246 PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND.. 

clase is centrally imbedded in a larger one of the substance analysed, indicating 
that the latter was of later formation. Very rarely the red orthoclase is 
penetrated by crystals of the oligoclase. 
The analysis, though pointing most clearly to oligoclase, is not altogether 
inconsistent with the mineral being albite,—unfortunately the crystals, though 
fairly well formed, had faces too rough for measurement. They decompose 
more rapidly than the orthoclase; this points to DE BUE and not albite. 
There was no visible striation. 
1° 302 grammes yielded— 
Silica, , ; japba 
From Alumina . ~ *008 ! '. 
-839 = 64:439 
‘Alumina, , ; ; ~ 20° 436 
Ferric Oxide, . ‘ Sian : 4 
Manganous Oxide, . : * 384 
Lime, : ; I | eae 
Boiaehier sally bus, elabeies 
Soda, sie Ex : oir 963 
Water "1..." ..7 oikodee 

100 : 029 
Loss in bath, ‘47 p.c. Insoluble silica, 1 * 668 p.c. 
OLIGOCLASE. 











Sola ine : aes Si. | alo | F,0 |Mn.| Mg.] Ga. | Ky. | Nag. | Hy.| Total 
Rispond, . _—. | White 86 14 | 2°636 | 61-85|21-7 | 3:37 | -2 | -09| 4:13 | 1-63 | 6-95-| -37| 100-29 
Coyle, . .| Cream 86 32 | 2°627 | 63:54] 21°45 | 1°86 | ... | -23| 8°88 | 1:07 | 7°64 | +44] 10071 
Barra Hill, . | Milk — 86 12 | 2°834 | 64°67 | 22°18] 1°44 | ... | 01] 1°89 | 1:54 | 7°62 | 15] 99°58 
Dyce, . «| White 86 15 | 485/282 | ... 1... ]°2 | 96 | 3°77 |-812 | 01) Joram 
Sclatty, . .| White |... ... | 59°58 | 21-05] 1°81 | ... | 88] 3°63 | 4°73 | 7-23 [1-88] 100-75 
Rubislaw,. —_. | White - 2:637 | 62°53 | 23°52 | 1:28 | ... | 86] 4°97 | 1°32 | 6-19 | 6 | 100°78 
Craigiebuckler, | White 86 14 | 2°622 | 61°58|22° | 1°28] ... | 82) 4:19 | 152 | 8-27 | -54] 99-67 
Lairg, .  .|Colourless| 8615 | 2°618 | 62°81|22:92] 16 | .. | 08] 425 | 84 | 853 | -29] 99°88 
1 Canisp : . | Cream We on ane 64°44 | 20°47] ‘88 | 38 os 1°3 | 1°18 | 9°96 |1°46) 100°02 
ANDESINE. 
From Granular Limestone in Micaceous Geiss. 
1. From Glen Urquhart. — 
The serpentine of Polmally is on the north-east, wrapped round with an un- 

