106 FLORIDA GEOLOGICAL SURVEY-TWELFTH ANNUAL REPORT 
who have looked more closely it is apparent that such is not the 
case. It is true that the problems of geology are made more diffi¬ 
cult by the lack of frequent and continuous exposures, but they are 
not necessarily made impossible of solution. The numerous stream 
channels, railway and public road cuts, drainage canals, and drilled 
wells afford- records from which the stratigraphic succession and 
structure of formations may, with patience and persistence, be 
worked out. Fortunately many of the formations of the State are 
richly fossiliferous. Nowhere else in the- United States do the 
Tertiary and Quarternary formations contain a more abundant, 
more varied, or better preserved marine invertebrate fauna than 
in Florida. In this respect there is an embarrassment of riches. 
Dr. Dali in his study of the fossils of the Caloosahatchee marl, 
recognized in that formation alone the presence of more than 600 
species of mollusks. Vertebrates, although as a rule not so well 
preserved as the invertebrates, are relatively numerous. No state 
east of the Mississippi, perhaps, contains, so many Tertiary and 
Quaternary vertebrates as does Florida. Fossil plants, although 
less abundant than either invertebrates or vertebrates, are not 
wanting. It is seldom the case that a single formation holds both 
land and marine fossils, yet, something of an insight into the inter¬ 
relation of the marine invertebrates, land animals and land plants 
is secured in the Florida Miocene and again in the Florida Pleisto¬ 
cene. In the study of the fossils Florida is in many respects a 
State of exceptional opportunities. 
TOPOGRAPHY 
In topographic details and surface configuration Florida is by 
no means lacking in variety. In this respect the State presents 
much greater diversity than would have been anticipated in view 
of the fact that the maximum elevation within the State scarcely 
exceeds 300 feet above sea level. In the upland section of the 
State the intimate relation between topography and geology be¬ 
comes apparent. The limestones under the influence of a heavy 
rainfall and an excess of humic acids in the ground water have 
dissolved rapidly, and when lying near the surface have produced 
a characteristic topography. The lowlands bordering the coast, 
on the other hand, have been but little affected by erosion, and in 
