es oS =o Set Se Sete = MELT Ry! oon tay Nett Pe Mita Nes os fai Sepa - 7 SNP orang ty, hae eb ne h >, 7 A : gs. —— ie = ST i 5 PR YS ale eae ae es wR. be : m =e PARAS Ee a ee YS ts- . conde Se ee A 4 ; tee pips ap as ie oy Doyen 19) ‘QOUS gj] UO JING WSU UA YY NEG IS Wy BI.UO ALI ayL aAage oUOISIWIT YAYORY BY JO aINSOdNA Jyn|g a aes (UVMELIMON HATS MEL df ONTAOO'T A (IdvY MIMO) THL 40 L004 1Y [ddlSSISSI AHL NO AMAA, “S2U/Oy SAG YI] 99% S/ftp) e ee > ’ " : * “4 3% Sear RS cra Lal ‘f art Nee a4 a A ccsniapig BS. "RRR aspera ota ge ee ae at ee See eee. Sane RA MEIN 1 os ee iS ro Se . : . - , ait i Ri wae: qt ma 9 NES REPORT ON THE GEOLOGICAL SURVEY STATE OF IOWA, TO THE THIRTEENTH GENERAL ASSEMBLY, JANUARY, 1870, CONTAINING RESULTS OF EXAMINATIONS AND OBSERVATIONS MADE WITHIN THE YEARS 1866, 1867, 1868, AND 1869. Be CHARLES 2. WHITE My D. GEOLOGICAL CORPS: CHARLES A. WHITE, - State Geologist. OrEsTESs H. St. Jonn, Assistant. RusH Emery, - - - Chemist. AITO MRL Ss ed DES MOINES: PRINTED AND PUBLISHED BY MILLS & 0O., FOURTH STREET. 1870. I EO ———— Entered according to Act of Congress, in the year one thousand eight hundred and seventy, by F. M. MILLS, State Printer, for the State of Iowa, in the office of the Librarian of Congress, at Washington. PREF ACH. There is probabiy nothing an author regrets more than to be obliged to publish the results of his labors in an incomplete form. While all fall short of their wishes in this regard, it is not unfrequently the case, that the nature or magnitude of the subject treated renders a near approach to perfection impossible. This is especially true of geolo- gical subjects, and peculiar trials beset those who undertake the preparation of reports upon State Geological Surveys, as they are usually organized. Instead of adopting a definite policy for the work, and making suitable and reliable provision for maintaining it until it shall be completed upon a carefully devised plan, the State Legislatures usually authorize these surveys by special legislative acts, appropriating, at the same time, only sufficient funds to commence them. These acts are not only liable to be repealed by any subsequent legislature, and the work thereby arrested, but it is in constant danger of being suspended by the failure of those legislatures to. provide funds for its support. Examples of such legislation may be seen in the copies of laws in the historical part of the introduction on pages eight to twelve. Under such circumstances, the person appointed to con- duct the work feels obliged to adopt, not such plans as he IV PREFACE. knows to be best in case it were sure to be completed, but such as will ensure the most creditable results for the short time he may have charge of it. Thus, the full realization — of the objects for which the people, through their represen- tatives, support these works, is seldom attained. In gathering together the results of the past four year’s labor to be embodied in this report, which is ordered to be published without further addition, it has been my aim to so arrange and present them that the subjects treated should be not only as complete in themselves, as the circumstances would permit, but that the report should also serve as a basis for future labor of the kind, if the legislature should ever order it. Besides the mention in my letter to the Governor, on pages three and four, of persons who have conferred especial favor while the survey was in progress, I desire here to acknow- ~ ledge the earnest efforts of the publishers, Messrs. Miris & Co., to present the work to the public in a creditable manner in all its parts. C. A. WHITE. ieee (Om CONTENTS. Letter to the Governor .......... APTS As kA oe a ck aA Page 1 a INTRODUCTION. By C. A. WuirTz. Tees 8 TROT Ge aa ee So Denar), My NA Sot oe a Page ied Ze Op Warne mplAWAGW) a). o50 cs oaleade vs 2 ee5 ac es +’ « 12 ; Ce ne LSS MCAIOM Ol. LOWa) LOCKS... 2 ce sicie. vic deceles aces es) , eterna beboescd q PHYSICAL GEOGRAPHY AND SURFACE GEOLOGY. —_ CHAPTER I—SURFACE FEATURES. By C. A. Wurre. as de os OMG aMes AMG GAMER, 5 Fao hw a) k.ehiaww'aigveo none oe Page 28 PG CHerAl LOWOPE APN. a caice aes satus okinca es ce. vs 29 e ‘ Spe MURIT AMC: SUV SCINS. CA uHe) sy Xlcrala|'napissn’ a's atate, «mw Ore 35 3 2. Givers and ther valleys... 2. ..2.0.-2-2-.-+s--+- 38 5. skutvers ofthe Western System. .....5..c.06s00 62. it Go Eytyers of file, Hasterm SYSteM, © 1200 Ts % 1000 a 800 Dubuque. Mississippe Riv er. 200 Low Water, Mississippi River at Keokuk.) Ne2 >= -_—™s 27 24 2# 78 15 /2 9g 6 3 o 1200 : = N 2 8 1000 3 Ots S 2 ~ 300 QR =p >= Ee ee 600 = oO = S s = ~ +00 77 S 200 =, x S Nes 30 are 24 21 18 15 72 3 Co 3 RS grapes 1000 o. = = 800 < o-< R 2 ‘ 2 600 = A 3 _ls00 St eee ere ee eee S oF 200 Mississippi River at Keokuk.) Ne 4. [ --ay e Tee Gy 72 g 6 oF @ 4 > Fi ee = a PRoFicENY General Elevations trom M Gregor w tre Big Stour River’ 800 : N°2 u ” Dubuque toapoumt 12 miles north of Siu Gly, a ” N°3 D ” » Clinton ¢o Decatur’ Neb. » Not " " » Davenport 4 De Soto, Acb, -° " NOS ” " ” Burlington to Plattsrnouth, 200 iW’ SS é & = A & ro & ; z & : : s : E F — — x ~~ ~ e 2 cS —- Gaia’ st S § g x z 5 i : — 1860 — Pos = - = ¥ —= Piet * 8 4 x : « z : = {> —— sae S = is x s : S . Spree t = eo = 5 y ut g = 5 +a TABLE of ELE = ~ << = = — 5 z = N ry = 2 ES - of ELEVATIONS. <5 a = ee e bs = 3s z g iS S Flue MGr og or. chore tow water at Neetu (98 reer aati = i rt — >= ise Dubuque . . 160 i T - sa Panton WS avenport f = : ae § nee : as a5 IE | I = Burlington m3 $ 2 = = 3 : = okuk ar Sra 3 A x S$ 8 x XS Ss = z 3 Ses > S é £ cies zé 3 3 N < z = Se 2 a ee : i os Sess 5 zo 2 [= Dor 4 4 ¥ a7 7 s x = 3 = 4 ahs 3 = s x ktye = x 8 = B33 = = S SS = ay LaaN = 2 S s ai 8 sé 5 s = : s g > : S Ke & rt & s s 3 $ 8 4 Se : ry 5 aS = s = Turkey Creck § g vs 3 = § s = Ss 190 as iS = < tay" = & S & A gape oN = 5 EE foo é Aden iS mas 1% 34 Rig 6” Oe, Z ad = 27e ET ze == L 2 ae 8 3 2 t 8 S = z = Fy S s 8 2 5 ; z§ Seo RS § E 2 ‘ < PRorice Nl oewral inutons rom M Gregori eae Big Stter River iia S g S 2 3 NOB © = = Dubuque comport 12 miter north of tue Gly. = NPZ Clinton te Derntur: Neb, a © Mom » = Davenport f Desora Neb, WweS5 ~ © Burlington @ Mattern, rT ea a aa ers hee om TR. SURFACE FEATURES. om It will be readily understood that profiles on so small a scale as that upon which these are drawn upon the accompa- nying sheet can do no more than to give an approximate outline of the surface, which indeed is all that they are intended to do. The difficulty also of constructing such profiles from the independent notes of so many different persons will be understood. Mr. Morley says, in explana- tion of his work: “Ta preparing these profiles, I have used as far as practicable the elevations just as they were givea by the dificvreat railroad surveys, but in some cases I have been obliged to depeud upon other data. Much of this was furuished by yourself and Prof. St. Johu, and the remainder was calculated from the known slopes of rivers and watersheds. The elevations west of the Great Watershed which were furnished by the railroad eogiueers, for the most part run dowa some river valley instead of keeping on a direct line across the State. ‘Lo follow these would not give a correct idea of the general elevations of the summits between the streams, I have, therefore, been obliged, to some extent, to use other data in determining general elevations of the surface in such cases. In profile No. 1, a part of the elevations are from railroad surveys, but the greater part are from data furuished by the Geological Survey, and by estimates irom kuowa river slopes. There are, however,,euough accurately kuown eleva- tions to insure a fair degree of accuracy along the whole line. In profile No. 2,,we had a continuous line of levels from Dubuque to Sioux City, furnished by Mr. J. #. Ainsworth, and also another line irom Fort Dodge to Sioux Uity by a differeut route, furuished by L. Buractt. Use has been made of both of these, and. the whole profile is constructed from them except that portion of it between the Floyd and Big Sioux rivers.. This part of the line was,.as in the case of the others also, produced directly westward from Floyd river instead of following down its valley to Sioux City. In protile No. 3, the elevations are obtained from surveys made by the Cedar Rapids aud Couucil Bhitis Railroad Company (nuw the Chicago and North- western.) These elevations are those of the located line of that compa.sy from Clinton to the Boyer river, where instead of following dowa its valley as the road now does, the profile is continued directly westward to the Missouri river. I was enabled to do this by the aid of notes of a former survey made by Mr. U W. Irish in the interest of the same company. Protile No. 4, was constructed from Davenport to Cass county from notes furnished by the Chief Engineer of the Chicago, Rock Islaud, aud Pacific Rail- road. In Cass county, the road bends much to the northward, aud again, soon after, almost directly southwestward, but the profile is coutinued directiy west- ward in order to show the contour of the country along a line running across the streams nearly at right angles with their course. That portion of the profile oD PHYSICAL GEOGRAPHY. westward from Cass county was constructed from data furnished from the Geo- logical Survey notes, and by estimating the elevations from known slopes of rivers and watersheds. Profile No. 5. ‘the elevations on the line of this profile from Burlington to Highland in Union couuty, (the highest point on the line between the two great rivers) are those of the Burlington and Missouri River Railroad. Westward from Highland, there being a discrepancy of from fifty to seventy feet between the elevatious as given by that railroad and those obtained from other sources, and which may be connected with the same terminus, the elevations given in the profile are somewhat raised to correspond with those other data, ail of which point to higher elevations than those of that part of the Burlington aud Missouri River Railroad levelings. Regarding other work, with the data furnished by the railroad engineers and obtained from other sources, there has been some difficulty in correcting the levels and reducing them all to the same datum, owiug to the fact that iu the majority of cases where two different lines intersect, but oue gives the elevation of that particular point, thereby re.dering it somewhat difficult to determine the exact difference of data. In some cases, however, both liues have given their elevations at the point of intersection. Ja such cases the results are geuerally satisfactory. We have Nicollet’s elevations along the Mississippi river with which we are able to compare the lines of railroad leveliugs at their outset, aud where it has been possible to test the accuracy of his determiuations, the error, if any, has generally beea found to be small. The differences from a true level in the various lines of railroads across the State seem to be cumulative towards the west; or, in other words, the farther they are extended in that direction from their starting point, the greater the error from a true level; so that we may expect greater error in the elevatious as given in the vicinity of the Missouri river than in those nearer the Mississippi. Whea authorities differ as to the elevation of any point, if the diffvreuce is shght I have taken the mean. lf the differences were cousiderable I have adoptcd those which seemed most authentic aud fully corroborated. Ou the whole, however, the elevations given have all a degree of accuracy that reflects great credit upon all the engineers concerned ia their determiuation, and the results will give a good general idea of the topography of the State.” Since, with few exceptions, the different railroad levelings show the actual position of the road-bed, and since those roads necessarily follow the valleys of streams as far as practicable, for the purpose of securing an easy grade, profiles drawn from their data alone would not present an outline exactly corresponding to the general contour of surface along independent lines across the State. Therefore a dotted line has been added to each of those profiles for the = ee + a a {noun Ulewes 07 si ‘ety "@UT] PONCP AGG SYR oy} Buraieju0s pues sepsog Inj ¥ Guyaey “yeoys ysemoy eUy, i=] of, ez << 53 = 5) So ms a eo) * | aD, 3 = O on Sk ea od ri hae SE 5S An ge. of rat 3 = cS) hod So my 7c) we oH g= = x oO. sy a | & 3 so rm hee es << @® 29 ) i ; ¥ : gia _ in ip ee ve Ue eT : “ ee 5 - « eee ie » > -— i a. ~ - a << ee re - Y a q = : . a : ing Shee YT gee PS ce. > a r SD Nae ina PN Fore gS gE a . ~ - ie ot ‘ ' TH ye ay ' at Hi i i Wi ifn: : ae hn i Bll it Hi By Ne ie ih} on, i} ! i Wi Milt i | i Hi i, ‘ 1 i (ei ail : mia. ony) cree Radi hy Nag ——— Sf === Sah MLAs Ss! ST SS SSS = aS ext 4 pS SS RS Oe == == 2 Fa SS APTA SEEK F = =S5 49 SS GY PTL Pate De —— - —— a = EF = ene === = Ee Sse; seed = = = Z woe Fe as == —- f= : J . a a “gt | hh a=. = z A y 4 . i He it a a ) oe li ii i i Na i = : a = z 2 SSS SSS === SS == = = - = SS = E —— Se 7 = = Se = = St ee eo aa SS = = ! Reso te fat ES = =25 =u === AIO DAME 3 : bee 5 Sas iaie Sa eee = é : rl —— ~e FE GNO IE =: = == 7s i =: ————— = 3 — = == =e = E = ses \ = -. | ’ WINNEBAGD | Cos \ oa yon : SI Pe ; Clear Laie. rs ~~ | HANCOGK er) G0RDO ! ne we ; ) | OBRIEN } nar . § i) = | re ae \ zy Saas ee Pe ee ee (Sea nah ag A ee Pap\- He Seaman deena cope oa (ae! if ow \ vy At . ity nie RIG KR FRANKLIN | BUTLER onenpree BUENA ldo | POGAMONTAS | ae 7) Hate _BLAG HAM BU ‘ANAN | aragine | WARDIM | GRUNDY © | ee i << 1 ' 1 J== CRA weorD_- | i 1 ot 1 t wus: ! He ’ | : : ee i cl POWESHETK | = SLOWA i t -scoTr : ae emi Peres Geen oe S op { ee rare | Davehport. (ioe Sear a2 ie eo Ss | MUSCATINE | ff So H GLE e vMageatine yar H i WASHINGTON \ \ | ip i eh soe ; > Kt senate i y Ley PERSONS ee a ee ; HENRY J DES MOINES J By pas Stonaf, H ) 1 TAYLOR ¥ ' . 'RINGGOLD \ i DuBuqare | pu BUDUE ‘x SURFACE FEATURES. 39 C purpose of indicating more correctly, the general contour of surface. It will of course be borne in mind, that diagram profiles of this kind cannot be drawn so as to show the natural propor- tion of the distance to the height, because the actual height of the highest elevations of any region bears so small a pro- portion to the distance across it. Therefore due allowance must be made for the great apparent inequality of surface, as shown in the diagrams, necessarily consequent upon repre- senting the distance upon a much more reduced scale than the height. Taking into view the facts that the highest point in the State is but a little more than twelve hundred feet above the lowest point; that these two points are nearly three hundred miles apart, and that the whole State 1s traversed by gently flowing rivers, it will be seen that in reality the State of lowa rests wholly within, and comprises a part of, a vast plain with no mountain or hill-ranges within its borders. Perhaps a still clearer idea of the great uniformity of the surface of the State, may be obtained from a statement of the general slopes in feet per mile, from point to point in straight lines across it. The following table of general slopes are approximately correct: 7 TABLE OF SLOPES OF THE GENERAL SURFACE OF THE STATE. From the N. E. corner to the S. E. corner of the State....1 foot 1 inch per mile. rom ime Ni He corner to Spirit hake... so... ees ee et 5 feet 5 inches per mile. Brom the NSW: comnertoiSpirit Lake. s6.. 022s... 6. 5 feet 0 inch per mile. From the N. W. corner to the 8. W. corner of the State 2 feet 0 inch per mile. From the 8. W. corner of the State to the highest ridge between the two great rivers (in Ringgold county) ....4 feet 1 inch per mile. From the dividing ridge to the 8. E. coruaer of the State. .5 feet 7 inches per mile. From the highest poiat in the State (aear Spirit Lake) to the lowest point in the State (at the mouth of Des omMeSsRiver re yeni cts 2) afeciel=. « 2x late fehaeanoeme So 5 cho sk A feet 0 inch per mile. Thus, if it were possible to reduce the surface of the State to a perfect plain, preserving only the general slopes as just ~ -) 34 PHYSICAL GEOGRAPHY. given, the greatest of these would be so slight that it could not be distinguished by the eye from a perfect level. It will be seen, therefore, that there is a good degree of propriety in regarding the whole State as a part of a great plain, the lowest point of which within its borders, the south-eastern corner of the State, is only 444 feet above the level of the sea. — The average height of the whole State above the level of the sea is not far from 800 feet, although it is more than a thou- sand miles inland from the nearest sea coast. The foregoing remarks are of course to be understood as applying to the surface of the State as a whole, taking a general view of it; but when we come to consider its surface features in detail we find a very interesting diversity, and even much romantic, beauty in some parts. Nearly all this diversity of surface, however, has been produced by the for- mation of the valleys out of the general level, as will be explained on following pages, under the heads of Rivers and Surface Deposits. The general level that has just been assumed for the State has even now to some degree a real existence, for we are usually able to detect in all parts of it a general upper level of surface between all the streams, down from which the valleys of those streams have been eroded by the action of their own waters during the unnumbered years of the Terrace epoch. This character of surface is strikingly seen in the southern part of the State, where the upper surface, usually prairie, often presents to the eye a well marked level line upon the horizon as seen in the distance. In the northern part of the State, however, the surface has from the begin- ning been more undulatory, but this subject will be again referred to under the head of Drift Deposit and elsewhere in the report. It is in the northeastern part of the State that the river valleys are deepest; consequently, the country has there the greatest diversity of surface, and its physical features are most strongly marked. In all parts there is a pleasing diversity of surface, which becomes much increased in SURFACE FEATURES. 3D appearance with the cultivation of the country and the growth of trees upon former prairie surfaces. 3. DRAINAGE SYSTEM. Those two great rivers, the Mississippi and Missouri form respectively the eastern and western boundaries of the State, and receive respectively the eastern and western drainage of it. The drainage of lowa was very properly divided into two _ systems by Prof. Whitney, the one comprising the tributaries of the Mississippi, and the other those of the Missouri; those of the eastern system running in a southeasterly direction, and nearly at right angles with those of the western system, which latter most generally run in a southwesterly direction. I cannot however agree with Prof. Whitney that the courses of these streams were respectively predetermined by a series of folds or flexures in the strata, the courses of which coincide with those of the streams; for our investigations have satis- fied us that such flexures do not exist in such positions. The reasons for this opinion may be found in the chapter on General Geology, in that on surface deposits, and in the long plate of sections accompanying this report. In the first of these it is shown that the folds or flexures of strata which really do exist have different directions from the courses of those streams; andin the second it is shown that the streams, particularly those of Western Iowa, have through a large part, and in some cases through the whole of their courses, eroded their valleys out of the incoherent surface deposits alone, and would have run in any other direction just as well if a similar slope had been given to the surface they traverse. To assume the existence of folds coincident with the courses of the streams, it seems necessary to assume also that the disturbance which caused them took place immediately upon the close of the Glacial epoch, and that the drift surface which the waters there rested upon took part in the same folding. Of this we have no corroborative evidence, but we have much SE ee tia dail > 36 PHYSICAL GEOGRAPHY. reason to believe that the surface deposits received their positions independently of any folds of the strata, and that they have not since been disturbed by folding. It is worthy of remark in this connection that the general course of the streams of the eastern system—these having more generally reached the underlying strata than those of the western sys- tem—coincides very nearly with the trend of the outcrop of the formations along or upon which they run. Possibly, some of these eastern streams received their initial direction by longitudinal depression left in the surface of the drift, consequent upon the greater or less facility with which they were respectively eroded along the lines of their outcrop during the Drift epoch. The eastern drainage system comprises not far from two- thirds of the entire surface of the State, and is more complete in itself than the western system, because its rivers are larger and have the principal part of their courses within the State; while a large part of the area occupied by the western system is drained by the upper branches of streams that constitute a large part of the drainage system of the State of Missouri. An interesting feature of the division of these two systems consists in the peculiar character of the Great Watershed, or that which divides the drainage between the two great rivers. This watershed is formed by the highest land between those rivers along the whole length of a line running southward from a point.on the northern boundary line of the State near Spirit lake, in Dickinson county, to a nearly central point in the northern part of Adair county.* : From the last named point, this highest ridge of land, *Preliminary railroad levelings along the western part of the line of the Chicago and Northwestern Railway, show that at a few points along the secondary watershed , between Boyer and Soldier rivers, the elevation is actually greater than that of the Great Watershed where the railway crosses it, This may have resulted from a greater erosion of the Surface Deposits at that point than at others, both along the Great Watershed, and along the upper portion of the secondary watershed just hamed; or, it may be, that the Bluff Deposit which constitutes that secondary watershed, was origin- ally so accumulated, that its surface actually occupied a higher level than the surface of the Drift Deposit did further eastward. This subject is again referred to under the head of Bluff Deposit in the chapter on Surface Deposits, SURFACE FEATURES. ob between the two great rivers, continues southward without change of character through Ringgold county into the State of Missouri; but southward from that point, in Adair county, it is no longer the Great Watershed. From that point another and lower ridge* bears off more nearly southeast- ward, through the counties of Madison, Clarke, Lucas, and Appanoose, and becomes itself the Great Watershed. Thus, as one goes westward along the line of the Burlington and Missouri River Railroad, or along the southern boundary of the State, he passes the Great Watershed long before he reaches the highest land between the two great rivers, and at points that have more than two hundred and fifty feet less elevation. The accompanying diagram, Fig. 1, gives a gen- eral view of the drainage system of the state: Fia. 1. re: | Xora at aw =e i u = - =) a < < = ov = =< *The meaning of the word “ridge” as used here should not be misunderstood. The ridges which constitute the watersheds of Iowa, are seldom sufficiently elevated above the surrounding surface to be distinguished by the eye, and their presence is usually recognized only by observing the direction of the drainage, or by actual leveling with instruments, 38 PHYSICAL GEOGRAPHY. The double dotted line indicates the position of the Great Watershed, while the single one indicates that of the highest ridge of land between the two great rivers where that ridge does not constitute the Great Watershed. The general surface of the State, as before stated, is gently undulatory, and it is mainly the development of its drainage systems that has caused it to be so. This fact is beautifully illustrated upon the prairies of southern Iowa which have a better defined general level than those of other parts of the State. As one stands upon those broad prairies and sweeps the well-defined, ocean-like horizon with his level, he finds the bubble everywhere resting upon the cross-wire, except where the distant, dark line of forest foliage reveals the presence of a stream; here the original level has been lost by erosion. Approaching these slightly depressed regions he finds the surface to become undulating, like the smooth rolling of a sea; but looking closely, he will see that every depression leads into a still deeper one, until the upper branches of the streams are reached, the waters of which are often more than a hundred and fifty feet below the prairie level from which he started, and the surfaces of the larger streams are sometimes near a hundred feet deeper still. These details of the drainage are too minute to be repre- sented in the foregoing diagram, or even upon the largest maps. The streams themselves are considered .under the following head: 4, RIVERS AND THEIR VALLEYS. Since rivers, next to mountains, constitute the most con- Spicuous features in the physical geography of a region, and Towa being, as already shown, quite destitute of mountains, or even ranges of hills, a brief description of its rivers and river systems is here introduced, for the purpose of presenting as clear an idea as possible of the surface features of our State. Its inequalities of surface are due almost alone to its streams, for these, as before intimated, have eroded their own “| ei eom mye phil ate ) a ‘ SURFACE FEATURES. 39 valleys out of a primitive general level. Thus our so-called hills are only valley-sides; or, in other words, their apparent elevation is due to their having been left in their original positions, when the surrounding or intervening material was removed by the denuding action of water and the atmosphere; which agencies are perhaps as active now as they have ever been. Consequently the rivers and streams of Iowa, and more especially their valleys, constitute its most conspicuous physical features. All streams that rise in Iowa, rise upon the incoherent surface deposits, occupying at first only slight depressions in the surface, and scarcely perceptible. These successively coalesce to form the streams. Those portions of the valleys of the upper branches thus formed which run upon the surface deposits alone have usually sloping sides, indistinct flood-plains and muddy banks. In the following descrip- tions of rivers, these portions so generally uniform in all, are omitted, the depressions they occupy being included when reference is made to undulations of the surface. As preliminary to the consideration of the rivers of Lowa, - in groups or as individual streams, the reader is referred to the map of the State accompanying this report, to show its geographical as well as geological features; and also to the following table which is introduced to show the slope in feet per mile of the more important of them. In the case of the two great rivers, those portions of their courses which border upon fowa almost alone are considered; and in the case of the smaller rivers, it will be seen that the slope of their prin- cipal portions only are given in the table, the upper portions of them and their branches being omitted. Physical geographers use definite terms to designate different portions of the courses of rivers, and also of dif ferent parts of their valleys. Thus the river valley is divided into sides, flood-plain* and channel or bed. There is hardly *The flood-plains of rivers are usually called ‘‘ Bottoms” and ‘“ Bottom-lands” in this part of the country. 40. PHYSICAL GEOGRAPHY. a river in the world whose valley does not possess all these features more or less distinctly marked. They. also divide streams rising in moustainous regions into cascade, torrent, and river portions, er upper, middle and lower. This division of the stream itself is more especially applicable to such rivers as take their rise in mountainous regions, and flow down into and through a level country, thence into the sea or another river. | Remembering what has been said of the general topog- raphy of the State, it will at once be seen that such a division of the different parts of the courses of our Jowa streams is not applicable, because they run through a flat country all the way from their sources to their mouths. It will also be seen that those portions of them which are omitted from the table are free from torrents or cascades, because they pass along upon the incoherent surface deposits alone, not having reached the firm underlying strata: A TABLE Showing the Slopes of the Principal Rivers of Iowa. | SLOPE NAMES. | PART OF COURSE. PEE MILE. AUTHORITY. Mississippi .....|From Lansiig to the conflu- | ence of the Missouri ...... 0 ft. 6in.!J. E. Ainsworth. IVLSS OUI siarsternrere rs From Sioux City to Council BLUES bs 2 Ut npn lece & anree 1 ft. 0 in.;Railroad levels. Des Moines ..... From Fort Dodge to Ottumwa/2 ft. 4 in.|Railroad levels. Des Moines ..... From Ottumwa to the mouth.|1 ft. 11 in./Railroad levels. vaCCOOM eee ee From forks of the river to its MIOULDG AR eos kee eames 2 ft. 11 in.|Railroad levels. N. Raccoon ..... From Jefferson to the forks. .|4 ft. 0 in.|Railroad levels. NS suiiake haan ecnete From Colfax station to Oak- Tae a Saec Bees eee peer 2 ft. 2 in.|/Railroad levels. Sima ee cb lehosiee From Oakland to the mouth .|1 ft. 6 in.|Railroad levels. OWE) eerie distor (From Iowa Falls to Iowa City|3 ft. 1 in.|Railroad levels. Towa...........-|From Iowa City to the mouth|2 ft. 4 in.|Railroad levels. COCBiRA ARS Aoeniae From State boundary to Cedar Balls) pec eee, sy ate ariceage 3 ft. 7 in.'Railroad levels. Cedar ye cession From Cedar Falls to Moscow.|2 ft. 5 in.|Railroad levels. CeO Aisi te arene From Moscow to the mouth ./2 ft. 0 in.|Railroad levels. Wapsipinicon....|From Independence to the HANOI ect oe ilps ae ee 2 ft. 10 in.|J. E. Ainsworth. Maquoketa...... From Manchester to themouth|3 ft. 4 in.|J. EH. Ainsworth. (VOIR EY GyoRs ae .|From Crane creek to the HOUYO1 EO Rep ER Re TERROR, SaaS. ats 5 ft. 0 in.|Railroad levels. Upper Iowa.... |From Decorah to the mouth.|8 ft. 6 in.|Railroad levels. SURFACE FEATURES. 41 Slopes of the Principal Rivers of Iowa—— Continued. NAMES. PART OF COURSE. SLOFE AUTHORITY. PER MILE. _E. Nishnabotany.|From C. R. I. and P. Railroad| ial | Fo cme. Monthh spe. beens 2 ft. 5 in.|Railroad levels. W. Nishnabotany|From C. R. I. and P. Railroad HO Mes INO Ws. oie) 4 35:0 ae: Sry 2 ft. 8 in.|Railroad levels. BON (CLS Ais eee nia From Dennison to the mouth./3 ft. 3 in./Railroad levels. Little Sioux..... From Cherokee to Smithland,'2 ft. 6 in.|Railroad levels. little Sioux... . From Smithland tothe mouth|0 ft. 4 in./Railroad levels. Big Sioux... ./ From N. W. corner of the State to Indian creek...... 3 ft. 2 in.) Approximate estimate. Ie SIOUX. s+... From Indian creek to the LAV 0.1010: A POS ta ear a 1 ft. 4 in.|Approximate estimate. 1:1 070 rea From fork of Willow creek to TM *TMOUGINY s).).%4 dares abies + 6 = 3ft Oin.J|J. E. Aicsworth. The rivers of Iowa alone would furnish material for a much more lengthy discussion than the limits of this report will allow, but the most that can be done at the present time is to give an outline of their general and peculiar characters, confining remarks in reality more to the valleys than to the the streams themselves. Notwithstanding the general flatness of the country through which our rivers pass, the characters of their valleys are some- what varied by the difference in the character of the forma- tions out. of which they have been eroded, and over which their waters flow; and also by the depth to which the slope of the surface from their sources to their mouths have re- quired their erosion. The conditions being the same, the character of the valleys and their streams would everywhere be uniform, and there is consequently a great degree of uni- formity among lowa streams. This uniformity is due to the depth and universal prevalence of the surface deposits more than to any other cause. It is especially so in Western Iowa where the stratified rocks are generally and deeply covered by those deposits. In attempting to divide the rivers of Iowa into classes for more convenient description, each class having certain charac- teristics In common, no more natural division can be made than that which separates the two drainage systems as before deseribed. 6 49 PHYSICAL GEOGRAPHY. The Drift and Bluff Deposits are-both so thick in Iowa that its streams not only rise upon their surfaces, but they also frequently reach considerable size upon, and have eroded their valleys to a considerable depth into these deposits alone. In a few cases, as for example near the dividing ridge between the two great rivers, where the Drift Deposit is deepest, the valleys, small as the streams are there, have been eroded by those streams to a depth of nearly or quite two hundred feet from the general prairie level, showing nothing but drift anywhere in their bottoms or sides. It is © known that the Bluff Deposit also reaches fully as great a thickness in southwestern Iowa, where some of the valley- sides and bottoms are composed entirely of that homogeneous material. In consequence of the great thickness of the surface deposits, many of the streams, more especially those of western Iowa, are very largely and some of them wholly without exposures of rocky strata along their whole course. In other words, such streams rest wholly or in large part upon the incoherent surface deposits alone, and into which they have eroded their valleys. When the material out of which a valley is eroded, especially in Iowa, consists of alternating hard and soft strata, the valley is usually wide and the soft beds fre- quently give rise to broad, flat, flood-plains; but if the valley is cut out of material of uniform character it is usually deep, narrow, and gorge-like. When the valley sides are wholly composed of the incoherent surface deposits, they are of course never precipitous like those which contain rock in their composition. They are sometimes, however, quite steep, but always slope more or less directly from the surrounding highland to the flood-plain or the stream. The upper branches are, almost without exception, prairie streams; their valleys not being well defined as such, but form a part of the general undulatory character of the surface. - When the valley is cut out of the stiff, clayey drift, like some of that of southern Iowa, the sides are SURFACE FEATURES. 