SOUTHERN CALIFORNIA ACADEMY OF SCIENCES. 83 



Large areas in Butte, Lake, Shasta and other counties lying 

 north of the Bay Region ; and in Contra Costa, Alameda, and 

 other counties south of that region, and on the eastern slope of 

 the Coast Range nearly the entire length of the San Joaquin 

 Valley show cretaceous strata, and prove their submersion at 

 that time. 



In Santa Barbara and the northern portion of Ventura, there 

 is undoubted evidence that the entire region during the Creta- 

 ceous Age was submerged to a great depth. 



In the southeasterly portion of Santa Barbara County, at 

 an elevation of seven thousand feet above the sea, the writer 

 found well preserved shells of cretaceous age, Ammonites, Au- 

 cellas, Dentaliums, etc. 



Allowing for the erosion of past ages, since the mountains 

 were uplifted, and for the depth of their submersion while being 

 formed, it is probable that an elevation of at least two miles 

 above sea level has occurred at that point. ("Pine Mountain of' 

 Santa Barbara"). 



The estimated depth of the deposit is "at least twenty-five 

 thousand feet," ^ thus indicating for the lower portion of the 

 deposit, which is exposed at some distance easterly, an elevation 

 of five or six miles, without taking into consideration the depth 

 of the water in which the deposit was made. 



In San Benito County, on the eastern side of the Mt. Diablo 

 Range, there is an exposed thickness of twenty thousand feet 

 of rocks of this age. 



Thus it will be seen that the Pacific Coast of that time was 

 probably connected with,, and was practically a part of Asia, a 

 Avide sea separating it from the portion of the present conti- 

 nent east of the Wahsatch Mountains ; while Florida, Texas, 

 New Mexico, Louisiana, Alabama, Georgia, Mississippi, Indiar) 

 Territory and other portions of the country now lying south 

 and east of the confluence of the Ohio and Mississippi rivers 

 were submerged, together with portions of Colorado, Wyoming. 

 Montana, Nebraska, Dakota, and a large portion of Western 

 Canada, and the Pacific Ocean extended to the foothills of the 

 Sierra Nevada Mountains. 



We now come to what the late Professor Joseph Le Conte 

 termed "one of the Critical Periods of the History of the Earth." 



These Critical Periods he defines as "periods of very general 

 readjustment of the crust of the earth, and therefore of wide- 

 spread changes in physical geography, so great and so general 

 as to affect profoundly and widely the climates of the earth. 

 These physical changes, in their turn, gave rise to still more 



Fairbanks in "Geology of the Coast Ranges." p. 95. 



