30 
TERTIARIES OF EUROPE AND AMERICA NOT COEVAL. 
examined, greater similarities will be observed, and tbe now partially connected chain may 
be made a series of uniformly interwoven links ; and wbat an extensively developed series of 
tertiaries will it not prove to be ?—interesting, as well from tbe novelty of its fauna, as from 
its very great thickness, in which latter particular it rivals any known beds. It appears, from 
tbe examination of Mr. Conrad, that there is not one Eocene fossil in tbe 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 tbe 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 
tbe 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 tbe 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 G-aviote 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 sucb attenuated proportions may easily be 
overlooked, and bence it may happen that while, as now in California, tertiary beds are 
declared to exist to the exclusion of the palaeozoic 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 in 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 G-avilan ; 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 
