CHAPTER VII. 



GEOLOGY OF THE LAKE DISTRICT. 



*J|lIHIS is the smallest of all our areas of description. It properly 

 Jf% embraces the hydrographic basin of Winnipiseogee lake, the flat 

 country to the north, and the rest of the territory as far as the state line 

 of Maine. There is a large tract in Maine represented upon the map, 

 chiefly of Montalban rocks ; and the extremely few facts concerning them 

 in our possession would properly be noted here. For convenience, I will 

 include the whole of the porphyritic gneiss of the Squam Lake region 

 and the Montalban and Moose Mountain granite areas lying partly in the 

 Coast district. I will leave out a very inconsiderable tract of mica schist 

 in Alton. Thus limited, we have only three stratified groups to sketch : 

 I. Porphyritic gneiss. 2. Lake gneiss. 3. Montalban. The eruptive 

 rocks are more plentiful and varied, consisting of i. Conway. 2. Albany. 

 3. Chocorua granites. 4. Porphyry. 5. Pequawket breccia. 6. Labra- 

 dorite diorite. 7. Sienite. 8. Granite, not allied to any of the foregoing. 



I. PoupiiYKiTic Gneiss. 



The principal area of this rock has the shape of a fish-hook. It comes 

 out of the White Mountain district into Sandwich and Ashland, makes 

 its principal curve in New Mampton and Meredith, and runs to the point 

 just south of Squam lake, while the barb takes a course east of south 

 through the east part of Meredith, and crops out occasionally along the 

 west shore of Lake Winnipiseogee. On the north-west side are two 