43 usually steeper than they are when it is eroded out of the more sandy and gravelly drift of a part of northern Iowa. If the valley is eroded out of the Bluff Deposit, its sides may be either gently sloping, or even occasionally so steep that a man can climb them only with great difficulty. The peculiar physical properties of this strange deposit are described upon subsequent pages. The majority of the streams that constitute the western system of Iowa drainage run, either along the whole or a part of their course, upon that peculiar deposit described in another part of this report under the head of Bluff Deposit. As these streams seldom reach any more solid material, their banks and beds are always muddy; the stream itself occupy- ing a narrow, tortuous ditch in usually a narrow flood-plain, and having banks so steep and muddy that they are almost impassable to man or animals except by bridges. Other portions of some of these streams and the whole of some others of the western system, as well as the upper, branches of all those of the eastern system, rest upon and within the Drift Deposit alone. As the last named deposit is not quite so uniform in its composition in all parts of the State as the Bluff Deposit is, the characters of the beds and banks of the streams which run upon it are a little different in different parts of the State. Thus as sand and gravel are more prevalent in the drift of northern than in that of southern Iowa, the beds and banks of the streams in the first named portion of the State, are frequently pebbly and firm, while those upon the same deposit in southern Iowa are sometimes nearly as muddy, and possess much the same characters as those do which run through the Bluff Deposit. The immediate beds, however, of all streams upon the drift are usually gravelly; the gravel being the residue from the large amount of the finer drift material that has been removed by the streams to form its valleys. From the foregoing description of the beds and banks of the streams of western Iowa, it will be properly inferred that 44 PHYSICAL GEOGRAPHY. they afford comparatively few secure mill-sites, although their fall per mile is very considerable, as shown by the table on a preceding page. Wherever any practicable mill-site does occur upon these streams, they are occasioned by the exposure to a greater or less degree of some of the strata that underlie the very heavy surface deposits. Another cause of the great uniformity in the character of the river valleys of western Iowa, is the simplicity of the stratigraphical geology of the region. Almost the whole of the region occupied by the streams of the western drainage system is underlaid by only two formations; namely, the Upper coal-measures and Cretaceous. The strata of the last named rocks are usually so friable and easily disintegrated that they have offered very little impediment to the erosion of the valleys; and, for the same reason, they do not often appear as exposures along the valley sides, even when they are known to exist beneath the surface. It is for this reason, in addition to the fact that the surface deposits are upon the whole thicker in western Iowa, that exposures of strata are so much more rare there than they are along the rivers of the eastern system. In view of the intended limit of this chapter, comparatively little discussion can be devoted to each individual stream, which fact must serve as a sufficient explanation of the brief manner in which they are treated. 5. RIVERS OF THE WESTERN SYSTEM. All of the rivers of the western system of drainage, except the Missouri itself, are quite incomplete as rivers, in conse- quence of their being really only branches of other larger tributaries of that great river; or, if they empty into the Missouri direct, they have yet all the usual characters of upper branches of Iowa rivers, from their sources to their mouths. Chariton and Grand rivers (or rather the upper branches of rivers which bear those names in, and drain a part of the SURFACE FEATURES. AD State of Missouri), both rise and run for the first twenty-five or thirty miles of their courses upon the Drift Deposit alone. The first strata that are exposed by the deepening valleys of both these streams belong to the Upper coal-measures, and they both continue upon the same formation until they make their exit from the State, near the boundary of which they have passed nearly or quite through the whole thickness of that formation down to the top of the Middle coal-measures. Therefore, as might be expected, both these streams are very similar in their general characters so far as their Iowa portions are concerned. ‘Their valleys are usually pretty well defined; but sometimes the surrounding high land slopes for a mile or more gently towards the stream. They grad- ually deepen from their upper portions downward, so that within fifteen or twenty miles, they have reached a depth of near a hundred and fifty feet below the general level of the adjacent high land, which depth they retain with little in- crease until they pass beyond the limits of the State, because the general slope of the country is nearly concurrent with the slope of the streams. The strata of the Upper coal-measures consist, in this part of the State, of beds of limestone alternating with those of clayey and shaly composition. The latter readily soften and disintegrate upon exposure to atmospheric influence and the action of the streams. Thus when the rivers have cut their valleys down through the series of limestone strata, they reach those of clayey composition before mentioned. Upon these they widen their valleys and make for themselves broad flood-plains which become conspicuous features in their scenery; the soil of which, owing to its origin, is stiff and clayey, except where it is modified by sandy washings. These broad bottom lands are particularly noticeable in the southern parts of both Appanoose and Decatur counties. A considerable breadth of woodland occupies the bottoms and valley sides along a great part of their length, but their upper branches and tributaries are mostly prairie streams. Platte river. This is also a river belonging mainly to 46 PHYSICAL GEOGRAPHY. the State of Missouri, the upper branches of which pass through Ringgold county from north to south, and together with those of the West Fork of Grand river,* drain a consid- erable region. The highest ridge of land between the two great rivers (not the Great Watershed as before explained), also passes through it in the same direction. Here the Drift Deposit reaches its maximum thickness on an east and west line across the State, and the valleys are eroded in some instances to a depth of two hundred feet below the general level of the adjacent prairie, apparently through this deposit alone, and not even then exposing its base except in a single instance, which occurs near the south line of Ringgold county. There all the valleys of these streams have the general features before described as characteristic of drift valleys. These characteristics are well marked in Ringgold county, because the valleys there are so much deeper than drift valleys average throughout the State. The county is nearly all prairie, and as the traveler is passing across it, he is hardly aware of the existence of the valleys until he is just upon their borders. Then he sees the stream winding through a narrow, scarcely defined flood- plain, usually having a narrow, often interrupted belt of forest trees along its banks, which were quite invisible at a distance in consequence of the depth of the valley. One-Hundred-and-Two river is represented in Taylor county by its Hast and West Forks, the valleys of which have the same general character as those just described, only they are not so deep. The East Fork has an exposure of Upper coal- measure limestone upon its banks at Bedford, but itis not sufficient to modify the general drift character of the valley. Nothing but drift appears in the valley of the West Fork so *The meagre nomenclature of the pioneers has given rise to much subsequent incon- venience, for, instead of giving a Separate name to each stream, they often applied the name of the main stream to each one of its principal tributaries with the addition of North, South, Kast, West or Middle, as the case might be. Thus we have the North and South Chariton, East, West, and Middle Nodaway, Hast and West Nishnabotany, etc., etc, SURFACE FEATURES. 47 far as now known. The country around and between these streams is almost entirely prairie. The Hast, West, and Middle Nodaway rivers and their val- leys are very fine examples of the small rivers and valleys of southern lowa. They have the general characters of drift val- leys with beautifully sloping and undulating sides. These characters are very slightly modified at several distant points, by the presence in their beds and immediate banks of limited exposures of Upper coal-measure strata. As the southerly dip of these strata, however, coincides almost exactly with the slope of the southerly flowing streams, they offer com- paratively little obstruction to their flow, yet they are sufii- cient. to cause a few good mill-sites on each of the streams. The Nodaways drain one of the finest agricultural regions in the State, the soil of which is tillable almost to their very banks. These banks and the adjacent narrow flood-plains are almost everywhere composed of a rich, deep, dark loam. The average depth of these valleys, from the surrounding prairie level, is not far from one hundred and fifty feet, the southerly slope of the country Keeping the depth of the val- leys nearly uniform along a great part of their length. Their width varies from an eighth to a quarter of a mile, but their margins blend gradually with the prairie surfaces of the high lands. The Hast and West Nishnabotany. Both these rivers, from their sources to their confluence, and also the main stream from thence to the point where it enters the great flood-plain of the Missouri, run through a region the surface of which is occupied by the Bluff Deposit described in a following chap- ter. They have so eroded their valleys that the underlying Drift Deposit is exposed in their immediate beds along almost their entire length; but the valley sides, flood-plains, and even the banks, are everywhere composed of the Bluff De- posit. This is owing to the fact that near their sources the Bluff Deposit is thin and gradually increases in thickness towards the Missouri river, at a rate that coincides very nearly with the slope of the streams. ye a 48 PHYSICAL GEOGRAPHY. The characters of these valleys receive very little modifica- tion from the presence of the Drift Deposit, yet they do not differ very greatly from the drift-valleys in general appearance, more especially along their upper portions. Both these rivers have a few exposures of the underlying strata in their valleys, but they occur only along their middle portions above their confluence. These do not, in consequence of the ereat thickness of the surface deposit, modify the character of the valleys to any extent. The West Nishnabotany is probably without any valuable mill-site, although it has a _ few slight exposures of Upper coal-measure, limestone, and Cretaceous sandstone in its valley. These occur only in the southern part of Pottawattamie county and in the western part of Mills county. In the western part of Cass county, the East Nishnabotany loses its identity by becoming abruptly divided up into five or six different creeks, near which point several exposures of the Upper coal-measures, and a few also of Cretaceous sand- stone are found in their valleys, and also in that of the main Nishnabotany. A few exposures of the same rocks are also found at rare intervals below the point referred to, in the counties of Pottawattamie, Montgomery, and Page. A few good mill-sites occur on this stream in the western part of Cass county, near the exposures of stata before mentioned; but none that are thought to be really reliable, exist on either of these rivers or on the main stream below the confluence, except perhaps, one or two in Montgomery county. The general appearance and character of the valleys of these two rivers from their sources to the middle, respectively, of Cass and Pottawattamie counties, are those of ordinary prairie creeks, or of valleys excavated in the drift alone. The valley sides are gently sloping and undulatory like those of such streams; but below the points named they begin to assume their peculiar characteristics. The valleys gradually widen to a width of from a quarter of a mile to one or two miles, or even more; their sides being still undulatory and SURFACE FEATURES. is CO usually sloping very gently to the flood-plain. The flood- plains of these valleys are in some respects unlike those of other streams, for they usually have a slight but regular slope from the valley-side to the stream without any appear- ance of terraces; and yet much the larger part of the surface of these plains is entirely above the reach of the highest floods. Near the confluence of the two streams the valleys are still further widened, and the slopes of their sides from the uplands are very gentle. Below the confluence the united valley has much the same appearance, and from the distant high ridge, which separates it from that of the Missouri river, the view is often very beautiful and extensive, for the elevation at that distance from the river is upward of two hundred feet above the Nishnabotany. From the point where the Nishnabotany enters the great flood-plain of the Missouri river, it meanders through it for many miles as a tortuous, muddy canal, and finally empties into the great river within the State of Missouri. The two valleys throughout their entire length possess considerable, but unromantic beauty; and the soil, both of the valleys and the entire intervening uplands, possesses remarkable fertility. It is seldom the case that the valley sides are steep, like the bluffs of the Missouri river flood- plain, although they are composed of the same material that those are; but when we approach the point where the united valley joins that of the great river, we begin to see the abrupt and peculiar outline of the bluffs so characteristic of the valley-sides of the Missouri river. Boyer river, until it enters the flood-plain of the Missouri river, runs almost, if not quite its entire course, through the region, the surface of which is occupied by the Bluff Deposit; but like all others of the principal streams that run through this deposit, it has cut its valley out of, and entirely through it along almost its whole length. In consequence of this, some pebbles and sand are usually to be found in its. imme- diate bed, but nothing except the fine material of the Bluff Deposit is elsewhere to be seen. This prevails so fully that 5O PHYSICAL GEOGRAPHY. the bed and immediate banks are everywhere muddy; and the soil of the whole valley differs little if any from that of the upland. The only rocks exposed along the entire course of Boyer river are those of the Upper coal-measures, and these occur only at a single locality near Reel’s mill in Harrison county. The exposures here are slight, and unimportant, except that they are the only exposures of underlying strata in the county, and the most northerly ones of the Upper coal-mea- sures now known in [owa. The valley of Boyer river has usually gently sloping sides, and an indistinctly defined flood-plain. Its depth from the adjacent uplands varies from one hundred to one hundred and fifty feet; but the upland borders of the valleys of the stream which traverse the Bluff Deposit, are not usually so well defined as those of the streams which traverse the Drift Deposit alone frequently are. Along the lower half of its course, especially, the adjacent upland loses the originally well defined surface level, and presents a surface of the bil- lowy character, so common near the valley of the Missouri river and peculiar to the Bluff Deposit. An unusually well marked example of this billowy surface of the same deposit, may be seen in the sketch accompanying the chapter on northwestern Iowa. It will thus be seen that the whole valley receives its characters from the surface deposits alone, without any modification from the underlying strata. Soldier river presents very little that is peculiar to it, as compared with the other rivers which traverse the Bluff De- posit thus far described. However, near the point where its valley joins the great flood-plain of the Missouri river, it presents some examples of more or less distinct terraces, which are comparatively more rare in the Bluff Deposit than in the drift, owing to the peculiar composition of the former. The mode of formation of these terraces will be discussed in the chapter on Surface Deposits, accompanying which, will be found a sketch of the locality where the valley of Soldier river joins that of the Missouri. SURFACE FEATURES. 51 The whole course of Soldier river, except that part which traverses the great flood-plain, is through the region occupied by the Bluff Deposit. It has cut its valley down through this deposit to the drift, along a great portion of its course but nowhere far into it. It has no exposure of strata along its entire course, and is consequently, a characteristic stream of the surface deposits unmodified by underlying strata. Little Sioux river. Under this Kead are included both the main and west branches of that stream, together with Maple river, which is also one of its branches. Like Soldier river, both the West Fork and the Maple run their entire courses—except their upper branches which are mere prairie creeks upon the Drift Deposit—through the region occupied by the Bluff Deposit, and are so similar to the Soldier in all respects, that they need no separate description. The main stream, however, has its rise near the northern boundary of the State, and runs a great part of its course upon the Drift Deposit alone, before it enters the region occupied by the Bluff Deposit, which it does in the southern part of Cherokee county. That portion-of the valley of the Little Sioux, from its source to the place where it enters this region, may be regarded as a typical drift-valley as they occur in Jowa, for nothing but this deposit is to be seen within or around it, and so far as is now known, it is not at all modified by the under- lying strata whatever they may be. The two principal upper branches near its source in Dickinson and Osceola counties, are merely small prairie creeks. with gravelly beds and banks, and shallow, indis- tinctly defined valleys. Upon entering Clay county the valleys begin to have considerable depth, and after their confluence there, the valley soon reaches a depth of about one hundred and fifty feet. The depth continues to increase so that the part of the valley that has a westerly course along and near the boundary line, between Clay and Buena Vista ‘counties, reaches a depth from the general prairie level, which is here quite distinct, of nearly two hundred feet. The valley here apparently cuts across the ridge which constitutes 52 PHYSICAL GEOGRAPHY. the Great Watershed in this part of the State, along which portion of its course it has well-defined borders, and a width of from one quarter to half a mile. Even here, where the valley is so deep, nothing but drift is to be seen in its bottom or sides, from which fact it is inferred that the Drift Deposit is about two hundred feet thick at this point. Just as the valley enters Cherokee county it turns to the southward, and becomes much widened and has its sides usually gently sloping to the uplands, which gives it the appearance of being shallower than it is farther up; but this is really not the case. When the valley enters the region of the Bluff Deposit, the surface soon begins to assume that billowy appearance before described, and its borders are consequently more or less obscured; yet it retains a general depth of about two hundred feet from the adjacent plas until it joins the valley of the Missouri. The lower portion of the river, from the last named point, is wholly unlike any other part of it; but is like similar portions of every other stream that crosses the great flood- plain within the State. Its a narrow, sluggish ditch, which is frequently filled with back-water from the Missouri river, so as to cause an overflow of the water of the upland portion of the stream upon the flood-plain. Indeed, the lower portions of these streams are only accidental channels for the escape of their waters to the great river across its flood- plain. The Missouri river in former times ran along the foot of the bluffs on the Iowa side of its valley, where traces of its channel still remain. The Little Sioux now flows along a portion of the old channel of the great river, where it unites the West Fork, the Little Sioux, and Maple rivers into a common channel as they successively come down upon the uplands. Formerly these were independent streams and each emptied directly into the Missouri river. No exposures of strata of any kind have been found in the valley of the Little Sioux nor in those of its branches. floyd river is a small stream, essentially like those just ee ie: eee ee ee See ee OU ve SURFACE FEATURES. described. It rises upon the drift, and flowing southward, it enters the region of the Bluff Deposit a little north of the centre of Plymouth county, and continues upon this deposit from thence to its mouth near Sioux City. Along this part of its course it has not, like the other streams of the region of the Bluff Deposit, cut its valley down through it, so as to expose the drift, except at a few points near Sioux City; although it seems certain that the drift cannot be anywhere very far beneath its bed. This river is, almost from its source to its mouth, a prairie stream, with gently sloping valley-sides which blend gradually with the uplands, giving the valley the appear- ance of being very shallow. It reaches a depth of about one hundred and fifty feet from the adjacent uplands. = j CZ Oe Ae Ci URE ae ZZ zzzzddaau’§» gg SZ OWEST FREEZING LINEs LPAI ae A=LZZZZZZZ DD Zieh The above diagram shows the relative positions of the embankments, the high and low water levels, and the lowest level of freezing. The embankments vary in height from two to ten feet, and. from five to twenty or thirty feet across the top, their size and outline varying according to the materials which com- pose them. If boulders were numerous upon the bottom, the adjacent embankment is largely composed of them; if sand prevailed, a broad, gentle, rounded embankment resulted, just such as might be expected from that material; and if mud, filled with the fibrous roots of water plants and sedges, were brought out by the ice, a steep, narrow embankment was formed, because such material will stand more erect in a ridge or embankment than sand and boulders will. Such embankments of fibrous mud are often found separating a peat-marsh from the lake which was once a part of it. These are erroneously cailed Beaver dams by those who forget that beavers never attempt to dam still waters; but dam running streams only, that they may have ponds of still water for the use of their colonies. : It has been observed that the embankments are often largest on the sides opposite the prevailing winds. This may be accounted for, at least in part, by the fact that the ice being burthened with the materials to which it had frozen fast, would be floated to those shores when the spring-floods had raised the water in the lakes; and in part also, by the fact that the dashing of the waves would be most constant and forcible against those shores. The objection that the material thus taken up and floated by the ice would be as likely to drop anywhere else as at the shore, loses force when it is remem- bered that wherever else they may drop they are subject to be 18 PHYSICAL GEOGRAPHY. again removed by the causes before mentioned, but once dropped at the shore they remain there. Thus we see that the same natural force that brought the boulders down from their northern home, also placed them in the embankments of those lakes; namely, the expansive power of ice. These embankments are really very interesting natural -objects, and it is not strange that they have attracted much attention; but with a correct knowledge of natural forces it is difficult to understand how any person could suppose that human hands had anything to do with their construction. There is certainly nothing in the arrangement of the materials that indicates such an origin; and the liveliest imagination refuses to suggest any object for which human beings could have desired them, or to point out any evidence of human intelligence in their location and plan. 10. SINKHOLES AND SPRINGS. Among the minor features that are found to mark the surface at some limited localities in the State, and which always arrest considerable popular attention, are small circular depressions known as sinkholes. They are almost without exception in the surface of the uplands, and only where these immediately border a valley in the sides of which limestone ledges or cliffs are exposed. The mode of their formation is this: the water which falls upon the surface finds its way by percolation down to the underlying strata, and through fissures and interstices in these, out upon the valley-side below, where it issues in the form of springs. A little of the fine surface material is constantly taken into the subterraneous passage by the water which falls upon-the surface, and is conveyed by it into the valley in the form of sediment. Upon the surface imme- diately above the point where the percolating water enters the fissure in the rocks, a depression is formed by the caving in of the surface material. Depressions thus commenced deepen by the same cause until the sinkholes are formed, | SURFACE FEATURES. "9 having the shape of an inverted hollow cone, with a depth at the apex, sometimes reaching twenty or thirty feet from the > surface, and even more. Water accumulates in these sinkholes from every hard rain, but it soon drains out again through their subterraneous passages—hence their name of sinkholes. Sometimes they are larger than has just been indicated, and have miniature ravines leading into them through which little rills of water flow in time of rain. Just eastward from the town of Decorah, in Winneshiek county, a good sized creek empties into the south side of the Upper lowa river. About a mile up from the mouth of this creek, it is seen to issue from _ the abrupt end of its valley in the form of a huge spring, and is immediately set to work by an enterprising citizen to fur- nish power for a woolen factory. Going back from this point upon the undulating uplands, we come upon the creek valley again within about half a mile, and see the creek disappear beneath the surface in a depression, which is really a sinkhole on a large scale, with a constant stream of water running into it. With the exception of this half a mile of subterraneous passage, however, the creek is in all respects an ordinary one. It is the peculiar fissured and laminated character and great thickness of the strata of the age of the Trenton lime- stone, which underlies the whole region, and forms the valley- sides of its streams, that has produced this interesting phenomenon, and which also gives origin to numerous sinkholes along the upland borders of the Upper lowa valley. From the same cause, also springs of large size are very numerous in that valley, a number of which, since they have so great a fall, give sufficient water-power for small mills. . Springs, of course, issue from all formations and from the sides of almost all valleys, but they are more numerous and important when the underlying strata are of such a character as to facilitate the percolation of the surface-water down to a certain level there to be arrested, so that it will flow out upon the surface below. No mineral springs, properly so-called, have yet been 80 PHYSICAL GEOGRAPHY. discovered in Iowa, but the water of artesian wells is frequently found charged with soluble mineral substances, as ~ will be seen in the report of Prof. Emery, in volume two. 11. CAVERNS. Although a large part of Iowa is underlaid by limestone formations, there are no caverns in the State that are remark- able as such; yet, in consequence of associated circumstances, some of those that do exist are worthy of mention in this connection. The most noted of.these are the lead caves of Dubuque and the ice-cave of Decorah. The lead-caves are usually mere vertical fissures extending through a great portion of the whole series of strata which constitute the Galena limestone formation. They vary in width from a mere fissure to two or three yards. They are very numerous and are fully described by Prof. Whitney, in his chapter on the Dubuque lead region in the former geological report. The /ce-Cave at Decorah is a vertical fissure in the face of the cliff of Trenton limestone that forms a part of the north valley-side of the Upper Iowa river. The fissure is nearly parallel with the face of the cliff, and seems to have been produced by a slight settling away of a portion of its face at the base, causing its slight separation from the solid portion. The fissure or cave is about one hundred feet long in all its windings, and varies from two to six or eight feet in width. Its height is irregular, as the two walls come together irregularly at the top. | The ice collects upon its bottom and upon its inner wall near its base, in the form of an encrusting mass. No water was seen flowing or accumulating anywhere; the ice seemed dry and well frozen, and was evidently accumulating at the time of our visit, (June 1st, 1869). The cave was cool and apparently dry, and no strong current was passing through it. The ice is said to be most abundant about midsummer and entirely absent in winter. The formation of the ice is probably due to the rapid evaporation of the moisture of the earth and rocks, caused by SURFACE FEATURES. 81 the heat of the summer sun upon the outer wall of the fissure and valley-side. This outer wall is from ten to twenty feet in thickness where the ice was seen to be most abundant. The water for its production seems to be supplied by slow exuda- tion from the inner wall of the cave. Ice caverns, more extensive than this are known in various parts of the world, but this is, so far as now known, the only one in lowa, and has consequently excited much popular interest. 11 CH ARES ULE. SURFACE DEPOSIT Ms The surface deposits, which it is proposed to discuss in this chapter, are those to which the names of Drift, Bluff, and Alluvium have been applied; all of which rest upon or above the stratified rocks that form, so to speak, the foundation of our State. It is from these almost alone that our soil has been derived, and, covering the underlying rocks so generally, the materials of which they are composed are more familiar to our eyes than any others which enter into the composition of the earth’s crust. 1. DRIFT. The deposit to which the name of Drift is applied, has a far wider distribution than any other surface deposit. It meets our eyes almost everywhere, covering the earth like a mantle and hiding the stratified rocks from view, except where they have been exposed by the removal of the drift through the erosive action of water. It forms the soil and subsoil of the ereater part of the State, and in it alone many of our wells are dug, and our forests take root. Occasionally it is itself covered by another deposit; as for example, by the Bluff Deposit of western Iowa, in which case, the latter forms the soil and subsoil. No other deposit, however, intervenes between the drift and the stratified rocks. Physical Conyposition. The drift is composed of clay, sand, gravel, and boulders, promiscuously intermixed, without stratification or any other regular arrangement of its mate- rials. It varies in character in different parts of the State, ; 82 SURFACE DEPOSITS. 83 but the variation is principally due to the varying pro- portions of the component materials. These materials are always incoherent; that is, they are not cemented nor con- solidated into rock, but may always be excavated with more or less facility. All the materials of the drift being so intermixed, it is somewhat difficult to give any definite description of each, especially of the finer ones. Such descriptions, therefore, must be merely general. The clay of the drift, which is always present in greater or less proportion, is always impure; always finely dissemi- nated throughout the whole deposit, but not unfrequently, irregular masses of it are separated from the other materials. Its color is usually yellowish from the per-oxyd of iron it contains, and which when it is burned into bricks gives them their red color. The clay is frequently sufficiently separated from the other materials, to assume the peculiar fissured character which sepa- rates the mass into small, irregular, angular divisions, in which condition it is popularly called ‘‘joint clay.” Again, particularly within the limits of the coal-field, it has frequently the same character as that into which the clayey and shaly beds of the coal formations are seen to become weathered, where they crop out in the valleys of the streams of that region. Much of the so-called clay of the drift, and also of the soil, is however, not wholly a silicate of alumina, as true clay is, but it is often largely intermixed with more or less pure silica in a finely divided condition. Besides this, it usually contains varying proportions of the carbonates and silicates of lime and magnesia, the carbonates being much the most abundant. The proportion of lime in the drift of Iowa, is so great that the water of all our wells and springs is too ‘‘ hard” for wash- ing purposes; and the same substance is so prevalent in the drift clays that they are always found to have sufficient flux when used for the manufacture of brick. It is frequently the case, that the sand and gravel have 84 PHYSICAL GEOGRAPHY. naturally combined with the clay in such proportions as to produce a mass of extreme hardness, which, together with the toughness imparted by the clay, renders its excavation almost as difficult as that of rock. The sand of the unaltered drift is seldom separated from its other materials in any degree of purity, but it is not unfre- quently the case that it exists in excess of the others; and in some cases small local accumulations or pockets of it are found, having a considerable degree of purity. The sand is quite variable as to fineness, and it sometimes approaches or grades into gravel. | The gravel of the drift is derived largely from rocks that are more or less purely silicious, but occasionally they are _ found to be of granitic composition. In southwestern Minnesota, the Sioux quartzite is often found in the form of beds of considerable thickness, composed of a mass of silicious pebbles, varying in size from coarse grains of sand to three or four inches in diameter. Such beds are not so hard and compact as the ordinary quartzite is, but the pebbles often separate with considerable facility ; although this, as well as the quartzite, has undergone metamorphism. In western and northwestern Iowa also, the Cretaceous sand- stones are found to contain beds of silicious pebbles scarcely cemented together at all. The pebbles of both these forma- tions are silicious and never granitic. From these sources, and also from the beds of rivers that existed upon the surface at the commencement of the Glacial epoch, it is believed a large part of the pebbles of the drift were derived. These of course were already formed as pebbles at the commencement of the Drift epoch, some having been worn in Azoic and some in Cretaceous seas; while others received their form in the beds of pre-glacial rivers. It is not denied that a part of the drift pebbles may have received their rounded form by glacial attrition, or other causes subsequent to the glaciers; but there can be no doubt that a large part of the drift gravel of Iowa existed as gravel before the Glacial epoch. Gravel constitutes only a small SURFACE DEPOSITS. 