Fig. 21.—Diagrammatic sketch of geologic structure of Florida from north to south passing through the hard rock and pebble phosphate fields, showing relation of the phosphate deposits to the underlying formations. After Sellards.
The genus Hipparion is not confined to the Tertiary. Teeth have been discovered in the Aftonian of Iowa (Hay, Geol. Surv. Iowa, vol. XXIII, p. 150) and in Missouri (op. cit., p. 149). The writer has described a species of the genus, Hipparion cragini, collected by Professor Cragin in the Sheridan beds in Kansas (Kansas Univ. Sci. Bull., vol. X, p. 42).
One may be justified in suspecting that Procamelus lived on into the Pleistocene. Not only has it been found associated with Pleistocene fossils in five places in Florida—Archer, Williston, Dunnellon, Hernando, and Ocala—but it has been met with in possible Pleistocene deposits (the Idaho formation) in Idaho, which furnishes Equus, Cervus, Castor, and Stegomastodon mirificus (the type of which belongs in the Sheridan beds). Furthermore, the writer has had occasion to describe a collection of fossils, believed to belong to the early Pleistocene, which was obtained at Anita, Coconino County, Arizona. Among these fossils are two species of Procamelus much like those described by Leidy from the Alachua formation (Proc. U. S. Nat. Mus., vol. LIX, pp. 622–626). The writer believes that the genus Procamelus persisted into the early Pleistocene.
Two species of rhinoceros have been collected in the Alachuan formation, Teleoceras proterus Leidy and Aphelops longipes Leidy. Both occurred at Archer, while T. proterus was found near Williston and A. longipes at Dunnellon. A rhinoceros has been discovered in the Idaho formation, with the Pleistocene species named above in connection with Procamelus of these beds. In Oregon Cope made a collection which has been examined by Dr. W. D. Matthew (Bull. Amer. Mus. Nat. Hist., vol. XVI, p. 321). Here again Teleoceras was supposed to have been found with Hipparion, camels belonging to Camelops (or Procamelus), Elephas, and Equus. Matthew thought that there had happened, either before the fossils were collected or afterwards, a mingling of elements of two distinct faunas.
To the writer it seems improbable that the commingling of Procamelus and the rhinoceroses with Pleistocene forms should occur thus accidentally so often and at such widely removed localities. It appears more probable that these Tertiary genera did not become extinct so early as has been supposed and that the association was not a secondary one. The association is what might be expected in collections made in deposits of the earliest Pleistocene.
It must not be forgotten in these discussions that the Pleistocene genera and species with which the collections in question are being compared are those of the so-called Equus beds, which appear to represent the fauna of the first interglacial stage. This, however, was preceded by the Nebraskan, the first glacial, which probably occupied a long period of time; possibly it was half as long as all the rest of the Pleistocene (Chamberlin and Salisbury, Geology, vol. III, p. 383). About the vertebrate life of this long stage we know as yet very little. The writer is quite convinced that the Idaho formation and the Alachua, or Bone Valley, belong to the earliest Pleistocene.
Marion County.—In a fissure in the limestone-rock quarry at Ocala there has been found an important collection of vertebrates. The following list is thought to include all that have been reported:
A part of this list was published by Sellards in 1916 (8th Ann. Rep. Florida Geol. Surv., p. 103). The tortoises were described in the same volume.
Inasmuch as Trucifelis floridana has been found in the Pleistocene at Vero, Florida, one may safely regard the specimen found at Ocala as also of Pleistocene age. All of the other mammals are admitted to be of Pleistocene age except Procamelus minimus. The fissure may have been open during some part of the Nebraskan stage.
Volusia County.—At Daytona, situated on the east coast, therefore on the youngest terrace, remains of Mammut americanum (p. 122) have been found. At DeLand there has been recovered the skull of a dolphin which Sellards (8th Ann. Rep. Florida Geol. Surv., p. 107, plate XIV) has described as Globicephalus bœreckii (p. 20). It was found at a depth of 10 feet, in sands which overlie Pliocene shell marls. The sands are regarded as belonging probably to the Pleistocene. DeLand is on the Tsala Apopka terrace. At a depth of 10 feet there was reached the supposed marine base of this terrace.
Orange County.—As stated on page 196, a tooth of an extinct horse was found somewhere in the county.
