168 REPORTS ON THE STATE OF SCIENCE. 
No. 544A. 
Mass of Dolomite in Carboniferous Conglomerate. Lliqgny Bay. 
I, THE, 
Residues insoluble in HCl : + OR, 1:21 
Al,0O,+Fe,O, . 3 : : A pelle@ikss 17-07 
CaO . i 2 : : : . 29°67 29°88 
MgO. 3 , ; : ’ . 10:02 9°95 
COpae ; : : ; : . 42:28 42-22 
100-15 100°33 
Percentage CaCO, = 52°98 53°35 
+ MeCO, = 21:04 20°89) 
This is from some curious, irregular masses that occur in very coarse 
conglomerates at the base of the Carboniferous series. 
No, 5114. Red Muddy Sandstone. 
TNE. Traeth yr Ora, 
i BE 
Residues insoluble in HCl 4 « 8479 85:03 
Al,O,+Fe,O, . 6 ; : jee Sh! $18 
CaO . 5 . 3 5 ° ; ea) 1°28 
MgO. 5 ee 2-06 
en ee eee Ye Tee ER 352 
99-95 100-07 
Percentage CaCO, = 2°08 2°25 
3 MegCO, = 4-41 4:33 
This is perhaps the most prevalent type of rock in the Old Red 
series. In it occur many beds of cornstone. 
No. 478A. Forsterite Limestone. 
3 .S.L. 500 to 800 feet N.E. of Rhosmynach. At Contour. 
i sit 
Residues insoluble in HCl ' ee Lua BT 44 
PAO ee ha arg ne eas ED 2°35 
¥e,0,. ; ; ; : 5 . 3:03 3°10 
CaO . ; : : : . . 29°05 29°37 
MgO. : : : ; : peeaks 2:27 
EC, Obs ema eae ae eta 25°56 
100°20 100-09 
Percentage CaCO, = 51°87 52-44 
This rock is one of a group of limestones that occur in a highly 
crystalline gneissose complex in the N.H. of Anglesey. They are 
all rich in crystalline silicates (to which is due the high percentage of 
insoluble residues), and among these are pseudomorphs that are almost 
certainly after Forsterite. An analysis of the insoluble residues will 
probably reveal much more magnesium than that which still remains as 
a carbonate. 
Notr.—The analyses completed up to date may be summarised as 
follows:—A series from the Hornfels group, to which it will not be 