85 proportion of the bulk of the drift, but it is always a charac- teristic constituent of it. Boulders constitute a very conspicuous and characteristic feature of the drift, although they form but a small pro- portion of the bulk of that deposit in Iowa, where its fine materials are everywhere greatly in excess of all others. The boulders of Iowa drift are composed of granite, quartzite, and limestone rocks; those of granite being much more numerous than all others in eastern Iowa, and those of eranite and quartzite both largely prevailing in the western part of the State. Limestone boulders are comparatively rare anywhere, but they are found most frequently in the middle portion of the State as one traverses it from east to west. The largest as well as the most numerous of the boulders are those of granitic composition. Occasionally these are quite large, reaching fifty tons in weight or upwards, but they are usually very much smaller than this. Although generally they have at least a somewhat rounded form, they seldom present any real appearance of having been water-worn as the pebbles have. Their rounded forms seem due rather to the concentric decomposition of the broken fragments of rocks, thus rounding off their angles; or to the somewhat concretionary character of the mass of which it was originally a part. This, it is thought, is particularly true of the granite, which is known sometimes to contain con- cretionary centres in which the rock is harder and more compact than the greater part of the mass is. Rare Substances and Fossils are sometimes found in the drift of Iowa. The fossils are always those of the older rocks, none of any kind having been discovered in it that are properly referable to the age of the drift itself. Lumps of copper, lead-ore, and even traces of gold, have been found in it. Also lumps of impure coal, pieces of wood, and other traces of vegetation. All these have been transported and are aS much strangers in lowa as the granite boulders are. Their origin will be referred to on a subsequent page. Distribution of the Drift. No evidence of anything like 86 PHYSICAL GEOGRAPHY. general stratification, or successive changes in the vertical accumulation of the materials of the drift as originally deposited, has been observed in Iowa. Modifications of it, in some cases closely approaching true stratification, have taken place, but this was evidently subsequent to its original deposition, and will be presently noticed under the head, of Altered Drift. It may be remarked here, however, that the eye may occasionally catch a trace of a horizdntal arrangement of large pebbles and small boulders in such places, for example, as the face of a railroad excavation in the drift upon the high prairies of the State. This apparent modification probably has no direct connection with the more distinctly stratified altered drift of the valleys, but the subject will be again referred to further on. Neither the clay, sand, gravel, or boulders, are confined to any particular part of the deposit vertically, but either or all of them may occur at its base, middle or surface. Generally, however, the whole surface of the drift, especially that of the higher prairies, 1s covered with the finest materials alone, the coarse materials and stiff clays being usually covered from sight. This is particularly the case in eastern and southern Iowa, where boulders upon the higher surface are rarely seen, but in northern Iowa the higher surfaces sometimes have boulders and gravel exposed quite conspicuously upon them. The different materials of the drift have little more regu- larity in their geographical distribution than in their vertical arrangement, but that distribution, indefinite as some of its outlines are, throws considerable light upon the origin of the deposit. It may be said in general terms that in northern and northwestern Jowa the drift contains proportionally more boulders, pebbles, and sand, than elsewhere, and that in other parts of the State it contains proportionally more clay and other finely comminuted materials; yet in the first named region there is enough of the clayey material, as a general rule, to produce an excellent soil. Occasionally, however, the elevated ridges and knolls there have a poor SURFACE DEPOSITS. 87 soil, composed of little besides gravel and scattered boulders; but such places are very small compared with the space occupied by good soil, and would hardly attract attention anywhere except in a region so fertile as Iowa. Boulders being more definite in their character than the other materials of the drift, we are able to make more satis- factory observations concerning their distribution. We find that they are more abundant in some places than in others; and also, that those having a certain composition prevail in some parts while such are entirely absent in others. Besides this, we find that in one limited part of the State, boulders of all kinds are almost entirely absent. The outline of this boulderless region may be approximately described as follows: Commencing upon the north line of Winneshiek county, go southeastward to the center of the west line of Clayton county, thence to the northwest corner of Jackson county, and thence to the Mississippi river, near Clinton, the space between this line and the Mississippi river, is the region referred to. Itisnotentirely boulderless, but boulders are exceedingly rare there. It is, however, by no means a driftless region; because the other characteristic materials of the drift are present, except upon some of the hills and in some of their _ valleys near the great river. Occasionally the drift clays are found to be of considerable thickness within this region. Going westward from this boulderless region, we find inmediately bordering and parallel with it, extending from Mitchell, to Cedar county, another region in which boulders are unusually prevalent as compared with other parts of the State. Even in this region, where boulders are most abun- dant, they are never so numerous as to constitute a blemish upon the fair surface, nor to cause any impediment worth naming to farming operations. After crossing the Des Moines river we find, in western Iowa, a variety of boulders that do not appear at all in eastern Iowa. These are of red quartzite, identical with the Sioux quartzite, and are distributed, in connection with the 88 PHYSICAL GEOGRAPHY. common granite boulders, from the northern to the southern boundary of the State. In that portion of the middle third of the State, extending from its northern boundary to the city of Des Moines, occasional boulders and transported masses of light yellowish magnesian limestone are found. These are usually rare, but they have been found sufficiently numerous in some places to serve the first settlers with material for limited quantities of lime. With the exception of the quartzite and limestone boulders, all others of the drift of Iowa are of some of the varieties of granite, usually a reddish syenite. Even this variety varies considerably by the varying proportions of its characteristic minerals with occasionally slight additions of mica. The Drift Deposit varies much in thickness in different parts of the State. This difference is partly due to the original deposition, and partly to subsequent erosion. It is thickest all along the dividing ridge before described, which consti- tutes in great part the watershed between the two great rivers. Along this ridge it evidently reaches a depth of not less than from one hundred and fifty to two hundred feet. Itis known to reach a hundred feet in thickness in many other parts of the State, and with few exceptions, it covers the surface every where so deeply that wells or other artificial excavations very rarely reach the stratified rocks, unless made upon a valley-side. For this reason we have no present means of knowing what the real depth of the deposit is over a great part of the State. There are two principal regions in the State where the Drift Deposit is comparatively thin. One of these regions 1s trav- ersed by the Shellrock river, from the southern part of Worth county to the confluence of that stream with the Cedar; and the other is that portion of southwestern and western lowa which borders the Missouri river, and within which the Bluff Deposit rests upon the accumulation of drift. Itis true that the underlying strata are there covered deeply from view, but it is mainly the Bluff Deposit, and not the drift, that covers them. SURFACE DEPOSITS. 89 These regions of varying thickness of the Drift Deposit, and varying distribution of its boulders, have a more or less definite northerly and southerly extension, so that as one goes westward across the State, he crosses them successively For example, starting from the Mississippi river in Clayton county, he has already crossed the boulderless region when he reaches West Union, in Fayette county, and he there enters upon the region in which boulders are more than usually abundant. Reaching the valley of the Shellrock, at Clarks- ville, he is in the midst of the region where the Drift Deposit is comparatively thin. From this point the drift gradually increases in thickness until he reaches the Great Watershed beyond the Des Moines, where it is evidently some two hun- dred feet thick. From the Great Watershed westward, it continues of considerable thickness to the Big Sioux, but crossing that river into Dakota, it is found to cover the Creta- ceous strata there only to a very slight depth. Again, if he starts westward on the line of the Burlington and Missouri River Railroad, he finds the drift to be of con- siderable thickness all the way, and reaching the dividing ridge in Union county, he finds indications that the drift there is upward of two hundred feet thick. Continuing westward, he finds it to diminish in thickness so rapidly and gradually that less than a dozen feet of it intervenes, in many places along the valley of the Missouri river, between the Bluff Deposit, which there overlies it, and the underlying rocks in situ. Occasionally in that region the drift is entirely wanting, the bluff material resting directly upon the stratified rocks. 2. ORIGIN OF THE DRIFT. It is not proposed here to discuss at length the question of the origin of the drift, but as reports of this kind are expected to be more or less devoted to popular instruction concerning the principles involved in the statement of facts observed, brief explanations of that kind are here made. 12 90 PHYSICAL GEOGRAPHY. Every one who examines the drift attentively cannot fail to see that it is composed of more or less finely comminuted rock which existed in other forms prior to its accumulation as drift, and that the questions to be considered are: to what extent it has been derived from rocks that now underlie it, to what extent from rocks elsewhere, and by what agency was the comminution, transportation, and accumulation of the material accomplished. After long and extensive examinations of the drift in all parts of Iowa, no doubt remains that a large part—probably much the largest—of it was derived from rocks within the limits of the State, and very largely from the rocks that immediately underlie it. It is also just as certain that a considerable part of it, including nearly all its boulders, was derived from the region lying wholly beyond the northern boundary of the State. As to the means by which the drift has been accumulated and transported, the greatest number and most important of known facts warrant the belief that it was accomplished through the agency of ice, which, during the Glacial epoch, covered the whole or the greater part of the northern hemisphere, far enough to the southward to reach quite beyond the southern boundary of our State. This former wide-spread glacier has receded until the southern limit of its remnants is now quite within the frigid zone, and they are now producing phenomena there similar to those the effects of which we daily witness in the drift of Iowa. The Evidences of the Northern Origin of at least a large part of the material composing the drift, consists mainly in our ability to trace up the boulders it contains to their original ledges far to the northward, and also in the fact that they cannot be so traced in any other direction. This is the most tangible proof; but there is a vast amount of evidence which corroborates this, and nothing which disproves it. It is quite evident also that much of the finer material of the drift, as well as the boulders, is of northern origin, but as its identification would be doubtful or impossible we rely upon the identification of the boulders alone. SURFACE DEPOSITS. 91 For example, profusely scattered in the drift of all western Iowa we find boulders of a very hard red quartzite intermixed with those of granitic origin. Following these northward we are able to trace them step by step until we come upon the original ledges from which they were derived, in the extreme northwestern corner of Iowa and the adjacent parts of Dakota and Minnesota. These ledges belong to the Sioux quartzite formation, described elsewhere in this report, and are the most southerly exposures of that formation yet known. Continuing northward into Minnesota we find these quartzite ledges to disappear, and the quartzite boulders also to disappear from the surface with them, while those of eranitic composition remain as plentiful as ever. Going still farther northward into the valley of the Minnesota river we find there extensive ledges of the same kind of granite as that of which the boulders are composed, and no doubt the same ledges from which a part, at least of our lowa boulders were derived. These granite ledges are found all along the valley of that river from Fort Ridgely to near its source, and similar granite is also known to exist in northern Minnesota, extending as far east as the Mississippi river. Therefore, we are not surprised to know that boulders of this granite are found in the drift of all parts of Lowa. But going back to southwestern Minnesota, near where we first found the Sioux quartzite in place, we are able to trace it eastward as far as New Ulm, a town on the Minnesota river, and no farther in that direction. Nowno red quartzite boulders are found in the drift of northern Iowa at any point eastward of a line directly south from New Ulm; but if a line be drawn from that town to Algona, onthe East fork of the Des Moines in Jowa, thence down the Des Moines river to the southern boundary of the State, it will describe approxi- mately the eastern limit of their distribution. It thus seems evident that the glacial current which transported these quartzite boulders, at least those along the eastern limit of the region they occupy, was not directly south, but that its general direction was a little east of south until it reached the 92 PHYSICAL GEOGRAPHY. centre of the State, and there it then swept more directly to the southeastward. Again, occasionally in the central and eastern parts of the State we find loose masses of buff colored magnesian lime- stone in the drift, which, in addition to: its lithological identification with strata in Minnesota and northeastern Iowa, we have the evidence also of the contained fossils that they are identical with and derived from those ledges. Evidences of Glacial Origin. Drift scratches and other phenomena observed in relation to that deposit are regarded as quite unmistakable evidences of its glacial origin since we have become better acquainted with the character of the glaciers of Greenland and the Alps; but they are in reality no more so than the great fact of the existence of the drift itself, but which loses its force as an illustration on account of our familiarity with it, now that it is no longer associated with ice, and of our unfamiliarity with glaciers in action. The drift scratches are found both upon the upper surfaces of the rocks in their natural position and upon the flattened surfaces of the boulders themselves. The flattening of the surfaces, together with their scratches, were produced upon each respectively by rubbing upon each other, the boulders having been frozen firmly into the bottom of the glacier while it was moving over the ledges, The scratches vary in distinctness with the difference in the character of the rock acted upon. Upon limestone, the scored surfaces are usually quite flat and the scratches distinct. The scratches vary from mere lines to grooves of such a depth that one might lay his finger within them, all being as straight and parallel as the joints in a floor. Upon granite, the rock being harder, they are less distinct and deep, but still, they have the same general character. Those upon the Sioux quartzite are less distinct than any others on account of the extreme hardness of the rock, but yet they are quite unmis- takably of the same origin. On account of the friable character of a large part of the rocks of lowa,or the facility with which they become disinteg- SURFACE DEPOSITS. 93 rated, the scratches and other traces of glacial action that were once doubtless abundant upon them, have to a great extent gradually become obliterated. For this reason, together with the fact that the drift so generally and deeply covers those surfaces which may be supposed to yet contain such traces, we seldom have an opportunity to observe them in our State. The only places where such scratches have been observed upon ledges of rock in Iowa, thus far, are upon the Burlington limestone—sub-Carboniferous—near Burlington; upon the Upper coal-measure limestone, in Mills and Pottawattamie counties, and upon the Sioux quartzite in Lyon county. Boulders, having their sides flattened and striated are how- ever found in various parts of the State, and at great distances from the localities just mentioned. We observed a very interesting fact in southwestern Minne- sota in connection with the glacial-scored surface of the Sioux quartzite. This rock, as before said, is intensely hard, almost glassy in fracture, and has the peculiarity of containing numerous vertical fissures at right angles to the plane of stratification. These fissures or cracks were observed to have their angles splintered in a peculiar manner when their direc- tion was eastward and westward. If in other directions, particularly northward and southward, they were compara- tively intact. These fissures are really but mere cracks, the vertical faces being only very slightly separated, so that they form sharp right angles with the upper surface. These angles were found to be unbroken upon the distal or southern side of the cracks, but on the northern or proximal side the angle was alwas chipped off, as if by the presence of some ponderous, southerly-moving, unyielding body, the chips remaining in the fissure. It is only in such hard and glassy rock as this that such effects could be produced, or that would admit of such distinct preservation after they were produced. The instruments which produced this smoothing, scoring, and chipping of the quartzite, were the granite boulders which were frozen firmly into the bottom of the glacier that once moved over it, and the power was the moving glacier itself. These granite 94. PHYSICAL GEOGRAPHY. boulders we found there with their sides also flattened and scored by the contact, resting upon the surface of the quartzite; thus, as far it was possible, we detected them in the very act of producing the effects we have described. This scoring and chipping of the rocks in place is regarded as not only satisfactory evidence of glacial action, but also of the southerly movement of the glaciers. Direction of Glacial Currents. Speaking in general terms we say that the movement of the glaciers was from north to south; but the distribution of the boulders which were derived from any particular northern point or region, shows that the current or currents in which they were transported varied from a true north and south line. So also we find the direction of the strie or scratches which the glaciers have produced to have been various, and considering that the country is, and has always been without strongly marked surface-features that would have necessarily deflected the ice-currents, the great variation from a south line in the direction of‘ some of the strize is quite remarkable. The direction of the striz observed upon the Burlington limestone, near Burlington several years ago, was found to be south,* about twenty-two degrees east.t The locality in Mills county, described in-another part of this report, is upon section 16, township 71, range 43 west, being upon the borders of the valley of the Missouri river and about twenty miles below Council Bluffs. Here there are two distinct sets of scratches upon the same surface and crossing each other, showing that the current was changed while the glacier was moving over it, or that one of two neighboring currents over- powered and displaced the other. One set has a direction south, twenty degrees east, and the other, south, fifty-one degrees east. The striae of both sets were found to be, as is * As we have such unmistakable evidence that the glaciers moved from the north, we always take the most southerly end of the strie to indicate the direction in which the glacial current was moving at that particular place. +No allowance is made in any of these cases tor the variation of the magnetic needle, which the local surveyors in the Missouri valley estimated at 11° east of north. SURFACE DEPOSITS. 95 usually the case, perfectly parallel with their fellows, distinct and straight. An exposure of the same limestone on the Nebraska side of the Missouri river, opposite Council Bluffs, and only some six or eight feet above the ordinary stage of water in the river, shows similar scratches. These, however, have a very different direction from any of the others, it being south, forty-one degrees west. Those observed upon the Sioux quartzite in southwestern Minnesota and the adjacents parts of Iowa and Dakota, have various directions, usually east of | south, from ten to twenty degrees. It is of course not supposable that the glaciers had a uni- form movement to the south, even if we had no evidence to the contrary, for it is evident that their currents would be more or less deflected from that direction by the inequalities of surface over which they passed. On the contrary, we have abundant evidence that the currents of the glaciers were numerous and various in their directions, even in so flat and open a country as ours; but what was the cause that actually did determine the direction of those currents in every case we may never know. Our observations, however, show certain coincidences that are worthy of mention, but they are not presented as anything like conclusive evidence. By referring again to the degrees of divergence of each of the sets of strize just described, it will be seen that those of the set near Burlington coincide pretty nearly in direction with the general direction of the streams of the eastern system of Jowa drainage. Those of the set which were observed opposite Council Bluffs coincide quite as nearly with the general direction of the streams of the western system; while the two sets observed upon the same surface in Mills county, represent currents which, at that point at least, are approximately coincident in direction res- pectively, with the general course of the Missouri and Platte rivers. It is not impossible that these currents of the great wide- spread glacier, which it is assumed in former times, spread over the surface of the State, and the currents of the present 96 PHYSICAL GEOGRAPHY. - gtreams are not only coincident but also that they were both determined by a common cause. It is evident, however, that we cannot rely upon the direction of glacial scratches at any one particular point to indicate the general direction of former glacial currents, because these may have changed a few degrees within the distance of as many miles, even in the flattest country, so that the most reliable indications we can ever hope to obtain of the direction taken by those glacial currents must be derived from a study of the dis- tribution of the materials they have transported. At present this subject is not well understood and needs long and careful study; but a few facts, however, have been brought out with considerable clearness during the last two or three years of the Geological Survey. Among these are the known dis- tribution of red quartzite, granite, and limestone boulders before explained; but we have observed other facts that do not now admit of so complete an explanation as these do, and yet further investigation will doubtless cause them to be as clearly understood as the others. This refers especially to the discovery in the drift of substances that, however well satistied we may be as to the places of their origin, we do not know it so positively as we do those of the boulders before mentioned. Native Copper has been found in the drift in various parts of the State. It occurs in irregular lumps of a few ounces or a few pounds in weight. One lump found in Lucas county by Col. W. 8S. Dungan, of Chariton, weighed upwards of thirty pounds. These specimens are in all respects like the native copper of the Lake Superior mines, and this region is the only one known to us in which they could have originated. If they did originate there the fact imples the existence of a glacial current, during some part of the Glacial epoch, having a southwesterly direction, and at right angles with the one supposed to have coincided with the eastern drainage of lowa. Lead Ore. Fragments of the common sulphuret of lead have also been found in the drift, but these are quite rare. owe ee sees ee ee — Ne) ~l SURFACE DEPOSITS. They were provably derived by glacial action from the Dubugue lead region. Gold. Traces of gold are reported to have been found in the drift of Iowa, and such no doubt exist. If so, it may be supposed to have originated in northern Minnesota. It seems almost unnecessary to say, what every person may be expected to infer, that the existence in the drift of any of these substances is no indication whatever of the existence in the vicinity where they are now found, of natural deposits of the same metals or minerals. ~ Neither is there any reason to hope that any of them will be found in the drift of Iowa in sufficient quantity to pay for the trouble of seeking for them. Coal. Lumps of impure coal have frequently been found in the drift of northern Iowa, so much to the northward of the northern boundary of the Iowa coal-field, that its origin in that coal-field is not believed to have been possible. It is known that a bed of impure coal, a few inches in thickness, exists among the Cretaceous strata of northwestern Iowa and southwestern Minnesota. This bed is believed to be the real origin of the coal found in the drift of northern Iowa. Unless that formation extended much farther eastward in pre-glacial times than it does now, the existence of these lumps of coal in the drift where we now sometimes find it, pre-supposes a southeasterly direction of the current which transported it. Wood. Pieces of wood are frequently found in the drift of different parts of the State, by digging’ wells and other excavations. They have not only been found in the Altered Drift and Alluvium, but also in the unaltered drift. This wood must have been of pre-glacial origin, because we cannot suppose that trees grew in Iowa during the Glacial epoch, any more than they now grow in the glacial region of Greenland. These pieces of wood are not petrified, but are always so far mineralized that they are but slightly, if at all, combustible. Every piece thus far examined by the microscope, shows the peculiar structure of coniferous wood 13 98 PHYSICAL GEOGRAPHY. in a good state of preservation. This wood had its origin to the northward of where it is now found without doubt, but exactly where and how far, we can probably never know. Fossils. No fossils of any kind have been found in the drift of Iowa which may be said to properly belong to it. Those found in it belong to other formations, and have been trans- ported from their original strata together with the other materials of the drift. Mr. P. MclIsaac, of Waterloo, Iowa, has shown me a specimen of a Cretaceous Ammonite which he found inthe drift near that place, and a fragment of a Baculite has been found in the drift near Iowa City. Coal-measure fossils have been found in boulders in Des Moines county, and Lower Silurian fossils have been previously mentioned as occur- ring in the limestone drift-boulders of central Iowa. Some shark’s teeth have been found in the drift of southeastern Iowa, and supposed by others to have originated in a northern prolongation of the Gulf-border Tertiary formations; but it seems not improbable that they originated in the Cretaceous strata to the northwestward, and were transported thither dur- ing the Glacial epoch; although, it is not to be denied that they approach more neatly to Tertiary than to Cretaceous forms. The last indication of glacial action we shall notice here, is that of Moraines(?) The phenomena here referred to with doubt as moraines, may be properly regarded as of doubtful character; but yet, they are nevertheless well worthy of notice. They seem at least to be accumulations of drift material which mark periodical arrests of the recedence by melting, of the glaciers to the northward as the Glacial epoch was drawing to a close, as a consequence of a gradual change of climate. They consist of two well-marked but slight elevations in the general surface of the country. They both have an easterly and westerly direction, and are gradually lost at either end in the general prairie surface. One of them extends through the northern part of Boone and Story counties, and is known to the inhabitants as ‘‘ Mineral ridge.” It consists to a con- siderable extent of a collection of slightly raised ridges and knolls, sometimes interspersed with small, shallow ponds; SURFACE DEPOSITS. : 99 the whole having an elevation probably nowhere exceeding fifty feet above the general surface, but being in an open prairie region it attracts attention at considerable distance. It is composed wholly of drift, and it is perhaps needless to say, that it is not likely to yield any ‘‘ mineral” to explorers, as its name might suggest a hope for. The other ridge extends from the eastern part of Palo Alto county through Kossuth into Hancock. The greater part of this ridge has the general, but indistinct character of a terrace, facing the south, and elevated only from fifteen to twenty or thirty feet above the general level of the surface to the southward, while the general level to the northward stretches away from the top of it. It is nowhere very distinctly marked even in so flat a region as this, but yet it is sufficiently so to have caused its existence to become generally recognized by the inhabitants. Its eastward extension into Hancock county becomes broken up into a well-marked strip of ‘‘ knobby country.” Here it consists of elevated knobs and short ridges wholly composed of drift, and usually containing more than an average proportion of gravel and boulders. Interspersed among these knobs and ridges are many of the peat marshes of that region. One knob in the extreme north- eastern corner of Hancock county, is well worthy of especial notice on account of its height. It is visible above all the others, and at considerable distances in the country around. Jt is estimated to be at least three hundred feet above the water of Lime creek, near which it is located. It is a conspicuous object in the region around, and is called “ Pilot Knob,” by the inhabitants. Some other matters relating to the drift, but more especially local in their character, will be referred to in the chapters on County and Regional Geology. Close of the Glacial Epoch. What was the real condition of the surface previous to the Glacial epoch we can never fully know; but its features were certainly largely obliterated by the action of the glaciers and the accumulation of the drift, so that at its close the surface of our State was comparatively a uniform level, unmarked by strong features and without a 100 PHYSICAL GEOGRAPHY. completed system of surface drainage. That the waters derived from the melting of the receding glaciers modified the surface of the drift to a considerable extent is quite certain; but how far they did so or how much the present condition of the surface between the valleys is due to such modification, and how far it remains now in the condition in which the glaciers left it, seems impossible to determine. There seems very little reason to doubt, however, that much of the surface of Iowa is now essentially in the same condi- tion that it was left at the close of the Glacial epoch. We may safely assume that after the recedence of the glaciers, which was, of course, accomplished by a change of climate, and before the surface waters had formed new valleys for the present rivers, or re-excavated for themselves the old valleys which existed before the Glacial epoch, but which became filled by the drift, numerous shallow depressions existed upon the surface. These filling with water from the rains or melting ice, became ponds and lakes, some of which exist at the present day, but the majority have doubtless become drained. If these depressions were longtitudinal or connected in chains, as many of them doubtless were, they would have given initial direction to the future rivers, and become drained by their deepening valleys so that no trace of them would remain. Those lakes and ponds that now exist are mostly found in the regions where the streams have their rise; many of them rest directly upon the watersheds. They have remained because no accumulation of water beyond has sent currents across them to cut channels for their outlet. A part of these have been described under the head of Lakes, and a part of them will be found referred to under the head of Peat, in another part of this report. The depressions in the primitive drift surface here more especially referred to, were all comparatively shallow; but one of extraordinary size and depth existed upon the western border of the State. Like the others, it became filled with water as the glaciers receded, and afterwards filled with its own sediment. This sedimentary formation is described under the head of Bluff Deposit. SURFACE DEPOSITS. 