Pinellas County.—On the western shore of Tampa Bay (p. 159), near St. Petersburg, at Indian Rock, a tooth of Elephas columbi was found.
Hillsboro and Manatee Counties.—The region around Tampa Bay is important because of the wealth of vertebrate fossils dredged up by the collectors of phosphate rock from the beds of Hillsboro, Alafia, and Manatee Rivers. Unfortunately, few accurate records have been kept of localities and conditions of occurrence of the fossils, and we usually know only that a collection was made in a certain river, perhaps not so much as that. For that reason it is concluded to group together all the fossils regarded as Pleistocene and known to have been found in Hillsboro, Manatee, and Sarasota Counties. In order to indicate as far as possible the localities, the names of the species are followed by contractions which apply as follows.
The bones of man belonged to the skull and are as completely fossilized as the bones of a horse and are wholly free from organic matter.
Among the mammals of this list there are no genera and few species that have not been found in the Pleistocene at many places in the United States. The presence of Elephas imperator and three species of Equus and Chlamytherium apparently indicate Pleistocene of about Aftonian times.
From Palma Sola, Manatee County, there have been sent to the U. S. National Museum by Mr. Charles T. Earle many specimens of fossil vertebrates, found at various times washed up on the beach. Some belonged evidently to deposits older than the Pleistocene, probably to Miocene, and included teeth of sharks, a beak of a platanistid porpoise, and a lower tooth of a sirenian, Metaxytherium floridanum. Other specimens, as bones of a camel, parts of the shells of tortoises, alligator or crocodile teeth and bones are of uncertain age. Ten species of the list are referred to the Pleistocene. All of the teeth are isolated, but many are well preserved and little water-worn. The bones are mostly fragmentary, some worn, some not.
Polk County.—On page 159 is an account of a tooth of an elephant. Elephas columbi, reported as being found at Kingsford, Polk County, under 19 feet of phosphate rock and sand. It may belong to E. imperator. On page 196 is detailed the finding of several teeth of Equus in the phosphate mines of Kingsford. The species E. leidyi and E. littoralis are recognized. Unless these elephant and horse-teeth had been incorrectly reported or had been secondarily introduced into the phosphate beds, they are, in the writer’s opinion, to be referred to the first glacial stage, the Nebraskan. Dr. W. H. Dall has somewhere reported the finding of tusks at Bartow; these were supposed to have belonged to Elephas columbi (p. 180). At Nichols the large land-tortoise Testudo hayi Sellards has been recovered from a phosphate mine. From phosphate mines at Brewster has been secured the following list of vertebrates, obtained from Dr. Sellards’s reports (Florida Geol. Surv., vol. VII, pp. 100, 106, 108; vol. VIII, pp. 95, 96, 98, 100).
All of this list are referred by Sellards to the upper Miocene or lower Pliocene. The writer regards them as belonging to the first stage of the Pleistocene.
From a phosphate pit at Christina, Sellards (Florida Geol. Surv., vol. VII, p. 106, fig. 35) has reported a tooth of an undetermined species of Gomphotherium.
Sellards (Florida Geol. Surv., vol. VII, pp. 72, 110) has reported the collection of remains of Hipparion sp. indet. and of Teleoceras proterus (p. 211) from phosphate mines at Mulberry. In the U. S. National Museum are undetermined remains of Gomphotherium from the same place, sent in by Matson.
Brevard County.—In the Hopkins drainage canal at Eau Gallie have been found remains of Equus complicates (p. 196) and Elephas columbi (p. 159).
Zolfo, Hardee County.—At Zolfo, near the border of the Bone Valley area, have been found Megatherium (p. 38) and Elephas columbi (p. 160).
De Soto County.—With one exception, apparently, fossil vertebrates have been discovered in De Soto County only in deposits along Peace Creek. The exception is a place called Tourner’s or Turner’s, on Caloosahatchee River. The elephant found there will be considered among the fossils found in Lee County. At Calvenia, at the entrance of Charlie Apopkee Creek into Peace Creek, Equus leidyi (p. 198) has been secured.
Most of the fossils found below Calvenia are accredited to Arcadia. According to Leidy (Trans. Wagner Inst., vol. II, p. 19), those of his list were found on a sand-bar at Arcadia; but certainly others have been taken from phosphate rock dredged both above and below the town. As complete and as accurate a list as the writer has been able to prepare is here presented.
