0 F THE ROCKS OF LA K E S U P E II 1 O R. 



251 



greenish, with the lustre of silk. The tourmaline is ruby-coloured, and appears in 

 minute crystalline masses, disseminated through the actinolite. 



539. Mica slate. 



540. From a vein traversing mica slate — very coarse, with plates of silvery mica 

 largely predominant. The mica slate is perfectly studded with garnets. 



541. Talcose slate, containing numerous quartz crystals. 



543. Gneissoid granite — coarse-grained; colour, gray. 



544. Granite — very coarse-grained, with large crystals of felspar, and large plates 

 of yellow and brown mica. 



545. Mica slate — dark brown mica predominant. 



546. Mica slate — traversed by grains of felspathic granite. 



547. Greenstone — colour, gray ; crystalline ; coarse granular fracture ; very 

 tough ; weathered surface, iron-shot. 



548. Gneiss — very fine-grained ; structure, a little inclined to slaty ; colour, from 

 light to dark gray ; traversed by veins of granite. 



549. 550. Same as No. 548. * 



551. Mica slate — the felspar, red, giving a reddish tint to the rock, passes into 

 gneiss, and the gneiss into No. 552. 



552. Granite — coarsely crystalline ; white felspar and black mica. 



553. Gneiss — fine-grained ; the felspar predominant ; dark brown mica, traversed 

 by granite veins. Passes into No. 554. 



554. Very fine-grained mica slate. 



555. Greenstone — fine-grained ; compact ; fracture conchoidal. 



556. Greenstone — very fine-grained ; structure slaty. 



557. Greenstone — colour, gray; numerous small specks of white felspar; the 

 weathered surface of a lighter gray colour than a fresh fracture. 



558. Greenstone — colour, greenish gray ; porphyritic ; the embedded crystals are 

 albite. This is a beautiful rock, and resembles some of the Bavarian porphyries. 



559. Slaty greenstone — tolerably fine-grained; colour, greenish; graduates into 

 mica slate. 



560. Mica schist — passing into mica slate; colour, gray. 



561. Greenstone — very compact; even fracture; colour, light green; in some 

 places inclines to a slaty structure. 



562. Mica slate — very fine-grained; colour, gray; structure occasionally fibrous. 



563. Greenstone — colour, light green; compact; fracture rough. 



564. Greenstone — colour, dark green; compact; rough fracture; sometimes 

 shows a slight disposition to a slaty structure. 



565. Gneiss — fine-grained ; felspar, flesh-coloured and predominant ; mica, black. 



566. Hornblende slate — compact; sometimes amygdaloidal ; colour, green ; might 

 be called variolite. 



567. Hornblende slate ; fine-grained ; no amygdules, and darker coloured than 

 No. 566. 



568. Porphyritic greenstone — colour, very dark green, almost black ; hornblende 

 greatly preponderating, giving the rock a nearly black colour. 