101 2. ALTERED DRIFT. It has already been shown that the drift as originally deposited was a heterogeneous accumulation of various mate- rials, without any arrangement of them into strata, or any regular separation of them from each other. The greater part of it remains to this day in apparently the same con- dition in which it was left by the glaciers; but the waters resulting from the latter as they receded by aggressive melting along their southern borders, together with such as constantly fell and still falls upon the surface, have produced a certain degree of modification in a part of it. This modifi- cation consists in the production of more or less horizontal arrangement of its materials, or a more or less complete separation of them from each other. The materials thus modified we designate as Altered Drift; restricting the use of the term, so as to apply only to such materials as have been re-arranged but not transported to any considerable distance since their accumulation as drift. This restriction seems necessary, because reference is here had only to the Altered Drift as it appears in the valleys, and where it is sometimes difficult to define the limit between it and the unaltered drift on the one hand, and between it and the alluvium on the other. The truth is, in the valleys these surface deposits are all composed of or derived from the same materials and differ from each other only in the degree to which their materials have been disturbed, separated, or re-arranged since their original accumulation.* Some good examples of the Altered Drift may be seen along the base of the bluffs which border the flood-plain *Tt will be observed that little reference is here made to the alteration of the drift that must have taken place upon the surface immediately upon the close of the Glacial epoch, and before the river valleys were excavated, There seems to be Some evidence that this modification was almost co-extensive with the deposit itself, and that those cases of indistinct stratification upon the high prairies before mentioned, are a part of the same wide-spread modification which the original deposit may be supposed to have received. Prof. St. John reports observations in central and western Towa which led him to some such conclusion. Much further observation is necessary before a complete knowledge of this subject can be obtained. 102 PHYSICAL GEOGRAPHY. of the Missouri river. The stratification there is sometimes very distinct, and in some instances the limy water that issues upon it from the Bluff Deposit has so cemented the sand and gravel together that it has thereby produced real, although worthless, sandstone and conglomerate, the beds of which are so regular as to have caused many persons to mistake them for outcrops of regular ledges of rock. These examples of Altered Drift along the bluffs of the Missouri river are unusually distinct. Other examples of the more slightly Altered Drift may be seen in the valleys of almost any of the rivers of the State that have attained considerable size. They are particularly observable in those valleys that have been eroded out of the drift alone, such as those of Rock river and the upper part of the Little Sioux; those of the upper branches of the Des Moines, etc., the bottoms of which to a great extent do not consist of Alluvium, properly so-called, but of Altered Drift, often only slightly modified. Another phase of the Altered Drift, as included in these descriptions, may be seen near the mouths and confluence of rivers. Here the alteration is greater, and approaches the alluvium in character. Sometimes upon the sides of valleys the Altered Drift assumes somewhat the form of river terraces, but they are really quite different in composition. The river terraces are always composed of finer materials, and are atways free from boulders, while the others may contain both gravel and boulders in comparative abundance. 3. ALLUVIUM. The deposit here designated as Alluvium is that which has accumulated in the valleys of rivers by the action of their own currents. The materials composing it are all derived from the rocks or deposits out of which the rivers have eroded their valleys, and consequently it has all been transported to a greater or less distance by their waters. It is this deposit that always constitutes the flood-plains and deltas of our rivers, aS well as some of the terraces of their valleys. Some SURFACE DEPOSITS. 1038 of these terraces, particularly those occupying comparatively high levels in the valleys, have been deposited in stiller waters than those of the rivers as they now flow. The material of these latter terraces is fine and silt-like, and will be more particularly referred to on a subsequent page. The Alluvium proper is largely composed of sand and other coarse mate- rials, but some of the best and most productive soils in the State are upon that deposit. Besides being an inseparable feature of our river valleys, the Alluvium has a certain degree of interest as being the latest of all the deposits, and is even now in process of deposition. 4. THE BLUFF DEPOSIT. The bluffs which border the broad flood-plain or bottom land of the Missouri river, along all that part of its course _ which forms the western boundary of Iowa, are so peculiar in character and appearance that they cannot fail to attract the attention of every one who sees them for the first time. Their strangely and beautifully rounded summits, occasionally mingled with sharply cut ridges, smooth and abruptly retreat- ing slopes, and the entire absence of rocky ledges, except in rare instances when they appear only at their base, cause them to present a marked contrast with those of the Missis- sippi and other rivers of the eastern part of the State where rocky ledges support and compose the greater part of their bulk. From the mouth of Big Sioux river to the southern boundary of the State, these bluffs present a continuous, serrated and buttressed front to the flood-plain of the great river, from which they rise abruptly to a maximum height in different ‘parts of the line, varying from one hundred to little less than three hundred feet. Although the front they present is so definite and continuous, it is nevertheless frequently and deeply cleft, not only by the tributaries of the great river, but also by small creeks and short ravines that drain the surface- water from the uplands beyond, in which the bluffy character is soon lost. 104 PHYSICAL GEOGRAPHY. Sometimes the bluff-range, departing a little from the general direct line, presents a full crescentic front to the plain with an arc of several miles in length. Such, for example, are seen at the town of Crescent, and again about seven miles southward from Council Bluffs. At these p!aces, their peculiar outlines are shown in an interesting manner, and the form and arrangement of the numerous rounded prominences present views of impressive beauty as they stretch away in the dis- tance or form bold curves in the line of hills; while the broad flood-plain of the Missouri river, level as a floor, stretches miles away to the westward to meet the turbid stream near the line of bluffs which borders the western, as those of Iowa do the eastern side. Trees often fill the sides of their deeper ravines or skirt their bases, but usually their only covering is a growth of wild grasses and annual plants; and, as the mound-like peaks and rounded ridges jut above each other, or diverge in various directions while they recede upward to the upland, the setting sun throws strange and weird shad- ows across them, producing a scene quite in keeping with that wonderful history of the past of which they form a part. The accompanying sketch of a smaller one of these curves in the line of hills known as Sergeant’s bluff, is taken from a point about two miles below Sioux City.* General Characters. Upon near approach to these bluffs, we find that their peculiar features are due to the no less peculiar character of the material of which they are composed, either wholly or in part. When not wholly, that material which differs from the great bulk appears only at the base and does not modify their outlines. It is very distinct in character from any other formation or deposit in the State; but is very similar to that deposit in the valley of the Rhine, known there by the provincial name of “loess.” It was called ‘* silicious marl” by Dr. Owen, in his geological report to the * The plain between the two extremes of the crescentic line of hills as shown in the picture is a part of the Missouri river flood-plain, and has some historic interest as the death-place of Sergeant Floyd, a member of the famous Lewis and Clark Exploring Expedition. | ODEL CaVMHLNOS ONTIOOT WAN IG SNOSANOH], NOMA Sad 1G SLNATAVS 10 mar E . K Ne wISaty Butt SAR ed ipa teat SURFACE DEPOSITS. 105 general government; and its origin rightly referred by him to an accumulation of sediment in an ancient lake which was afterward drained when its accumulated sediment became dry land. By Professor Swallow, State Geologist of Missouri, who examined the deposit in that State, where it is continuous with the same in lJowa, it was given the name of “ bluff.” This term, as a specific name for the deposit, is not unobjec- tionable, but it is not easy to find one that every person would consider to be better. Neither is it often expedient to change established names, therefore, that of Professor Swallow is used in this report; although it is thought that the term Zacustral Deposit would have been better, as it 1s expressive of the mode of its origin, and would accord with such accepted terms as Alluvial, Diluvial, &e. The material of this deposit is perfectly homogeneous in composition and uniform in color throughout, even where it is two hundred feet thick. Specimens taken from the bluffs at Sioux City, and compared with specimens from the bluffs upon the southern boundary of the State, although nearly a hundred and fifty miles apart, are not distinguishable from each other. It is of a slightly yellowish ash color, except where darkened by decaying vegetation; very fine and silicious but not sandy, strictly speaking, for by the unassisted eye one can hardly discover it in particles of granular silicious matter, so coarse as to deserve the name of grains of sand. At the surface it forms excellent soil, and if taken from a depth of two hundred feet from the surface it proves to be equally fertile. Although the material is so finely comminuted, it is not very cohesive and not at all plastic, and the soil composed of it does not ‘‘bake” or crack in drying, nearly so much as that which contains an appreciable amount of clay in its composition. The following is in part the result of Prof. KEmery’s analysis of a sample from Sioux City—a full account of which will be found in his report on another page. RS iaaics eases omelet Ute te Ras Cals pe ke NS e Loctatlete a 9 82.15 Tso ogre pee ae ee) Sag chs wuckelinlhene craves win cai» 3.89 PASIELIVIUIVA Pec Velate aire ta Se: wholes) as tel stots aie" tia etas Os 67 Car POrake OurMMe Ta sc. sce Pees cect sey tae} 9.66 | 14 106 PHYSICAL GEOGRAPHY. | The silica is in the form of clean, white microscopic grains of sand, which, as will be seen, constitute the greater part of the deposit. That it contains much lime is also apparent from the presence of numerous calcareous, concretionary lumps, some- what resembling pebbles in shape and size, which are generally distributed throughout the mass. It is also shown in the abundant accumulation of calcareous tufa, around the springs which issue in considerable numbers at the base of the bluffs just where this deposit rests upon the drift. The water of these springs has fallen upon the surface, and percolated through the whole thickness of the Bluff Deposit, and escapes laterally in the form of springs upon the less pervious drift. Rain water always contains at least a minute quantity of carbonic acid dissolved in it, and after it has penetrated the air cavities of porous earth, much more. This renders some of the carbonate of lime which the deposit contains slightly soluble. When the water, holding this excess of carbonate of lime in solution, reaches the atmos- phere it becomes precipitated there in the form of the tufa before referred to. It is the lime thus precipitated which cements the sand and gravel of the Altered Drift in those localities, which have been mentioned on a previous page. Except the limy concretions before mentioned, not a stone or pebble of any kind is to be found in the whole deposit, but all is uniformly fine and homogeneous. Physical Properties. Some of the physical properties of this deposit are so unusual that they merit especial mention. When itis Known that there is no rocky support to these Missouri river bluffs, although they are frequently so steep that a man cannot climb them, it is very apparent that the material composing them is different from the earth ordinarily met with, and which it resembles upon its ordinary surfaces. Its peculiar property, however, of standing securely with a precipitous front, is best shown in artificial excavations. For all practical purposes of building-foundations, even of the most massive structures, and for roads, etc., the ground it — SURFACE DEPOSITS. 107 composes is as secure as any other, yet it is everywhere easily excavated with the spade alone. Notwithstanding this fact it remains so unchanged by the atmosphere and frost, that wells dug in it require to be walled only to a point just above the water line; while the remainder stands so securely without support of any kind, that the spade-marks remain visible upon it for many years. Embankments also, upon the sides of roads or other excavations, although they may be quite perpendicular, stand for many years without change, and show the names of ambitious carvers long after an ordinary bank of earth would have softened and fallen away to a gentle slope. Lime kilns, fashioned entirely out of this material, even including the fire-arch, have been carved in the side of a hill by*the spade, and used for burning lime during a whole season or longer, without any interior or exterior wall or other support. of any kind. Even potters’ kilns have been thus constructed and successfully used. For such purposes a place is selected which is unusually dry, such as a narrow ridge from which all water falling upon the surface is rapidly drained away. In some instances small, temporary stables, or cattle-shelters have been excavated in the side of steep banks, and used for a few years, the roof standing with considerable security in the form of an arch. Indeed so securely does the material of this strange deposit remain when excavations are made in it, and so easily is it excavated that subterranean passages of many miles in length might readily be constructed in it without meeting any impediment. Any fortifications built upon these hills, which form a continuous line along the greater part of the western border of Iowa, if future emergencies should ever require them, might be readily undermined by digging such subterranean passages; and if there were any cause or use for such works, catacombs might be successfully constructed in any of them that would rival those of ancient Rome. Beyond the influence of the atmos- phere, they would probably endure as long as they. The peculiar property possessed by this material, of standing unchanged in form when exposed to the weather, 108 PHYSICAL GEOGRAPHY. is doubtless due to the slight cementation of the minute grains of silica which constitutes so large a part of it. This is effected by the partial solution of its carbonate of lime by the carbonated waters which fall upon and percolate it as before mentioned, and the reprecipitation of the same in those parts nearest the exposed surfaces, whether artificial or natural. The cementing material thus formed, is never sufficient in amount to interfere with its porosity, for this is another of its peculiarities. The cause of its being so per- vious to water is no doubt due to the distinct granular form of its silex although so minute, and the fact that the minute grains are not compacted and rendered coherent by impalpa- ble clayey matter. Thus water passes through it just as effectually as though ordinary sand, but not so quickly. That the deposit is very pervious to water may be readily seen by observing the line of springs that issue at its base near the foot of the bluffs, and nowhere above that line. That it is so pervious, also appears from the fact that wells dug in it, so far as has, yet been ascertained, have never afforded a supply of water until the base, or very near the base of the deposit was reached. Often the whole thickness of the deposit must be passed through in digging the well, and the water when found, is obtained in the sandy or gravelly drift which everywhere underlies the Bluff Deposit. It will thus be seen that this strange deposit, although it is compact, has the property of being very porous, so that the water which falls upon its surface never collects there in ponds, nor does it accumulate within its mass as it is known to do upon the surface of and within the drift and the stratified formations. Consequently, there is great risk that wells dug in its deepest parts must necessarily be dug to an impracticable depth before reaching water, for a well two hundred feet deep would hardly be practically useful. Where the deposit is thinner, however, it may be entirely pierced, and water obtained at little if any more than the ordinary depth required in the drift deposit alone, which forms the surface of the greater part of the State. Although SURFACE DEPOSITS. 109 water does not accumulate in the Bluff Deposit, it should not be inferred that it is not always moist, for it always contains sufficient moisture to give it the ordinary coherence of common soil even at the surface; and crops growing upon it suffer no more from drought than they do upon any other soil. Asa soil, it has the additional advantage of being constantly and completely underdrained. Physical Features of the Region. Hitherto the Bluff Deposit has been spoken of in relation to the character and aspect it exhibits in and near the range of bluffs that border the flood-plain of the Missouri river. It now remains to speak of the physical features of the region occupied by the deposit, in a more general way. In this connection it will be necessary to give some account of the geographical extent of the region it occupies, together with its Known thickness, when that has been ascertained. The limits of this area have nowhere been ascertained with absolute accuracy, but these may doubtless be defined with as much precision as we can define the exact limits of any of the formations which underlie the drift. The difficulty of defining its limits arises from its gradual passage into the fine top soil of the drift, or rather from the fact that the finely comminuted, humus-stained soils of both deposits are so nearly alike in aspect when unbroken by natural or artificial excavation, that it is difficult to say where one ends and the ‘other begins. However, the following outlines are assumed to be not far from its eastern and northern limits in Lowa: Commencing at the southeast corner of Fremont county, follow up the watershed between the East Nishnabotany and the west Tarkeo rivers to the southern boundary of Cass county, thence to the centre of Audubon county, thence to Tip-Top station on the Chicago and Northwestern railway, thence by a broad curve westward to the northwestern corner of Plymouth county. The last named point is probably very near the most northerly-one to which the deposit any- where reaches, certainly the most northerly one to which it reaches in Iowa. Less is known of its nothern limits in 110 PHYSICAL GEOGRAPHY. Dakota and Nebraska, and of its western limits in the latter State and Kansas. It is known, however, to extend as far west as the valley of the Elkhorn in Washington county, Nebraska, some twenty-five or thirty miles west of the Missouri river. There is reason to believe also that it occupies a continuous region of an equal average width, bordering that great river, and extending as far south as Kansas river. In Missouri, it occupies a large area adjoining that of lowa, the whole having been, originally, an united and continuous deposit before the Missouri river had eroded its valley out of and through it. What its southern limits are is not known, but it is reported by Prof. Swallow, of Missouri, to extend far down into that State. The Bluff Deposit is thus known to occupy a region through which the Missouri river runs almost centrally, and measures as far as is now known, more than two hundred miles in length and nearly a hundred miles wide. The thickest part of the deposit yet known is in Fremont county, where it reaches a thickness of at least two hundred feet above the drift. There is reason to believe that its thickest part is in the immediate vicinity of the valley of the ereat river, because it occupies almost equal areas on each side, and thins out in all directions from it to the outer margins of the deposit. The whole height of the blufis in Fremont county, is at one or more points about three hundred feet above the flood-plain of the Missouri river; but in that case one hundred feet of itis made up of the Upper coal-measure strata and drift which supports the Bluff Deposit. Going northward from that county along the line of the bluffs, the Upper coal-measure strata are seen for the last time, in that direction, at their base a few miles noith of Council Bluffs. The next stratified rocks to be found by con- tinuing northward, are of Cretaceous age. These are found occupying the base of the bluffs in Woodbury county, first appearing at the town of Woodbury, seven miles below Sioux City. The distance between the most southerly point in the line of bluffs at which the Cretaceous strata are exposed, and SURFACE DEPOSITS. 111 the most-northerly point at which the strata of the Upper coa!_ measures are found, is fully seventy-five miles. Along this entire distance no rock is to be seen, and only occasionly can the presence of the drift be detected. Beyond these two points in either direction, the strata appear so seldom, and so near the base of the bluffs, and the exposures are so small that they never modify the peculiar aspect which the Bluff Deposit imparts to the bluffs everywhere. Sometimes the presence of the drift may be detected at the base of the bluffs by an indistinct terrace, but usually its presence is known only by the appearance of clay, sand, or gravel upon the surface, and by the issuance of springs. Along a great part of the whole line, the drift is evidently beneath the level of the great flood-plain, because nothing but the material of the Bluff Deposit appears to view from base to summit of the bluffs. The drift is evidently very thin where the Bluff Deposit is thickest, and the latter has been deposited in a broad depression hollowed out of the general surface, principally in the drift alone. The topmost strata of the Upper coal- measures are, however, occasionally found scored by glaciers, which indicates that the hollowing process extended into the stratified rocks also. Indeed the drift is nowhere known to be very thick in the vicinity of the Missouri river, and in a couple of instances at least the Bluff Deposit was found resting directly upon the limestone. Within twenty-five miles east of the eastern border of the Bluff Deposit there is evidence that the drift reaches a thickness of about two hundred feet. The valleys of all the streams of western Iowa, which reach the flood-plain of the Missouri river within the State, traverse the region occupied by the Bluff Deposit. The streams and their branches not being very far apart, the surface is often much broken; but it nowhere presents those peculiar outlines that are so striking a feature of the bluffs of the Missouri river. The valleys being of considerable depth, and not far apart, the aggregate slope from the watersheds to the 712". PHYSICAL GEOGRAPHY. streams is greater than it is elsewhere in the State. This is well shown in the profiles which illustrates the topography of the State opposite a previous page, and has made railroad building a difficult matter in some parts of western Iowa. This difficulty has usually been avoided by running the roads down some one of the smaller valleys to reach that of the Missouri river. The banks and beds of the streams which traverse this deposit receive from it quite peculiar characters. The beds are of soft, fine, dark-colored homogeneous mud, and the banks are composed of the same material in a dryer con- dition. The banks are often, even upon the small streams, from five to ten feet or more in height, quite perpendicular, so that they make the streams almost everywhere unfordable, rendering them in consequence a great impediment to travel across the open country, where there are no bridges. The value of the material of this deposit as soil will be dis- cussed further on, but it may be remarked here that it is unsurpassed by any soil in lowa for real value. It is true, also, that forest trees grow as triftily upon it as upon any other soil, even where there is no other kind of soil within many miles of them, nor within a hundred feet beneath their deepest rootlets. A thrifty growth of young forest trees is now spontaneously springing up everywhere upon this deposit, and rapidly encroaching: upon its hill-sides and prairies whenever they are by any means protected from the annual prairie fires. This is at present more apparent upon the hill-sides than upon the flatter prairies, and as one passes along the road which traverses the length of the Missouri river flood-plain, in view of the ever-varying and ever- interesting bluffs, he can hardly avoid a feeling of regret that the primitive beauty of their nakedness is so soon to receive a forest-mantle of nature’s own weaving, by which their graceful outlines, now cut so clearly against the sky, are to be forever lost; so rapidly are the hitherto fire-stunted trees assuming forest proportions and multiplying their numbers, See = SS See = 3 Sr ares BLUFF 2. ———) Wits on nA é hh i % i | AL) Na | int | \ RUE yh lL i ry HH i ali sl u i) yeunossiw Mh | A << “DRIFT. "mw — SURFACE DEPOSITS. 115 Origin and Geological Age. As to the real geo- logical age of the Bluff Deposit there can be no question; any difference of opinion upon the subject would amount only to a difference of terms. It is of more recent origin than the drift because it rests upon that deposit, and it is not of later origin than the earliest part of the Terrace epoch, because river terraces are formed in itself as well as in the drift. While fully recognizing the correctness of the views 24 entertained by those who refer certain post-glacial changes along the Atlantic border of the cuntinent, and elsewhere, to a distinct epoch, subsequent to il | the drift and previous to the Terrace epochs, called the Champlain, the existence of any phenomena in the valleys of the Mississippi and Missouri rivers, in and adjacent to lowa, which indicate post-Tertiary changes that require more than two epochal subdi- visions, is not recognized. These two are the Drift and Terrace epochs, and the Bluff Deposit is referred to the earliest part of | the Terrace epoch, because the material of which it is composed originated as such by fluvatile ero- sion, which occurred immediately upon the close of the Glacial epoch. The material was at the same -| time deposited as lacustral sediment in a broad depression in the surface of the drift which was left there by the retreating glaciers. The accompanying diagram, figure 3, shows the relative position of the Bluff and Drift Deposits, as well as the relation of the river valley and the Upper coal-measures to each. This broad depression formed a lake-like expan- sion in the Missouri river, which was then, as now, one of the muddiest streams upon the globe, and became rapidly filled by its own sediment, which its waters gave up as soon as their impetuous current was checked by the stiller waters of the lake. The 19 sil PHYSICAL GEOGRAPHY. filling of the depression with sediment must have been com- pleted very early after the recedence of the glaciers, because, as shown by the present height of the surface of the deposit, it reached as high a level as that of the highest surrounding land, before the Missouri river, which emptied into and flowed from the lake, had deepened its channel below it sufficiently to commence its drainage.* From that time until 'the deepening of the Missouri river valley had well progressed, the surface of the deposit no doubt existed as a broad, undrained marsh. As the deepen- ing of the valley below the then filled lake progressed during the remainder of the Terrace epoch, the river readily swept out enough of the soft material which its own waters had previously deposited to form its valley in that also, and at the same time caused the deepening of those of the tributary streams. The cutting out of the great valley in this deposit was accomplished, as in the deepening of all valleys, by the vibration from side to side of the stream, alternately occupy- ing every square foot of its flood-plain, and at times hugging the sides until the bluffs were left as steep as they would stand. Cross-cutting by tributary drainage gave the bluffs their serrations, and rains and frosts completed the rounding of their summits and slopes so that they now appear, as they really are, like miniature mountain ranges of dried mud. During the deepening of the valley of the great river, few real terraces seem to have been formed in the Bluff Deposit, compared with the number usually found in the valleys of those strcams, which have been eroded out of other * This deposit now extends a little to the eastward in some places, of what is now the Great Watershed in lowa, and appears upon some of the upper branches of Raccoon river. This may have resulted however, by the gradual extension upward, even beyond the border of the ancient lake bed, of those branches necessitated by the deep- ening of the principal yalleys which took place during the Terrace epoch. It is shown also by the levelings of the Chicago and Northwestern Railway, that at some points the surface of the Biuff Deposit is afew feet higher than the surface of the drift is where that railway crosses the Great Watershed. Further investigations are needed to ascertain what the actual relative level of the surface now is there,and what changes have taken place since the Bluff Deposit was all accumulated, LONCUIO] JJNIG a Jo SaoeIay, -—“WIMOTOC NOSIRIVE] AIASNMQ] NOSHOM[ MANY MANCIOG dO ABTINY SH dt ONTO MAI, 1 reahoyeay (491) 20 76S it erin ieee eM agohy AABN S . R » seve < at i A galt : eee ; SMM ae “ ot oS AA erueanedy ttt YS VOTE Peay SRY pete eee SURFACE DEPOSITS. 115 material. But such terraces do sometimes appear in this deposit, and are of the same character as those observed in the drift and alluvium of other valleys. The accompanying sketch of the valley of Soldier river, just where it joins the great flood-plain of the Missouri river, shows the remains of several successive terraces that were formed while the two valleys were in process of deepening. These terraces in the Bluff Deposit, notwithstanding the fact that it is newer than any other deposit except its own alluvium, are certainly of the same age as the other terraces of the same river that have been formed in the drift or any other formation, for they all originated from the same cause, and nearly or quite simultaneously. The evidence that this deposit was formed as sediment in a fresh water lake may be summed up thus: The material is very fine and homogeneous, such only as could have been deposited in comparatively still waters. It contains a few shells of fresh water and land mollusks, and no other.* Neither does it contain any marine remains. It is therefore not of marine origin; besides which, no inland deposit of marine origin is known, that has, like this, occurred subse- quent to the drift. The material of the deposit is essentially the same as the sediment of the Missouri river at the present time, as will be seen by referring to the analysis of both in Prof. Emery’s report on other pages. This sediment is so abundant now in that river, that if it were possible to throw an obstruction across its valley as high as its bluffs it would become rapidly filled with essentially the same material that it originally deposited and subsequently in part swept out. This is constantly illustrated in the reservoirs of the St. Louis water-works, which become filled with the sediment of the water taken from the river, so that they must be periodically re-excavated. The proportion of sediment contained in the water of the river in its earliest history, was probably somewhat greater * No true branchiate shells have been found in the deposit except a few Unios, the greater part being pulmonate gasteropods. 116 PHYSICAL GEOGRAPHY. than it is now, and any lake-like expansion that may have existed in it at that time must have become so quickly filled as to have occupied an insignificant part of the time-history of its valley, although the act was an important one in that history. It seems not improbable that the broad lake that occupied a part of what is now Western Iowa, was mainly filled with sediment while yet the glaciers hovered around the upper course of the Missouri river, and were there grind- ing the material which served for the filling. That there were formerly other similar lake-like expansions of the Missouri and lower Mississippi rivers, and that they were filled with the same kind of sediment, is not improbable, for it was then in the condition that Carl Ritter aptly terms an ‘‘ unfinished river.” Indeed, it is certain that there were such, for Professor Hilgard, State Geologist of Mississippi, speaks, in his report on the geology of that State, of a similar deposit there, occupying a similar relative position to the Mississippi river that ours does to the Missouri. Itis not thought possible that our Bluff Deposit, and that of the State of Mississippi, could have ever been continuously connected as the same deposit, although they were, doubtless, exactly contemporaneous; but it is quite probable that other lake- like expansions besides these two existed between them in the course of the river, their deposits being all alike because all were formed from the same sediment and furnished by the same river from the same sources. Such remains of lakes or lake-like expansions in the courses of rivers are common in all parts of the world, and as each river system became “ finished,” to use Ritter’s term, by the. deepening of their valleys, the sedimentary filling became dry land. The filling was, of course, most rapid in the case or the muddiest rivers, and those which flowed over formations that are not readily disintegrated, could contain but little sediment. Therefore, their lakes are not filled. If such a river as the Missouri had emptied into the great northern chain of lakes, they would have become so com- pletely filled with its sediment that they would never have SURFACE DEPOSITS. 