Peace Creek, or Peace River, has been the source of many fossil vertebrates, the greater part of them obtained at or near Arcadia. Most of the species were described by Joseph Leidy in 1889 (Trans. Wagner Free Inst., vol. II, pp. 19–31). The region was examined by Dr. W. H. Dall, whose report was published in 1892 (Bull. 84, U. S. Geol. Surv., pp. 128–133). He referred the bed bearing vertebrate fossils to the Pliocene. Cope (in Dall’s report, p. 130) regarded them as equivalent to the Equus beds of the Great Plains, or between these and the Loup Fork. Sellards (Florida Geol. Surv., vol. VII, pp. 78–83) places the formation in the Pleistocene.
Of all the genera and species of mammals and reptiles appearing in the list, there is none that it is necessary to suppose was derived from Pliocene deposits, or even from those of a Pleistocene stage earlier than the first interglacial. The marine fishes and sharks have been derived possibly from the Arcadia marls. On the other hand, the presence of Elephas imperator, the species of Equus, Hipparion, Glyptodon, Chlamytherium, and the gigantic tortoise Testudo crassiscutata furnishes evidence that the age was about that of the Equus, or Aftonian, beds of the Great Plains.
St. Lucie County.—At Fellsmere, a place near the northern border of the county and about 10 miles west of Indian River, teeth of both Elephas columbi (p. 159) and Mammut americanum (p. 122) have been found, in the construction of drainage canals.
The most important locality for Pleistocene fossils in St. Lucie County, one may say in the whole State, is Vero. The topographical, geological, and palæontological conditions found here are described in the Eighth and Ninth Annual Reports of the Florida Geological Survey. Papers on the subject may be found also in the Journal of Geology for January 1917 and for October 1917; also in the American Anthropologist for the first and second quarters of 1918. Besides the large number of species of vertebrates found here, the interest is heightened by the fact that, associated with these, are human bones and objects of human manufacture. Through the valley of an insignificant stream was dug a large drainage canal, the construction of which brought to light vertebrate bones and teeth. Three beds of Pleistocene materials were exposed. At the bottom is found a bed of marl filled with marine mollusks and which is the geological equivalent of the coquina rock at St. Augustine. The same deposit is found in various places along the coast and has received from Dr. Sellards the name Anastasia formation. Above this lies a stratum composed mostly of sand, but containing also some muck. In the discussion of the locality this bed is designated as No. 2, the marl being No. 1. No. 2 has a thickness of about 2 feet. It in turn is overlain by No. 3, which consists mostly of vegetable matter and sand. It is called also the muck-bed. In places the muck is replaced by a bed of marl, which here and there may become pretty firmly consolidated. The thickness of No. 3 is about 2 or 3 feet. Vertebrate fossils are found in both No. 2 and No. 3. It is the purpose of the author first to present lists of the fossils which have been found in each of the upper beds, beginning with the stream of sand, No. 2.
Besides those remains which are to be assigned with certainty to one or the other or both of the strata, there are a few others about whose place in the deposit there is uncertainty:
At a point about 3 miles west of Vero, a lower jaw of Elephas imperator (p. 163) was found in the bank of the drainage canal. It was embedded in a matrix of brown sand which rests upon the stratum of marine shell marl.
The list of mammals found in stratum No. 2 shows that there are 29 species and that 21 of these are extinct. This high proportion of species no longer existing is of itself enough to show that the deposit is an old one. Again, such species as Elephas imperator and camels occur in the glaciated region only in Aftonian beds, and outside of the glaciated region only in those which are quite certainly of approximately the same age.
In the list of species found in stratum No. 3 there are 25 mammals, of which 12 species are extinct. These form, therefore, 48 per cent of the whole, indicating apparently a more recent geological time, perhaps about the Sangamon stage. It is true that the geologists hold that there has been continuous deposition and that no interval elapsed between the laying down of No. 2 and No. 3. In a region so near to the level of the sea, where the streams are small and short and have little fall, deposition must have gone on with extreme slowness; hence there may have been no period when deposition ceased. Apparently, too, there was a time when the region was somewhat lower than at present and salt water came up the stream as far as the locality where the fossils are found. The presence of Chelonia mydas, Caretta caretta, the two species of Caranx and Aëtobatis narinari may thus be explained.
