REVIEWS. 
Dre ERUPTIVGESTEINE DES KRISTIANIAGEBIETES. Ie ADS 
FencEBIET IN TELEMARK, Norwecen. By W. C. Bréccer. 
Vid. Selsk. Skrifter IL.M.N.K1. No. 9, pp. 1-408. 1920. 
ie a memoir of four hundred pages, furnished with nearly forty 
mineral and rock analyses, Professor Brégger has added a 
fourth volume to his classic series on the eruptive rocks of the 
Kristiania region. : 
The Fen district of Telemarken forms a small isolated area of low 
relief of approximately 4 square kilometers extent, situated on the 
south-west shores of Lake Nordsjé, and surrounded on its landward 
borders by abruptly rising Precambrian granites. The area is 
best approached from Skien, by canal boat to Ulefos on Lake 
Nordsjé. The occurrence of iron ore and limestone in the Fen 
region had early attracted the attention of Vogt and other workers, 
but the unique significance of the area was not appreciated till the 
discovery by V. M. Goldschmidt in 1918 of microlite, alkali pyroxene, 
and hornblende, as constituents of the limestones. After this dis- 
closure no further incentive was necessary for a more detailed 
investigation of the area, which Brégger has completed in the present 
memoir. 
The rocks comprised within the Fen area include a group of 
magmatic carbonate rocks, intimately associated with alkaline rocks 
showing a variable content of primary calcite. No less than thirteen 
new rock-types have been defined and described from this unique 
area. The characteristics of these new rock-types and their 
associated rocks may precede in description the geological history of 
the Fen region. 
(1) Vubetorte. 
This is the name given to the oldest intrusive of the silicate magma. 
It is a melanocratic, often coarse-grained rock, practically without 
felspar or nepheline, and consisting of hornblende, pyroxene, and 
biotite, and usually rich in apatite (3°51 per cent P,O;) and calcite 
(6:30 per cent CO,). : 
(2) Rocks of the Urtite-Ijolite-Melteigite serves. 
These rocks form a continuous series, consisting essentially of 
nepheline and green pyroxene. The melanocratic member melteigite 
is a new type from the locality Melteig, and characterized as con- 
taining less than 45 per cent nepheline, associated with a green non- 
aluminous pyroxene (in part aegirine-diopside). True jacupirangite 
with an aluminous titanium-bearing pyroxene is not recorded in 
situ. A group of dyke rocks accompany this series, including 
micromelteigites, tinguaites, and melteigite-pegmatites. 