117 been known as lakes to civilized man, but tributaries of the St. Lawrence river would have traversed the regions they now occupy. Primary Origin of the Bluff Material. Ascending the Missouri river, we find in Nebraska, Dakota, and even in northwestern Iowa, the source from which the material of the Bluff Deposit was derived. Stretching from here far away towards the Rocky mountains, and bordering the great river on either side, is an immense region occupied by the most friable formations on the continent—those of Cretaceous and Tertiary ages. Seeing these we at once cease to wonder that the waters of the Missouri are muddy, because it is so evident that they could not be otherwise. The Tertiary strata are largely silicious, and the Cretaceous are scarcely less so, but a part of the latter are not only calcareous, but mnch of it is very nearly pure chalk. It is from the last named strata that the Bluff Deposit has derived its nearly ten per cent of carbo- nate of lime. Allthese friable strata are even now furnishing abundant sediment to the streams that flow into the Missouri river, but at the close of the Glacial epoch, the fine sediment was, if possible, still more abundant, because then the whole region was strewn with the grindings fresh from those ‘‘ mills of the gods ”—the glaciers. 5. OTHER ANCIENT LACUSTRAL AND MARSH DEPOSITS. Besides the Bluff Deposit just described, there are other post-glacial deposits found along the borders of the valleys of the Mississippi, and some of the rivers of the eastern part of the State. So far as yet observed, these are confined within the river valleys or to their immediate vicinity, and evidently originated at different periods in the history of their erosion from the general level that existed at the close of the Glacial epoch, because they are found occupying different levels, varying from almost as high as the general level of the uplands down to a level only a few feet above the highest floods of the rivers at the present time. Some of 118 PHYSICAL GEOGRAPHY. them are similar in character to the Bluff Deposit, but having been derived from different materials, they are never pre- cisely like it. They always contain a considerable amount of clay, which the Bluff Deposit contains almost none at all of. Others are remains of marshes and not lakes, or at least of marshes which may have existed upon the borders of lakes; for the waters in which these deposits took place, are ‘believed in every case to have been lake-like expansions, or comparatively still portions of the rivers upon the borders of whose valleys these deposits are now found. Those that are more distinctively lacustral in their character are composed, in varying proportions of fine silicious and clayey silt, such as would be deposited in comparatively still waters. They are found upon the sides of the valleys, where they show indistinct traces of stratification when they are freshly excavated. Those of this character thus far observed, have been found almost alone upon the valley sides of the Mississippi, and almost always near its lower part, or not far above the level of the present flood-plain. Traces of such terraces are to be found in almost all cases where the valley of a creek or small tributary comes into the flood-plain of the great river. These, however, can hardly be said to be parts of the proper river terraces which they very much resemble, the latter being abandoned flood-plains, and the former a deposit of fine silt in waters stiller than those which brought it down from the uplands. An interesting example of such a silt-like deposit exists within the city of Burlington, having been produced by Hawkeye creek when the Mississippi occupied a level higher by forty feet than it now does. Much of the deposit was removed by the deepen- ing valley of the creek, and much has lately been removed for railroad purposes from the vicinity of Fifth and Market streets, where it was once finely exposed by the artificial excavation and seen to rest upon the drift. Such of these deposits as partake more of the character of marsh accumulations are found in somewhat similar positions, but all seem to have taken place at an earlier period in the SURFACE DEPOSITS. 119 process of deepening the river valleys. For example, one of these deposits occurs almost upon the very brow of the bluffs that border the valley of the Mississippi, near Davenport. This example is one of unusual interest, in consequence of the existence there of an extensive bed of ancient peat which is covered to the depth of several feet beneath the prairie soil, and the discovery in the clay above the peat of the remains of a Mammoth. The accompanying diagram, fig. 4, and the following explanation by W. H. Pratt, Esq., Secretary of the Davenport Academy of Science, shows the position of the deposit in relation to the drift. Fia. 4. The exposure was made by the excavation for the Chicago, Rock Island, and Pacific Railroad Company, previous to which there was no appearance at the surface to indicate the presence there of any thing more than the ordinary Drift Deposit. Mr. Pratt’s notes and references to the diagram were obtained while the excavation was fresh. “No. 1. The ordinary prairie soil, one foot. The prairie here extends to the edge of the bluff, gently sloping backward towards the north. “No. 2. The “yellow clay” or loam, twenty feet thick, iron-stained, frequently distinctly laminated ; Jamine curved and have their layers of sand interstratified in some places. It contains small calcareous nodules and shells of the genera Succinea, Helicina, and Pupa. 'This clay makes good brick. “No. 8. Bluish-gray clay, three to five feet thick, not stratified ; contains a few shells like those of No. 2. A tusk, several teeth, and some other portions of Hlephas primigenius (?) were found just at the junction between Nos. 2 and 3. “No. 4. A bed of browu peat one foot thick, which burns tolerably well. In some places the peat-moss, Hypnum aduncum, was so well preserved as to be recognized. Quantities of much decomposed coniferous wood are distributed throughout this bed. 120 PHYSICAL GEOGRAPHY. “No. 5. Ancient soil, two foot thick, very dark brown, resembling the peat but more decomposed. Cozxtains no shells or other fossil remains. “No. 6. Blue clay, very tenacious, containing sand, gravel, and small boulders. Pebbles and boulders all water-worn and many of them distinctly glacier scratched. Thickness uaknown. “The dotted line represents the railroad grade. The point represented by the top of the diagram is 167 above low-water mark in the Mississippi river at the railroad bridge.” This deposit is quite remarkable in many respects; in none more so perhaps than in the fact that the bed of peat rests upon a bed of clayey silt, and is in turn covered by a similar but much deeper one, these varying conditions evidently having been produced by the shiftings of the adjacent and then sluggish river, in that very early period of its post- glacial history. The extent of this peat bed beneath the surface is not known, as there is nothing in the surrounding surface to indicate it. It was exposed by the railroad exca- vation for a distance of thirty or forty rods. Another deposit of ancient peat has been found in digging a well a couple of miles southward from lowa City. It was found at a depth of thirty feet beneath the surface, and that surface is fifty feet or more below the general level of the uplands in the vicinity, The locality is upon the gentle slope of the valley-side of the Iowa river, and about a mile from it. The position of the peat, although so far beneath the surface, is yet much above the level to which the highest floods of the river now reach. The peat was evidently formed where it is now found, and in what was then a marsh upon the borders of the river-valley as it then existed, but during the process of the deepening of the valley, and by the shift- ings of the stream, it became covered by the sandy deposit which we find now resting upon it, having mostly the general character of Altered Drift. Neither this deposit of peat, nor the one near Davenport, are fit for fuel, as they are not nearly so combustible as recent peat, and if they were, they contain too much impurity to be practically useful. Both the deposits contain numerous pieces SURFACE DEPOSITS. 17¢ of wood and twigs, all of which, so far as yet examined, ‘prove to possess the structure peculiar to conifers. It is worthy of remark in this connection, that no conifers having a wet habitat as these evidently had, are now to be found living within the State. Several fragments of the elytra of a coleopterous insect were found in the ancient peat of both Davenport and Iowa City; but their specific and generic relations have not been determined. The peat of both these localities is referred to the age of the Terrace epoch, although at one time it was thought the one near lowa City might prove to be of pre-glacial origin. A small deposit of similar ancient peat was also discovered. in Adair county, and will be found mentioned in the description vf the geology of that county in another part of this report. Tt will be observed that in the foregoing discussion of all that pertains to the post-tertiary geology of Iowa, it is assumed that no appreciable changes in the elevation of the surface above the sea, have taken place during that time. It seems unmistakably evident that all our rivers have eroded their own valleys, and produced their own terraces without the aid of any elevation or depression of the surface. It is for this reason that no reference is made to the Champlain epoch in discussing Iowa geology. We date the Terrace epoch from the recedence of the glaciers to the present time. 16 CHA PTE: aaa SOILS, ETC. The soil of Iowa has become justly famous for its fertility, and it may well be doubted whether there is an equal area of the earth’s surface that contains proportionably so little until- lable land, or whose soil has so high a degree of average fertility. -After careful consideration of the results of my examinations, I do not hesitate to thus publicly announce my estimate that ninety-five per cent of the surface of Iowa is tillable land. The State being, as previously explained, with- outranges of mountains or hills, or other barren surfaces, and every where covered with a soil of such fertility and depth, its agricultural capabilities are almost beyond computation, and agriculture must ever remain the principal element in the prosperity of our Commonwealth. The desirableness of gfving to the public all possible information concerning our soil is fully appreciated, but being convinced that little really practical good can result from a series of quantitative analysis of them, these have been omitted and discussions of the subject are confined to the physical examination and general description of its varieties.* The soils of the State may be separated into three general divisions which not only possess different physical characters, *For views upon the subject of soil‘analysis which are eminently correct and well expressed, the reader is referred to an article in the American Journal of Science, Vol. XXXII, II Series, by Prof S. W. Johnson, of Yale College, and non-resident Professor in the Iowa State Agricultural College. See also later publications by the same author. ee: 22 SOILS, ETO. 123 but also differ in the mode of their origin. These are the Drift, Bluff, and Alluvial soils, and belong respectively to the deposits bearing the same names. The drift soil occupies a much greater part of the surface of the State than both the others; the bluff soil has the next greatest area of surface and the alluvial least. 1. DRIFT SOIL. All soil is disintegrated rock, and its excellence or sterility depends both upon the composition of the rocks from which it is derived and the degree of comminution to which they have been subjected. A soil composed of material that has been suspended in and thus transported by the waters of a stream and then deposited, as the bluff soil has, always possesses a sufficient degree of fineness, while both the drift and alluvial soils may, and sometimes do, contain too great a proportion of coarse materials for good soil. This, however, is very seldom the case with the drift soil of Iowa, for upon the greater part of it not a pebble or boulder is to be seen. This character of the drift soil of Iowa arises primarily from the character of the rocks from which its drift- material was originally derived. If the rocks from which a drift deposit has been derived were hard and unyielding, the accumulation of drift from them would have been comparatively slight, although they may have been subjected to violent glacial action during the whole Glacial epoch. The soil of such a slight accumulation of drift would also be light and poor, because the materials | of it would lack, for the same reason, that degree of fineness necessary to the formation of good soil, although both they and the rocks from which they were derived may contain all the elements necessary for it. These facts are believed to afford sufficient explanation of the cause of the sterility of much of the soil of New England, and of the remarkable fertility of the drift soil of Iowa. As stated in the preceding pages, the drift deposit of lowa was derived to a considerable extent from the rocks of 124 PHYSICAL GEOGRAPHY. Minnesota, but the greater part of Iowa drift was evidently derived from its own rocks, much of which has been trans- ported but a very short distance, if any, from the place where it originated. Many of the strata of Iowa rocks are soft or friable, and nearly all of them are sufficiently yielding to have been comminuted with facility by the glaciers. This is also true even of many of the granite rocks of Minnesota. We found the greater part of the granite exposed in the valley of the Minnesota river to be too soft and easily disintegrated to be useful even for good common building stone; and at the mouth of the Redwood, a tributary of the Minnesota, we found a cliff of decomposed granite, upward of one hundred feet in height, so soft from top to bottom that it could be crushed to the condition of fine soil in the hand alone. Indeed, it graded imperceptibly into the fertile soil which covered it, but with this exception, the deposit had never ‘been disturbed from its original position. In southwestern Minnesota this friable granite is overlaid by what remains from glacial action of the Cretaceous rocks which were once continuous with those of western Iowa. These Cretaceous rocks are all so soft and friable as to have yielded readily to glacial action, and have evidently contributed largely to the fine materials of the drift. It will be seen then, that the supply of material here for transportation as drift into Iowa was abundant, and well adapted for the production of good soil for our State as well as for the region where it originated. The Drift Deposit of Iowa is so thick and the proportions of its component materials so nearly uniform throughout the State; the soil of that deposit has also a great degree of uniformity. But still it may not unfrequently be observed that an underlying formation has impressed its character upon the soil. We may, perhaps, say in general terms that the constant component element of the drift soil is that portion which was transported from the north, while the inconstant elements are those portions which were derived from the adjacent or underlying strata. For example, in western Iowa, wherever that Cretaceous formation, known as the . ee SOILS, ETC. 125 Nishnabotany sandstone exists, close observation shows the soil to contain more sand in its composition than else- where; yet it is never sufficient in amount, even there, to cause it to approach barrenness. On the contrary, it adds a warmth and mellowness to the soil which are beneficial. The same may be said of the soil of some parts of the State occupied by the Lower coal-measures, the sandstones and sandy shales of that formation furnishing the sand. In northern and northwestern Iowa the drift contains a ereater portion of sand and gravel than elsewhere; conse- quently the soil also partakes of the same composition, but yet even there the barren spots are rare exceptions to the general fertility, because the proportion of coarse material is greater beneath than upon the surface. The sand and gravel of this region was doubtless derived from the Cretaceous rocks, that now does or formerly did exist there, and also in part from the conglomerate and pudding-stone beds of the Sioux quartzite. Again, in some parts, as for example, in southern Iowa, the soil is frequently stiff and clayey, but very fertile. The subsoil, together with the whole thickness of the drift, is also clayey. This preponderating clay is doubtless derived from the clayey and shaly beds which alternate with the limestones of that region. It must not be understood, however, that clay is anywhere absent from the drift soil, not even from that of those parts where the underlying rocks contain only a minute proportion of clay; for, as before stated, much of the fine material of the drift, and consequently of its soil also, had its origin to the northward—some of it being derived from the granitic rocks there which contain, in large proportion, the necessary material for the production of clay. The origin of clay and of soil from such rocks, when decomposed, may be finely illustrated by taking a handful of the decomposed granite from the valley of the Redwood before referred to, and stirring it up thoroughly in a vessel of water. The fine grains of quartz it contains disseminated throughout the mass become at once precipitated to the 126 PHYSICAL GEOGRAPHY. bottom of the vessel as a layer of sand, while the feldspar, hornblende, and mica also, if present, are suspended for a time in the water and are then deposited as a layer of common clay upon the sand.* Mixing the whole together again we have a handful of common soil in a condition fit for the growth of vegetation. To constitute a proper fertile soil the mineral ingredients must of course have an addition of humus, derived from decayed vegetation. This has been abundantly supplied to Iowa soil by the growth of prairie grasses and other vegetation which has flourished upon it during the unnum- bered years that have passed before civilized man disturbed its virgin repose. This accumulated fertility of the past now constitutes our great agricultural wealth; for itis a fact not to be disguised that our present agricultural prosperity is due to the primitive fertility of our soil, and although it is now of almost marvelous fertility, yet the time is soon to come when we must enquire with an earnestness, excited by necessity, into our resources for its fertilization and restoration. The materials of the drift are so nearly uniform from top to bottom, and so'great a proportion of these are finely comminuted, that almost any part of it, after proper exposure to the atmosphere and frosts, may be brought to the condi- tion of good soil; so that the depth of any given soil, as the term is generally understood, is indefinite, but it may be said to have the depth to which the fibrous roots of the primitive vegetation has reached, and thus added humus to the mineral constituents. This depth is usually from two to four feet, but no lowa farmer has any fear of plowing so deep as to reach through his soil. It will thus be seen that the subsoil does not differ materially from the soil proper. Hence no possible objection can be urged against subsoil plowing, while the nature of the subsoil itself suggests its great value. *This also well illustrates how stratified rocks are formed and how they derive their materials from the crystaline or unstratified rocks. SOILS, ETC. 127 Although the greater part of the drift of lowa is composed of materials that are fitted to produce good soil, it should be stated that the portion which now occupies the first few feet beneath the surface is in much the best condition for it, and that the surface is almost everywhere free from the coarse drift materials, being usually occupied by the finer portion alone. Consequently the soil is almost everywhere fine and excellent, even when the drift beneath, as is some- times the case, contains much sand and boulders, and in other cases stiff clay. It should be also borne in mind that even where the boulders are most abundant, they are not sufficiently so as to interfere with agricultural operations, nor to impair the value of the land for agricultural purposes. 2. BLUFF SOIL. The bluff soil, as its name denotes, is that which rests upon and constitutes a part of the Bluff Deposit before described. The description of that deposit is really a description also of the soil, for with the exception of the accumulation of humus in it at the surface; it is perfectly homogeneous from top to bottom, even where it is more than two hundred feet thick. Neither does it vary materially in composition with geographical extension, as will be seen by Prof. Emery’s analysis of specimens of it obtained from different localities; there is, therefore, no proper distinction between the soil and subsoil of the region it occupies. The area occupied by this soil is the same as that occupied by the Bluff Deposit, described on previous pages. In Iowa, itis found only in the western part of the State and adjacent to the Missouri river, and may be said to contain a superficial area within the State amounting in round numbers to about five thousand square miles. This bluff soil grades imperceptibly into the some- what similar drift soil to the eastward of it, but as a whole it presents a marked contrast with all the other soils of the State, and occupying as it does, so large an area, its peculiar- ities are well known and easily recognized. Although, as 128 PHYSICAL GEOGRAPHY. shown in Prof. EKmery’s report, it contains less than one per cent of clay in its composition, it is in no respect inferior to the best drift soil, and many of those who occupy it claim that it is superior to any other. \ Its fertility is unquestionably as great as that of any, while the advantage claimed for it is that it is perfectly under- drained in consequence of the porosity and depth of the deposit of which it constitutes a part, and containing no clay, it never becomes heavy and “ sticky,” and never ‘‘ bakes” in times of drought. There being not a stone or pebble to be found in it there are no obstructions to its perfect cultivation. 3. ALLUVIAL SOILS. These are the soils of the Alluvial flood-plains of the river valleys, or as they are popularly called in Iowa, ‘“‘ bottom lands.” They vary much in character and fertility, but the best of them are the most fertile soils in the State, from the fact that they contain the washings of the other soils, in addition to a large amount of decayed vegetable matter derived through the agency of former floods from the luxurious growth along the borders of the streams. Those flood-plains, or portions of them, which are period- ically flooded by their rivers are, of course, of little value for agricultural purposes, but a large part of them are entirely above the reach of the highest floods, while others are reached only by extraordinary floods at intervals of several years. Such as those last named are frequently cultivated, the farmer estimating this occasional loss of a year’s crop to be com- sated for by the great productiveness of such soils in other years. The lower portions of the flood-plains, even if they were not annually reached by the floods of the streams, are almost always too sandy for cultivation; but the higher ones are usually covered with a’fine silt which forms the soil, and is often many feet in depth. The silt is almost always under- laid by layers of sand and gravel, formerly deposited there by the stream, so that the alluvial soils are usually well SOILS, ETC. 129 underdrained by that means, although they are, as arule, quite flat. The alluvial lands of the valleys of the two great rivers are the most important, but all the valleys of their principal tributaries contain valuable areas of alluvial soil. That of the Missouri river flood-plains partakes largely of the cha- racter of the peculiar bluff soil which borders it; and that of the flood-plains of those smaller rivers which traverse the region occupied by the Bluff Deposit, is scarcely different in charac- ter from the adjacent upland soil from which it was derived. All varieties of Iowa soil are suited to the production of any crop to which our climate is adapted, with perhaps the only exception that winter wheat succeeds best upon alluvial soils, and those which have been reclaimed from the woodlands. 4, ADAPTABILITY OF IOWA SOILS FOR THE GROWTH OF FOREST TREES. Notwithstanding the fact that the distance from the northern to the southern limits of the State is more than three degrees of latitude, in consequence of the slight difference in surface elevation, and the great degree of uniformity in the character of the soil, there is a striking uniformity in the character of the native vegetation ; for the same reasons also, there is an equal uniformity in the adaptability of the soil and climate to the production of cultivated crops. There are indeed many species of indigenous plants that are restricted to certain parts of the State, and others that are found only in habitats, rendered congenial by moisture, dryness, barrenness, unusual fertility, etc., as the case may be; yet these are only excep- tions to the general uniformity throughout the State, of all indigenous vegetation, including the forest trees. The subject of the distribution of indigenous vegetation is a very suggestive and interesting one in all its bearings,* but * Nature gives earnest and hopeful promises of future harvests of cultivated fruits in the wonderful profusion of wild grapes, apples, plums, cherries, etc., which every year load the indigenous trees and vines. These promises are now being redeemed in full to those who demand their fulfillment in proper form, Ih 130 PHYSICAL GEOGRAPHY. especially when applied to the growth of forest trees, it becomes one of unusual practical importance to every citizen of lowa. The great importance which attaches to this part of the subject is apparent from the fact that the wood of forest trees for fuel, no less than for other purposes, is an indispen- sable element in the prosperity, and even the inhabitation of any country; not to mention the beneficial effects of forests upon the climate, the beautifying and adornment of its land- scapes, and the shading and sheltering of its homes. When the State was first settled, preference was always given to those parts where woodland and prairies joined. The open prairie was always avoided by the early settlers, among whom the belief was general that those portions of the State could never be occupied for want of timber. Time has proved the groundlesness of those views; but even now there is not woodland enough in Iowa to meet: the neces- sities of a population that its fertile soil is capable of supporting in the greatest plenty. It is a matter of regret that so distinguished a man as Prof. Whitney, and one whose accuracy of observation is usually beyond question, should have entertained and pub- lished views so erroneous in relation to the growth of forest trees in lowa, as he did in the former geological report,* where he expressed the opinion that ‘‘ the nature of the soil is the prime cause of the absence of trees upon the prairies.” If the Professor could now revisit those regions he had examined at the time he wrote those views, we are confident he would at once retract them. Duty to the State demands that we should deny the correctness of those views in the most positive manner, and it is for this cause alone that this personal reference is made. If there is really an unfitness of prairie soil for the growth of forest trees, then at least one- third of our State is worthless indeed. But this is not the case, for personal observation in all parts of the State, extending through a period of thirty years, has established a *See Geology of Iowa, 1858, Vol. I. part I., page 24, et seq. ° SOILS, ETC. 131 knowledge of the fact that all varieties of our indigenous forest trees will grow thriftily wpon all varieties of our soil; even those whose most congenial habitat is wpon the alluvial soil of our river valleys, or upon the rugged slopes of the valley-sides. This fact is now well understood by every farmer in the State, and they also know that it requires positive exertion on their part to prevent the natural encroachment of forest growth upon their prairie farms as soon as the bordering wood-land is protected from the annual prairie fires. This encroachment of forest growth is equally marked upon the alluvial or bottom prairies, the ordinary drift prairies, and those in western Iowa whose soil is composed entirely of that fine silt-like material before described under the head of Bluff Deposit. The rapidity with which all kinds of our forest trees will grow upon all varieties of our soil is quite astonishing, for the superiority of these soils is as strikingly shown in the growth of trees as it is in the production of the staple crops of corn and wheat. So rapid indeed is the growth of trees, both by natural and artificial propagation, that not only is there a gradually increasing area occupied by them, but there seems to be sufficient evidence that there is more wood- fuel now existing in Jowa than there was at the time of its first settlement, notwithstanding the constant consumption of it by the inhabitants since then. In many parts of the State the supplies of fuel are derived almost exclusively from trees that have grown from the seed since its settlement. Not only has the new growth reached a size that will answer for fuel, but hundreds of farms have been re-fenced with rails that grew in adjoining wood- land since they were first cultivated. These facts are certainly sufficient to show that there is no unfitness of any of the soil of lowa for the growth of its forest trees, and their original healthful growth, in all parts of the State, even in the smallest numbers, is sufficient evidence that their absence upon the remainder of the surface 132 PHYSICAL GEOGRAPHY. was not due to any unfavorable condition of climate. More especial reference has here been made to the natwral growth and encroachment upon the prairies of the forest trees, but it is proper to state here that the planting of these trees has become a recognized branch of the agriculture of the State, and every Iowa farmer knows that he may plant and grow a crop of wood with the same certainty that he can grow a crop of corn. 4, ORIGIN OF THE PRAIRIES. The question of the origin of the prairies has become more hackneyed perhaps, than any other of the speculative ques- tions which North American geology affords; and yet it seems to be no nearer a solution, satisfactory to all, than it was when it first began to be discussed. It is not now — proposed to discuss this question at length, nor even to present the different views that have been published by different authors, but only to state a few facts, offer a few suggestions, and perhaps leave the subject as unsettled in the minds of others as it was before. By the word prairie we mean any considerable surface that is free from forest trees and shrubbery, and which is covered more or less thickly with grass and annual plants. This is also the popular understanding of the term. It is estimated that about seven-eighths of the surface of Iowa is prairie or was so when the State was first settled. They are not confined to the level surfaces, but are sometimes even quite hilly and broken; and it has just been shown that they are not confined to any particular variety of soil, for they prevail equally upon Alluvial, Drift, and Lacustral soils. Indeed, we sometimes find a single prairie whose surface includes all these varieties, portions of which may be respectively sandy, eravelly, clayey, or loamy. Neither are they confined to the region of, nor does their character seem at all dependent upon the formations which underlie them, for within the State of Iowa they rest upon all formations, from those of Azoic to those of Cretaceous age inclusive, which embrace almost SOILS, ETC. 183 all kinds of rock, such as quartzite, friable sandstone, mag- nesian limestone, common limestone, impure chalk, clay, clayey, and sandy shales, &c. Southwestern Minnesota is almost one continuous prairie upon the drift which rests directly upon, not only the hard Sioux quartzite but also directly upon the granite. Thus, whatever the origin of the prairies may have been, we have the positive assurance that their present existence in Iowa and its immediate vicinity is not due to the influence of climate, the character or composition of the soil, nor to the character of any of the underlying formations. It now remains to say without the least hesitation, that the real cause of the present existence of the prairies in Lowa is the preva- lence of the annual fires. If these had been prevented fifty years ago Iowa would now be a timbered instead of a prairie State. Thus far we have stated facts and what are deemed to be legitimate deductions from them. The following are offered only as suggestions. We have no evidence to show or suggest that any of the prairies ever had a growth of trees upon them; notwithstanding the fact that those at least of the eastern part of the great prairie region will support an abundant erowth of trees after they are introduced, if protected from the fires. There seems to be no good reason why we should regard the forest as any more a natural or normal condition of the surface than the prairies are. Indeed, it seems the more natural inference that the occupation of the surface by the forests has taken place by dispersion from original centres, and that they encroached upon the unoccupied surface until -met and checked by the destructive power of the fires. Then arise questions like the following, not easily answered, and for which no answers are at present proposed: When was fire first introduced upon the prairies, and how? Could any but human agency have introduced annual fires uponthem? If they could have been introduced only by the agency of man why did the forests not occupy the prairies before man came to introduce his fires, since we see their great 134 PHYSICAL GEOGRAPHY. tendency to encroach upon the prairies as soon as the fires are made to cease? The prairies, doubtless, existed as such almost immediately after the close of the Glacial epoch. Did man then exist and possess the use of fire that he might have annually burnt the prairies of so large a part of the continent, and thus have constantly prevented the encroach- ment of the forests? It may be that these questions will never be satisfactorily answered ; but nothing is more evident than that the forests would soon occupy a very large propor- tion of the prairie region of North America if the prairie fires were made to cease, and no artificial efforts were made to prevent their growth and encroachment. 