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University of California . 



[Vol. 2. 



partly because the beds at Horsetovvn had long been thought to 

 belong to Gabb's Shasta group, and had even given the name, 

 Horsetown beds, to the upper division of the Shasta. It is evident, 

 however, from White's somewhat vague definition of the Horsetown 

 beds that the term was meant to include the strata immediately 

 above the Knoxville that contain the fauna so well developed on the 

 north fork of Cottonwood Creek, in the neighborhood of Ono, and 

 which really has no close relationship with this basal Chico fauna 

 of Texas Springs, Horsetown , and elsewhere. The confusion has, 

 doubtless, been increased by incorrect identifications of fragmentary 

 fossils. It is not intended to deny that there are species common to 

 the Horsetown and Chico faunas, but when the formations are 

 properly restricted the number of common species is not as great 

 as I once supposed, and the sandstones at Horsetown and Texas 

 Springs containing the above-mentioned fauna belong to the Chico 

 rather than to the Horsetovvn. 



"This lower Chico horizon is known to occur at a number of 

 localities in Oregon, as facksonville, Grave Creek, and Crooked 

 River, usually resting unconformably on pre-Cretaceous rocks. 

 The beds at the ' '49 Mines ' near Phcenix, Oregon, described by 

 Anderson, probably represent about the same horizon. From the 

 fossils published by Whiteaves it seems that this horizon probably 

 occurs in the Queen Charlotte Islands on the shores and islands 

 of Skidegate Inlet and probably of Cumshewa Inlet, where it has 

 been grouped in the 'lower shales and sandstones' with beds that 

 are considerably older. During the last field season I have seen 

 evidence that it is also represented, though with a different faunal 

 facies, in Los Angeles and Riverside Counties, Southern California. 

 In this region, as at many of the northern localities, it is not 

 accompanied by older Cretaceous beds, thus indicating a general 

 and widespread transgression of the sea upon the land at the 

 beginning of the Chico epoch." 



At Mitchell, about eighteen miles northwest of Spanish Gulch, 

 there is exposed a thick section of sandstone, conglomerate, and 

 shale, lying below an early Tertiary formation. The upper portion 

 of this section is made up of sandstones and conglomerates resem- 

 bling the Chico at Spanish Gulch. The lower beds are shale, 



