39

sumed that the nearly horizontal strata of the chalk, abut against the more rapidly sloping quartzite, and that such is the case also with any strata of intermediate age that may lie between. That there are such strata is clearly shown by the borings at Le Mars and Sioux City, and that these strata belong to the sub-carboniferous series, and all other strata, if they ever existed (which is not probable), were eroded and totally carried away before the commencement of the cretaceous period, has been previously intimated in this article. The writer has no doubt whatever that these borings in every case terminated in the quartzite or the granitic rocks below.

It is to be understood then that the quartzite at Le Mars lies about 400 feet below the general surface of the ground, while at Sioux City it is as least 1,200 feet below; that at Le Mars, between the cretaceous rocks and the quartzite, intervenes only eighty or ninety feet of marls and sandstone and oolitic rock, while at Sioux City, if the gray limestone No. 71 represents the oolitic beds, these intervening rocks must have a thickness of over 800 feet. However, the data are to be considered, as has been heretefore stated, only in general terms. The existence of the strata in the order given, and their geological horizon, may be relied on, but not their exact thickness, nor the exact point of juncture of the different overlying formati6ns.

The cretaceous rocks of this region have been the subject of greater interest and have attracted the attention of more scientific men than any single formation in the United States. It was for a long while contended that they were not cretaceous, and eminent scientists from Europe, and even the great Agassiz himself, came to Sioux City to see and determine for themselves. But these questions have long since been settled, and what will be said, therefore, will be more like a popular lecture than a scientific treatise. First let us look at the general area occupied by this formation, and its conditions when the rocks began to be laid down. Away back in the illimitable past there was in this region an intricate maze of narrow, shallow seas, full of islands, some quite large, all of low elevation, no mountains, nor any but moderate hills on islands or shores, many of them flat and just above the surface of water. The general conformation or the country was much as would be shown were the present surface to sink until the water nearly reached the summits of our river bluffs. In fact, in the preceding epoch, a vast area lay at the bottom of deep

40

HISTORY OF WOODBURY AND PLYMOUTH COUNTIES.

sea, and gradually rising at the commencement of this period, had just emerged from the waters enough to afford considerable areas of dry land, and the process of upheaval had ceased and slow depression just set in. Every bit of land had its stream or streams according to its size.

The valleys of the Missouri, the Floyd, the Big and Little Sioux, and of some other streams, existed long before, but now they were beneath the waters of the sea, and filled with debris of the older land which had existed and sunk in a former epoch.

The higher ground along the courses of these ancient streams was the boundary of straits, bays and currents of the shallow seas.

The eastern boundary of this sea has not been traced to the Gulf of Mexico, but it is found in northern Texas, and passes northerly through eastern Kansas and Nebraska, crosses the Missouri valley below Council Bluffs, passes as far east as Guthrie county in Iowa, and thence to the point where the Des Moines river crosses the Minnesota line, thence north to the mouth of the Big Cottonwood. It has been seen 130 miles farther north, reported in British America, and is well known to have reached Greenland and the Arctic seas. Its western boundary is not fully determined, but presumably it is to, be found in the foot hills of the Rocky mountains. It has been examined for a width of more than 200 miles in the Arkansas valley, and in Iowa and Nebraska from sixty to one hundred miles. Through this archipelago of low islands, in channels intricate and sometimes of considerable breadth and depth, but usually narrow and shallow, the mighty gulf stream probably poured its tepid waters into Arctic seas. We behold, as the result of low level and tropic currents, a landscape draped in continual mist and frequent rains-no snow or frost-full streams, so full that the estuaries and bays were freshened into brackishness till fresh water shell-fish could maintain life therein. The vegetation is tropical or subtropical; luxuriant even in Greenland, beyond the vegetation of our present era. Every foot of land was clothed with trees, for the most part so densely as to preclude undergrowth, and so the remains of lower vegetation are few and of inferior grade. Nevertheless, the general effect of latitude or life is plainly apparent. Proceeding northward we observe that vegetation is not less abundant, yet it diminishes in size and in the number of species. In Kansas are found sassafras leaves a foot across, in Wood-

41

WOODBURY COUNTY.