5. FOREST TREKS. Although the subject of the growth of wood is not, strictly speaking, a geological one, yet it is proper to consider it in this report in addition to coal and peat, as a part of the fuel resources of the State; and it is introduced here as having also a natural connection with the subjects discussed in the pages immediately preceding. Wood is, and always has been, the principal and preferred fuel of the inhabitants of the State for domestic use, and were it everywhere in sufficient quantity, they would probably never care to change their established habits in the use of fuel by discarding it for any other. It has been feared by many, that the amount of fuel which Iowa could be made to produce ; would not be sufficient to meet the wants of the prospective inhabitants that her fertile soil is capable of supporting in plenty ; but it is believed that an examination of the subsequent pages upon the subjects of coal and peat, will show the groundlessness of such fears, even if no other sources of supply are considered. In addition to that, it is proposed to show in this place that a sufficient amount of fuel, at least for domestic use, for all the present and pro- spective inhabitants of the State may be produced from the soil alone by the growth of forest trees. It has before been stated that forest trees can be cultivated SOILS, ETC. 135 as successfully as a crop of corn upon all varieties of our soil, and this question being settled in the minds of those interested in the subject, it becomes necessary to consider the time within which the result may be practically accomplished; because to meet the wants of the rapidly increasing popula- tion, it is necessary that some almost immediate supply be provided in the case of the broad prairie districts. Some such districts are upon, or adjacent to the coal-fields. Some are adjacent to considerable bodies of woodland, and others have important deposits of peat; from all of which sources immediate supplies of fuel may be obtained. But besides these, there are other broad and fertile tracts that have none of the advantages just named, and those who occupy them must rely for their supplies of fuel upon distant sources or upon its production from the soil. Railroads are being rapidly constructed which will carry coal from our coal-field to a large part of these prairie regions, but a large proportion of the inhabitants of Iowa must depend alone for their ordi- nary fuel upon the growth of trees. By first planting those trees which have the most rapid erowth, to be followed immediately by those of slower erowth and greater density of wood, one not acquainted with the subject would be surprised to see how quickly a sufficient supply of fuel may be obtained, and how a future supply of the best kinds of wood can be established. ‘The principal kinds of trees indigenous to the State, which are or may be used as fuel, are the following given in the order of their estimated relative abundance by natural growth at present in the State at large: Oaks—several species—cotton- wood, elm, white maple, linden, hickory, sugar maple, black walnut. The oaks form the greater part of the firewood now used in the State. In some parts cottonwood is scarcely used at all for fuel, but in others, better wood being scarce, it constitutes the greater part of the fuel used by the inhabitants. Other trees, such as hackberry, ash, honey-locust, slippery-elm, butternut, etc., are occasionally used as fuel, but they are comparatively 1386 PHYSICAL GEOGRAPHY. so few in number that they hardly deserve mention as varieties of fuel. In the new natural growth of these trees the relative abundance is somewhat changed, the black oak, hickory, and black walnut increasing. The following named trees are those which will probably be most used for cultivation. They are given in the order of their estimated rapidity of growth: Cottonwood, white maple, black walnut, oaks, sugar maple, and hickory. | The relative value of each of these kinds of wood for fuel is estimated to be in the same order, cottonwood being the poorest and hickory the best; or, in other words, the slower the growth of the tree, the more valuable it is for fuel. But taking into account the necessity that exists for immediate supplies of fuel in many parts of Iowa, the cottonwood becomes one of our most valuable trees because of its rapid growth. As soon as it has performed this valuable pioneer service, it should be laid aside to give place to more solid and useful varieties. The most congenial habitat of the cottonwood is upon the sandy alluvial soils of the river-valleys; but it grows with astonishing rapidity upon all varieties of soilin the State, and flourishes as well upon the prairies as in the valleys. Instances are numerous of the growth of this tree from the seed, or from a riding stick stuck into the prairie soil, to the size of from twelve to fifteen inches in diameter, a foot above the earth, within the space of ten or twelve years. So rapid is its growth that those well acquainted with it estimate that ten acres planted with the seeds or young shoots, will, at the end of five years, supply a large family continually with all neces- sary fuel. Indeed a large number of persons have practically proved the correctness of these estimates. Cottonwood may be propagated either from the seed, cuttings, or by transplanting the young trees. The seed, which is very light, is sometimes scraped up from the sandy surfaces along the streams where it has fallen from the trees, the seed and sand mixed together and sown broadcast upon ground prepared for it, as small grainis sown. Sometimes SOILS, ETC. 138 the slender poles are cut from the dense growth that often springs up along the streams, trimmed of their branches, and then notched with the ax at intervals of a few feet along their entire length, then placed end to end in furrows at proper inter- vals, and covered with soil by the plow. Sprouts quickly start from the sides of the notches and rapidly become thrifty trees. The most congenial habitat of the white maple is also upon the low-lands, but it thrives well upon the prairies. For rapidity of growth it ranks next to the cottonwood and makes better and more durable fuel. It succeeds well upon all varities of soil and may be readily propagated from the seed, or by transplanting the young trees from the places of their natural growth. The black walnut has been proven to succeed well upon the prairies by artificial propagation. It is propagated from the seed with certainty and little labor. These three kinds of trees are those now most commonly used for the production of artificial groves and woodlands by the people of theState, since the failure of the black locust, in consequence of its destruction by the borers. It is well known that all the other indigenous trees may be artificially cultivated, but these seem to have been wisely chosen for the rapidity of their growth and the small amount of labor required in their propagation and cultivation. These tests which the people have made extensively through- out the State, prove beyond the possibility of doubt that a sufficient amount of fuel and fencing material may be produced from the soil alone in any part of Iowa. People have hitherto been in the habit of regarding the great proportion of prairie surface in our State as a calamity; but with a knowledge of the facts just stated it is evident that views directly opposite should be taken, because the labor and expense of procuring all necessary fuel by the means just explained, is but a tithe of what would be necessary to prepare the land for cultivation if it had originally been covered with forests, such as formerly pre- vailed pie a large part of the States of Ohio and Indiana. 138 “PHYSICAL GEOGRAPHY. In a prairie region like ours the farmer selects the finest lands for cultivation, every acre of which is ready for the plow, and sets aside the more broken and less tillable portions for his future woodlands. Thus he may not only choose the location of his fields and woodlands, but also the kinds of crops, whether of grain or trees, that shall be grown upon each. A CATALOGUE OF THE INDIGENOUS FOREST TREES OF IOWA. Acer Dasycarpum—W hite maple. Acer saccharinum.—Sugar maple. Aisculus glabra.—Buckeye. Betula nigra.—Water birch. Carya alba.—Hickory. Carya amara.—Pig-nut hickory. Carya olivaeformis.—P ecan. Celtis occide: talis—Hackberry. Cerasus serotina.— Black wild cherry. Fraxinus Americana.— White ash. Gleditschia triacanthus.—Honey locust. Gymnocladus Canadensis.—Kentucky Coffee bean. Juglans cinerea.—Butternut, White walnut. Juglans nigra —Black walaut. Negundo aceroides.—Box-elder. Platanus occidentalis.—Button, Sycamore. Populus monilifera.—Cotton-wood. Populus tremuloides.—Aspen. Quercus alba.—W hite oak. Quercus imbricaria.—Laurel oak. Quercus macrocarpa.— Bur oak. Quercus tinctoria.—Black oak. Tilia Americana.—Linden, Bass wood. Ulmus Americana.—Common elm. Ulmus fulua.—Slippery elm. Some of the trees enumerated in this catalogue can hardly be said with strict propriety to be a part of our forest trees on account of their scarcity. A few others might also be men- tioned that occur in small numbers within the State, besides several species of the smaller class of trees; but the object of this catalogue is only to give .a general view of the arboreous flora of the State to those who are not acquainted with it. Ole ar Ry. EV Ca As es The climatology of the State can only be properly ascer- tained from a careful comparison of a long series of observations made at different points in various parts of the State. Yet.much of great value, to the agriculturist and others, may be learned from a study of the observations made at a single point, and their value enhanced as they extend over a longer period of time. The observations upon which this chapter is based, prepared at the request of C. A. White, M. D., State Geologist, to accompany his report upon the Geology of the State, were made by the writer at Musca- tine, (Bloomington, until 1837) and Iowa City, commencing January, 1839, and continued until the present time. Those at Bloomington, 1839-1847, were furnished the Government through Prof. Espy, of the Treasury Department, until the organization of the ‘‘Smithsonian Institution,” where, at the request of Prof. Henry, Secretary thereof, they were con- tinued at Muscatine from 1847 to 1860 and at Iowa City from 1860 to 1869. The difference in latitude is about one-tenth degrees, and longitude about five-tenths degrees. I have calculated the means of the observations at Muscatine for twenty years and at Iowa City for ten years, and find that the difference is so very slight that I have not hesitated to * Professor THEODORE S. PARVIN, of the State University, has generously contributed the entire contents of this chapter-—C. A. WHITE. 139 140 PHYSICAL GEOGRAPHY. regard the observations as taken at one point and used them accordingly. The instruments used are a barometer, thermometers, psychometer, wind-vane, pluviameter, (rain gauge,) all of the best quality, and manufactured by James Green, of New York. Accompanying these observations are records of the frost; flowering of fruit trees; times of the opening and closing of the Mississippi river, etc., etc., presenting facts in regard to the seasons of great value to the farmer, stock and fruit raiser, as well as shipper. The observations were made at the hours of 7 A. M., 2 P. M.,and9 P.M. In their collection and reduction, I have, in order to make them of comprehension to the unscientific reader and observer, avoided as far as possible the use of either scientific terms or formula. : The array of facts here presented will, it is hoped, prove of interest not only for the residents of this State and the Missis- sippi valley, but also for the dwellers upon the sea-board, as furnishing data from which a comparison may be drawn as to the difference in the temperature, amount of rain-fall, the source thereof, &c., &c., as also their distribution through the several seasons of the year. Eastern meteorologists have been greatly surprised at the large amount of precipitation of vapor in the valley, overlooking the fact that there the rain winds are N.E., here, 8.W. The amount precipitated has not diminished since the first settlement of the country, and probably will not, as the area covered by timber has not decreased with the settlements of the State and is not likely to in the future; on the contrary, is increasing and will con- tinue to increase with the growth of settlements, in age and extent. The peculiarities of our soil and climate are such that the past three decades have demonstrated that our State can endure an extreme of drought or rain with as little or less loss than any other cultivated region of our country. No use has been made in this report of the barometrical observations taken in connection with the others used, nor of the relative humidity, &c., deduced from the observations of CLIMATE. 141 the psychometer, the latter of which especially bear so strongly upon the problem of health. It did not come parti- cularly within the limit assigned me and has more of a scientific than practical relation to my work and object. It may here be stated, however, that the atmospheric conditions of our climate are, in the highest degree, favorable to general health, and no people enjoy this boon in a higher degree than ours. 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F | 99|lo0es| St] eL|l09'88] 98} 96/0¢'¢9] SF 96|/0F'0L! 9G} 96|)"*° 05s eee eer €9'06 FEIeL||9G°63] B | SF ||GS'TF) GT] 99|/L9°SS] Go] 44]60'S9) PP) OLETGL) FS) 9B|e6'eL| BS) LB TT a ee PSE GOV ei9L!06'es) & | SPOTS! & | O9T\OL09!' TE! OShOT TH 88 PRiOVEL! GF S6iOAGLI Bgl G6 iseeseeeenaeeearenaese ess 6887 FRU EMEALELRIEUELELAL LEAL ERD Ede ae fax aoa || uaanaowg || “HaanAON ||” usaouw0 || awaaNarags || “asapav peels = SHYALVAATNAL NVAW GNV .WAWINTH ‘ponuyuwog—("é) ‘I WIAVDL HOKIXVW TIVPQNNVY GNV A THLNOW 146 PHYSICAL GEOGRAPHY. In Table I. (1)is presented the monthly mean Temperatures for the three observations taken, viz: 7 A. M.,2 P. M., and 9 P. M., for a period of thirty-one years, extending from 1839 to 1869, inclusive; together with the annual means for the same period. At the bottom of the table may be found the greatest and least of these means, with the mean for the whole. : An examination of the results here given, will show a great range in many of these means of many observations, an ine- quality far greater than might have been anticipated. In table I (2), the monthly and annual maximum (greatest) and minimum (least), and mean temperatures are given. In the column for the year the maximum and minimum are the means of these results. An inspection of this table will show that in this region—round about lowa City—November and March are essentially winter months, their mean temperatures rising but a little above the freezing point. September, much more than May, has a summer temperature ; the mean tem- perature of the latter month being 69.06 degrees; of the former it is 63.37 degrees. The mean temperature of October is 49.58 degrees, falling as low as 40.02 in 1863, and again in 1869 to 42.72. In order to show at a glance more plainly the variation in the annual mean temperature, we present the same in the form of a diagram (A), table I (8). The o in the left marginal column, represents the mean annual temperature for the period of thirty-one years, viz: 47.57 degrees—the range being three below 44.18 and five below 52.14, or, 7.96 degrees in all, as may readily be seen upon an examination of table I (2). Diagram B, table I (4), shows the extreme means of the monthly temperatures ; the upper dotted line, the greatest (maximum), the lower dotted line, the least (minimum), while the full central curved line shows the annual monthly fluctua- tions of temperature—all of which are deduced from the results presented in table I (2). CLIMATE. 147 TABLE I. (5.) TEMPERATURE OF THE SEASONS.—1850-69. SEASONS. TEMPERATURE. | MONTHS NEAREST SEASONS. 3) at! | a 47° 44/7 ROVER prtsernars 8S Se 48° 50/7 SYST 5 5 5 dacdtate & « 10° 377 VATIOBGs Osa asar OS vane 10° "707 POT AMIETT: 5. oi Sieie.e 44° §2/ Ocvouen x .45 zeae 49° 50/ WWMMECT 2. o oaia2 Seiecs 23° 377 December......... 23° 257 a Cae ee IEE OE, AAP Bleeder, oc aisobiic, dona | Sha ait Ge kee SRE RANGE OF TEMPERATURE. Highest........... Hap(MIOON 1 Naust sist iGod, ol) ele ciwicsiza seated cn! ts 30° 007 PAMMAEY ROC, LGAhe wel ue cee eice'ec aa ue Lee nee ae RO en estes serial cial mar Ewe hoi cs eras as 1 OE © on alae Table I (5) shows the temperature of the seasons, being the mean results for the years 1839-69 aforesaid: To this table is added the mean temperature of the months nearest thereto. The month of December is here joined to those of January and February of the same legal year. Following this is the range of temperature with the dates corresponding. The highest temperature here occurs in August, while July is the hottest month of the year by nearly two degrees, and January the coldest by three degrees. During a residence of more than thirty years in central eastern Lowa, I have never seen the mercury rise to 100 degrees nor fall below 30 degrees. The mean temperatures of April and October most nearly correspond to the mean temperature of the year, as well as their seasons of Spring and Fall; while that of the Summer and Winter is best represented in that of August and December. 148 PHYSICAL GEOGRAPHY. TABLE I. (6.) TEMPERATURE, TIMES OF HIGHEST AND LOWEST, AND DATES NEAREST. YEAR. HIGHEST, | LOWEST. | DAYS NEAREST ANNUAL MEAN. S50: Caeiterse oorres JULY (20% 2.5 2-906 Kebrodry 3°.) April 12. eee October 12... A SOMY sake reseherot re sie July 20 cca sae December 16 .\April 23...... October 138... TODD nee mei cians July 28.4: 622.2 January 19.../April 23...... October 31 1SDS. ANE wee ares August -IL..3.4\Mebrivary 8:.2) April 16722 228 October 17 USDA stesso to eum see August 31....|January 24...)/April 12...... October 17 1805s eee Tags hoe August 3..... January 23.../April 14...... [October 2 TSG) ssicsers eieyale re swecere June 242: February 4...|/April 12...... October 18 Sean Berets Afivtlgualic): be ae ys January 18...|April 3...... October 23 ABOSEN DS cinch aie ene | SUG ern ee alae Hebruary 10..|April 20...... October 18 SOO Na ein atioune sere Julivsall Sere aerate December 31../April 19...... October 21 de) 630 Neem Meade es Oe August 6..... January-1.... April lO... October 19 MS OUY is svete ous cuevenets August 4..... January 80.../April10...... October 25... UGG re johs onckeyeic te + ous ok August, Gry. se: February 14..|April 27...... October 10... LEG". seas 8 oe August 8..... December ot. .April 20nc..- Octobers Asics WE GA cot ovo nicctche ene ee July Vie coe January? 1, 2-7) Aprilior 2. e- October 13 .. sol alas mice Ne Sa istiliye Once December 21..|April 20...... October 20... SOOPER A. Lae secede ly gis caer... £ February 15..|April 14...... November 2.. WODT 5 clits ssuctls Welevers August 18....|January 29...|/April 30...... October 23... 1868I t Dhavstattatans duly LAF. se: a LO RaW OME cen. October 13... SCO ees patelee cies August 24....|January 11.../April16...... October —... Hagliesty ye une 2 eee [December 16. April |October 2. 32. Taba ste ss Fs [August 31....|/February 15..|April 30...... [November 2.. Meanke 55.99: \ornly 2 Se ee | Niemiutar ys QO Ah... Sis lee Nhe AAAS oh Acre has We add in Table I (6) the times or dates of the highest and lowest temperatures of each year for a period of twenty years, 1850-1869 inclusive; also the days of the months most nearly corresponding to that of the annual mean temperature. We learn from an inspection of this table that the period of greatest heat ranges from June 22nd to August 31st; the mean time being July 27th. That of the lowest temperature extends from December 16th'to February 15th; the average being January 20th. The range in each case being two full months. These mean times, it will be seen, fall in those months whose mean temperatures show them to be the extreme ones of the year. : Se 149 CLIMATE. SE ie A le GT eS EC oE oe SE SEE TE) Gr ar) | FE) ot Lr | 9h Sew acon [Ge re@. | et l@eelea We eon erenliG a Oe lege cs | be: len TORRE esasat 99 | Torl9'8 Is% llen 16 uns Tea eet Oe le tolaeses Lae iene |oe oe lioetio6 Ire leg [*‘sueon OM NOr |e inc 9 |8 Fi are an mallets eat Oy | 9 SEA GA eo) hi oF | 3 Veo 60er Oke ser ele ALG lsopel eR AE F ILSE shes GEO eee BOG Sie eae es | pe Gr = ete o gy ofl Ge I eee Tee atc Caja ET ah ely ee ifeae cts aca eal ose HSI Abs ITO SAL Ce me ea) ia ype tea ace) eI cee TE (re Ie Cay |) fee II voy p CIS pelea Bro Obce-a1e:-N-LE | 9) 96 ; CT eGrs CeO | Si Oe |epeal Oy SN e(i ge ol Ciel ages leet OOo Pap eroOmee NOOR o | Gere |g ria US Lat 2 Suh deena aC) eel aes beamed OMamN| CO) I heen he SCE Pa OL (aroy ony Serer atte Tet Aste lce el lel sll Olina ese (eG GT] Ge Be SGT Oe Oa ae teal Pele ee iG 1 ete eel ORT It | 0 | Pee a ee ON le leh alae pe OTE OT viol ere NON llieGuoll: Re a) 6 | Ly Fela ae Ge sl eeae = COG eee ee ee ee ee) ep Qe ie I Ono NG oo ETN Oil Ueliece -lisG) 0 O[emeO) e|ecee el een OT CoeletaaOwal hel Gr |-Ofete lec Neo | Oh | 108 | & Spee |e lik6 IG a0 Si ve Oy ne lnpelayd eee caer oem MeeieG leGialeGes fe Ir ete Wis! Oy iG 2) a Metis | pieiay eae Seale) a) Slope e | sou Ne rriec lsat pen (ace meeceneaa (yey etn OM pee rh ae eS, | OF OL o Otel Le | We 2 ee GrelG 1 a likes Tio 1-0 | GL ED Oc ROb 22 hse cen Fe ee UuleQuaieSe HieOke\c0 56° 160: sis ttal Ge | Grek Note Be BE RIOT Poe ol pe "ei ep ere alee no en CoPemiG | o-lo fo let le lhe h | @ leo Wie. lo. | onl @s let Obey bee lbGn OL onal Gaels eeueoicen Or ipeeeemse Ca Be 1G 6G eG Ve Ouch TR CO Gr WOT ITB le lias OTR Teka a PORt POR EO. eOnmeGie css Ogen OG eleOhe en iaQe (oO. let lee) ineiael Qe Or |e) Weta Cn Ge Gh lleOTles, lm cl Ope llien isQil (Cra Gena ama CGtE G | Get Cn GesG Ot lee Ob (Ge OL i SiGe) Bul hs Nec he oF Tf SIRS ae@> itruleys (ee sara CS ettmiecianewa| ah Oo Ic@ see eG =| bos) Ce | GE Wels) Creel we Kee Oleh a eee ir eye eGmal Ub Lies ecnen CEE RPO snQe econ Tb: jie pale lh Besa Np ea hy Ge eon) Goal Com GmelitiolnG lige dinsi) |e ess Sac Gen Bos leG) cO be @ieiioGe le) icebeleo | Olu| Ge | ee 187 ul Ge) Sree lies Slee) SC IROICIe. le@oul Gt Soo 22 ear Ses ey Pua sepa Miel Meh eke NeG a te SE oe bite eS 8) Beller ee : SSeS eel lee wep i 2s 2 Oeen riefetudelefelrfejelels ee rag ae ee] e ls | ¢ e |: a3 a eee ee eens ae Se, ee. ee es “SUVHA “ANOLP “AVA | | "TIUdV | *HOUVA | "AUVOAGAA = “AUVANVE "A'N ON OM FP O'S ‘S'S SA'S HS AN ON ‘I SAMO]I[OJ Sv ‘s10j1enb oy) 07BdIpU] F pue ‘g‘z ‘TSaiInsy ou NOZIYOH AHL AO SYUALNVQO YQOdA AHL AO HOVA KHOU AWVO SCNIM ONITIFAGNd AHL HOIHM NI HINOW HOVA NI SAVG AO THANAN CT) il (ata vii a eee PHYSICAL GEOGRAPHY. 150 eetlertiz6 Igotlist Ist i6 let low lor let (tr Ilet let let let [ltt lot let lin [lor [zt let lot lor loe ler ist 1° "11 *9809BOr) 6s Cou see ee eee Ee pelenieeleer wen le Ff eueltelic ols lo cee See T PITCOTI9 104 [16°St |9'2 [27 [6's [eet Ita [a'e Fe |/8'6 lo's l6'9 [e'9 [les lot [69 [e's [log lor e's Ire Iles lover Ie Ire |= sceopy eoecloeei[oeslee. ia amines @eeeloeosl|eosioe oe. ere Sars ay it id ig ¥ 11 g g T CT OL g a a TNS Sees Oe eae 8 OP eee 2 C118 Nee Gl ie ie le 1¢ ir iy lie Wet lee |**° = = “goer COE Pe OES CS. 7 OP Ore Ol 6 8 9 oe 7h ie lb 10 Wt Ie. le) lie “lon lopele| 2222228 =og7 GELEG \8h 89 |r If 8 6 |8 |9 6 IL ler lh jit lore |ct 4 jor 6 jor ie lig joe |9 lo | --*:-"*-* g9gT OTTOIT 89 |Th |/et je jf OT [A j8 ei je jit js ie 6 lio jor iF | Ils lex le Ile jor lo ly jcc °° ‘eget “BOTIGOTIOG [LL (IPE [4 (8 8 -10T jor 9 4p je1 2 le jig jet jg i¢ fio ltt itig le ltt |e le |ccttes +++ soet itles \79 joe lis i 6 [& jor fo e@ ja cris le ‘ce io ler fe fa llor te le It le & lo ler |< beet Coe CSO Cee eek OL Cle i ir NOR Woe iy 6 19 1% Pp gi letie eee soon QOTISET|PL |rk ||EE |r 10 |9 |2t JG j@ -l¢ | le [iT let Ils jet let lo lio jet ig Je I: Pee G1 10 2) tes eo CCH ROS OS VALE TG iG Gy fe 8 8 ik 6 BL 6 i iol lk le i —\pt i \lOL On lon |t | *°*:°>scooeT PEBCOR Ce Ca VOW cee ibe ire NG int i SiG epg ic joe l6- 16 S19 illo it |o: |G al tute = eeeaen SIL/GITSL [eo |/OT [St |E |S |#L le '@ 111 Ki Mest es WS WE SE SI OE HI NG) |) 2228 205 sae ay) LOTS OO ee aa ee eG ie ee be 6 ion ier i@ Gi ler ig io lie lep lye lo \ 202 2-"i aon OVL/EETISS joy [OT |@ 9 [& Itt |4 9 le [io lot et le {itt let io jt 6 let lo & Ile (Gre ORS Cae esac eesOce L6 |OTT/S6 199 |\7E [8 |G IF [Or |¢ | FF ls eT ig 9 |§ (6 OF is Gh HPS ES OB 1G | eee anor 8IT/86 |68 se oo ieee Sea) N69 elec (Oh str O° Ve a. Sey ie IG Oe lp | seas lose ear LIT/96 \€8 |89 |/et OT |r IF |8 6 F 6 it a jot le y¢ ig {or In lio let Ie le (6 |e |e |9 | ----7+ cc cecer SCOR Een mG Oe eer at Cl 8 8 8 10 1G 16 opie iy = levy ie lp lo. One| 23" > oe cop LOT/E6 |T9 |SOT|SE |e s AGL Se sy (Cl 18 IP 16 (eB 1g ar Se eae \Gs NCP es Ole itl Mon; =e Seaeen BUSOU TE CGE CE eee eee ele Ne 6 Be Wipe lies We seh lee lp 08 ee Bl no So ecoeen | | | | | sfelz|r|y ele] v elelr|ielele|ri|e fel ple fe|rile|e|e|s inne eas | ‘SUVAA “AVHA UHL AOL “AH aAWaOnG | “ADA NGAON | “ATOL i> MN p Lo} p < | “ad LO.LOO | “MHA NHLdas "MUN NAA FAA'S 'S '6 SHS HS SH NN ‘I—: SMOTIOJ sv ‘sroqaenb oy ojvoIpuT F pus ‘g ‘z ‘T sornSy ou, ‘NOZIYOH AHL AO SYALAVIO YNOA AHL AO HOVA KOUTA AWVO SGNIM YNITIVADYd AHL HOIHM NI HINOK HOVH NI SA¥PA AO YAIHNN ‘panuywuog— Tt) ‘Il WITAViL CLIMATE. 151 In this Table II. (1), are given the number of days in each month in which the prevailing Winds came from each of the four principal points of the compass. The first column (1), including the winds from the N. and N. E.; the second (2), those from the E. and S. E.; the third (8), the S. and 8. W. winds; and the fourth (4), the W. and N. N.W. winds. At the bottom of the columns is shown the greatest, least, and mean number, and the last right hand column the fotal number of days for the year. Of the direction of the wind for the year they blew seventy days from the N. N.E.; seventy-six from the E.S. E.; one hundred and five from the 8. 8. W., and one hundred and fourteen from the W. N. N.W., or one hundred and forty-six days from an easterly direction, and two hundred and nineteen days from a westerly direction. Ae Ts 2) WINDS OF THE SEASONS.—(1850-69.) WO a MONTH NEAREST MEAN OF SEASONS. THE WIND. SEASONS, Tie 8 ite ene aBere lee (ile ae al ie | 2. | Bia a en SPLIMG IS. cewcas - 19.0/19.9|22.2/28.8)| April April March April SUMMIT ss = ever oie 15.3/23.1/33.1/18.0)| July July August {June AUtUMMN sacs se 17.3/19.5/25.1/29.2)|September|September!October |October Wamter’ ...<)22%5,<.0,0 17.0|11.4|24.1|37.8]|December |December |December |December CAE tee eee |1'7.5|19.0|26.2/28.5]| | | | Table II (2) gives the winds for the seasons, the average number of days in which they blew from the four quarters of the horizon, with the month furnishing the number from the same direction nearest corresponding thereto. In the Spring, the winds of April correspond with nearly to those of each of the quarters of the horizon; for the Summer, June; for the ee Boner, and for ne Wag those of December. The same results are one an plainly exhibitedin Diagrams C and D, of Table II (8), the former showing the relative frequency for the year; the latter for the Summer, (June, July and August) in the full curve; and for Winter, (Decem- ber, January and February, of the same year, in the dotted curve. PHYSICAL GEOGRAPHY. 152 761 lebh |F'F los It [6 ef ie if 0 0 CEES Rs tig ee |) ee I I RE NTR ERR i AR RR “**19°6 [40 Phecee scion Sei cn me wee 7 |wole'ol lout Ig |8 apg B= iE. 8 : oii ee re 8¢_ [TTT 899 93 6h vo |89 06 |6 rt G2 ay (ad CROW IDNA HRNANNIDWDONASDMOMDHADONR CO CO &= OD GSO é a oD i RAM OSORNQNQNAEKONRGSOSDARNQNQNMDOHAHHODROW PS mS So TH OD 1D TH RID HD SO = OD HEH OD MIN 1D eee lee ee oe \0 a lO lO lo i) lo ln ESE ne ean epee GOOF ee Ist lor OE iG | sete oc (Bolboney Cl a eee aa) ° ie eae e eae Se Ae ci or teed eee ODO) 9 eG ea . 66 eseecoves eoeene « * Q98T pica) ie 16 len ose : zg , Se beser eared ices ascuvesee 198T . | eeceoer1 ese ses ovoevee esses eo ed o 998T ¢ 18 {8 | é 6 Tals eos me ‘ls a eee i ea) ae) re m 1! = @ ee | wet tat = re ° ° ° Nao] ° ° . ° Fees eee ee te neces trees sense BQGT Forte t eee esse ese essen es TORT Peete eee e eres eee cere n es QOGT Dente ene ee eee erseee eens: BOQT Feet b eee eeee ee ee eeereeees GagT eR 7c Peete eee te etree eee ereee es QogT ° e . ee! st OOO HS RH ND @D roe Donen eee etee eset secs renee pear Feet ee cette es tee ee nese ees QE OT Coenen tees ese cee essere OFOT Fatt e cece eee e eee eree eee e es FET Peet t ete e cece rece tee etree: GEQT Dance eee een tree eeee ete e es epOT Denese een eens eee cteeeee eee THOT cheese tence ee en ere esse ees QEOT settee eee ener eee ees cee ear m4 i COODNHOIAGCNDrOHDDOKREK | oee 219 SSO aC lf Ce ee Bess Bee OOO: ey. Bl 12.60]18.12/15.34) 5.42 Hire) ae Nees a lata! ot aA RY oy oid WALES m2 Wile (ops. oleae A ose ela 00 13.55|10.45| 4.18; 3.47 TSU Dog Ae lec Saitens epelaey elle eA scr aes Pr De 3.64] 9.99) 5.85| 5.62 1s) 11 De gcaoy @ es & Sint Merah n eae EER oP Or Be ae oy 9.65| '7.1'7/22.01| 7.06 LST 6 SERCO OS CE RE ee, Se ee a 13.01/16 47/11.88] 3.42 eye ee etary eerste te a Ace ds Sr a ok Cuisine Babee 7.69] 3.45/12.65| 9.97 eSB eee ee tenet a Nd dees ee essche coors: o? fgaNichjet su ijatw: e\iniel sie iotdt ere eiegedesepnisus’ 13.21)18.30/11.49| 5.57 LUSTER "e Cketd Beene eae on SEA Re oe ae MEDAL oR A, eae ee re a 15.60/15.61/10.35] 3.78 LSE OEP es 288 odd DRS Oe CAE ARIES, SiS Pat aes ey Pr oe eo 5.34/18.16/12.55| 7.32 TSE 5 2 BE & Rees 5s ee One eae ERE eae ee A 13.45)12.43) 9.65] 6.75 LGINS. Sie Seb + 5 SELIG ASE RE: aI OPE Riser an oe 18.43/12.10] 9 88} 2.49 erm eee on oe ei Nabe e toa 5 '7.65/26.27| 8.59]..... Geaned) | 3 ce eae ee |19.23|36.90|22.01|10.83 Libis oh ak 0 De a eee eee | 6.36] 8.45| 418] 1.65 Ripe ee eee ata BL Pah dds aero oa oo ys oath wale o + \11.89]14.93/11.22| 5.62 The total amount of rain for each of the seasons for twenty y ears—1850-69—is given in table III (4). Much the largest amount being in the summer, as may be seen from the amounts greatest, least, and means, at the bottom of the table; spring and autumn having the same mean—eleven and one-third inches—while summer is nearly one-third more, and three times as much as during winter. Illustrating table III (5), we give diagram G, exhibiting the same results in a more visible form. 156 PHYSICAL GEOGRAPHY. TABLE III. (5.) DISTRIBUTION OF RAIN THROUGHOUT THE SEASONS, WINTER, SPRING, SUMMER, AND FALL, 1&50-69, A PERIOD OF TWENTY YEARS. Winter, total, 117.29 inches; mean, 5.86 inches. Spring, total, 237.11 inches; mean, 11.85 inches. Summer, total, 278.06 inches ; mean, 13.90 inches. Fall, total, 216.73 inches ; mean, 10.83 inches. Winter taken as unit, as 1.00, 2.02, 2.38, 1.88. TAPLE. TM. 6.) RELATION OF RAIN TO THE DIRECTION OF THE WIND. SPRING, SUMMER. AUTUMN. WINTER. ! R THE YEAR- Peer hy pie ea teniealan TT PTEMES Taio EMEA F Zea es | 4. 1850... | 2] 1) 2 4) 6/11) 1) 3) 3) 8) 6 2) 2 2) .. Jeo, ea] 8 aa HS 9). 3)..) 3il 2) 2). Sill oils ill asia e652 | Bl Bl lel. al..}. 514i} 3i-3i 5) Bil alee i 10N) 3s) eae 1863 (04. BB GO Oh Bt ARC I an) 8) a oe 1 St ight i ean 1854... | 2) 4) 2! 1)| 4 4) 2, 3 ee Re oc| acll (BI 2122 me 1855 .. Ava 1} 4/11; 2)| 7 @ 4{ 6] ..)..) 4) 4|| 12) 12] 23) ae 4850 .-| 3) a] 3 3 3] 3/30] al) Al 2) 9) 4) al al 4) 3) a5) 10) 26) a4 1857... | 4) 8! 6] 5i} 1! 6} 5] 121i} 2 6/10] 2i| 3) 4/10, I} 10) 24] 31] 10 1858... | 6] 8/14) Zl 4! 7/17) 5i| 8] 6/11/10 sbakal ll és 931 50] 22 1d Be call ath lO 2) eal ale aieh eee 1560 <<) 3] oni) 8] jo] af a] a) 83) 3/4) al al 3 9| 25} 26) 13 1861 .. | 5] 6| S| 4} 2) 2) 3] 4} S| 5] 2)13/! 4) 3] -2) ..\) 13] 16] 15) of a ea ehgt ol clita) give] wellei ao al ee ee ein A868 .. +16) ..| S|. 4]| “5! a) 2) Bit 2] 1] Si Bil 2] 4] 2) 2) 45) 6) Ba) ay 1864... | 11) 1/10] 5i| 5! 3/14) 1// 5! 6/10) 14); 2)..) 2) 2) 22] 10: 33] 22 1865 .. | 6| 5/9] '31| 3] 4/10/40) “7 3) si Si) 3] 3) al 1) 49] a5) B0)-a8 1866 9| 7] 3i All ..| 6113) Zl 6! 3] 6] 6Il 4l.-1 4.) 91) 29 dé) Saini 1867 5} 5) 8! dil 383i 5/15!) 3il 3l..| 8! 3 al 2.{| 14! 10] 34) 44 1868 q 15 7 | 1| 2/10] 2 1 js 8 Be A hoe 2 8| 39] 17 1869 2) Al 517] 2)) 5) 9) 20h bt a. ahh Mean |5.0/4.5/6.8/3.1||2.7]4.3/9.1[3.3]|2.6|3.4]6.7|5. 3} il, aL ap. 81. 1]/12.8/11.4]26.3/12.4 SHL. 4226. 312.4 The relation of rain to the direction of the wind for the year, and also for the seasons from 1850 to 1869, is here given, table III (6). In this table we have sought to enter only the days when any considerable quantity of rain fell, and not all rainy days. The figures 1, 2, 3, 4, at the head of the column refer, as before, to the principal points of the compass, 1 being N. N. E., etc. the CLIMATE. 157 The same results for the seasons and the year are much more conspicuously seen in the diagrams EK and F, table III (7). The former gives the results for the year, the latter for the seasons: Summer, March and August inclusive; and Winter, September and February inclusive of same year— the dotted curve for winter and full curve for summer. These diagrams show very interesting results. The rains curve during the seasons and during the year accompanied with southwest winds, or, in other words; the rain-winds are from the southwest, the very opposite to the rain-winds of the Atlantic States. Twenty per cent of the rainy days are accompanied with N. N. E. winds; 18 per cent by E. 8S. E. winds; 42 per cent by S.S. W. winds, and 19 per cent by W. N. W. winds; or, to sum up, 62 per cent occur in connection with winds from a westerly course. TABLE III. (8.) RAIN. Greatest fall of rain, 10.71 inches, August 10th, 1851—11 P. M., 10th, to 3 A.M., the 11th, 4 hours. Wind N.E. both days. SNOW. Harliest—October 17th, 1859. Latest—April 29th, 1851.. 2 Greatest—December 21st, 1848, 20.50 inches. December 28th, 1863, 15.10 inches in twelve hours. Table III (8), furnish brief statistics of rain and snow, the greatest fall of the former, and the earliest, latest, and greatest of the latter. 158 PHYSICAL GEOGRAPHY. or | ee | ct Il et | 08 | gt Il _gt | ee! ef |i etl og | 0g || et | og | 02 Il et | 92 | or A(peCm nian ROmeomiece [Ey ire fesiteere le iro fr fe ie fo te sr irotlee ilo lest |e te lserloe ll a2 lortl¢'s lls9 lost re lien lost| 96 Or eee | 8 Se S| Oo ae ey | Ore oe a6 ee CeCe es io Oc 8" lee Gr | € “ie TE | OF | OF rE Me Sl O ESTs O0 | ve meee ie soled 8 Siete ies OP er rers Ol 16) |S | er a |G | et be | ee eee ee ese es CeseSeR VE | O aieeec| Oe |e) OF |G: 6 16) jemtaerE | ee Se Cre eee eel Ee SG Tre eee Ober 6" |) Th | TE | @ iP \cye oO: | CC eemlee eae RG RTS Gy 8 |e | Tr | Se ek ler | er |e ec Ml, aie Cle| Ge ire) a6 et | Be Ge To AS SO kote ee 2k SRS GGeseGr eG weOlel Ghigo) (eG li Gielemp | 7 iS (Sims | ISM Pa | a a ce eer al | e | gt ia Oey seen een ec ier| Yoe mera eea Ol MONTE pat ae eMC ee ele Se eo Sel | Mies Sos 0e).% | kool BE || Shiv |e 9 | 91/8 | OF esie lect | 6 SIS Oe | SE Ws OIE OT tos oa a Moles ae CMTE Gteeo Olan Or |) oor | on fer lie | y | op ills |e | an mea ee alee oracle OR Ney Sete | @ teers |e) eb € io | cr ben |e = epee Os Oe 001 6s leo a\ 06 ir ie GCa Gee Oca eo ee Bes POl ie ete Pele gah OG Wek 9 8 ir |r | 06 FOr | Gan os Pe Ce ena Por GOI eG eC 20h |G ee er |S lik sei 6 |G | ple | eee eee Ols OT kG Ol Cos Ome UE lye || 97 OF 19 |e | eh | ur | Pee eom ee 0c OR IG SON ee 6 er ye | Sie Or Nee BPO UP 0c er aie |0e 18 | eT | 4 rca | Q Wy) We I Sere CeecCueOme ie e0cn| UanlleGeribcc Ie eo) bono WO 0¢ ) ei 6 a ie - 3 S eine AM eo Q Slee ts ils lela 2 |e |e | Sele leds | eo) 5s lee ie Pee eeeeee | ecie (Fee te lie te |e le le. alee Me ey ape Siclee el 2 he Se ey | eo e D> e i . i ° fs © | ® | casey sac Saami [Soe cael eat 2 HNOL "AVU | "WaAadV | *“HOUVu | “AUV OANA | “AUVONVE | AdQ0TOI XO CT) ‘AL ATViL “BAVA eeooeeeeoeszee eee ee se eceee eee ees | eeeeeeeeeseeeeceese ee ee eevee oe SOS SOs OD oC neers 4S0qVoIb) * 4svory “SUBITL fee agar S/S) 800) 0. © (0,0) 00h @)e) © (e\(e.0/ (0) 28) oie 0) 0 ee) @ we we 4.64 exe “898T “LOST “998T “S98T “P98T “S98T “698E “T98T “O98T “6981 “SS8T “LEST “9C8T “SC8T “PS8L “SS8T “6S8t “TS8E : OS8T @ITIVIAVA ‘IVATO SVM YHHLVAM FHL HOIHM NI SXVd HO YXAHAN TWANNV GNV ATHLNOM 159 ost] ee! srril st | es | ot || ot | er | ot Il pt i gs | ot ll tr | es | 08 Il 2 | ee] ot |] 6b | bel Tr Woe as agar Seo se eee wool 0 ees lst th Cale GeO OSS 0 te Ote ste lle Ga a0 leone || Pres: Sgeuary 08 | 69T! 9ttl| 16 lest lo6 lis's Igeties {len [6st lor |l9'9 aL sor a 16 VT WOU NG Fe (OPIS er die us cots == 2° og eeee eeoleceelieeceeseecevl[eerve 6 ieee G ial val 9 OT 6 | joa OL II OL ST Gaps ee he ee BOOT. 86 | GST| STL] 6 | er | 6 || St |e | OL | 8 | ST | OF |) OT rot OF || g | er | at P| Ceo eae pees See eee ROe) 93 | 6ST] OGt|| OF | FL) & || | et] st ll 9 | St] Vt il 9 CE || Bee OF | Seah WO ee ede OGL 06 | L9t! SOT!