34 PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 
BLACK MICAS. 
SL. | Ale: | Fee Be, | Wim 4 CGme wate, || de. |oNes ll omeell ane ‘Ti. | Totals. 
Biotite— 
Glen Urquhart, . | 38°69 | 17°66 *26|/12°95| ... 116 |17°54) 8°92] 18) 2:14 52 99°96 
Loch Laggan, . |89°5 |15°04|) +24/10°23) °75 |) 1:4 | 18°46) 9°37] 62] 3°21 73 99°55 
Shinness, . . | 39°77 | 16°68 *65| 6°73) “62 | 2:2 | 20°92) 6°5 48 | 5-4 i 99°95 
Glen Beg, . . | 89°46 | 16°45 *39 | 10° ‘53 | 1°59 | 19° 8°22 "26 | 3°34 32 99°56 
Hillswick, . . |89°8 |14°19] 2°59/11°78| -24 "1 | 18°32] 8:43) 2°11 | 2°52 “56 100°64 
Milltown, . . | 40°31] 12°58] 1°81) 3°35) °38 | 7°58 | 21° 656] ‘95 | 5°74] nd. 100°25 
Haughtonite— 
Roneval, . . | 87°16 | 15° 7°69 | 17°35 | 1°04 | 1°3 8°88) 818] 16 | 2°12 100°17 
Capval, é . | 86°81)15:°22) 7°61)17°35| °96 | 1:54 | 8°78| 8°31} 1:34 | 2°47 100°40 
Loch-na-Muilne, . | 36°46] 17°25| 4°18} 15°33 54; °69 | 12°23) 9°2 66 | 3°39 99°92 
Foinaven, . . |86°75]}17°88| 2°78|15°18| -42 93.) 11°17 | 9°44) 1:25 | 4:23 99:99 
Rispond . . | 86°54] 22°28} 2°43)16°01| °78 | 1°25 | 10 8°26) 79} 1°51 99°86 
Clach-an-Eoin, . | 35°85 | 21°54) 4:48/18°31| -31 | 1°25 | 808) 7°76) -79 | 1:96 100°33 
Kinnaird Head, . | 85°67 |17°95| 7:19) 18°06 | 2° 14 15 | 9°27) 3°81 | 3:2 100°05 
Cove, . . . |85°47;18°8 | 4°61)19:19); 64 9 7°01); 8:19; °24) 4:97 100°02 
Nishibost, . . | 85°15 | 16°7 5°96 | 19°06 | 1°02 *82 | 7°46) 9:24) 1°26 | 3:13 99°81 
Lairg, ; . | 35°56] 16°69 | 1°88|18:04} “69 | 2°72 | 8°47) 9:9 ‘11 | 5°71 99°77 
Portsoy, : . | 84:08] 17°34 | 38°61 | 18-70 88 | 3°23 | 10°54) 6°78| 1°19 | 4:05 99°9 
Ben Stack, . . | 85°69 | 20°09 | 2°28) 14:01} 1 1°89 |14°77| 7:38] ‘53 | 2°46 100°06 
Foreign do.— 
16. Brand, . | 87°18] 17°53 | 6°20) 15°35) ‘31 79 | 9°05| 5:14] 2°93) 3°62) ... 2°47 || 100°57 
17. Brand, . | 37°06 | 16°78 | 6°07 | 15°37 | tr. 57 | 9°02| 5:96] 2°86 | 3°77 one 3°64 || 101°1 
18. Hartzburg, 36°17 | 18°09 | 8:7 | 18°72] ... 52 |11°16| 7°59] tr. 2°28 36 gnc 98°59 
Schwarzwalder,* | 33°6 | 15: 4:99} 19:29| ... 3°36 | 11°62} 7°53) ‘51 | 4°58 | tr. .-- || 100°48 
Tyrberger,t . |35°5 | 18°01] 9°24)12-11) tr 3°02 | 10°86} 9°18] 1°93] ... Pa = 99°85 
Cape Wrath, . | 34°15 | 14°84 | 10°96 | 13°47] 1°38 | 1°81 | 10°31) 7:93) 2:14 | 2°8 99°79 
Clova, . : 5 eye i acl 6'51| 9°8 67 ‘93 | 6:17] 7:08] 1°63 | 3°47 100-33 
Lepidomelane— 
Achadhaphriz, . | 40°38) 12°11 |14:53| 3°03) 3:17 | 1:03 413: (ls) || ales |i B85 99°72 
Tongue, ; : 40°08 | 12°41 | 18°47] 2°67 "62 | 1°08 | 14°66} 7°57] 2:15 | 5:29 99-99 
In the above table I have inserted three analyses by other observers—16, 
17, 18—from Dana’s list, and two from a more recent source. 
A condensation of this table gives the following averages of the composi- 
tion of these micas,—from which averages the oxygen ratios are calculated ; 
the Irish lepidomelane being the average of Dr Haughton’s analyses :— 
* Hebenstreit. From gneiss, with axial angle small. 
+ Hebenstreit. From the granite of the Tyrberger water-fall ; specific gravity, 3°07. Zeitschrift 
fiir Krystallographie und Mineralogie, Zweiter Bund, erstis heft. 
{ One or two of the Haughtonites were not included in calculating the average, their analysis 
having been very lately executed ; as they agreed with the others, their exclusion does not effect the 
result. 
