go WARREN DUPRE SMITH AND EARL L. PACKARD 



discordant dips support Diller's contention of distinct formations. 

 Other field evidence indicates an overturning of these formations, 

 making the Galice the older. 



Marine invertebrate fossils from the Gahce formation are the 

 basis for the correlation of these beds with the Mariposa Jurassic 

 of California. The fragmentary remains found in the Dothan re- 

 semble those from the Galice. 



Franciscan Jurassic outcrops along the California-Oregon 

 boundary for a distance of at least ten miles from the ocean shore. 

 This region on the Oregon side, mapped as undifferentiated Jurassic 

 by Diller,' undoubtedly contains Franciscan rocks. They also 

 occur farther north in the Roseburg Quadrangle, where certain sedi- 

 mentary and metamorphic rocks possibly once included within the 

 Myrtle Cretaceous have been called the Dillard^ and correlated upon 

 their lithologic pecularities directly with the Franciscan. It is not 

 improbable that these rocks connect with the Franciscan eighty-five 

 miles farther south. Subsequent work by W. D. Smith^ and by 

 Davis"* confirms the Franciscan age of these beds and adds weight 

 to the prevailing opinion that these rocks are of Jurassic age, and 

 that they are probably either younger or older than the Galice. 



Igneous activity was pronounced during the middle Mesozoic. 

 Various batholithic masses were intruded into the sedimentaries of 

 British Columbia and the Coast states, resulting in regional meta- 

 morphism and often mineralization of earlier rocks, and either 

 initiating or accompanying the uplift of the Sierras, Klamath, 

 Blue, and Wallowa mountains. 



In northeastern Oregon one or more granodiorite batholiths 

 are now exposed as the cores of Wallowa and Blue mountains. 

 Associated with these are diorites, gabbros, and peridotites cutting 

 the pre- Cretaceous rocks of this region. The intrusion of the Siski- 

 you tonolite batholith was preceded by andesitic extrusives and 

 intrusives, and basic rocks now largely altered to serpentines. 

 These extensive intrusions of quartz diorite were later cut by dacite 

 and aplite dikes. Although it is possible to determine the relative 



' S. Diller, op. cit., Fig. 2. ^ G. D. Louderback, Jour. GeoL, XIII, 528. 



■' W. D. Smith, Am. Jour. Sci., XLII, 299. 



'' E. F. Davis, Univ. Cat. Publ., Bull. Geol. Dept., II, 40. 



