30 TERTIARIES OF EUROPE AND AMERICA NOT COEVAL. 



examined, greater similarities will be observed, and the now partially connected chain may 

 be made a series of uniformly interwoven links ; and what an extensively developed series of 

 tertiaries will it not prove to be ? — interesting, as well from the novelty of its fauna, as from 

 its very great thickness, in which latter particular it rivals any known beds. It appears, from 

 the examination of Mr. Conrad, that there is not one Eocene fossil in the whole number ob- 

 tained ; and as most of these beds reposed directly on primary or plutonic rock, there is no 

 place for Eocene rocks, and it may yet appear that there are no Eocene beds in the southern 

 counties of California. The eminent naturalist whose report is annexed classes the whole 

 collection as Miocene, and in describing the Santa Inez fossiliferous beds, they have been, with 

 some hesitation, likened to the faluns of Touraine. But the writer believes it to be neither safe 

 nor useful to classify our tertiary beds synchronously with those of Europe. It must ever be remem- 

 bered that tertiary deposits are but local, and cannot, on that very account, be over any extent of 

 the globe synchronous. Their periods of formation and duration bear a certain relation of time to 

 the strata upon which they lie ; but it is not by any means certain that their periods of forma- 

 tion were to any extent cotemporary with congeneric beds in distant continents. 



Almost all the strata are wholly of marine origin ; and though not deposited in very deep 

 waters, yet few were settled where brackish water could exist. The upper sandstone of the 

 Sierra Monica, with its blue calcareous stratum, appears to be the only one which shows an 

 " estuary action in the minute shells of brackish water which are scattered through the mass, 

 and in the fact of the occurrence of a small portion of dicotyledonous wood found included in a 

 nodule of the limestone. A few casts of fucus in the brown sandstone of the Gaviote pass are 

 the only distinct traces of marine vegetation ; and of the flora of that period, with the above 

 exception, not a single trace. The sandstones with lignites, which are found so abundant near 

 the Bay of San Francisco, have had no representatives found out by the survey. 



It is easy, in making out the geological relations of a country or district, to fill in the detail, 

 and apparently so complete the work that but little would seem to be left desired in the future 

 examinations. Does not the history of the science during each year disclose to us the fact, that 

 new strata and even new epochs of geological history are discovered in localities where the 

 'number and frequency of observation would seem to have precluded either error or omission ? 

 A bed of thin power, perhaps a few feet of thickness, is the only representative of what else- 

 where is a few thousand feet in depth. A bed of such attenuated proportions may easily be 

 overlooked, and hence it may happen that while, as now in California, tertiary beds are 

 declared to exist to the exclusion of the palfeozoic strata, future explorations may expose to 

 view all the representatives of our eastern continental slope. Yet this cannot do away or lessen 

 the great fact disclosed \n this survey, namely, that the tertiary period in California was by 

 much the most prolonged, and that in this epoch three distinct periods are well defined : that 

 of the deposition of the brown sandstones, with traces of lignite, as in the sandstones of Monte 

 Diablo and Gavilan ; the calcareous beds of the valleys, as at Santa Margarita ; and the 

 quartzose, bituminous and polythalamous beds of the coast. That these deposits follow each 

 other in chronological order is evident, and may have their representatives, to some extent, 

 along the Atlantic coast, and those who desire to connect periods of deposit may class the 

 Californian tertiaries with those of the southern States ; but as tertiary beds are but local 

 deposits, and are produced by similar circumstances acting under similar conditions, it is, 

 perhaps, hasty to conclude that the tertiaries of both slopes of the continent are coeval ; there 

 is only with certainty implied that the circumstances were similar ; that the conditions and not 



