280 PETROLOGICAL ABSTRACTS AND REVIEWS 
WorkMAN, RAcHEL. “Calcite as a Primary Constituent of 
Igneous Rocks,” Geol. Mag., VIII (May, 1911), 193-200. 
Blsi2. 
In this short paper is presented a very interesting description of the 
alkali igneous complex on the islands of Alné and Langérsholmen, 
Sweden. The evidence seems conclusive that in this group of rocks 
calcite occurs as a primary constituent; in fact the two chief types of 
igneous rock are nephelite syenite and an almost pure calcite rock. 
Between these two extremes there are all gradations. No definite order 
of crystallization can be observed but the calcite is as a rule the last 
mineral to crystallize. The same minerals occur in the two types of 
rock except that cancrinite, which is abundant in the nephelite syenite, 
is absent where calcite is abundant. 
The author calls attention to other areas of igneous rocks where 
calcite has been described as a primary constituent and discusses briefly 
the possible magmatic history of the mineral. Daly’s theory of the 
absorption of limestone by a subalkali magma does not seem to be 
applicable here for lack of the necessary limestone. H6égbom’s conclu- 
sion is, that the calcite has crystallized from the magma in a manner 
exactly analogous to the other minerals. 
B: R. Lroyp 