The fresh-water and terrestrial mollusks of stratum No. 2 were submitted to Dr. Paul Bartsch, of the U. S. National Museum, who has reported on them (Rep. Florida Geol. Surv., vol. VIII, p. 144). He lists 29 species, all living.
The marine mollusks found in the stratum called No. 1, and which the writer refers to the first glacial stage, have been studied by Mr. W. C. Mansfield, of the U. S. Geological Survey (Rep. Florida Geol. Surv., vol. IX, pp. 78–80). Seventy-four species are specifically determined, and of these 61 are identical with living forms. Three or four species are possibly extinct. There is no question that the deposit belongs to the Pleistocene.
Nearly all of the plants were found in the bed designated as No. 3, the upper or muck-bed. These were studied by Dr. Edward W. Berry, of the Maryland Geological Survey. His report, published in 1917 (Rep. Florida Geol. Surv., vol. IX, pp. 19–33), states his conclusion that the plants belong to the late Pleistocene, either the Peorian or the Late Wisconsin. It may be stated that Dr. Berry adopts the theory that the terraces supposed to be found along the Atlantic Coast were formed during stages of submergence beneath the sea, the lowest one late in Pleistocene time.
Lee County.—The whole of Lee County is occupied by Pleistocene deposits which form a part of the Pensacola terrace. Naturally the Pleistocene is overlain, generally, at least, by accumulations of Recent materials, and it may not always be easy to distinguish the one from the other. So far as the writer knows, all the vertebrate fossils discovered in this county have been collected along Caloosahatchee River above Fort Myers. The geology of this river has been described by Heilprin (Trans. Wagner Inst., vol. I), Dall (Bull. 84, U. S. Geol. Surv., pp. 142–145), Matson and Sanford (Water Supply Paper 319, pp. 134–138), Sellards (2d Ann. Rep. Florida Geol. Surv., p. 123, 6th Ann. Rep. Florida Geol. Surv., pp. 41–46). The Pleistocene is underlain by Pliocene marls and hard and soft limestones and consists of beds of muck, marl, and sand of little thickness. At Labelle it is said (Sellards, 2d Ann. Rep., p. 126) that there is a fossiliferous Pleistocene marl covered by 3 feet of sandy loam. The following seem to be the species which have been found in the Pleistocene in this region:
The presence of Elephas imperator is an indication that the deposits belong to the early part of the Pleistocene. None of the species appear to indicate an older stage than the Aftonian.
Dade County.—Sellards (8th Ann. Rep., p. 106) records that some fragmentary remains of a proboscidean had been found in Miami River, Dade County.
Palm Beach County.—On page 105 of the report just cited, Sellards stated that Elephas columbi (p. 160), Mammut americanum (p. 123), Equus complicatus (p. 200), and Bison sp. indet. (p. 264) had been found in the Palm Beach Canal, constructed to drain the Everglades.
At some unknown point in the Everglades, possibly in Lee County, there was found many years ago a tooth of an elephant which the writer believes belonged to Elephas imperator, already mentioned on page 163. It was formerly reported as E. columbi.
An account of the Quaternary formations of Alabama may be found in Eugene A. Smith’s “Report on the Geology of the Coastal Plain of Alabama.” This was published in 1894, and the part pertaining to the Pleistocene is found on pages 28 to 65. Along the coast Smith recognized the presence of a formation which he called the Biloxi. The upper part of this was regarded as belonging to the Recent, while the lower portion was thought to be the equivalent of Hilgard’s Port Hudson, those deposits numbered 1 to 4 in the section shown on page 387, under Geology of Mississippi. The thickness of the Port Hudson is given as about 100 feet. Borings revealed the presence of shells and lignitized wood.
Along the rivers which traverse the Coastal Plain are found three terraces. The first or lowest is that which is subject to annual overflow. The second terrace, “the second bottom,” occurs along most of even the smaller streams of the Coastal Plain. It may be as much as a mile wide. The height above low water may vary from 10 to 15 feet in the lower courses of the rivers to 60 feet farther up stream. Near water-level a blue clay is frequently found which contains stumps, roots, and other remains of vegetation, often well preserved. Smith concluded that this second terrace was the substantial equivalence in time to the Port Hudson.
