So STRATIGRAPIIICAL GEOLOGY. 



The Map. 



The map (Plate V) that accompanies this chapter embraces the ex- 

 treme northern part of New Hampshire, with a small portion of the 

 adjacent territory on the west. Its southern limit is the beginning of 

 the White Mountain region. A few lines have been drawn to show the 

 area of the principal formations. 



The larger figures show the locality where the rocks of the sections 

 were collected. The smaller figures show where specimens were col- 

 lected, to illustrate the geology of the entire area. In some places, on 

 account of the large number of specimens collected, the figures have 

 been crowded away from the exact locality where they should have been 

 placed. The area west of the line running through Pittsburg, Clarks- 

 ville, Stewartstown, Colebrook, and Columbia belongs to the Coos group. 

 The line southward from Columbia, nearest the Connecticut river, sepa- 

 rates the Huronian rocks from the sienites, granites, porphyrites, and 

 gneiss to the east. The latter occupy a part of Jefferson, most of Kil- 

 kenny, a part of Northumberland, Stark, Odell, Millsfield, Stratford, 

 Columbia, and a small area in Dummer, Milan, and Berlin. East of the 

 Coos group and this granitic area the Huronian rocks occupy most of 

 the remaining territory, and are conveniently divided into several groups, 

 one of which is separated from the rest, and is included in the lines be- 

 ginning at the eastern boundary, near the north-east corner of the state, 

 and ending in Milan. Each of these areas has been already described. 



Many errors will undoubtedly be found in the map, as must necessarily 

 follow from the limited time given to work where so many figures are 

 concerned. Figure lo in Section XII should be where 9 is, and that 

 figure should have been put farther east; 285 in Odell should be 385; 

 while 42 of Section XI should be near the line of Stark and Northum- 

 berland. 



