336 CALIFORNIA ACADEMY OF SCIENCES. 



In favor of nonconformity is the difference in the fauna, 

 several of the extinct forms of the lower beds, as Scutella 

 interUneata Stimp., Cre^idiila grandis Midd., Vemis -pa 

 jaroensis Con., and others, not occurring in these upper 

 beds. Also differences in the strata, the entire absence 

 in the upper formation of the conglomerates and sand- 

 stones which ring when struck with a hammer, and which 

 are abundant to the very top of the lower formation. 

 Slight structural differences, for while the lower beds 

 range in dip from 35° to 78" and over most of the expo- 

 sure are between 65° and 75° the upper beds will only 

 range from 5° to 30°, though locally rising to 40" and 50° 

 in one or two places. Further, while in some places the 

 strike of the strata is nearly the same, at the point of con- 

 tact there is a marked change of nearly 90°. The strike 

 which along the landslide is practically the same as the 

 course along the beach, just south becomes nearly at 

 right angles to the beach. This difference may be influ- 

 enced by but is not due to the landsliding, the change 

 being very marked in the cliff back of the slide. It was 

 found impossible to correlate strata of the upper and lower 

 formations. The manner, for example, in which the up- 

 per gasteropod beds run under the beach and do not ap- 

 pear again can only be explained by a nonconformity or 

 a fault. The same thing is true of the bed exposed in 

 the bluffs back of the slide. There seems, therefore, to 

 be good evidence of either a fault or nonconformity or 

 both at the south end of the long landslide. Some of the 

 evidence is best explained by a fault and some by a non- 

 conformity. In Twelve-Mile Creek the contact appears 

 to be near a fault. 



The third area, from Redwood City southward, gives 

 the following list of fossils : 