Smith presents a geological section taken along Black Warrior River, in Hale County, 150 miles above Mobile. The section included about 50 feet. As caving went on, stumps and logs were frequently brought into view. Similar sections were found on Coosa River, above Montgomery, and on Alabama River, 50 miles above Mobile.
The third terrace is found at elevations of from 50 to 100 feet above the second. It is sometimes 3 miles or more in width.
In his paper on the Citronelle formation (Prof. Paper U. S. Geol. Surv., 98, pp. 167–208), Matson discusses briefly (pp. 189–190) the Pleistocene of the area studied by him. This extends from the western end of Florida to Mississippi River. Here he recognized four terraces, from the youngest to the oldest, the Pensacola, the Hammond, the Port Hickey, and the St. Elmo. The St. Elmo merges into the Natchez formation, which Matson, quoting Chamberlin and Salisbury, regarded as sub-Aftonian. The Port Hickey terrace is stated to take its name from a locality on the Mississippi River where the typical materials of the Port Hudson formation are exposed. The Port Hickey terrace may, as suggested by Matson, be of post-Iowan age. Naturally, these correlations require confirmation.
Berry has described fossil plants (Amer. Naturalist, vol. XLI, pp. 689–697; Amer. Jour. Sci., ser. 4, vol. XXIX, pp. 387–398) which were found along Chattahoochee River, not far below Columbus, Georgia; on Warrior River, up to 356 miles above Mobile. Pleistocene deposits must occur along all the larger streams still farther north, and these deposits will yield in time bones and teeth of vertebrated animals.
Notwithstanding the considerable area of Pleistocene deposits discovered in Alabama, the number of species of vertebrates met with is remarkably small. On page 40 is recorded the finding of Megalonyx jeffersonii somewhere about Tuscumbia. At Newbern, Hale County, have been found an incisor tooth of a horse (p. 200) and a molar of a bison (p. 264). At Bogue Chitto, Dallas County, have been collected Equus leidyi (p. 200), Mammut americanum, and Elephas imperator. The last species indicates that the deposits probably belong in the Aftonian. The writer knows of no other localities in the State where vertebrate fossils of the Pleistocene have been obtained.
The geological history of the lower part of the Mississippi Valley during Quaternary times appears to be particularly difficult to understand and at present is far from being unraveled. It is easy to see that such a region will offer great difficulties. Here debouches into the ocean a majestic river which drains not only the glaciated portions of the United States from western New York to northwestern Montana, but the larger part of the region south of this from the Blue Ridge to the Rocky Mountains, and brings down every year enormous quantities of sand and silt, which are dropped partly on its flood-plain, but mostly near its mouth. Through the ages during which this has been proceeding, this river has been ever changing its bed, sometimes eroding away one bank, sometimes the opposite one; so that its flood-plain is, in most places below the mouth of the Ohio, many miles wide, varying, according to Russell (“Rivers of North America,” 1898, p. 267) from 5 miles to 80 miles in width. During the Quaternary there have been also elevations and subsidences of the bed at least from Cairo northward, as a result of which at one epoch the current was hastened and the valley cut out deeper; at another the current was checked, the channel clogged up, and the river forced to seek a new channel or even new temporary or permanent outlets to the Gulf (E. A. Smith, Geol. Surv. Alabama, 1894, pp. 30–34).
