History of Linn County Iowa

ogy of L

TON, PROFESSOR OF GEO

al, and moral life of the people. The metropolis of Linn county, for example, owes its name and place to the rapids of the Cedar, and the rapids find ultimate cause in the fact that some millions of years ago nature stopped laying a softer rock upon the ocean bed and deposited upon it one of more resistant texture. In the eastern part of the county the Chicago & Northwestern Railway runs for very good and sufficient reasons where once rested the edge of a long tongue of glacial ice, and west of Cedar Rapids its route is determined by the course taken by the turbid floods issuing from the melti

is used in a number of the business blocks and private residences of Cedar Rapids, as for example in the old office building of the Republican. Belonging to the Algonkian, an era so remote that its age must be reckoned in scores if not in hundreds of millions of years, the quartzite at the bottom of the deep well tells of time inconceivably remote when Linn county was part of a wide sea floor on which red sands were washed to and fro and finally laid to rest in thick deposits of sandstone. Tilted and folded and hardened by pressure, the Algonkian rocks were uplifted from the sea to form dry land of mountainous heights. After the lapse of ages the old land sunk beneath the sea, a

on C., R. I. & P. Ry

T KENWO

LIMESTONE IN MILWAUKE

W OUT,"

TTLER, NEA

ISA

This impervious bed of altered clay stops the descent of ground water, which thus is stored in large quantities in the overlying limestones and supplies some of the important wells of the county such as that of the town of Mount Verno

SILU

e country rock in the eastern tier of townships. In some of the quarries one may see the ripple marks into which these coral sands were heaped by the pulse of the waves

little semblance of bedding structures are to be seen. Here and there the rock is conglomeratic, consisting of rounded masses of the rock cemented by a less resistent matrix. The cavernous recess in the rock wall of the Palisades, misnamed the Blowout, is due to the solution of the weaker matrix and the dislodgement of the rounded masses. The rock may consist also of angular broken blue-gray fragments in the matrix of a buff and friable limestone sand. Again, the mounds, at least in part, may be made up of massive limestone with little trace of structure of any sort. On the sides of the mounds and merging into the conglomeratic or other structures the rock of the LeClaire often is stratified and the layers dip outward at angles surprisingly high. In places these tilted layers may show sharp folds. The

due to its chemical composition-for dolomite weathers far less rapidly than a non-magnesian limestone-and to the fewness of those planes of weakness called joint-planes. The joints o

e of magnesia present makes it a cool lime, slow to slack and slow to set, and it is to such limes that architects, masons, and plasterers now invariably give preference over the so-called hot limes burned from non-magnesian l

ness with which it weathers make it specially

he limestone is soft to work but hardens on exposure. The saw encounters no obdurate materials and the chisel finds the fracture even and regular. Bedding planes are so even and smooth as to be at once ready for the mortar with little or no dressing. Much

terial, whose dates run back to the forties and early fifties, have been so little affected by superficial decay that th

ey are confined pretty closely to the townships of the eastern tier, but

TRAM LI

heavily bedded gray rock which weathers almost white. At a number of places along Big Creek it forms picturesque cliffs, and hillsides covered with huge boulders of disintegration. At one point it is seen to overlie the Anamos

IS LIM

upward into drab non-magnesian limestones carrying the principal fossil of the magnesian beds in considerable numbers. The upper limestones of the Otis differ within rather wide limits. The most common type is seen at the base of the high cliff at Kenwood on the

NDEPE

Cedar Rapids both on Indian Creek and on the Cedar. On the Wapsipinicon it is well seen at Cedar Bluff (sec. 24 Spring Grove Tp.), at the "Wolf's Den" a mile up valley, and again in the railway cut north of Coggon. In the long cut of the Chicago, Milwaukee &

be as fine as sand. The formation is marked by irregularities of deposition, channel cutting by drift currents, lenses of calcerous material, and rapid l

exceeding an inch in thickness, was found at a depth of ninety feet in a well on the farm of Mrs. C. Hemphill, near LaFayette. Pieces of the coal were taken to Cedar Rapids and Marion. A mining company was formed, and without seeking for any expert advice from geologist or mining engineer, and without an

NPORT LI

ct, and of finest grain, and so far as known are unfossiliferous. The upper Davenport is a tough, gray, semi-crystalline limestone which contains an assemblage of fossils of many species. Highest of these are the first ver

been broken into bits and re-cemented, forming breccia. These brittle rocks could hardly give way to such immense stresses without causing sharp and vio

into a mass of small sharp-edged fragments, while the tough heavily bedded upper Davenport ledges have been fractured to large blocks, which sliding on each other have smoothed and groove

VALLEY L

ounty. The remaining limestones of the Devonian are grouped together under the name of the Cedar Valley. These consist of limestones of variou

ARBON

ts of wide sheets of similar deposits now removed by denudation. A mile and a half south of Marion (southeast quarter of section 12, Rapids township) a well twenty-three feet deep penetrated a bed of dark shale which carried leaf impressions of a number of ferns characteristic of the undergrowth of the Carboniferous forests. A third of a mile southeast of Lisbon, and again about two miles south of the same village, at Bertram at the east end of the railway bridge, and

C AND T

and the lands seems to have remained so low that little erosion was possible. We are permitted to conceive that over our savannas in Mesozoic times there roamed monstrous reptiles of strange shapes, such as are known to have existed in adjacent states. In the later ages of this era it is not impossible that during the great submergence which brought the Cretaceous sea over the

STOR

1839, Looking South The S

CARROLL

als evolving into higher and higher forms. Among these denizens of the county were probably herds of pig-like creatures, three toed horses little bigger than foxes, and ancest

LACIA

moving glaciers hundreds of feet thick. The proofs of their existence are found in almost every cutting which goes below the soil. Any quarry will show the rock deeply rotted and pitted by long preglacial decay. Here and there upon its surface will be found remnants of the deep red residual clays, the subsoils of preglacial times. Upon these clays formed from the decaying rock r

some of our prairie landscapes. These, the "first settlers," traveled to their destinations far more leisurely than any ox carts of the immigrant pioneers; for th

example, one extending north from Prairieburg; and the farmer now plows his corn in fields which lie two and three hundred feet above the channels of ancient rivers. In places the old valleys were left to be re-occupied by the rivers. Such are the reaches of wide valley of the Cedar south of Center P

rivers have cut their beds a score of feet and more below the deposits of glacial floods and in many places, as near the Ivanhoe bridge, remnants of these ancient flood plains are

LO

eir elevation. Over the lowlands it is thin or absent. This yellow earth has been and is to be of greater value than mines of yellow gold. It is of inexhaustible fertility. It contains abundant mineral plant foods, partly constituent, and partly brought up into it by ground water; and these foods

ficient where hill slopes were grassed over. But where forests have been thoughtlessly cut down, and steep slopes turned to plow land, it is but a few years until the brown top-soil is all washed away and the fields in spring wh

he valley of the Upper Mississippi has so beautiful and wide and varied prospects. Over more or less of their course the rivers of the county have cut their channels lengthwise in the ridges, thus giving rise to the bold scenery of the Wapsipinicon above Central City, and of the Cedar near Mount Vernon. Some of these picturesque reaches of river and cliff and fores

on. These returned to the area after the final retreat of the ice and their remains are found in the peat bogs and river gravels. In the earliest of the interglacial epochs it is quite probable that some of the gigantic groundsloths of South America made their home here, since they are known to have done so in the western counties of the state. No traces of man have been