| 8 | TE | st He OO ee asa ariel Or or OT ie To |G dle etl | iit ieee eee chee cea Oo PSO CE CEE Gee OE OL | Go Phe OL oie! Ole @ il 7 eGbaleye ee SISO el Ge Or @y | cia) leeecora cers Coceiaa gar 18 | SOT! LTT 8,.| OL | & | 8 PEA eG SST Gba| oO IO TSG Teh, ep ieal Or ey |e Ole 2 ceteaenea ae enna sta epee SPU PEO: ss Ee Serie a Orla.) Cece teem OMe Gh meatal Me MiG ml (NO iii = cee ert keiee heres e aetna GIL] SVT] TST] SE | L- | Vt ie CO SOS eOhs Ob OL IL SGT 20: Seo! OT WG sy) Te IG) ie ee eee er ey CPHSS Gr | OL ath Gran? elieoeae Ole Cla Pialstee) WisG) fii Ge ING sO len |e cce cere ao ee PCa POU Mer TCs OF Oh Vp IRE | Oo lope SiG | eal eG eSB Tan ti ecl| eG ean Gi oll Tess) Cites (i I iencaeenca cheer aaron ey oT es Pe sao GC nie Geo piel een AGIs Oe |Oriental CO! Meier pl Na Mens Gir lle =| aie aa seers nsec eer ceenareat ay H OST] 16 | PFT oF | Pet Gis tet tae Ne Ge Goat y 10) SOG WO O's Ce SGTaelOe a0 aallig corse og atno ae omer = Of SLE SEH Gs OL | et || | ot | & i 8 1 IL | st " CeO be GuGesGOe (6 me le(ts yo satan seis mee dace a COG) Mean Hatta) Ab Go. oleh Gro 8 CleBe eee) BEG RCRA en NG ep ieer lS S70 | Gl eee ee ot cueL = | UE EEE etalk NG ler |e ll eet 1G 8 Lalit Gr sO LcIOUn Ween Gl Oboes goku a tem CON Rca (Cr MOmmeciee Gn Naya m0 ssO04| Sasa ieGealh Ge Nepali lil spall omliceielaGy elle ga cue oe * ee: ose eo 6@ | SLT) Tet] 4 | et | ir |) 6 | or} es | % [et | we] 9 | Tr] et ilo | or | ot |) Sal aE] TT |iectts etree ecer Gout Comecte CeO Or Or lek ll Th) Gel salle smGnele gt i NeOfe Th “la Ee Tal se cea eee oe ee CLO POM Tel eee een etia Ge g SOIeISOis| <2 lee Nhe) Chel Ue IROL WKOE le@e cla O: lle sl sGie'| Gp lc * ae cis nero as Pose Syaloce OMe rcriee ro (6h © ile cies Oise. Weegee dG sieoal PRO el ROr lel Wests oe eee eee ot ere Ay Cops Rice Pose eho oer eres ren cere en eae e ||: JH HETEVETEPLETETELATEL: oy 5) re Qu i) i a Be a 9 ie Qu ) s 2, © m Qu 9 ee q o o eer enes ‘ o < o q o = o ; o ‘lea o ae | ie o o | : sar © : I D cia ‘SUVILA | lilies fe. UN IE «| “UVHA HHL WOW | ms OC G2 A\Gr €@}c Cen “HHA WAHAON "AdaOLIO ps OC Gs G0 Wire RC Boy ‘“LSOYV NAV oar | "ATOL AGQAOT XO ATAIVIYVA ‘YVATO SVM WHHLVAM AHL HOTHM NI SA¥VC AO YWHAINAN TVANNY GCNV ATHINOW ‘ponupyuog—'T) “AI WIAVi 160 PHYSICAL GEOGRAPHY. TABLE IV. (2.) RELATION OF CLEAR WHATHER TO THE DIRECTION OF THE WIND. SPRING. SUMMER. AUTUMN. ___ WINTER, ; | FOR THE YEAR. wes] ca |e le 12 [3 ea ee ee ee 1850 j11 ea ee eae 21-9) 46) .910 5). Bl, Oly SIE eh Bel masimaS 1851 | 5/ 5] 2] 1); 10) 6| 1] 3]] 6 7 4} ail 6} 8} 7 all 27] 26) 14) 9 1852 a zt al ai 5) 5) 2/..j/i/ 10; of vl sl a el oll 26) 2s in| 19 1853 | 9/ si 5] 2i| 2} 3) 4] ail 9} 4} 6] aii 7 4) 8] ail 26} 20) eal 6 1854 | 8/ 8| 4] Sl} 2/12/13) 3) 4/10] 4) 11]! 5} 4) 3) 151) 16] 34] 24) 937 1955 | 9)x1) 6} af ol | al loa) | a] 4) a) & 23] 24) Bo) ai) ap 1856 | 4| 9| 6] 8i| 5; 12) 14/121) 2) gf 1a) 4 A 4) 4) 20/| 11| 34) 35] 44 4857 | 11 IG) Wl) 5 410 8) SAG) Ss) TAS als Wis 18) eae 1858 | 4| 8| 15/18// 5| 7/12) 4)| 5] 2115] 13/| 2} 3) 23! ev: 16) 30 75 62 1859 | 1! 5/11] 8i| 6) 12] 10] 7/10] 4/10) 16] 1/ 1/13] 20/| 8] 22] 44) 51 1860 | 2| 7 11/20|] 4/13] 3] 12)| 3) 7} 5] Gl} 4) 4/15) 19|) 13] 31) 39] 57 ASG cil aiteetnt lc GIs loeleS le al as ea ee 5) | 2/10; 15]! 18) 14] 41) 33 1862 | 7| 6} 5] 3) ..|11/ 19] 7] 3) 740 20) 6| ..| 6; 13)| 16} 24| 40) 43 1863 | 8] 6! 6) 16]| 8/ 14] 10 si 6| 4) 6) 10/1 1) 3) | Bil 25|0 87) 27 33 1864 | 7) 1{ 7 14)) 5] 9) 10] 10)/ 6) 3] 6] 10]| 2! ..1 15) 20)! 20) 13) 38) 51 1865 | 2| 2| 10/131] 5) 7) 15} 41]| 4) 7/12) 131) 6] 2) 6] 16]! 17] 18] 43) 53 te eee| cies ae al aa 8] 12/| 8} 12] 1] 8|| 5] 2] 5] lel 138} 24) 18] 47 1867 | 5} 9| 10/25]! 4) 6) 14) 4]; 4) 2] 14) 11]/ 3! 2) 8) Jo}; 16) 19) 46) 50 1868 | 5] 3 ‘| 3)| 3) 10 i 3|] 2 ; ; 15) 4 2) 5 5) 14; 20 a) 36 1869 | 3) 11a Abell 9c 16| col; -2lleceal cae alb et ell lee cl oe real crea ee ace Mea 115. ||5.2|6.4|9.3|/4.7|8.3]9.5| 5.9|/4.9| 6.0|7.7/8.5||2.7/2.1/8.0],13.1|/17.5| 22.9] 32.3/364 The Weather, as to its character of Clear, Variable, and Cloudy Days is given in Table IV (2), for each month and also the year. This Table is introduced that it may be seen which relation the Clear and Cloudy Days bear to the whole number. The Clear Days are 82 per cent; Variable, 46 per cent; and the Cloudy, 22 per cent of the whole number. The relation of clear weather to the direction of the wind for the seasons and the year, is given in Table IV. (2.) For the year, the mean number of clear days in twenty years are distributed as follows: 17.5 occurs where the wind is N. N. H. 22.9 occurs when the wind is EH. 8. E. 82.3 occurs when the wind is §. S. W. and 26.4 occurs when the wind is W. N.W. By comparing this table with that exhibiting the relation of rainy days to the direction of the wind, we shall see that the greatest number of rainy days occur when the wind is S. S.W., while the clear days occur when itis W. N W. CLIMATE. 161 In the diagrams H and I, we have the same results in the more visible form. That of H for the year, and I for the seasons, the full curve for summer and dotted curve for winter, including the months of September and February ; while summer includes - those of March and August. The greater number of clear days are accompanied by winds from the W. and N. W., while the S. and S. W. winds furnish the next greatest division not- withstanding this is the quarter from whence comes the rains. TABLE VY. FROST AND ICE—HARLIEST AND LATEST OF THE SEASON, DISAPPEAR- ANCE FROM THE GROUND, ETC, ETC. | FROST. | ICE | Tee Seairame (he gate aes e aie ee | eal aa ee e |33 2 5 | cf lag 2 fh aus Re arte eee ee 55300) Ree ne eee Sl die PAS Cre rie. 2) ager eee Mar’h 25|Noy. 7.... Oars ct ake cis eae a eee AES MIE DL. Op rcds/bs oetahis ws. « ADEM: 1S)OGh oP Slio:. (ic! 1 ee eee ae ApsiiSepts hi {HAL ih... - April pe; 17)... i [}5/2 2) eel ee UME: 4 Sep Me oC) cle Apr Sa Ocis cSt. Sen Sey vaslvecinctenstcle a eise tore Bay OG Ve eS se jMay .. 1Qebt. .-8h.2. He hers ah ore Aart Slo a May. 2hOct. Vio... .8.,. Mar'h 30|Qet.. -16) 2... MTs ever Sesratar deonctanveie'< 2 35 May 2oiSept. 21)......5. April. 8:Uek.. > bls)". [SHE eS ae Ree WAgiril 110d. V2) ..uete is April 13/Oct. 18].... He eee Cas > oo eeey, eelOe: WOR Ilsa. . EOE hed Domes ehh chats May 1\Oct. I Pave. eee a 2 April 20/Oct. 18).... PEDO M Ses 36 os lowe ewes ee April 2aiSept. “iis. .t..0a. «2 April 23/Sept. 29].... IED Wey Sean ciate = aeeeteneig ae wee May S\Sept. 28).......- Sy aah bay,» i Oetbs (EB) 2 2. Raves oy orca a 8 divarcinca an? as May 20\Sept. 26 cy eegiea.s sau cpapril .22/Sept. -26).. : Mew acids ciistaro Ace e dass May. 25)Sept. 10)........ 1. .apMay . -L38/Qeb. - 2)... PSOE A ltl ae May 2|Oct. Bap... .. 306 vee piay . 2i/Oet.. - 1b). 2 .. WOO Ma sp cbaey as a/c hacs eet ws May. .-GiSept. 27). 2..2... ose Mlay » es6j/ Vet. » 251)... SOU wes orss Dine Sa ean eats April 19|Sept. 24/April 10| 29/April 19|/Sept. 24} 27 TSO erect a's cates ae [May 20|\Oct. 14;May 5] 14)May 12/Oct. 20) 12 MSO eo a sate okhatc April 26|Sept. 12;April 1) 12)/April 16;Oct. 7 10 SSO feo Sasc oie anereh 42. ose April 23|Sept. 2)April 1| 11/April 23/Oct. 6! 10 OOS 5+ detoiags wanes May i\Sept. 11|Mar’h 20| 11)April 2)Oct. 24) 11 LSE) os oe ee a oe NR May 4/Oct. 23|/Marh12) 20/April 16|/Sept. 24! 21 MSU yan a) ieOR SS oa ae April 24;Oct. 11]/April 1} 20jApril 6/Oct. 25) 20 iS Cee es Site eee hoe gee *Aug.25)/Aug. 29|April 2| 18)April. 8/Oct. 7 20 TST E, 5 SCG. Sane a ee ae ne May 11/Sept. 19|April 17; 18)April 14'Oct. 18) 20 {Oo Os Eas ene eee May 11|Uct. 2{April 10| 20)April 6)Oct. 15} 18 Re ry scree ears cas Orns May 2|Sept. 21;/May 7 20|April 6)Oct. 381] 24 Pe eicisd, ohn Grae tess dee Son nr May 6/Oct. 23\|May 23) 18/April 6,Nov. 4] 18 LUC To Ao. Oe ne ee April 5/Sept. 17)April 15 20;April 8|Nov. 1] 22 AS a actot us, do's) os.nrs May 19|Sept. 26;April 7| 21/April 13;Oct. 13; 20 LIES at Go a eee |May 26/Oct. 23|/May 23] 29/May 13|Nov. 7 27 BO a Fi orsiy Ek i ee a a ....jApril 5j/Aug. 29|Mar’h12| 11|April 2|Sept. 24; 10 bee as eee ee |\May 4|Sept. 24|April 10; 18/April 18|/Oct. 15] 18 *1863—Frost every month in the year; the last hard frost, April 13th. 21 . 162 PHYSICAL GEOGRAPHY. The year 1863 was a peculiarly cold year. Frost occurred each month, and for comfort as well as health, it was necessary to keep up fire occasional each month, July not accepted. October was very cold, more so than this month of 1869. The mean time for late frost is May 4th; early in the fall, September 24th. The latest in the spring was May 26th, 1847, the earliest, August 29th, 1863. It has happened but once or twice in the last thirty years that the frost has, over a great extent, seriously injured the corn crop. When the spring is late, the fall is either quite hot or lengthened so as to afford the crop to mature. TABLE VI. FLOWERING OF FRUIT TREES—1848-69, YEARS. | APPLE. | PEACH, cHerRy. | PLUM, | PEAR. | eure, DRC co a eee, Ob ec ices April 23|April 16! April 18/ April Pill ois Rises ete [sie eee Soe GU were erro Yea gee key .| May, .3|May ) oS) May. May 4)o5. jase. eee PSO. Sepak aliases os Ske ely eee May. 3iMay 1) May. AlMay. Alec te eee TSO hc See hae eee ee May. 3/May 1)\May 1 diApril 29)... 02s elec SOD val aan whee ce 6 -.ceanares May 10;\May 10/May Sd)May 1)May 4)........ LSD sFe Sota Pe een ears May 4jApril 30|May 1|/May 3\/May 3)/May 5 DSO ss Waal) aka aah Cees Be April 24|April 20|April 22)April 21;April 20/April 24 SOD ia eee eee be RU nie April 29|May 1|May 1)May 10)May 1)|May 10 SO OER ak pints, eters fue eer May 12|/May 10|May 9j)May 12/May 15)........ LOOT Sak eisai tees Se ki detats alls @ ened wiallie cuarobeue es fentretmee ell SEI eaiacel «eect | ee folic hee eee Sas en en MO pre EAA Sree aod ne CS ess clas So sila sos << RoHS Eee erate ct arcanrmes! Sie .|\May 4|May 2jApril 30;April 380;)May 2|May 8 col] Ne et mmr Cn rrr seem ames amt a Ai Gry ole Ran Ele OG Ge Sk 3. - TSG tsep eles: sae eio Seep May) Sah Agri olen ene Rel Apral 24 cee USO 2 eae ohana eye Maye doe ck SIR ease UNGay) 6) Mayor Oi, eee SOS rate Coie eee esate May 3)May 1/April 27j)April 30|May 1|May 10 1864 5x, ae So ht eager iopos May 10!May 8/May 4\May ‘7|May 8 May 17 TSO discreet eae May 3)May = 1jApril 27j|May 1|May t1;/May 10 BOG.) 529.5 che ee eee Re Aleve May 24|May 20|May 17;May 14)/May 16|/May 25 SGM cl iis Oe eee cere ee May 18);May 13|/May 14/May 12|/May 105)........ AS OBS Sths..' ss rh Oaege eee May 10|\May ‘7)/May 6|May 4/May = 9)........ SOO ice... cat ole eeaoeeeeree Miaty-) o)o..eeiens April 3U|May 3/May 4i........ Mea ie 1:5 3. oa kee [May 6|May 3|May 2|/May 2|May 45/May 10 BAUME St. ev cuca |April 23|April 16|April 18|April 21|April 20|April 24 BATES isos Brides Siepeue ete |May 24|May 20|May 17|May 14|May 16|May 25 The foregoing table may prove of interest and value to the horticulturist. The peach is winter-killed to such an extent as to prove valueless. The mean time for late frosts CLIMATE. 163 being May 4th, and the mean time of the flowering of fruit trees being May 5th, it will be seen that the young buds are often injured in the spring and a partial loss occurs. WNever- theless, experience has proved that in many localities, with many varieties of fruits, lowa is fast becoming a fruit-growing State. TABLE VII. MISSISSIPPI RIVER AT MUSCATINE —TIMES OF OPENING AND CLOSING AND NUMBER OF DAYS CLOSED. NUMBER OF DAYS CLOSED YEARS, : OPENED. CLOSED. CONSECU- TIVELY DUR- ING YEAR. Rees NERECIE Peon ee ow cc as nace © Mest ss | Sao Mle ogy OSes Wecsmner Pe eh oe 80 Sacer RE NEUAEY AU. Gas oe cu’ aselet Ieee a cc oeiaist Woveleeelcs Gut 78 51 PSAP RPP CHEMALY (QI. ccs sac es dec «5 SRREMERE NEON, ats wade ne ce oa nla Ae Pees MICECRINEE RP hia 4 toast es chs ores 45 1338 Mee) Esc) TA Re ee ena ene IECEMIMEDIA 6 pie. snneicmaie,s ses 60 | 63 Wo teesta| PEDEUALY 20) oo woud ces bees INOVEeRIDEr Pi: oo. 635/420.) 62 93 tee MEU R yee eee wep 2 ouch SER Rly Sie cakes Sie abcils «aed a Se lesa ob *133 99 1844... .|February 23.............4. REY See cos ses eee une 1 ee DSR ERED Siro cca'c cc's ace es sis he ad els 30 POE yeas: | COEUAL WLS s.5-cu.6 bak ee vale @ « DGCEMEREE bo. Secae cic +s 2S 52 79 LEN sl ee ee ArnLU GR MO SA ee Ee Sh 2 eee 60 29 RS ele ced WEEN, on. oc Ce hoe Bere y hetiaey Guise sae 3 vee sce Dh wl Rs os Beeember fart. 2.3 ot ee SA Ge oe 88 PS4G os SUM elmer yy, UGs rs Seed ss bee hid o December ore lec cans 63 63 Ieee AoW NECRECR Bet acces Ges, spaa’ Sast ls ogi WIECEMBEE O04. ce Ven se oc - 88 86 POOU TS POMEMAEYy 19s . odes Jeeves 3 Ver racer Nae ee Mare a ee cea ue 64 50 Gods OE ebm yo oh ccc «oie oie ewe JATMAEY cc's & Sec ge we dews's Beet Wiens cn PCE EMEP Rees taciak cose auhs oi = on: a7 fG5e.., aN Pebeuam ys Ot de t.92 oes: INeowenmiber 182 225.5 .Gelede. 70 98 Phase. |. (REORUALY 2 e5../00coeees we < December St. ooo ects ses 3s 99 56 GOT oc MAREN Doe \des cutie cece bee he Eos aioe sac Wes e cad ¢ 60 60 Pelee: MAREN ms a os, 6 kote eth d «2 PAWUHEM Bee. 5 Sea's baie 3 oe LD eer IDGecntber coc. tssaciagees. 5 whe se xe 50 woah S00 Marche 2On cust Sosetascke hPecemmber G05. 208 ee ds. 3. 94 | 113 eC PMEDEMELY, Qoac sae ce cena ¢ [November 25.00 2086 do ocn oily Me ING VERNER Shc as saae seicere ee okie a Le ote meee e Ren oes *5 63 1858*, .. Pas fP COLHAEY Ole. c.<- cee ee ves PRE nC i Ge eel eis os vous Le pee Mecember Silas secices secs hk so S3c 68 Pattee |Hebriary 26. sc... s< jimpunelclaysi 2... 2-2. ele = shee 36 feet. No. 1. Bluish, clayey shale, containing occasional thin layers of impure Me StOMe remem etter cs. cues era's ce ee eee 5 feet. Mota Ze paeeien. csc h coke ook ape n eee 85 feet. Tt is along the valley of Grand river, and those of its tribu- taries which have their confluence with it in this county, that all the exposures of strata yet observed are to be found. The Drift Deposit is very thick here, as is shown by the fact the exposures of strata, which are found only in the valleys, are seldom, if ever, less than a hundred feet below the general level of the uplands. The section on preceding page, (Fig. 17), is the most extensive one measured in the county, the exposures it represents having been observed near Davis’ mill in the valley of Grand river, about eight miles south- ward from Leon, the county seat, and four miles northward from the south boundary of the county. No. 1 is referred to the upper part of the Middle coal- measures, and all the remainder to the Upper coal-measures. Near the mill, the clayey shales of the lower portion of No. 2 are crowded with specimens of the minute ostracoid crus- tacean, Beyrichia Americana. Below Davis’ mill, to the southern boundary, there are Fie. 18. very few exposures of strata, but : all that appear are equivalent to some part of the preceding sec- s\j2’ tion. Going up the valley, from that point, the next exposures =e c’ found, are upon both banks of = z the river near the village of Terre =\0' Haute. The accompanying sec- = tion, (Fig. 18), was measured at an exposure Ae amen atl upon the left bank of the river. Section at Terre Haute. No: 57) (Gray marley fossiliferousiclay.-e eee eer. nies 3 feet. No. 4. Hard, gray limestone, with marly partings.............. 12 feet. GEOLOGY OF SOUTHWESTERN IOWA. aoe No. 3. Black, fissile, carbonaceous shale, becoming clayey at top. 214 feet. No. 2. Compact limestone in two layers with marley parting.... 114 feet. No. 1. Bluish, argillaceous shale, passing beneath the river bed.. 10 feet. No. 1, of this section is regarded as equivalent to No. 2, of the section at Davis’ mill, and although only a part of it is exposed here, it is probably as thick asit is there. If this identification of the strata is correct, Fig. 19. none of the beds of the Terre Haute section are so high in the series as the highest of the section at Davis’ mill are. At Mansfield’s quarries on Short creek, (section 29, township 70, range 26), a few small exposures occur, and the accompanying section represented by Fig. 19, was measured there. Section at Mansfield’s Quarries. INO Os -COMPpPACH Maia yr MMMNSLOMNE? sa serch os 26 ova ciatdaren delves eiedlne s 316 feet. Non. Yellowish» caleareo-silicious. shale, ..5. sco. coos ccede os 2 feet. INO: 33, Yellowisheshaley Limestone... ois as ae cl sie sdc e es vive n ols 3 feet. INO. 2... bluish wera Compact lmmesione:. . 10 Was Gniens ack es ou he 2 ~— feet. No. 1. Unexposed down to the level »f the creek............... 4 feet. Totaly Mae Sa Tate ios attra Soe Pe ela 141¢ feet. At the point where this section was measured, No. 5 is quite compact, but the corresponding layers in the neighbor- hood are usually not so. The stone of this bed is almost everywhere largely made up of the Forameniferous shell known under the uame of Musulina cylindrica. Crossing over in a westerly direction to the valley of Grand river again, we find a few exposures of the strata of the Upper coal-measures. An exposure near Funk’s mill reaches almost sixteen feet in vertical thicknes of limestone with marly partings. 324 COUNTY AND REGIONAL GEOLOGY. Several interesting exposures occur in the valley of Elk creek, a western tributary of Grand river, and in those of both its princi pal branches. The accompanying section, (Fig. 20), was measured ata point a little below the confluence of those branches, and on section Le eA eR SS 34, township 69, range 27. Elk Creek Section. Compact limestone, (one uniform layer) ............... 1... foot. Marl ysoleive. Wo)3) <%leeareessi tears sigotled Rais cad dew eraeiee Rae cule. Seeae Vy foot. Gitay UsheligMeStOMe jon. scpice sail cleiteeicee es aene Bo apA ase 2 feet. Grayish limestone, somewhat shaly..................... 12 feet. Bluish, clayey \shalevc fh. 20 5. aad Gets oe, seine he hae 114 feet. Black, fissile carbonaceousishale 212.4) sia- seicites ©» er 1 foot. Bligh, clayey, SWalle cele iase se sueseeecouere uals aves ei neeeencmern ane 3. feet. OUTS « inte'c work chasse artes pronto ere einer ene 21 . feet. The next section was also measured in the valley of the south branch of Elk creek, com- mencing a little above the place of that just given, and adding the strata to that, as they are successively exposed within a quarter of a mile. ee RO IG CON SIBNS ord Section on South Branch of Elk Creek. Thin bedded, bluish limestone, with shaly partings ...... 3 feet. Brownish, mottled, clayey shales ..........ecseeeeeeeees 2 feet. Black, fissile, carbonaceous shale ...........eeeseeeeeees 21 feet. Compact layer of limestone ...........-2seeeeeeee cence 1¢ foot. Bluish, clayey shale ..........200secencecssceccersecsees 11 feet. Hard, gray limestone ....... 2... cee cence cece eee c erence 114 feet. Bluish, clayey shale ......... 0. cc cece seers cece cece eens 1 foot. Hard, grayish limestone .... 2... .e cece reer cece c cree eens Bm beet. Bluish, calcareous, clayey shale..........sssecereceeeeee 316 feet. Ota 4 soe Ree Meets cores Coeie Gk icc ele at “teat. GEOLOGY OF SOUTHWESTERN IOWA. 325 All the strata represented by the foregoing sections, and all others observed in Decatur county, evidently come within the verticle range of the section at Davis’ mill in the southern part of the county, so that there are no higher beds within its limits than those of the Upper coal-measure formation. Economic Resources. Stone is the most valuable mineral product yet known to exist within the limits of Decatur county, or, at least, the only one at present accessible. By turning again to the sections of Decatur county strata, it will be seen that stone is comparatively plentiful in the valleys, particularly in those of the west half of the county. All these strata that are hard enough to receive the name of stone, are limestone; all of which, besides being suitable for building purposes, furnish material for a good quality of lime. Layers of it are not unfrequently found from which the common forms of dressed stone for buildings may be obtained. Such stone was observed at Mansfield’s quarries and also at several points in the valley of Elk creek and those of its branches as well as elsewhere. It will be observed that ‘‘ black fissile carbonaceous shale” is men- tioned as occurring among the strata represented in some of the preceding sections. Some of this shale splits readily into thin uniform sheets, closely resembling slate, which name is often popularly applied to it. Sometimes it decom- poses into a soft, coaly-looking mass, and being itself in a slight degree combustible, it has been popularly believed to indicate the existence and close proximity of coal; or, that if these beds of shale were followed by drifting into the valley-sides, they would be found to have changed to coal. It may seem hardly necessary to say that these opinions are fallacious in all respects, and that the substance in question is entirely valueless. It is trve that similar car- bonaceous shales exist in connection with coal, but they are just as often found where no coal exists; not only in the unproductive portions of the coal-measures, but in other formations also. : All the rocks of this county, as before stated, belong to the 326 COUNTY AND REGIONAL GEOLOGY. coal-measures, and almost entirely to the Upper. It will be seen that no coal, not even the thinnest seam, is represented in the foregoing sections, and it is not probable that any exists among the exposed strata of the county. It is evident, therefore, that if coal is ever obtained in Decatur county, it must be sought beneath the level of Grand river. Again, the question comes—how deep must we go to reach a profitable bed of coal? This question cannot now be answered fuily, but the following suggestions are offered: It is known that at the western border of the Middle coal- measure formation, as shown by Prof. St. John, in another chapter, its thickness is about two hundred feet. There is some evidence of a considerable thickening of the formation to the southward and westward, so that it may possibly reach three hundred feet in thickness in Decatur county. Again, in the northern part of this formation it contains no bed of coal of sufficient thickness to be worked with profit to a great depth, although a number of thin ones are known to exist there among its strata. We have indications, however, that some of these Middle coal-measure coal beds thicken in different directions, and they may probably be found of profitable thickness when reached by sinking shafts to them in this county. This, however, is doubtful, and the main reliance for success in any enterprise of that kind should be upon reaching the Lower coal-measures, the strata of which are known to contain the thickest and best beds of coal. If explorations for coal by deep mining should ever be undertaken in Decatur county, the work ought to be com- menced in the valleys. This will save an amount of digging and raising of the coal when found, equal to their depth from the general surface. Grand river valley is the deepest ~ one in the county, and reaches the lowest strata to be found exposed within its limits. These lowest strata, as would naturally be inferred, are found in the southern part of the county, and if coal is to be found within its limits, it is just as likely to exist in that part as in any other; therefore the chances are in favor of reaching coal there at less depth than GEOLOGY OF SOUTHWESTERN IOWA. ATA in other parts. Some thin beds of coal, and possibly one of profitable thickness, belonging to the Middle coal measures, would doubtless be passed through within the first two or three hundred feet. In any case it is thought that the whole thickness of both the Lower and Middle coal-measures, together with all the coal-beds they may contain, would be passed through by a shaft five or six hundred feet in depth from the point before named in Grand river valley; and the hope of finding one or more good beds of coal within that depth may be reasonably entertained. The proportionally large amount of woodland in Decatur county, in a great degree, compensates for the present want of coal. This is sufficient, not only to supply the inhabitants with all necessary fuel, but also with their fencing material and a large part of their building lumber. A very large proportion of the trees are oaks of several species, but the other ordinary varieties of forest trees are well represented. Brick clays of good quality are obtainable in many parts of the county, especially upon the ridges and approaches to the valleys where the soil proper is thin. Thus with its timber, stone, and brick clays, Decatur county is compara- tively well supplied with building materials of its own production. The soil may be designated in general terms as clayey, at least enough so to make it retentive and durable; preser- ving its primitive fertility undiminished through many years of cultivation without manuring. It is claimed by the inhabitants to be peculiarly adapted to grass and pasturage. The question of the success of fruit raising has not yet been fully tested, but there are good reasons to believe that the ordinary orchard fruits and grapes will prove a complete success. The numerous valley-sides and slopes possess the same general characters in every respect, and the same climate that those portions of Lee and Des Moines counties do whose fruits have already become so justly celebrated. 328 COUNTY AND REGIONAL GEOLOGY. 6 RINGGOLD COUNTY. Boundaries and Area. Ringgold county lies immediately west of Decatur, which consequently borders its whole eastern side, Union and Taylor counties bounding it respec- tively upon the north and west, while the southern boundary line of the State forms that also of the county. Like Decatur county, it is four townships in width east and west and a little less than four from north to south. The southern boundary line of the State, although intended to be straight and uninfluenced by any geographical features, does not exactly coincide in direction with east and west lines of the linear surveys. Following the boundary line from east to west, it is found to diverge to the southward of the section lines of the surveys, amounting to about one mile in seventy. In consequence of this divergence of the State boundary line, Ringgold county, although nominally of the same size as Decatur, really contains a little greater superficial area. It amounts to about five hundred and forty square miles, or three hundred and forty-five thousand, six hundred acres. Geology. If our knowledge of the geological character of the strata that underlie the surface of this county, beneath its thick covering of drift, were derived from all examinations which it is practicable to make within its limits alone, we should know very little with certainty about it; for so far as is now known only two exposures of rock in place are to be found within its boundaries. These are very slight exposures both belonging to the Upper coal-measures, and consist in each case of only a few layers of limestone. One of them is upon section 1, township 70, range 28, in the extreme north- east corner of the county, and the other is near its southern boundary on section 19, township 67, range 29. It is consequently more destitute of stone than any other county of southwestern Iowa. Judging from these exposures and from those observed in the adjoining counties, there is no doubt that all the strata which immediately underlie the drift belong to the Upper coal-measures. The drift here is very GEOLOGY OF SOUTHWESTERN IOWA. 329 thick, amounting probably to two hundred feet in thickness over a great part of the county. Surface Characters and Drainage. The reason of the creat infrequency of rock exposures here is due to the unusual thickness of the drift which has covered up all the strata so deeply, that the streams, although their valleys are pro- portionally of more than average depth, have failed to reach and expose them, except in two instances befored named. The unusual accumulation of drift in this part of the State is an interesting fact, particularly when taken in connection with the further fact that the highest ridge of land in south- ern Iowa passes down into Missouri through this county. This interesting feature together with its connections is discussed more at length in the chapter upon the physical features of the State. Ringgold county is drained by two of the upper branches of Grand river, and by the east branch of Platte river. These streams flow through the county in a_ southerly direction, having at its northern border already attained considerable size, and in their passage through it have eroded their valleys so deeply from the general surface of the uplands that the full grown forest trees which skirt the borders of the streams cannot usually be seen even at short distances from the valley-sides. These valleys are interest- ing as being the deepest and largest purely drift-valleys in the State. They are from one hundred and fifty feet to more than two hundred feet deep, from the general level of the uplands of the county; and yet, except at the two points before mentioned, nothing but drift material is to be seen in their valley-sides from top to bottom. It is from these and other indications that the Drift Deposit is estimated to reach a depth in Ringgold county of about two hundred feet. Its depth of course cannot be certainly known without digging shafts down through it. The surface of the county is almost all prairie, and its general aspect is peculiar and interesting. A stranger pass- ing mae the county by the ordinary routes of travel is 330 COUNTY AND REGIONAL GEOLOGY. quite unconscious of the presence, within the range of his vision, of the deep valleys with their wooded banks, for the general surface which his vision falls upon is apparently all an undulating prairie. Upon approaching the streams he sees them winding through the rather narrow valleys, with a light border of trees upon their banks; and crossing them, they are soon lost to view again among the general undu- lations of the surface. The whole county is so well drained that hardly a single pool of water can be found within its borders, but yet with its numerous streams it is practically well watered, and in addi- tion to this, water may be readily obtained upon the more level surfaces of even the higher prairies. Material Resowrces. It cannot be denied that at present, the only known resources of Ringgold county are almost wholly confined to its fertile soil. This is the usual deep, rich, drift soil, so characteristic of southern Iowa. It is not only capable of producing abundant crops of all varieties of farm products that are adapted to the climate, but also the fuel necessary to supply as dense a population as the soil will support, may be grown upon the same soil in the shape of forest trees. For reasons frequently given upon previous pages it is thought probable that coal exists beneath the surface of this county at a not inaccessible depth. Should the explorations recommended for other counties in search for coal, be under- taken in this, and prove successful, in future times when the whole surface shall become covered with fine farms, and studded with rural villages and multitudes of groves of artificial planting, Ringgold county will hardly be recognized from the foregoing description. : 7. UNION COUNTY. Boundaries and Area. Union county is one of the second tier of counties from the southern boundary of the State, and is bounded on the east, south, and west respectively by Clarke, Ringgold, and Adams counties and on the north by GEOLOGY OF SOUTHWESTERN IOWA. ook Madison and Adair. Like the greater part of the counties of the second tier, it is three townships in width from north to south, and four in length from east to west. It is thus a true parallelogram, containing four hundred and thirty-two square miles or two hundred and seventy-six thousand four hundred and eighty acres. Drainage and Surface Characters. With the exception of half a dozen square miles of the extreme northeastern corner, which are drained into Clanton’s fork and thence into the Des Moines, the whole of Union county is drained by the tribu- taries of the Missouri river, principally by Thompson’s fork of Grand river. This stream, together with its branches, has a general course through the county from northwest to south- east. It will be seen that the Great Watershed which divides the drainage between the two great rivers, passes across the extreme northeast corner of Union county, yet the highest land of the county is not there; but upon a secondary watershed, that which divides the drainage of Grand and Platte rivers. The profile in the first part of this report, prepared from notes of Mr. Thielsen, Chief Engineer of the Burlington and Missouri River Railroad, shows that Highland, near the center of the county, is the highest point on the line of the road between the two great rivers, being seven hundred and ninety- four feet above low water in the Mississippi at Burlington, and twelve hundred and eighty feet above the level of the sea. The lowest point along the line of this road within Union county is in the bed of Grand river, which is about three hundred feet lower than the surface at Highland. The valley proper of Grand river, however, is only from one hundred to one hundred and fifty feet deep from the general level of the upland in its neighborhood, and the great height attained at Highland is by a gradual rise of the general surface from the vicinity of Grand river valley. | The valley of Twelve Mile creek, the principal branch of Grand river, in this county, has a similar average depth and character, but it has no exposure of strata along its entire Soe COUNTY AND REGIONAL GEOLOGY. length, except near its confluence with Grand river, and consequently, it presents the usual characters of a drift valley, as do also all the other smaller streams of the county. The surface in the immediate vicinity of the larger streams is somewhat broken and partially wooded, but much the greater part, even of the eastern half the county, has that gently undulating character of surface known as rolling prairie. 3 Geology. If Union county be divided into four equal parts by east-and-west and north-and-south lines, all the exposures of strata, with a single exception, so far as now Known, will be found in the southeastern quarter. That exception is a small exposure in the banks of a creek about two miles northeast from Afton. All these strata belong to the Upper coal- Fia. 22. measure formation, and nearly all of them are found in the valley of Grand river. 16’ On section 36, township 71, range 28, just where Twelve Mile creek joins -{,, Grand river, the section represented by Fig. 22, was measured. Section at the Mouth of Twelve Mile Creek. No: 3. Yellowish gray, thin bedded limestoney.. 