Reviews—Zircon, Monazite, etc. 523 
material in the neighbourhood. The age of the mountain is quite 
uncertain ; it may be post-Karroo, as a fragment of rock, probably 
of Karroo age, was found in the vent, but this is by no means 
proved.—W. H. W. 
IV.—Zrrcon, Monaztrz, and orHEeR MINERALS USED IN THE PRo- 
DUCTION oF CHEMICAL CoMPOUNDS EMPLOYED IN THE MANUFACTURE 
oF Ligeutine Apparatus. Bull. No. 25, North Carolina Geological 
Survey. 1916. 
TP\HIS publication with a clumsy title contains a very interesting 
account of the occurrence and exploitation of the large number 
of rare-earth minerals that are now used in the manufacture of 
incandescent gas-mantles and filaments for electric lamps. The 
minerals now used on a large scale for these purposes are monazite, 
zircon, gadolinite, columbite, tantalite, and wolframite. Other 
minerals capable of being used for the same purposes if found in 
sufficient quantity are also dealt with. As is well known, many 
of them are found in considerable quantity in North Carolina, 
especially monazite and zircon. The processes employed in mining 
and manufacture are also described in an attractive manner.—R. H. R. 
V.—Grotocy oF THE CranBrook Map-area, British Cotumpia. By 
S. J. Scnorrerp. Canada, Dept. of Mines, Geological Survey 
Mem. 76. pp. 245. Ottawa, 1915. 
{J\HE area described in this memoir consists mainly of the central 
_ portion of the Purcell. Range, an area that once formed the 
western flank of the ancient Rocky Mountain geosyncline. A detailed 
account of the Purcell Series (of Beltian age) and of the well-known 
Purcell and Moyie sills is given. On the east the Purcell sediments 
continue underneath an unconformable blanket of Palaeozoic forma- 
tions, while to the west there still remain patches of pre-Beltian 
schists that seem to be relics of the parent land from which the 
Purcell Series was derived. The Purcell sills consist of hornblende 
gabbro accompanied by irregular masses of hornblende granite, and 
with the latter copper deposits of some importance are associated. 
However, the area owes its economic prosperity more particularly 
to the presence of valuable silver-lead deposits associated genetically 
with small stocks of granite that for the present are thought to be of 
Jurassic age. The memoir is copiously illustrated with thirty-three 
plates and is accompanied by a coloured geological map.—A. H. 
VI.—THE Grorocy or Paranyspa anp Rio Grande po Norte, 
Brazit. By R. H. Soper. Proc. Am. Phil. Soc., vol. li, pp. 1-20, 
1916. 
ITH the exception of a narrow belt along the coast and a few 
isolated patches of the interior, the whole of the two states is 
made up of the crystalline rocks known broadly as the Brazilian 
complex. This consists of gneisses and schists thickly threaded with 
quartz veins and pegmatites, and intruded upon by numerous bosses 
of granite which form the axes of the principal serras. Along the 
