FROM THE TERTIARY LAVAS AROUND BEN MORE, MULL. 33 



to the top encloses remnants of turbid fibres of scolecite, the various portions of which are optically con- 

 tinuous. The dark inclusions at the centres of several of the prehnite areas are small garnets. The large 

 crystal near the top towards the light is epidote ; other crystals are seen at the margin on the right, and 

 at the margin towards the bottom on the left. North-east slope of An Gearna, Ben More, Mull. 



Fig. 3. Metamorphosed Amygdale [15], magnified 27 diameters. — The clear area to the right is primary 

 prehnite enclosing diopside which is turbid and full of chloritic inclusions. The large crystals at the bottom 

 and on the left are epidote, showing the core-and-rim structure. The turbid inclusions of diopside are con- 

 fined to the colourless, secondary material of the rims. North-east slope of An Gearna, Ben More, Mull. 



Fig. 4. Metamorphosed Amygdale [50], magnified 27 diameters. — The clear areas are prehnite, mostly 

 secondary after thomsonite, whilst the turbid areas at the top and towards the right are secondary albite 

 enclosing fragments of secondary prehnite and thomsonite. The corroded scrap in the prehnite at the 

 centre is a zeolite, either scolecite or thomsonite. The crystals towards the bottom showing cleavage are 

 epidote. Beinn Fhada, north end, east side, Mull. 



Fig. 5. Metamorphosed Amygdale [41], magnified 27 diameters. — The turbid fibrous material is garnet 

 secondary after a zeolite. The clear area at the top is also garnet enclosing and replacing prehnite. The 

 colourless areas in the turbid material consist of garnet showing weak birefringence ; it probably replaces 

 epidote. Beinn Fhada, north-east slope, near the granophyre, Mull. 



Fig. 6. Metamorphosed Amygdale [41], magnified 55 diameters, nicols crossed. — The large crystal cross- 

 ing the field is epidote, secondary after prehnite some of which it occasionally encloses. The dark areas are 

 garnet replacing prehnite and epidote. Beinn Fhada, north-east slope, near the granophyre, Mull. 



TRANS. ROY. SOC. EDIN., VOL. LI, PART I (NO. 1). 



