LIST OF FIGURES. 245 



Fig. 2. A basal section of microcline from the Notcli, as seen between crossed 



Nicol prisms — page 102. x 50 



Fig. 3. A section of fibrolite schist from the Notch, as it appears between crossed 



Nicol prisms — pages 107 and 216. x 50 



Fig. 4. Staurolite in a section of the staurolitic slate, as it appears with a single 

 Nicol prism. The simple character and excessive impurity of the 

 crystals are shown — page 1 1 r . x 30 



Fig. 5. A section of diabase from Dixvillc notch. Concretions of chlorite are 

 shown, which between crossed Nicols are traversed by a dark cross, 

 the arms of which are parallel to the planes of the Nicol prisms — 

 page 121. X 50 



Fig. 6. Apatite crystals in a section of gabbro from Waterville — pages 123 and 



167. X 50 



Plate IX. 



Fig. r. A section of diabase from East Hanover — page 150. x 50 



Fig. 2. A crystal of labradorite in a section of labradorite porphyry from Ossi- 

 pee. The fractured and recemented character of the crystal, as it 

 appears in polarized light, is shown — page 155. x 30 



Fig. 3. A crystal of augite in a section of the olivine diabase from Campton 

 falls, showing a concentrically banded structure in polarized light — 

 page 158. X 30 



Fig. 4. An altered olivine crystal, as it appears in a section of the olivine dia- 

 base from Campton falls, with polarized light — page 158. x 30 



Fig. 5. Hornblende in a section of porphyritic diorite from Campton falls, as it 



appears with a single Nicol prism — page 161. x 30 



Fig. 6. Hornblende and augite associated together in a section of diorite from 

 North Lisbon. The prisms are parallel. The hornblende is fresh 

 and unaltered, while the augite has decayed and been removed, and 

 its place has been filled by an aggregate — page 162. x 30 



Plate X, 



Fig. I. A section of gabbro from Waterville, as it appears in polarized light — 



page 167. X 30 



Fig. 2. A section of quartz porphyry from Mt. Lyon in ordinary light — page 179. x 50 



Fig. 3. The same section in polarized light, with lines indicating the directions 



in which the planes of elasticity cut the section — page 179. x 50 



Fig. 4. A crystal of orthoclase, which is twinned according to the Carlsbad and 

 Baveno systems, in a section of the quartz porphyry from Groveton — 

 page 180. X 50 



Fig. 5. A section of a hornblende granite from Colebrook, showing the rela- 

 tionship between the quartz and feldspar in regard to the order of crys- 

 tallization — page 191. X 50 



