398 
SECOND REPORT- 1832 . 
that tertiary deposits occur in Maryland; but I am not aware 
that they have been recently explored. 
With regard to the West Indian Islands, Jamaica has been 
fully described by De la Beche; and De Jonne’s Histoire 
Physique des Antilles Franpaises contains much geological in¬ 
formation. As to South America, the completion of that part of 
Humboldt’s Travels which relates to Peru is announced ; while 
on the eastern side we have the works of Spix and Martius *, 
and of Pohl describing the structure of the Brazils : at the 
southern extremity of the continent Capt. King has observed 
chalk and green-sand in Patagonia near the Straits of Ma¬ 
gellan. 
Having thus cursorily reviewed the great progress of what may 
be termed geographical geology during the last few years, we 
have to advert to those particular branches which, from their 
especial development within this period, and peculiar relations, 
appear to demand a distinct consideration. 
And here we may first notice the great advancement of the 
history of the tertiary series of formations,—an advancement 
which does not merely consist in multiplying details, but in 
tracing the precise facts which mark an epoch perhaps the 
most important as to geological theory, in as much as the geolo¬ 
gical causes then acting, evidently most nearly approximated to 
the physical circumstances still operating under our own ex¬ 
perience and observation; and the former appear to have passed 
into the latter, not by an abrupt leap, but by a gradual transi¬ 
tion. We shall be more sensible of the importance and extent 
of the additions thus introduced, if we remember how short 
a period has elapsed since every geologist used to talk of the 
tertiary formations of London and Paris as the very youngest 
* These geologists describe a sandstone, considered by them as equivalent to 
the German keuper, as prevailing in the basin of the Amazons; and they assign 
the same formation, as the matrix of the diamond mines, a near approximation 
to the geological site of the Indian mines of this gem ; the sandstone of the plains 
of Paraguay is however said to be tertiary molasse. 
f The discussions by Prevostand De Serres, whether the succession of those 
formations, and the alternation of marine and fluviatile beds indicate such an os¬ 
cillation in the level of the surface as may have caused reiterated elevations of the 
ocean, so as repeatedly to submerge again continents once abandoned, or whether, 
on the contrary, an uniform and constant depression of the oceanic level, so as to 
convert oceanic basins successively into gulfs and asstuaries, (the character of whose 
waters varied as the tidal inundations of the ocean or land floods prevailed,) and 
into lakes generally of fresh water, (but still so situated as to be exposed occasion¬ 
ally to the incursions of still neighbouring seas,) can only be shortly alluded to in a 
Report like the present, but require to be studied at length by every one in¬ 
terested in the subject ; the same remark will apply to the views of De Serres 
on the distinctions of the tertiary basins which appear to have been originally 
connected with the ocean, and those dependent on the Mediterranean. 
