322 REPORTS ON THE STATE OF SCIENCE. 
TiO, was determined by the gravimetric method, being precipitated as 
metatitanic acid, ignited and weighed as TiOy. 
No. 3874 is a Mica Zoisite Diorite which occurs in the mica schists. 
Of this a silica percentage only was taken, and following upon it are several 
other rocks of which partial analyses or only silica percentage estimates 
were made. 
No. 3874. 
21 V.W. Coast North of Aberffraw. 600 feet L.0 Ynysoedd duon. 
I II. 
SiO, : ; é ped 02 47°10 
No. 377A is an epidotie schist occurring in the mica schists of the 
Holyhead region, and of importance as an horizon. It is evidently a 
basic rock. 
No, 377A. 
16 N.E. 300 feet North of Cilbach, Borthwen Rhoscolyn. 
I. 10E 
SiO, : : = . 42°23 42°30 
Nos. 3334, 335A, 336A are from the late dykes of the island, some of 
which, at any rate—possibly all—belong to the latest of all its rocks 
except the pleistocene. 
No. 333a is the prevalent type, an andesitic or sub-basic dolerite. 
The other two are much coarser, 336A containing some hornblende, and 
3354 being a true olivine dolerite. Many rocks of the group were 
described in papers by the Chairman, and their age discussed in a paper 
by the Secretary. | 
No. 333A. 
Llanddnyn Island. Coast North of Ffynnon Sais. 
SiO, = 50-92 
FeO, = 14:74 
C105 y= 8:51 
The above analysis is by Miss E. Reyner. 
No. 335a. 
11 MW. Holyhead. Wall's End. Penlas Cove. 
sid, . By te . : . 42°34 
Fe,0O,+Al,0,  . : 5 . 27°88 
CaO . ; : 3 : . 874 
MgO . - : : Ame RD 
The above analysis is by Mr. Wm. Roberts, B.Sc. 
No. 3364. 
11 M.W. Holyhead. Llaingoch. 
SHOE os ; é ; ; . 48:03 
Fe,0, . ; ; ; ; peeei((roul 
RE peed ccf 0.) ee 
CaO . K : é 6 tsa 
MgO . : j ; ed ene 
The above analysis is by Mr. W. C. Evans. 