bury county one six inches broad is a large leaf, and in Greenland the sassafras still grows, but with much smaller leaves. So also in regard to the trunks of trees. In Greenland have been found only 28 species, representing 16 genera of dicotyledonous trees, while in Iowa, Kansas and Nebraska have been gathered more than 50 genera representing at least 111 species, and the formation in Greenland has been very carefully explored. Among the Greenland trees are cottonwood, fig trees, sassafras, magnolias, sumach, and others akin to our forest trees, but here we find two species of sequoia (the California giant trees), 1 araucaria or South American pine, 2 firs, 1 bamboo, 1 palm, 2 sweet gum, 5 poplars (cottonwoods and aspens), 4 trees (their near relations), 6 willows, 1 tamarisk, 1 birch and one of its kin, 1 alder, 2 beeches, 6 sycamores, 1 fig, 2 laurels, 7 sassafras, 2 cinnamon, 1 ivy, 5 magnolias, 3 tulip trees (better known as southern poplars), 1 maple, 1 box elder, 1 walnut, 1 sumach, 1 pear, 1 cherry and numerous other dicotyledonous trees. There had been discovered up to 1875, at least 2 orders, 7 genera, 7 species of cryptograms (mosses, lichens and ferns), and of phanerogamous plants, gymnosperms (pines, firs, cedars, etc.) 2 orders, 7 genera, 9 species, monocotyledons (bamboo, palms, etc.) 3 orders, 3 genera, 9 species, and of dicotyledons (deciduous forest trees) 16 orders, 52 genera, 111 species, making in all no less than 23 orders, 69 genera, 130 species, and this number has been largely increased by later discoveries and doubtless many more remain unobserved.

Besides this luxuriant vegetation there are several very notable facts to be observed at this period. First, the apparent equability of climate. There seems to have been no storms. Impressions of rain drops are abundant, but the rain fell in a quiet atmosphere. Impressions of rippling waves are frequent, but they indicate only gentle motion. The streams were dull and sluggish. There are no accumulations of leaves and brushwood, such as are left by rapid currents or are brought from a distance by torrents. The leaves fell quietly on the margin of the stream or sea, and were buried, mostly in horizontal position, by the sediment from quiet or gently moving waters.

A second fact is the absence of animal life. In the sea a few shell fish were found, but no fish or reptiles; on land, so far as known, nor bird nor beast existed. The forests were like the dense forests that now clothe the middle slopes of the Alaskan mountains, the abode of death and desolation.

42

HISTOUY OF WOODBURY AND PLYMOUTH COUNTIES.

At the close of the preceding epoch Death seems to have passed over the earth and left no living thing throughout this whole region; not even a shrub, a spear of grass or a sea weed survived the general fate. With the beginning of this period a new creation began with the vegetable world.

We can see here that one day life was not, but soon as certain conditions prevailed it was luxuriant and varied. Below this group of strata in all the world, no trace of dicotyledonous trees has been found. Hitherto ferns, giant bulrushes, pines, firs, araucarias and cycas made the world's great forests. At once they give way in this epoch to deciduous hardwood trees in wonderful variety, no less than 111 species, comprised in fifty-two new genera and sixteen new orders. What became of the old? Whence came the new? These are questions which we have no time now to consider; they are still much in the dark. One thing further must be remarked, and that is that all these new species are identical, or near of kin with species now living, while of the species of larger plants in preceding eras, not one remains; only a few genera, a few orders of very simple structure still exist to connect the living present with the dead past. Here, at the base of the Dakota group, we stand between the dead and the new creation. Here, in place and time, so far as this region is concerned, God made the vegetable world. I have said before that at the very beginning of this epoch the progress of elevation had ceased and depression commenced. This depression seems not to have affected the eastern border of the area, but to have extended westerly, and more particularly to have been greater toward the northwest. During this slow sinking were deposited the various strata of yellowish, reddish, sometimes white sandstones, that make up most of the Dakota group. There are occasional alternations of various colored clays, and beds and seams of impure lignite, none of which are of economical value. In all the strata more or less silicified wood, and great numbers of leaves of higher types of dicotyledonous trees occur, but most of all in the very hard stratum of sandstone found at the bottom of the soft yellowish, heavy sandrock at the base of the Missouri river bluffs, and a softer, thinner sandstone some twenty-five feet higher. Down, gradually, the earth subsided, the water scarcely deepening, the material deposited nearly ir quite keeping up the bottom level, until the accumulated strata gain a general thickness of some 400 to 500 feet of

