396 J. S. DILLER THE JURASSIC FLORA OF OREGON 



continuous cover over the older rocks of the southern portion of the Ivla- 

 math mountains. 



This is demonstrated by the fact that the Shasta series of the Sacra- 

 mento valley area extending northwest laps up over the crest of the Coast 

 range (Klamath mountains) into the head of the Hay Fork country of 

 Trinity river, where there are a number of small intermediate masses^^ of 

 sandstone and conglomerate between those of Kattlesnake creek and Eed- 

 ding creek, showing that they were once connected by a continuous mass 

 and joined across the crest of the range with the main mass of the Shasta 

 in the Sacramento valley. 



During the time the Shasta and Chico were deposited the Pacific border 

 of the continent was subsiding and the sea transgressing the land. There 

 may have been interruptions, perhaps slight elevations at several horizons 

 within the epoch, as between the Knoxville and the Horsetown, which are 

 locally unconformable, but the general movement was downward, with an 

 advancing sea and successively newer marine deposits overlapping the 

 earlier land.^- 



At the base of the "Myrtle formation" in Oregon there is an important 

 unconformity and a decided overlap. The successively newer, overlying 

 strata of the "Myrtle" in general lap over farther and farther inland 

 beyond the limit of the older strata of the same series, just as the mem- 

 bers of the Shasta series do in California. Furthermore, the lower por- 

 tion and the greater part of the "Myrtle formation" is characterized by a 

 fauna in large measure identical with that of the Knoxville beds, while 

 the top part contains a fauna closely related to that of the Horsetown 

 beds. There -is good reason, therefore, for regarding the Shasta series of 

 California and the "Myrtle formation" of Oregon as equivalent. 



DiSTKIBUTION . OF THE ShASTA FlOEA IN THE "MyRTLE FORMATION" 



OF Oregon 



In the "Myrtle formation" of Oregon there are two floras, the "flora 

 of the Shasta" series and the "Ji;rassic flora of Oregon." They have not 

 yet been definitely found together and their geographic distribution is 

 significant. 



The flora of the Shasta series has been reported by Ward and Fontaine 

 in the vicinity of Kiddle, Oregon, in a mass of the "Myrtle formation" 

 connecting directly on the strike with that of the type locality on ]\ryrtle 



" O. H. Hei-shey's geological map of part of tbe Klamath mountains. Unpublished. 

 " Bulletin of the Geological Society of America, vol. 5, p. 453. 



