PREFACE 



This bulletin presents the results of a detailed study of the 

 geology of the Shepaug Aqueduct Tunnel and the area immedi- 

 ately surrounding it in the town of Litchfield, near the center of 

 the western upland of Connecticut. 



The tunnel was drilled by the city of Waterbury as a part of 

 an extension of its reservoir system, and this bulletin contains 

 a chapter by R. A. Cairns, C.E., city engineer of Waterbury, 

 giving the history of the project and the city's reasons for going 

 to this particular region for additional water. 



The geological investigation was undertaken in the tunnel in 

 order to study the seven-mile section so exposed before any part 

 of it was hidden by lining. It was an unusual opportunity to 

 examine a continuous section of the complicated metamorphic 

 rocks of the western upland of Connecticut, and much has been 

 learned concerning the details of structure and petrography of the 

 Berkshire and Hartland schists, the two most widespread forma- 

 tions, as well as of many less widely distributed. Such details are 

 presented here as a record of the geology of the region itself and 

 because of their bearing upon the problems of the geology of 

 western Connecticut and the neighboring areas. 



The field work occupied part of the summers of 1925 and 1926, 

 and the petrographic work was done in the laboratory of Yale 

 University during the winter of 1926- 1927. 



The writer wishes to thank Mr. R. A. Cairns and the whole 

 engineering staff in the field, particularly Mr. I. F. Story, engi- 

 neer in charge, for unfailing interest in the work and for assist- 

 ance rendered in many ways. He also wishes to acknowledge 

 the helpful criticism of Mrs. A, Knopf and the help of Professor 

 A. Knopf in the identification of certain minerals in thin section. 