43

WOODBURY COUNTY.

which about 150 feet are exposed to view in this vicinity. In all this thickness the only remains of animal life are a few unimportant species of gasteropods. Not a bone, not a tooth or scale of vertebrate fish, or air-breathing mammal, bird or reptile is found in the entire thickness.

Toward the close of this period the rate of depression seems to have rapidly increased, especially toward the northwest and west. Indeed it seems possible that some sudden catastrophic sinking occurred, for vegetable life disappeared as suddenly as it came, except perhaps along the new and distant shores.

Islands and adjacent mainland appear to have sunk suddenly beneath the expanding sea. With increased depth came multitudes of shellfish in great variety, and so abundant, that many feet in thickness of the deposit succeeding, are made up almost exclusively of the shells of a single species, the well-known inoceramus problematicus.

The progress of descent again resumed a slow and regular character, and there were deposited the strata of the Fort Benton group, attaining on the upper Missouri a thickness of 700 or 800 feet of dark gray laminated clays, alternating in the upper part with seams and layers of soft gray and light-colored limestone. This group has not much thickness in Woodbury and Plymouth counties, if it exists at all in Woodbury. Probably the sinking during this time was slight in this part of the seas, and the deposits, were therefore thin, while toward the northwest the depression was much greater.

The third or Niobrara group seems here to lie closely related, if not in actual contact with No.1, or the Dakota group. The fact seems of little importance, for it is very difficult to draw a distinguishing line between No.2 and No.3, the overlying Niobrara rocks being so finely developed along the Big Sioux at Talbot's farm, just on the south line of Plymouth county, and all along the river upward as far as Mill's farm, and more especially on the Nebraska side of the Missouri, near the mouth of Aioway creek. At the beginning of the Fort Benton (No.3) epoch, the rate of descent toward the northwest seems to have increased rapidly, and the general depth of water increased also, the sediment failing to keep pace with the descent, as it had nearly done while the Dakota group No.1 was laid down.

Now with the disappearance of land and increasing depth of water came animal life. At first shell, few in species, small in size, including a few survivors from the Dakota group.

44

HISTORY OF WOODBURY AND PLYMOUTH COUNTIES.

Oysters, nautilus, ammonites, and most of all, several species of inoceramus in countless numbers, until the upper strata are one mass of shells many feet in thickness. The inoceramus beds common to the Fort Benton and the Niobrara groups, suggest the waste heaps of some ancient gigantic oysterman, being absolutely made up of shells alone. This can be readily observed at any of the many abandoned lime quarries along the Big Sioux valley.

In the upper beds of the Benton group, appear for the first time vertebrated fish, a shark, a flying fish, an apsopelix and a crocodile, the vanguard of the multitude of marine monsters soon to take possession of the deepening, widening sea. The sea was now deepening rapidly, and deposits of yellowish, whitish limestone, largely made up of shells, and mixed with scales and spines, and occasionally entire skeletons of fish, are slowly accumulating at the bottom. As the sea grew deeper, life increased in variety and in multitude. At its greatest depth the waters seem to have been alive with minute, almost microscopic shellfish, whose shields fell quietly to the bottom, and formed thick beds of lead-grey, calcareous marl, whitish, sometimes resembling chalk, and the nearest representative of the English chalk found in America. Fine exposure of these beds are to be found at Pegar's, Dermody's and Mill's farms, and at other places in the Big Sioux valley. These beds abound in fish scales, teeth of sharks mixed with oyster and inoceramus shells in great numbers. Now appears life of a higher order, and as the Dakota group represents an epoch of creation, and luxuriant growth in the vegetable kingdom, so the Niobrara group marks the first appearance in this region, of abundant and monstrous vertebrate life, comprising orders, perhaps some genera or even species now existing. This is the beginning of animal life in forms with which we are familiar, though possibly all its particular species were swept away by succeeding catastrophes.

