92 North American Eastern Tertiary — Meyer. 
jection is usually raised. If we look at a geological map of the 
U. S., we see that we come from older -formations to younger 
ones, when we go from the interior towards the gulf of Mexico; 
we pass paleozoic, older mesozoic, Cretaceous and Tertiary 
formations and finally the Grand Gulf; the nearest to the Gulf, 
must be the youngest one, evidently all formations slope down- 
wards towards the gulf. This observation, however, does not 
invalidate the assumption, that the Grand Gulf existed as an 
island or a peninsula at the time when the Old-Tertiary deposits 
were formed. If we suppose that all the formations in un- 
broken succession were deposited in the gulf and gradually up- 
lifted in the way the above objection assumes, then we ought 
to have the following succession: i, marine mesozoic forma- 
tions; 2, marine Old-Tertiary; 3, marine Miocene; 4, marine 
Pliocene or post-Pliocene; a succession which may be found 
on the Atlantic coast. In place of No. 3, we have now the 
Grand Gulf formation. This is not marine and is unlike the 
Tertiary north of it. If there was nothing but a continuous 
deposition in the gulf, and an uplifting afterwards in concentric 
formations why was the process of forming sands, clays and 
limestones teeming with marine shells suddenly interrupted at 
the end of the Old-Tertiary period? And why were thick 
strata of sandstones, massive clays etc., deposited, in which 
not a single marine shell, but as yet only a few fresh water shells 
have been found? From the former general point of view 
I cannot find any real explanation, and those explanations 
which have been ventured [before the presence of fresh- 
water shells was knownj need only be cited* to create a sus- 
picion that there must be a mistake somewhere. 
We have thus very little knowledge of the stratigraphy of the 
Tertiary in Texas, Louisiana and Mississippi. In Alabama, 
however, the Geological Survey under Prof. E. A. Smith, has 
brought to light many facts, the main substance of which has 
been published in the Bulletin I of that survey. The possibility 
of error in this field is so large that one or more mistakes may 
have been committed in the work of the survey, but in general 
one cannot fail to see the great care which has been exercised 
> See Am. Journ. Sc, Dec, 1885, 12th, and 13th, pages of article. 
