural and Stratigraphic Features of the Basal Gneisses of 

 the Highlands. C. P. Berkey, N. Y. State Mus. Bull. 107 (Geol. 

 12) 361-368, 1907. 



16. The Granites of Connecticut. T. Nelson Dale and Herbert E. 

 Gregory, U. S. Geol. Surv. Bull. 484, 191 1. 



17. The Geology of the Poughkeepsie Quadrangle. C. E. Gordon, 

 N. Y. State Mus. Bull. 492, 191 1. 



18. Sulphide Bearing Rocks from Litchfield, Connecticut. Emest 

 Howe, Ec. Geol. X, No. 4, June, 1915. 



19. Geology of Massachusetts and Rhode Island. B. K. Emerson^ 

 U. S. Geol. Surv. Bull. 597, 1917. 