To get a correct idea of the Pleistocene geology of the lower Mississippi region, one must understand the situation at the beginning of this epoch. I. C. Russell, on page 267 of his work just quoted, calls attention to the differences displayed by the valley of the river within the glaciated region and that south of it. South of the mouth of Ohio River the wide flood-plain of the Mississippi lies from 300 to 500 feet below the general level of the bordering uplands. He states further that the hard rock bottom of the valley is only imperfectly known, but that the records of wells and borings show that an ancient valley has been filled with alluvium to a depth of at least 100 or 200 feet in its northern part and to an increasing depth southward. If to this thickness, given by Russell, we add the depth, 300 to 500 feet, which the flood-plain occupies below the bordering uplands, we get a measure of the depth of the great trench which once existed where now lies the flood-plain of Mississippi River. In his paper on the underground waters of southern Louisiana (Bull. 1, Louisiana Geol. Surv., 1905, p. 42, plate II) Harris presents the record of the Fabacher well, which was bored at New Orleans. At a depth of about 1,200 feet fossil remains were brought up which appeared to be of Pleistocene age. It is evident from these facts, as in the case of those obtained from the rivers of Texas, that at about the beginning of the Pleistocene, or more probably during the time of the so-called Lafayette, at the close of the Pliocene, the country east of the Rocky Mountains, at least, stood for a long time at a much higher level than at present and that, as a result of this elevation, there was an enormous general erosion of the face of the country and a great widening and deepening of the river valleys. This time of elevation was quite certainly followed by a prolonged period of depression, during which these canyon-like trenches and their tributaries, up to their last ramifications, were nearly completely refilled. This refilling must have occurred during the early stages of the Pleistocene, for in the materials are buried the bones of early Pleistocene animals. As quoted below, in considering the geology at Natchez, Chamberlin and Salisbury state that since the Natchez formation, 200 feet thick, was laid down, the trench of the Mississippi, 60 miles wide, has been excavated. One might change this expression and say that it had been re-excavated, but not to its original depth.
When we reflect that the greater part of the sediments which, during the Pleistocene epoch, were deposited at the mouth of Mississippi River and on its flood-plain from Kentucky southward, were certainly derived from the glaciated portions of its great valley, and that those regions were alternately affected by the events of five glacial and four interglacial epochs, we must conclude that corresponding deposits or phenomena of some kind exist throughout the valley. The matter is, however, so complicated that many years must elapse before a satisfactory solution will have been reached.
In his Report on the Geology and Agriculture of the State of Mississippi, 1860 (1863–65), the geologist E. W. Hilgard, on pages 5 to 46, described under the name of Orange sand a deposit which characterizes the greater part of the surface of that State. He referred this to the Quaternary and regarded it as being the southern equivalent of the northern drift. This formation is now believed to belong mostly at least to the Pliocene. Besides the Orange sand, Hilgard (op. cit., pp. 194–201) referred other formations to the Quaternary. These in order would be as follows, the latest above:
The Bluff formations were described as occupying a narrow belt along the borders of the Mississippi bottom in northern Mississippi and along the river itself in the southern part of the State. He stated that the fossils belonged to terrestrial species, and quoted Leidy’s list of vertebrates, already mentioned, remarking that the blue clay which furnished them was said to belong to the Bluff formation. He reported that the snails found in the Bluff formation seemed all to belong to living species. The yellow loams occupied a large part of the surface of the State, overlying the Orange sand and forming a great part of the soils of the State. The succeeding formations were found along many of the rivers.
In 1869 (Amer. Jour. Sci., vol. XLVII, pp. 331–346), Hilgard reported the results of a geological reconnaissance of Louisiana. In this he proposed the name Port Hudson group for extensive deposits of clays which were especially well displayed at Port Hudson. This formation was further described by Hilgard in 1872 (Smithson. Contrib. Knowl., vol. XXIII, No. 248, p. 5). Two geological sections taken near Port Hudson were presented, one of which is here reproduced.
| Section midway between Port Hudson and Fontana. | ||
|---|---|---|
| 6. | Yellow loam, sandy below | 8–10 |
| 5. | White and yellow hardpan | 18 |
| Orange and yellow sand, sometimes ferruginous sandstone, irregularly stratified | 8–15 | |
| 4. | Heavy greenish or bluish clay | 7 |
| 3. | White indurate silt, or hardpan | 18 |
| 2. | Heavy green clay with porous calcareous concretions above, ferruginous below; some sticks and impressions of leaves | 30 |
| 1. | Brown muck with cypress stumps | 3–4 |
| White or blue clay with cypress stumps | ||
The cypress stumps of No. 1 were numerous and well preserved.
The writer reproduces Hilgard’s geological map of the lower Mississippi region, in which is represented the distribution of the Port Hudson according to that writer’s views (fig. 22). It will be seen that it was supposed to pass eastward into the coast region of Mississippi, Alabama, and Florida. Westward from Atchafalaya River it was believed to occupy a large part of southern Louisiana and to pass into Texas and around the Gulf coast to near the Rio Grande. It will be observed that in the latter State it corresponds in a general way to what has been called by Deussen the Lissie formation.