Revieivs — Tlie Geology of the Lizard. 311 



as the first to solve one of the most fundamental, and at the same 

 time most obscure, problems of Lizard geology". 



With regard to the vexed subject of fluxion banding and foliation, 

 it is remarked that " in the plutonic and intrusive rocks of the Lizard 

 there is a foliation intimately connected with the injection of the 

 igneous magma, but it is clear also that earth-movements were going 

 on at the same time. The most important fact to bear in mind is that 

 the igneous rocks can be shown to have attained their present meta- 

 morphic state as soon as, or very shortly after, they had consolidated ". 

 The following sequence, in descending order, is recognized by 

 Dr. Flett :— 



Granite and Granite Gneiss. 



Kennack Gneisses (banded). 



Dolerite and Epidiorite dykes. 



Gabbro (with augen gabbro and gabbro schist) . 



Troctolite. 



Serpentine (Bastite, Tremolite, and Dunite varieties). 



Hornblende schists : Traboe schists. 



Treleague Quartzite. 



Man of War Gneisses. 



Hornblende schists : Landewednack schists. 

 [Green schists. 



Old Lizard Head Series j Granulites. 

 (Mica schists. 



It is pointed out that sedimentary rocks are represented by the 

 mica schists, granulites, and Treleague quartzite ; and that the 

 varieties of serpentine pass one into another, the dunite variety being 

 the marginal facies, the tremolite serpentine adjoining it, and the 

 bastite variety or Iherzolite being the central rock. 



In separate chapters full particulars are given of the subdivisions 

 of the metamorphic rocks of the Lizard Series. 



Turning now to the northern series of rocks, we find the sedi- 

 mentary Mylor, Falmouth, and P.ortscatho Series of Mr. Hill, grouped 

 as Ordovician (?), although as they presumably underlie the Veryan 

 Series regarded as of Llandeilo or Arenig age, and " probably Arenig ", 

 the three former series may include rocks that are pre-Ordovician. 

 Only the Veryan Series has yielded fossils, and with it are grouped 

 the Radiolarian cherts of Mullion Island. Lower Devonian is 

 recognized in the Manaccan Beds, which consist of slate, sandstone, 

 and conglomerate, with fragments derived from the Portscatho and 

 Yeryan rocks. The sequence maintained by Mr. Hill has, however, 

 been contested by Mr. IJpfield Green and Mr. C. D. Sherborn, who, 

 in their latest grouping, place the " Dartmouth, Falmouth, Ladock, 

 Grampound, Manaccan, Mylor, Portscatho, and Yeryan " Beds in the 

 Lower Devonian (Gedinnian) ; and they apply the term Yeryan to 

 "beds containing lenticular inclusions yielding Ludlow, Wenlock, 

 and Woolhope fossils", placing them beneath the Manaccan Beds 

 and above the Ordovician quartzites of Gorran.^ There does not 

 appear to be any justification for this application of the term Yeryan, 

 as it strictly belongs to the strata (thin limestones, Radiolarian cherts, 

 slates, quartzites, and pillow-lavas) grouped by Mr. Hill as Ordovician. 



^ See Geol. Mag. for 1912, p. 560. 



