1871.] 



GEIICIE — TERTIAET VOLCANTC KOCKS. 



29^ 



In Eigg the intrusive sheets at the base of the volcanic series are 

 much less strikingly exhibited than in Skye, Raasay, and Mull. 

 Some good sections occur, however, at the north end. In the lowest 

 group of the Oolitic series, as exposed on the shore and on the low 

 cliff to the east of Blarmor, there is an abundance of thin sheets of ana- 

 mesite, which, sometimes coincident with, sometimes traversing the 

 bedding-planes of the shales and limestones, harden the strata along 

 the line of contact. At that locaHty the succession of the rocks is 

 somewhat obscured by the effects of some large landslips ; and similar 

 disturbance extends all along the eastern flanks of Beinn Bhuidh. 

 In one of the streamlets, coming down from that side of the plateau, 



Fig. 4. Section of Tnterbedded and Intrusive Volcanic Rocks, 

 on the East Coast of Eigg. 



^1 ii* 



WmMm^^ 



-^ — 



1. Sheet of intrusive basalt, 4 to 6 feet thick. 



2. Sheet of fine-grained anamesite, 2 to 4 feet thick, 



a. Calcareous pale yellow shelly sandstone (Oolite). 



b. Columnar fine-grained anamesite or basalt, traversed by intrusive 



sheet (2). 



c. Dull amorphous fine-grained anamesite. 



d. Pale grey porphyrite. 



near the Rudh nan tri Chlach, and which is known as the Ault na 

 horsta mian, more than twenty intrusive sheets of dolerite, anamesite, 

 or basalt may be counted among the shales and limestones. They are 

 sometimes mere thin horizontal veins, not six inches thick ; and they 



igneous rocks of Trotternish, in Skye, must thus be abandoned (see Quart. 

 Journ. Greol. Soc. vol. vii. p. 104). I adopted his views in my first examination 

 of Skye ; and my reference of the volcanic rocks of Skye to an Oolitic date must 

 likewise be set aside (Trans. Roy. Soc. Edin. vol. xxii. p. 648 ; see also Proc. 

 Roy. Soc. Edin. vol. vi. p. 72, where this change of view is indicated). 



