FINANCIAL STATEMENT. The following is a summary of the expenditures of the Survey for the year ending June 2, 1908: SKETCH OF THE GEOLOGY OF FLORIDA. A scientific study of the mineral industry is necessarily based upon a knowledge of the geology. The summary of the geological features of the State is given briefly at this time since the subject will be dealt with in more detail in a later bulletin to be issued by the State Survey. Florida lies within and is a part of the general coastal plains deposits of the United States. These embrace a strip along the Atlantic and the Gulf coasts, varying in width and covering the eastern part of New Jersey, Delaware, Maryland, Virginia, North Carolina, South Carolina, Georgia and all of Florida, as well as much of the southern part of Alabama, Mississippi, Louisiana, and Texas. The formations of the coastal plains are sedimentary, containing much clay, shale, limestone and sandstone, and lie nearly horizontal or with but slight dip. The sediment making up these deposits, except the organic material of the limestone, came from higher lands to the north and west. The sea occupying the present position of Florida, was in early time remote from sources of sediment; so that the proportion of wash from the land was much less here than nearer the original shore line. This clear sea was favorable to the existence of an abundant shell life, their remains accumulating to form lime rock. Hence, in the Coastal Plains section, Florida is exceptional in the large amount of limestone that it contains. In its general geology, Florida is of comparatively simple structure. The rocks are all of sedimentary origin, no igneous or greatly metamorphosed rocks occurring within the State. The strata lie for the most part, either horizontally, as formed, or with a slightly accentuated dip, and have suffered no great distortion such as often characterizes the rocks of a mountainous country. These sedimentary formations consist of limestones, sandstones, shales and clays. The underlying foundation rock throughout the State, being a massive and very thick limestone. Formerly it was believed that the greater part, if not 2-GeoRepl all of the State of Florida, was of coral formation. This view was founded upon the observations of Louis Agassiz and Joseph LeConte. The first publication on the subject by Agassiz appeared in 1852 as an appendix to the report of the Superintendent of the United States Coast Survey for the year ending November, 1851. Agassiz believed that not only the extreme south Florida and the Florida Keys were of coral formation, but that the Peninsula as far at least as the 28th degree of north latitude was of similar origin. LeConte's paper appeared in 1857, and to the conclusions of Agassiz1 added the theory that the keys rested upon a substructure of inorganic sediment carried by the Gulf Stream. Previous to these publications the true character of the limestone of the mainland had been recognized and described by several observers. J. H. Allen, in 1846, described the limestone outcropping in the vicinity of Tampa.2 During the same year T. A. Conrad publishes two papers on these formations, giving in the second paper a description of a number of the fossil shells contained in them.3. Tuomey in 1851 concurred in Conrad's reference of the Tampa formations to the early Tertiary.4 Bailey collected fossil foraminifera during the winter and spring of 1849-505 from a locality forty miles west of 10n the agency of the Gulf Stream in the formation of the Peninsula of Florida. Joseph LeConte, Am. Assoc. Adv. Sci. Proc. X, 103-119, pt. 2, 1857. 2Some facts respecting the Geology of Tampa Bay, Florida. J. H. Allen, Am. Jour. Sci. (2), vol. I, p. 38-42. 1846. 3Observations on the Geology of a Part of East Florida, with a catalog of Recent Shells of the Coast. T. A. Conrad, Am. Jour. Sci. (2), II, 36-48, 1846. 4Notice of the Geology of the Florida Keys and of the Southern Coast of Florida. Tuomey, M. Am. Jour. Sci. (2) voi. XI, 390-394, 1851. 5 Microscopical Observations made in South Carolina, Georgia and Florida. Smithsonian Contr. Knowl. II, No. 8, 48 pp. 1851; Am. Jour. Sci. (2), XI, p. 86, 1857. Palatka and recognized the formation as the "White Orbitulite (Orbitoides) Limestone". The views of Agassiz and LeConte gained wide circulation and were for a generation the accepted views as to the origin of the peninsula. The credit for again establishing the true character of the limestone of the interior of Florida is due to Professor Eugene A. Smith, State Geologist of Alabama. Professor Smith's paper appeared in 1881, his observations on the geology of Florida having been made during the previous year, while acting as special agent for the cotton culture report of the 10th Census.* While the observations made by Smith were not sufficiently detailed to permit of a differentiation of the several formations occurring in the interior of the State, his conclusions as to the history of the formation of the peninsula were substantially correct. The Florida deposits are all of comparatively recent date geologically. The place of the formations as now known in the geological time scale is indicated by the table given on the following page. The Archeozoic at the bottom of the table is the oldest of the large time divisions; the Cenozoic at the top, is the latest. Similarly the Eocene is the oldest division of the Cenozoic, while the Pleistocene is the most modern and leads up through recent formations to the present time. The oldest formation known in Florida is the Vicksburg Limestone, which is believed to belong, as indicated by the table, to the Oligocene division of the Cenozoic. The conditions under which this limestone was formed were, as indicated by the rock itself, as follows: A clear sea of medium depth free from land sediment in which marine life, especially the minute organisms known as the foraminifera, abounded, the shells of these small animals, along with larger shells, making up the limestone. Of the many fossils occurring in this limestone the most *Am. Jour. Sci. (3) Vol. XXI, pp. 292-309, 1881. TABLE OF GEOLOGICAL TIME DIVISIONS, SHOWING FORMA- Lafayette formation, Chesapeake Miocene. Upper Oligocene (Chattahoochee and Chipola groups), Lower Oligocene, (Vicksburg and Ocala Limestones.) the It is probable that Eocene occurs in Florida underlying the Oligocene at some considerable depth. This inference is based on the occurrence of Eocene limestone to the north and west which dips toward the south beneath Oligocene limestone. It is possible also that Cretaceous rocks occur at still greater depth below the Eocene. There is at present no basis on which to judge the presence or absence of yet older formations beneath the Florida peninsula with the possible exception of the Archeozoic, which is presumably world-wide in its Occurrence. |