362 R. A. DALY THE OKANAGAN COMPOSITE BATHOLITH 



formation of new rock types, including biotite-epidote-hornblende gneiss, 

 biotite-epidote gneiss, basic hornblende gneiss, biotite schist, hornblende 

 schist, and recrystallized biotite granite-gneisses; in the basic intrusives, 

 development of metagabbro and various basic (dioritic) gneisses and 

 hornblendites. Simultaneous strong folding of the Cretaceous strata. 



5. Either accompanying or following the post-Laramie deformation, 

 the (chonolithic?) intrusion of the Kruger Alkaline body, which consists 

 of nearly synchronous masses of nepheline syenite and malignite. In 

 these at least ten different rock types, due in part to the splitting of an 

 alkaline magma and in part to later rynamic metamorphism, have been 

 recognized. 



6. In Tertiary time the batholithic irruption and complete crystalliza- 

 tion of the soda-rich Similkameen hornblende-bio tite granite, its contact 

 basification forming soda-monzonites and quartz diorites. 



7. In later Tertiary time the batholithic irruption of the Cathedral bio- 

 tite granite, Older phase, accompanied by the intrusion of the Park Gran- 

 ite stock, immediately followed by the injection of the Cathedral granite, 

 Younger phase, within the body of the Older phase. 



8. Eemoval by denudation of much of the cover over each intrusive 

 body. Complete destruction of the Cretaceous cover except at the Pasay- 

 ten Eiver overlap. Certain dikes of olivine basalt injected into the Cathe- 

 dral and other granites are apparently of Pleistocene age and represent the 

 latest products of eruptive activity in the Okanagan range. These dikes 

 are quantitatively of no importance in the development of the composite 

 batholith itself. 



Sequence of the eruptive Bocks 



The summary has been recast so as to show more conveniently the order 

 in which the various intrusions took place. The resulting table also con- 

 tains a column showing the average specific gravity of the rock composing- 

 each eruptive body. These values, as is the case with all values given in 

 this paper, were obtained by the use of entire hand specimens varying in 

 weight from a half pound to two pounds. A large, sensitive bullion bal- 

 ance was found to be specially adapted to the purpose. This method has 

 several advantages over rapid methods in which only small rock fragments 

 are used. The larger the specimen weighed, the greater is the probability 

 that the average density is secured and the smaller the chance for error 

 through adhering air bubbles. A third reason for preferring this method 

 is that the shape of a trimmed hand specimen need never be impaired in 

 obtaining the rock chip usually employed for specific gravity determina- 

 tions. 



