28 



as could be learned) : a heavy blue clay for 30 feet, followed by a bed of coarse 

 gravel, (drift) 18 feet ; clay, sand and gravel blue, 16 feet. These contain small 

 marine shells followed by a thick deposit of tough, blue clay, 150 feet, (contain 

 ing fossils,) the character of the earth below this point has not as yet been as 

 certained, nor have they yet struck the superior strata of the sedimentary rocks 

 a few yards to the north of the well. 



EXTENT OF THE INFUSORIAL GROUP. 



This group of rocks was found as far east as the foot-hills of Sierra San Jose, 

 and continue along the southern base of this part of the chain to the south of 

 the hills on the banks of the Arroyo Peros ; they were also observed among the 

 hills near the Conejo and La Poseto ranches. On the east bank of the Santa 

 Clara River a small deposit was found at an elevation higher by nearly forty 

 feet, than at any point east of this place ; after crossing the Santa Clara River 

 it is not again seen until near the Mission San Buenaventura ; here it again as 

 sumes its usual position as regard altitude and continues thus to the Mission of 

 Santa Barbara. After leaving this locality it is met with as a thick bed cap 

 ping a low ridge in the vicinity of the ranch Coral, and also between the latter 

 place and Paso del Gaviote. In crossing Point Conception the coast assumes a 

 more northerly trend, and the infusorial deposits follow the same line and make 

 their appearance at La Espada in the county of San Luis Obispo, continuing 

 along the line of the same direction nearly to the Bay of San Simeon. Beyond 

 this point I possess no information of its existence or position, until reaching the 

 Bay of Carmel, when it is found nearly continuous to the heavy deposits three 

 miles from the city of Monterey. 



In the County of Santa Cruz these rocks are again met with to the right of 

 the road crossing the Sousal, and also on the north bank of the Pajaro River 

 near the junction of the Pescadero. They are invested by sandstones and slates 

 in nearly every instance in which they are found, and their uniformity in altitude 

 is one remarkable feature attending the entire group. An observance of each 

 and all of their main characteristics may be noticed by one locality, viz : near 

 the town of Monterey, and what is observable here in this particular, will be 

 found a true index to all the rest of the group above alluded to, in any portion 

 of the State. It will be seen from what has been said respecting these rocks 

 that they are general in distribution within the limits of certain districts, hold 

 ing as they do an average height above the sea of about 330 feet, varying at no 

 place so far as known, over 22 feet from this line; the linear extent of the group 

 exceeds 461 miles. Their constancy with respect to the tertiary, miocene, (or per 

 haps later periods) would induce me to apply a name to this group that shall at 

 . once identify it as a marked feature of that portion of the tertiary era to which 

 it may ultimately prove to belong. Its uniformity of character in every partic 

 ular, connected with its extent and associations, fix it as a guiding mark that 

 will serve to separate the group to which it belongs from those that preceded or 

 followed it; I therefore propose the simple term of the Infusorial period, be 

 longing to the tertiaries of California. 



As before observed, the regularity of position and altitude of these deposits 

 leads us irresistibly to conclusions respecting the elevation or depression of this 

 portion of the Pacific coast. The evidences which they furnish are to the effect 

 that since the emergence, there has been but little of those violent disturbances 



