138 BALDERSTON : THE SILURIAN ROCKS OF INGLETON. 



being composed of: — orthoclase of red and pale tints ; perhaps a little 

 greenish oligoclase ; black and brown biotites ; dark green horn- 

 blende; occasional large crystals of quartz; pyrites; a few amygdaloid 

 nodules ; and having in one place two zeolitic bands running through 

 it. Its extreme points of exposure are 1584 yards apart. 



No. 2. — Lower Violet or Orange Dyke, (i) In the Twiss, 8 ft. 

 wide, and 6 in. from No. 1. (ii) In the Doe, 5 ft. wide and 168 ft. 

 from the Tow Scar Fault ; (iii) by the Skirwith Road ^ an inch from 

 No. 1. In the first position it is for the most part much decomposed; 

 in the second altered at one end ; in the third fairly fresh. The 

 colour varies from orange, through purplish in the Doe, to violet 

 and violet-grey in the two other exposures. Its line is apparently 

 nearly straight, though slightly running across the bedding so as to 

 get nearer the south to the S.E. This dyke is a granitic trap, 

 approaching minette, and is composed of: — orthoclase of red and pale 

 tints ; hornblende, black to green ; biotite, black to brown ; quartz, 

 more than No. 1 ; idocrase, of a yellowish green tint ; foliated, 

 micaceous pseudomorphs, after schorl ; chalcedonic nodules; pyrites; 

 and beautifully crystallised enclosures of granitel. Its extreme points 

 of exposure are 1,584 yards apart. 



No. 3. — Red or Upper Violet Dyke, (i) In the Twiss, 18 ft. wide, 

 and running 36 ft. to 45 ft. from No. 2, but their respective points 

 of exposure, where best examined, are about 54 yds. distant from 

 each other, (ii) In the Doe; width 13 ft. and 18 ft. from No. 2. 

 (iii) In the Skirwith Road, where I regard it as confluent with 

 No. 2 ; 9^ ft. wide, and ^ in. from No. 1. In the first position, in 

 deep water, the condition of the trap is good, but the extinction- 

 dyke section a short distance from the stream, is hardly recognisable; 

 in the second position, very good ; and in the third, fairly fresh. 

 In the Twiss the colour is violet -grey, but the pale grey, compact 

 variety is also seen here ; in the Doe the tints are orange, to purplish 

 red ; and by the Skirwith Road, violet to pale red. The line of 

 exposure is similar to that of No. 2, which may be regarded as an 

 almost parallel branch of this the greater dyke. The description of 

 trap is therefore the same, although in the Doe section of this dyke 

 the chalcedonic nodules are not notably present; but the enclosures 

 of granitel are abundant and of schistose, hornblendic gneiss less 

 common. The extreme points of exposure are 1,639 yds. in the 

 cleaved black slates and calcareous-ash slate series. 



No. 4. — The Great Felstone Dyke and its four Rhyolites. 

 (i) In Pecca Hill, three exposures. (ii) In the Twiss below, 

 apparently less than 36 ft. wide, with some 170 ft. of cleaved black 

 slates and dark limestone between it and No. 3. The widt h of the 



Naturalis 



