PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 775 



Qabbro. Quartz, calcite, etc.] 



No. 1743. GABBRO. (Mitch altered.) 



Same place as No. 1742, having a flint film or inclusion. 

 Ref. Annual Report, xxi, page 157. 



Meg. The same rock as No. 1742. 



Mic. The quartz has entered the feldspar in a micropegmatitic manner. The 

 feldspar, which had an ophitic structure with reference to the original augite, is 

 indeterminable in the section at hand. One (thick) section. 



Age. Cabotian(?) 



Remark. Although originally ophitic this great mass has the color, action and 

 outward aspect of gabbro. N. H. w. 



No. 1744. GABBRO. (MucU altered. ) 



Same place as No. 1742. 



Ref. Annual Report; xxi, page 157. 



Meg. Same rock, but having a different grain. 



Mic. So far as can be seen from the section at hand this is exactly the same as 



No. 1743. One (thick) section. 



Age. Cabotian(?) N. H. w. 



No. 1745. QUARTZ, CALCITE, ETC. ( Vein matter, altered. ) 



Same place as No. 1742. 



Ref. Annual Report, xxi, page 157. 



Meg. One foot thick, running straight in the rock of the headland for at least 

 twenty-five feet, when it becomes hidden under the water at one end and under soil 

 at the other. 



Mic. The section is so poor that it is only possible to say that the vein consists 

 of calcite, quartz and apparently of some fclil.^xn; stained and colored nearly black 

 by magnetite and leucoxene, involving pieces of diabase. One (thick) section. 



Age. Cabotian(?) N. H. w. 



No. 1746. GABBRO. (Much altered.) 



North side of Knife lake headland. 

 Ref. Annual Report, xxi, page 157. 



Meg. Apparently a conglomeratic or brecciated portion of the rock of the hill, 

 with many pyrite cubes. The rounded masses that are dislodged are from three 

 inches to eight inches in diameter, charged with pyrite, same as the rock itself. The 

 pyritiferous character gradually fades out upward and is entirely wanting at forty- 

 five feet above the lake. 



Mic. The section is from the pyritiferous rock, and with cubes of pyrite shows 

 much calcite and a little quartz with fine needles of sericite, clusters of grains of 

 zoisite and remnants of an indeterminable feldspar. One (thick) section. 



Age. Cabotian. 



Remark. This is evidently the rock of the hill in an altered condition. N. H.W. 



