6l6 STRATIGRAPHICAL GEOLOGY. 



this rock forms a high, precipitous ledge, of which the culminating point is Sunset Rock. 

 The buildings of the Theological Seminary appear to be on the boundary between the 

 coarse granite and the gneiss to the west. The most easterly outcrop of the coarse 

 rock is near Simeon's, west of H. Gray's, in the Holt district. The length of this 

 granite is a little more than four miles, and its greatest width 440 rods. The crystals 

 of mica and feldspar are sometimes six inches broad, and are universally very large. 



This area carries beds of limestone, in which Eozoon has been found, 

 as at Chehnsford, by L. S. Burbank.* The same fossil occurs at New- 

 bury. The occurrence of the Laurentian and associated rocks in this 

 town will be found further described under the topic of Economical 

 Geology. 



3. MONTALBAN. 



In Farmington is an area of excellent Concord granite, two or three 

 miles long, occupying the valley of a large tributary of the Cochecho river. 

 A hill back of the railroad depot is composed of the same material. The 

 drift is so extensive to the north of it as to make it uncertain whether 

 this area may directly join the Lake gneiss of New Durham, or be sep- 

 arated by a covering of mica schist. This series, without the granite, 

 crops out extensively in Sanford, Alfred, and the adjacent towns farther 

 north in Maine. There is a synclinal axis in it near Springvale. 



4. Rockingham Mica vSchist. 



This may occupy more space in this district than any other group. 

 Two areas may be noted, united to each other in Rochester. The first 

 is the continuation of one previously described, and extends from Aliens- 

 town to Alton, and to near Newfield in Maine. The second joins the 

 Nashua deposit, previously noted, and may be followed adjacent to the 

 Nashua & Rochester Railroad to Berwick, Me. The following positions 

 have been noted in the first area: 



Gilmanton. At J. L. Page's, dip 45° N. 50° W. 



At S. C. Place's, dip 65° N. 20° E. On Grant hill, dip 25° N. 80° W. 



At J. D. Nelson's, dip 30° N. 20° W. At east base of Lamprey hill, dip irregu- 

 At J. F. Nelson's, dip 57° N. 5° E. larly 30° N. E. 



At D. B. Morrill's, dip N. 30° W. On Hall's hill, south-cast corner, dip N. 

 West of D. B. Morrill's, dip 10° N. 60° W. 60° W. 



* Proc. Boston Society Natural History, vol. xiv, p. 190. 