These rocks have yielded two genera of lizard birds, with teeth and bony tails, and two species of swimming birds, one deinosaur, a gigantic kangaroo shaped monster, sometimes exceeding the elephant in size, four pterodactyls, an elasmosaur, the mightiest and most awful of created things, one plesiosaur and one polycotylus, four gigantic turtles, twenty-six pythonomorphs or serpent saurians, and forty-eight species of fish. Among the shellfish may be mentioned the giant haploscaph, of which one shell was found measuring twenty-seven inches across.

45

WOODBURY COUNTY.

All these fossils may possibly be discovered here in this region, and many of them have been. Some years ago an elasmosaur (?) or mosasaur (?) was discovered in the bluffs of the Niobrara group near Ponca, Neb. The vertebra found, measured nearly forty feet in length and it seemed likely that the living monster must have been quite seventy feet in entire length. In comparison with such a monster the ancient tales of dragons of the sea shrink into insignificance, and dragons of the air that in old-folk lore terrified even men of mature age, are scarcely worth mentioning by the side of pterodactyls whose jaws were thirty inches long and wings expanded more than twenty feet. Some pythonomorphs, notably the liodon dyspelor were probably longest of all reptiles, and indeed as large in bulk as the great pinner whales of modern oceans.

Are any of these monsters still in our modern seas? It is certain that in this group of rocks appear the first affinities to our modern vertebrates, and it is equally certain that of the many descriptions of sea serpents seen, or supposed to have been seen, in these later years, most would pass well for a description of the awful liodon dyspelor, the tyrant of the Niobrara seas, or the elasmosaurus the most frightful and destructive of all its class.

Before the close of this period, the land in this vicinity seems to have oscillated upward again-other cretaceous deposits ensued during the process of elevation, but probably they were very thin here, though of great thickness farther west and north. After a season the uprising land appears to have cut off the channels that poured warm water along far northern shores. Probably the quartzite, which stretches at least from the Missouri eastward across the Mississippi to the granitic rocks of Minnesota, rose high enough to form an impassable barrier.

There does not seem to have been any downward movement since the close of the cretaceous period, the drainage of the great lake in which the loess was laid, being probably brought about by the more rapid rise of the upper portion of the Missouri valley rather than by any sinking of the lower portion. Indeed it is the opinion of many scientists that the process of elevation is still continuous. It would be interesting, perhaps profitable, to examine the reasons for such a belief and the consequences of the process if it be actually going on, but for that there is now neither time nor space. Upon the close of the cretaceous period, succeeded the great cosmic winter with its

46

HISTORY OF WOODBURY AND PLYMOUTH COUNTIES.

enveloping ice and destitution of all life. Of this we have already treated, and in conclusion we would only say a word or two of the economic value of the cretaceous rocks. It is true that very few strata are compact enough to be useful in building large or permanent structures exposed to the elements, but in many placel3 stone may be found of considerable value for common use, and in the Dakota group there are sandstones hard enough to be useful and durable in all rubble work. The inoceramus beds furnish an inexhaustible supply of lime of fair quality, though generally the cost of shipping them and working them, is, near the railroads, greater than the cost of lime brought by rail from more favored regions east, and so the lime kilns of Woodbury and Plymouth are now mostly closed. In the Dakota group there are some thin ferruginous strata that, if ground finely, make a red paint of most excellent quality. There are also in the Dakota group at Sergeant's Bluff and Riverside, and in the Niobrara group in many places, shales, which, when properly treated, make the best of pottery clays. There are many places where these shales have been exposed and have become disintegrated, forming large beds of the finest clay ready for use. At Sergeant's Bluff pottery has been made successfully for many years, and recently large kilns have been erected and are now successfully worked at Riverside in Sioux City.

Clays equally good can be found almost anywhere along the Big Sioux in Plymouth county, and for some distance up the Broken Kettle, and doubtless in many other places. In the abundant material for the manufacturing of fine building brick, fire brick, tile pipe and pottery of every kind, these counties are far richer than if their stream; flowed over golden sands and their hillsides were seamed with occasional veins of golden quartz.

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