0-0... 6.0... cae 16 feet. No, 2. Conipact, orayish: lnmestone; (One layer). oc pete lates oc wee ele 1 foot. No. 1) | Bluish, coneretionary, marly: limestone. 222262... 0-6 o-5) 3 feet. LOUDER Cf ae lis Seana abetdis oleot otic a ytetaln or ap eeet a ones eben te, late Aird 20 feet. The base of No. 1 was not seen, nor were any lower strata found exposed there. The water being high at the time of Fig. 23. our visit may, however, have covered =S===)\2 some others. Going up Grand river 7 valley, the next exposure of any impor- tance is found in the right bank of the =" stream on section 14, township 71, range 28, at which point the following named strata appear and are illustrated by Fig. 23. GEOLOGY OF SOUTHWESTERN IOWA. ove Mos. liehbiedlered silieiousshalyemar) 3). 6.06 eles dee noe nee 2 feet. No. 2. Compact, thin-bedded grayish limestone.................... 7 feet. No. 1. Hard, shaly, marly clay, with thin bands of impure lime- SECT Cae al or ATE GPS ee ARS el oP OR COIDS 0 fig 4 feet PRU S aie cartel ove ie diate «karst de > oe poppet achical susp Gacndeoe 13 feet The base of No. 1 was not seen, being covered by the water of the creek. About a mile further up the valley, on section 11 of the same township and range, and in the left bank of the river, about ten feet in thickness of uniformly bedded limestone is seen, resting upon about five feet in thickness of bluish, fragmentary, argillaceous, limestone; the latter very fossiliferous. Continuing up the valley about Fie. 24. three miles farther, at Emerson’s mill, on section 31, township 71, SS 7 i — range 28, the following named strata 9 EEE EEN SaaS e —_ were found exposed in the left bank (5 Agge=====eee 1’ ,,v = = ee of the river and are represented ,¢ Sa aa aes 7 1 I an en ey ae Bi 6” by Fig. 24. Section at Emerson's Mill. No. 7. Yellowish, impure limestone, with frequent partings of calcareo-silicious shale of same color...... ape A ta % -feet. No. 6. Bluish, clayey shale, with occasional thin concretionary TIVeErS Gf TiN pie, MIMECStOME. oo 5.05 <0. < ces sc aele vec ces 4 feet. Nord. Blavle Cal DUR teCOUS SHAIe seta, de oe cas eee ese eka oe eee 1 > feot. No. 4. Bluish shale, very fossiliferous..............0cceueeeoess 14 feet. No.-3. Bluishclayey shale.. 2.22.4. 22.460. 00 SIONS ee Pee Fea 216 feet. WNo2. ? Roughameyashs limestone si. 6.46 5 oc cicins « Gepeorasg cee de dey 114 foot. No. 1. Grayish, clayey, and concretionary limestone............. 114 foot. Ota A aah tcc aas ones er tia ae Seas ec aaa ee 181 feet The water in Grand river reaching No. 1, no strata were seen beneath it. This lowest member of the section is largely composed of the shells of a very small variety of /usulina cylindrica, and the clayey partings of the layers of lime- stone are crowded with the same fossil. 334 COUNTY AND REGIONAL GEOLOGY. The next exposure seen in passing up the valley of the Grand river, is = /*' represented by Fig. 25. It occurs im ‘its ===”, left bank, on land belonging to Mr. === |, Carter, and near the crossing of the + Burlington and Missouri Railroad. Section at Carter's No.0.’ Dight colored marly shalem... tee. okt ae hee ee eee 3 feet. No. 4. Yellowish gray limestone in thin layers, with yellowish marly Paves. seemcae. Re RIOT TTT ES Ghee ao he ee 2 feet. No. is. s bluish marlyeshalle.. gece ope cies ple ern eh er ete ee nee 2 feet. No: 2.” Blacktcarbonaceousishtalen a. eee eee ine Mts sce 2 feet, No. 1. Blue clayey shale, alternating with thin layers of blue, hard and impure limestone..... BS L.c seallaateia ele Se EERO EIS 5 feet. Potato ee es Cove e ea a eet a eos oe mele eee 14 All the strata represented by the foregoing sections, together with all others found exposed in Union county, are of Upper coal-measure age, and all probably belong within a vertical range of thirty feet, so nearly do the slopes of the streams coincide with the southerly dip of the strata; and the strati- graphical equivalents of the whole of this vertical range are regarded as being included within the lower half of the limestone portion of the section at Winterset, in Madison county. Material Resources. As has been said of a number of other counties, the material resources of Union county, so far as at present demonstrated, consist of its fertile soil, its stone, and the forest trees that skirt its streams. Referring to the preceding sections of the strata exposed at various points along the valley of Grand river, it will be seen that a large proportion of them consist of limestone. These, together with some others in the valleys of small creeks and ravines that come into that river, and not before mentioned, will be found to afford large quantities of building stone, besides any desired quantities of excellent lime. All the strata found exposed in Union county belonging to GEOLOGY OF SOUTHWESTERN IOWA. 33D the Upper or unproductive coal-measures, it will be correctly inferred from what has been before written, that the hope of finding coal within its limits should be based upon explorations at considerable depth beneath its surface, which, to save useless labor, should be commenced in the valleys. If such enterprises as have been recommended on previous pages for Madison county should prove successful there, those who shall commence similar labors in the valley of Grand river or elsewhere in Union county, will have additional reason to expect similar success. The strata exposed in this county are referred to a horizon a little below the middle of the full)series of Upper coal- measure limestone, as exposed near Winterset, and shown in the section measured near that place, which will be found represented on a previous page. They are also referred to about the same horizon which those strata belong to, that contain the thin bed of coal found there; but that bed of coal seems to have entirely thinned out to the eastward, so that it is not represented at all in the valley of Grand river, and will probably not be found at all in Union county. Thus, although strata in those counties that are geologically equiva- lent to these, do contain a bed of coal there, yet a supply of that valuable material, if found at all in Union county, should be sought for by deep mining. | There is a sufficient area of woodland in Union county to meet the present wants of the inhabitants for fuel, yet the proportion in the western half of it is small. In the eastern half, however, especially along the valleys of Grand river and its principal branches, the supply of wood is quite sufficient for present and prospective use. The county is well supplied with water from its numerous streams, and wells of water may be obtained almost anywhere at moderate depth, even upon the highest surfaces. The soil is of that variety known as drift soil, except the small proportion of alluvial soil in the valleys. It is everywhere of the same fertile and excellent character as that which characterizes the whole region of southwestern Iowa. 336 COUNTY AND REGIONAL GEOLOGY. 8. ADAIR COUNTY. Boundaries and Area. Adair, like Madison, and also like the majority of the other counties of the third tier from the southern boundary of the State, contains sixteen con- gressional townships—four north and south and four east and west. Its superficial area is consequently about five hundred and seventy-six square miles, or three hundred and sixty-eight thousand six hundred and forty acres. Drainage and Surface Characters. The Great Watershed passes through Adair county, entering it from the north a little east of its northwest corner, and leaving it a little southward of the middle of its eastern boundary. The Chicago, Rock Island, and Pacific railroad crosses the Great Watershed almost exactly at the point where it enters Adair county, which point, according to their levelings, is nine hun- dred and seventeen feet above low water in the Mississippl at Davenport, or about fourteen hundred and forty-five feet above the level of the sea. After passing southeastward, nearly as far as the center of the county, the watershed sweeps abruptly to the eastward between the upper branches of Grand and Middle rivers, and continues thus until it makes its exit from the eastern boundary. The broad ridge of upland that constitutes the Great Watershed, where it enters the county, continues southward into Union county between the East Nodaway and Grand rivers, both of which are tributaries of the Missouri, and, although it thus becomes a secondary watershed, it has actually a higher elevation than the Great Watershed, which passes further to the east- ward, as before explained. Thompson’s fork, of Grand river, and both the East and Middle Nodaways, have their rise in Adair county, and both North and Middle rivers are only small prairie streams where they enter its northern boundary. Even a few rivulets of the upper branches of the East Nishnabotany reach within its western boundary line. It will thus be seen that this county, although not greatly elevated, is, nevertheless, es GEOLOGY OF SOUTHWESTERN IOWA. 337 a summit region in relation to the drainage of the sur- rounding country, and yet, unlike many similar summit regions, it is so perfectly drained that ponds and marshes are nowhere to be found. Like all the other counties that lie upon the Great Water- shed, the drift.of Adair county is very deep, probably two hundred feet deep in its central portion. Therefore, with the exception of that of Middle river, all its valleys are true drift valleys, and even that of the river named is only slightly modified by the few exposures of strata that occur along its course. Some of these valleys reach a depth of one hundred and fifty feet from the general level of the upland, and yet nothing but drift is to be seen within them. The surface of Adair county, although almost all prairie, is very undulatory, and in many parts is quite broken by deep, yet grassy ravines. This unevenness of surface renders a part of it untillable by the ordinary methods now in use. The soil of these steep slopes, however, is almost as fertile as that upon the more level surfaces, and the time will come when they may be cultivated with profit. Much the larger part of the surface of the county possesses not only an excellent soil, but it is also adapted to convenient tillage. The drift of this county, like that of the others adjoining it, is almost entirely composed of com- paratively fine material, so that the surface is never obstructed by boulders, or other impediments to agricul- tural operations, yet a few isolated boulders occasionally appear. A number of these granite strangers from the north are to be seen upon the surface near the head of Grand river, in the eastern part of the county. Geology. The only strata exposed in this county are found in the valley of Middle river, and consequently are confined to the eastern and northeastern. portions. These all belong to the Upper coal-measures; and, judging from our know- ledge of the geology of the surrounding region, the same strata occupy the remainder of the county immediately eek deep deposit of drift, unless, which is possibly 338 COUNTY AND REGIONAL GEOLOGY. the case, the extreme border of the Nishnabotany sandstone may intervene in some parts. The most northerly point in Middle river valley, at ona an exposure of strata occurs, is near the right bank of the river, about three miles southward from the north boundary of the county. Below this, to the point where the river enters Madison county, similar strata are exposed in the banks of the stream at rather rare but gradually increasing intervals, until, near the eastern border of the county, the exposures are somewhat numerous. All these exposures are referred to the lower half of the series of limestone strata shown in the Winterset section. It will be remembered, also, that all the strata exposed in the valley of Grand river, in Union and Decatur counties are referred to the same horizon. It is believed, also, that all the strata exposed in the counties of Adair, Union, and Decatur, belong within a verticle range of less than one hundred feet. Nearly all the strata exposed along the valley of Middle.river are limestone. They usually amount to only a few feet in vertical thickness, but one of them, on section 12, township 76, range 31, presents a vertical Fic. 26. thickness of about twenty feet ot limestone. More argilla- * ceous strata exist beneath these, “onl are exposed in the banks of Drake’s creek, on section 138, , township 75, range 30. These are shown in the following section and illustrated by Fig. 26. Section at Drakes Creek. No. 6. Black, carbovaceous shale, a few inches at top consisting of impure Coals 2:.cje walale we bie 2 ole opera Motel ietene tered 2b eck: Nolo: bi Marly Claviott oc co ia 2 aleuetese ee leune ioe te eet one we alee eine Ys foot. No. 4. Hard, bluish, impure limestone. .........0..-e cess eeeees 1s toot: No. 32. brownish, clayey shale:. 2.) om acteperteteree aretha ot 1 | foor No. 2. Hard, dark colored, impure limestome.......+-.-2+e--ee- 14 foot. No. 1. Five grained, micaceous sandy shale, becoming darker and more clayey at top... ......ceccncs cerns cece ncersesens 22 feet. Total- 24: Bese e eee ee eee els ovens 27 feet, e Pe 7? ee are id De, . all ila ial . ‘ay ; - GEOLOGY OF SOUTHWESTERN IOWA. B39 No. 1 is regarded as equivalent to No. 2 of the Winterset section, although it differs from it somewhat in its more argi- laceous character. In this respect it more closely resembles No. 2 of the section at Davis’ mill in Decatur county, with which it is also equivalent. Material Resources. Besides its fertile soil, the material resources of Adair county are unimportant. Sufficient sup- plies of stone for building purposes and for lime may be obtained along the valley of Middle river, but elsewhere in the county none of this important material is to be found. If coal should in the future be obtained in Madison county by deep mining, according to the plan before suggested, it may also be expected by similar mining in Adair county. Ancient Peat. On section 22, township 75, range 32, a bed of dark colored carbonaceous substance was found exposed in the bed of one of the upper branches of the Middle Nodaway river, which is there a mere prairie creek. This is evidently ancient peat, formed there before the surface had assumed its present well-diained condition at least, if it is not really of pre-glacial origin of which there are some indications. The owners of the land thinking it might prove valuable for fuel, sunk a shaft of a few feet in depth down to it from the bank of the rivulet, and the bed was found to be between two and three feet in thickness. The drift, appa- rently only slightly, if at all modified, rested directly upon it, and it was underlaid by a dull, bluish clayey bed. Although the proportion of ash in this ancient peat is only a little greater than that of some modern peat used as fuel, it is only slightly combustible and probably has no practical value. 9. ADAMS COUNTY. Boundaries and Area. Adams lies immediately west of Union county before described, and is of exactly the same size, being three congressional townships in width from north to south, and four of the same in length from east to west. Consequently, it contains a superficial area of four hundred 340 COUNTY AND REGIONAL GEOLOGY. and thirty-two square miles, or two hundred and seventy-six thousand four hundred and eighty acres. Drainage and Surface Characters. The county lies wholly upon the Missouri river drainage slope, the greater part * of it being drained by the Hast and Middle Nodaways and their branches, which pass through it in a southwesterly direction. Some of the upper branches of Platte river drain the southeast corner portion, while the west fork of the One Hundred and Two river rises in, and its upper branches drain the southern part. Its deepest and most characteristic valleys are those of the two Nodaways before mentioned, and the scenery along each is always interesting and frequently beautiful in its kind. If the county be divided directly through the middle, from north to south, it will be found that the eastern half is almost wholly prairie, there being interrupted belts of woodland along the banks of the Hast Nodaway and there only, besides a few clumps of trees upon the borders of the other small streams. In the western half, however, there are very considerable bodies of woodland along the valleys of both the Nodaways. The surface of the east is principally gently undulating prairie, almost every acre of which is excellent farming land. The western half is no less valua- ble for the same purposes, but it contains a somewhat greater, but still very small, proportion of land not easily tillable on-account of its greater unevenness. This, however, is more than compensated for by the presence of stone and coal in its valleys, neither of which are found in the eastern half. Geology. All the strata exposed in Adams county belong to the Upper coal-measure formation, and the exposures here enumerated are the principal ones to be found within its limits. A few feet in thickness of compact, bluish lime- stone, in somewhat regular layers, is found exposed in the right bank of William’s creek, on section 6, township 73, range 34. A similar exposure is also found on section 19 of the same township and range. Crossing to the Middle GEOLOGY OF SOUTHWESTERN IOWA. 341 Nodaway, the next exposure to be found in this part of the county is near Harader’s mill, three miles north of Quincy, where a few feet of clayey shales and impure limestone rest upon a bed of coal about eighteen inches thick. The stone is very small in quantity, and not of very good quality, but owing to the scarcity of stone in this region, it has been taken out to some extent for common use, and the coal has also been mined there, but not extensively. Three miles farther down the valley, and two miles west of Quincy, the same bed of coal has been quite extensively mined at several points within half a mile of each other. The exposures are upon, or near the banks of the river; the following described strata being exposed in the left bank, near the bridge: Section near Quincy. Noval. Bloch retily Wieetonies, ves. eueeenwec seu Sccs. es: es 20 inches. Non (90 Dank Colored saMiGe:. sven cixsman cee: we Sues Paes Sia ty 8 inches. NOe 8 Codle ocean seers ee oe orebsict on ache techieh heresy aioe sre 20 inches. Now et.) dhichiioliish, shally, fossuliterous clay... .s so... s.eeas 20 inches, In the year 1866, Messrs. Barnett and Smith commenced sinking a shaft within a few rods of this locality, with the hope of finding a deeper and better bed of coal. The follow- ing is Mr. Smith’s statement of the strata passed through: Barnett and Smith's Shaft. Nor 6) "Dari oraye clayey MmestOmel ion .. Setee sia) coereere eo le Se oe a 5 feet. Noe 5.) Dark colored canbomaceousisnales 2. .0he ss. k i 2. eo ai wees 2 feet. Non4. Darkenlored fossiimereus ImestOme. ce. At au. . < cets cna ace 1 foot Nowe. hich eray: limestone. witli Cuil fracuune. 2c. 45.04 5 feet. INO: Gi tay, Clave y cla Cha | cur ase e wean atns sy sreueterie Sesotho 6 feet. No. 1. Coneretionary clayey limestone, aiternating with clayey SOW eR peers Grins Aen 9 again Sas O18 ed See eee 20 feet. The enumeration of the strata passed through at the shaft of Barnett and Smith, commences at the top (No. 6), with the stratum which immediately underlies the lowest member of the section measured upon the bank of the river, (No. 7). 342 COUNTY AND REGIONAL GEOLOGY. The annexed diagram, (Fig. 27), is intended to illustrate the section just named, together with the measurements of the shaft : Fig. 27. 20 BY” 20 20° WILLE LLL LLLALZLVT SLT 2s t7/ NOLL LLL ESTP I ee We meee TET A ee Sess es TH) LU PLR AMLMLS Def TOS OTT TT, SF LTT aaa J SS d SS aoe eS > er LL. ZL — Z WHA Z — —_ LoD ee II ILL — e-e_—v...- cj}... eer oO ice INCOM OMRMCOniLea teens ik Oa cians Se RE Ee te cls Sigs 116 feet. No. 4. Bluish, shaly clay, containing vegetable remains......... 4 feet. No. 3) Compact, impure limestones ge oc. - se eee eee tee 1¢ foot. No. 2. Bluish, clayey shale, with occasional thin seams of impure JET GAY ERC 0) IV hae RIO SII i 4 Gio a So) SOGOU 6 feet. No. 1.) Compact; impure limestone). 2 mene erent = 1 i Atoct, GEOLOGY OF SOUTHWESTERN IOWA. 347 Tt is thought that all the strata exposed in the vicinity of Bedford belong beneath all those at Foster’s. If so, this gives a vertical range of between thirty and forty feet for all the exposed strata of Taylor county. Material Resources. Except the great and uniform fertility of the soil, the material resources of Taylor county are not important, or, at least, they would not be so regarded in more highly favored regions in that respect. But in a region like this, where coal and stone are both scarce, the small supplies of both these articles, that Taylor county contains, have a great local value. The quality of the coal at Foster’s bank is very good, and is much esteemed by blacksmiths. As to the prospect of finding other and thicker beds of coal by deep mining in Taylor county, little more can be said than to repeat what has been said concerning the other counties adjoining it. There can be no reasonable doubt that the formation which contains the important beds of coal that are now mined in the valley of the Des Moines river, extends beneath Taylor county, and it is reasonable to infer that it contains beds of coal there as well as where they have already been discovered. There is reason, however, to believe that the strata which rest upon those coal-bearing formations, as well as those formations themselves, thicken gradually to the westward and southward, so that the beds of coal before mentioned, if they exist at all in the farther parts of southwestern Iowa, will require considerable capital and labor to reach them. This subject is discussed more at length at the close of the chapter on the Upper coal-measures in another part of this repott. The stone at Foster’s coal-bank is not of the best quality, but it will serve for ordinary uses. That obtained in the vicinity of Bedford, makes good lime and is also useful for purposes of common masonry. Quite a number of buildings have been constructed from the stone obtained from Mr. Houck’s quarries, and he has a market for his lime extending all over his own county and into those adjoining. The soil of Taylor county is wholly drift soil, modified 348 COUNTY AND REGIONAL GEOLOGY. only in its valleys which are mostly small ones ; it is all excellent, and almost every acre is tillable. 11. PAGE COUNTY. Boundaries and Area. Page county is one of the southern tier, and second eastward from the Missouri river, lying between Fremont and Taylor counties and immediately south of Montgomery. It contains sixteen congressional townships, but, one half of them not being quite of full size, its area is estimated at about five hundred and thirty square miles, or three hundred and thirty-nine thousand two hundred acres. Drainage and Surface Characters. The county is drained by the East and West Nodaways, the East, Middle, and West Tarkeos, and the Kast Nishnabotany. These streams run through the county in a direction a little west of south, and drain it very completely. Much the greater part of the surface is prairie, but the valleys present much pleasing diversity, particularly those of the larger streams. Indeed, the whole valley of the Nodaway, from the northern to the southern boundary of the county is very beautiful, and that - of the East Nishnabotany scarcely less so. Narrow belts of woodland border the main Tarkeo, and also the west branch of the same river in the southern part of the county, but the other portions and branches of the Tarkeo within Page county are prairie streams. A somewhat larger proportion is found upon the borders of that portion of the East Nish- nabotany that crosses the northwest corner of the county, and also in the valleys of the Nodaways jn its northeastern portion. From the middle of the county southward, the valleys of these last named streams contain the largest bodies of woodland to be found within its limits, so that the southeast quarter of the county is well supplied with fuel. The remaining portions, or all outside of the larger valleys is prairie which has a gently undulating surface. The general character of the valleys of Page county, is that of the usual drift valleys, although the Bluff Deposit occupies a large part of its western half. Mk 1 ek ee GEOLOGY OF SOUTHWESTERN IOWA. 349 Geology. The Upper coal-measure strata alone have been found exposed in this county, but it is probable that some outliers of the Nishnabotany sandstone exist beneath the surface in the northwestern part. The strata thus far dis- covered are all referred to the horizon of the lower half of the series of limestones and shales of the Winterset section. At Hawleysville, Just upon the east border of the county, there is an exposure of about five feet in thickness of bluish, argillaceous limestone, with partings of blue, clayey shale. These are no doubt the equivalents of a part of the strata associated with the coal bed at Foster’s in the northwestern part of Taylor county, but no coal has yet been discovered in connection with the strata at Hawleysville. Crossing over to the valley of the West Nodaway, the next exposure of strata found were upon the left bank of the stream a little below Clarinda, the county seat. Here the same bed of coal is found again which is worked at various points in Taylor and Adams counties together with their associated strata. The coal is here of about the same thickness (from fifteen to twenty inches) as in the last named counties, and its associated strata have the same general characters. It has been mined just below the mill near Clarinda, and also at several points within a mile below Fic. 30. the mill on the east side of the a river. The following section, illus- trated by Fig. 30, was measured there, commencing with the surface of the river as the base of No. 1. Section near Clarinda. NewS: Hard, bluish; impure limestones. 2 ok gc kao hoes 2 feet. Mor smeiluish, Clayeyichale artigo) csc. etka pemeire: ott 114 feet. ite ee. | £50] Ress reece samen er cine ot St Et eo Se es 1Yy feet. No. 2. Light, bluish, clayey shale, containing fossil plants and MES cs, said w' sro ah cnehn arlcke Ave tend RETRO RAS eee ears « 2 feet. Noy Ey Wrexposed to the water's edge i954. 500. ...:.5-00s+s-- 10 feet. 8350 COUNTY AND. REGIONAL GEOLOGY. A short distance below this place, a quarry has been opened in some strata of hard, bluish, impure limestone that seems to belong beneath those of the foregoing section, but their actual relative position was not satisfactorily ascer- tained. Near this point a shaft of several feet in depth has been sunk with the hope of finding another bed of coal. It was reported that such a discovery had actually been made there, but no reliable account of the digging could be obtained, nor any evidence that any trace of coal had been found beneath the bed so well known. Going southward about four miles from Clarinda upon the west side of the valley, the same bed of coal and its asso- ciated strata are again exposed in the banks of a small creek Fie. 31. just before it empties into the Nodaway. The coal is mined there also upon land of Judge Ribble, and the following sec- is tion, illustrated by Fig. 31, was @):'6" measured there: Section at Ribdle’s Coal-bank. No.5. Yellowish,shaly, calcameous' clave =o wre ite -ereleaeteiee % feet. No. 4: “Hard, heavy, bedded Inmestonerny cer sere eee 216 feet. No: 3: “Blush, clayey Shalersces a. o= atreisiers ore tehnttes eatetatetel ere eile ers 216 feet. foie eee 610. | Wert mE UAE Sol ld te Uy aiocig Gad 2 Od 14 feet. No. 1. Light, bluish, fossilifcrous shaly clay....... Oe emer 1 foot. Totaly Peres set tae cit einichere toes 14, feet. Proceeding down the valley of the Nodaway, we find a very interesting exposure of strata in the right bank of the stream, Fie, 32. just below the dam at Brady’s _ mill. The locality is very near a” the south boundary of the State, a2 and the exposure is represented a =—{ by the following section, and Oe Wie, ae Seciion at Brady's Mil. No. 7. Yellowish, shaly marl, with occasional thin layers of IMpUNe MMESLOUE...\<.- 6. sik steeper em ciate Ole me fee l=» esi 516 feet. eae) es a 7 ’ yal P ' GEOLOGY OF SOUTHWESTERN IOWA. ool MonG. Layer or compact Limestone 1 As 2 <20ie bs sa slots be oe aN Le fopt, No. 5. Dark colored, carbonaceous shale, passirg upward into MOMEe OMG Cla We Vee Ales Maye cccls ss ss olaved ile 4a wee 6 oele 21 feet. No. 4. Layer of compact, bluish, impure limestone............. 1¢ foot. No. 3. Bluish, carbouaceous shale, with thia, calcareous seams... 4 feet. Nowe. Hands pitish, 1m pune WMmesiOne: 2.0%. sees = oah-ce sates eo 21% feet. No. 1. Bluish, concretiouary and shaly limestone............... 11g feet. NOI i Ae ge id i RN 17 feet. These beds are all thought to belong beneath the horizon of the coal bed farther up the valley, and seem to have been elevated here by a very slight fold or undulation in the strata. Going still further down the valley of the Nodaway, and about two miles within the borders of the State of Missouri, another exposure of strata is found Fie. 33. in the banks of the stream in which the same bed of coal is recognized that had been so often seen farther up the valleys of the same stream and its branches. The following , section and Fig. 23, represent the Z SEE strata exposed there. Section twv miles bilow Brady's Mill. Noro. pyellouwnsha manly Snaley ov. os.6es cc 8 5 au cle dees ale bias os NOt 4a Slalyemmmp Ute MMVESLOMC As. 6 ai, Sete: » wos vial are +!s 3 Sm vy aale'n e's INOS os pC Oma ec OUsps idles ce waive tate a Sado ile o's cn eicle' ese ete’ BS (Page Wiel OO ve dren RR SE ae Payee a a NR CaRE e EAP e No. 1. Light bluish shale with remaius of plants Going westward from the valley of the Nodaway, we find the next exposures of strata in the valley of the main Tarkeo. ‘These are slightly exposed at intervals from the northern to the southern boundary of the county. The following sec- tion, illustrated by Fig 34, 352 COUNTY AND REGIONAL GEOLOGY. was measured in the east valley-side of that stream, on section 7, township 70, range 37, near the residence of Hon. Joseph Cramer. Section near Cramer's. No. 5. Yellowish, marly clay with cecasional thin layers of lime- SHOMOL Len adlewh thy te Ma gasle 2 Rane RUE OR Spin dane ae ein G6 feet No.4.) (Compact, bluish wlimestonese. eee ee eee “1 24% Tee Nos 3) eddisheclaye acct. cee eres tS eas iets teen nia eae eee 21¢ feet. No: 24 \Bhutsh; marly clay ie: cee ce fe ate eee eee ee 216 feet. No. 1. Light bluish, sandy and clayey shales with thin layers of fine-grained micaceous sandstone, occasionally showing FEPPle MAaTKGs.2 ee lasek at ee al el oR ee eee I eee 20 — feet. f Wo) EON nS Poem nN RE ECR rts Tse oolg feet. The members of this section, from No. 1 to No. 3 inclusive, have a very strong lithological resemblance to, and are, no doubt, equivalent with No. 2 and No. 3 of the Winterset section, in Madison county. Passing down the valley of the Tarkeo from this point we find the harder and more durable strata of the foregoing section occasionally presenting slight exposures in the valley sides, at a nearly uniform elevation above the stream. Going westward into the valley of the East Nishnabotany we find a few exposures of strata similar to those in the valley of the Tarkeo. Material Resources. The soil of Page county is every- where excellent, a considerable portion of it being Bluff soil and the remainder, except the small portion of Alluvial, is Drift soil. There is scarcely an acre of it all that may not be tilled with facility and profit. So far as the existence of mineral resources in this county has been demonstrated they consist entirely of its coal and stone. The only bed of coal thus far discovered within the limits of the county is the one represented in the preceding section, and so often seen in the valleys of the Nodaway and its branches; and although it has not proved capable alone of supplying the inhabitants with necessary fuel, it has S © a) we GEOLOGY OF SOUTHWESTERN IOWA. neverthelegs thus far supplied a sufficiency of that kind of fuel for which there is no substitute for working iron, etc. No reasonable doubt can be entertained that the Lower coal-measure formation with its beds of coal extends beneath Page county; and if the region were a densely populated one, and capital abundant, the facts in the case, whatever they may be, would soon be demonstrated. While, however, there are such good reasons for believing that coal actually exists beneath the county, it is proper to caution persons of limited means against undertaking the enterprise of sinking a shaft in search of it, with the hope of accomplishing the desired result with the expenditure of only a few hundred dollars. If beds of coal exist at all beneath the one now mined near the surface, a profitable one will not probably be reached at less than several hundred feet below the surface ; but at the same time, there are good reasons for estimating the base of all the coal-bearing strata at a less depth than that at which coal is profitably mined in other countries. Although none of the stone thus far found in Page county has proved to be suitable for lime, yet taking the county as a whole it is very well supplied with stone for ordinary purposes. Page county possesses much that is interesting to the geologist, although the exposures of strata are fewer than they are in many other regions. Many interesting and characteristic fossils of the upper coal-measures have been collected at the several exposures. The only bed of coal in that formation worthy of the name is as well developed here as in Adams county. In the valley of the Nodaway near Clarinda some teeth of that huge extinct animal, the Mas- todon, have been found. ¥ 12. FREMONT COUNTY. Boundaries and Area. Fremont is the most southwesterly county in the state, being bounded on the south by the State boundary line, on the west by the Missouri river, and on the north and east respectively by Mills and Page counties. It 45 ———- eene en e ae 354 COUNTY AND REGIONAL GEOLOGY. is a little more than twenty-two miles across from its northern to its southern boundary, and about twenty-six miles from east to west across its widest part. Its outlier is a little more irregular than that of any of the other counties before described, on account of the meandering course of the Missouri river which forms its western boundary. It is estimated to contain about five hundred and twenty-four square miles or three hundred and _ thirty- five thousand three hundred and sixty acres. Drainage and Surface Characters. The greater part of the county is drained by the Nishnabotany and its branches, the Missouri river itself draining the remainder, which is only a small portion. The last named drainage consists of ravines and small creeks which reach the great flood-plain froin the uplands through the bluffs that border the flood-plain throughout the whole extent. All these creeks and ravines pour their waters out upon the flood-plain, and none of them, not even the largest, reach the river except by per- colatiuon through the earth, for they sink away and become lost soon after leaving the bluffs, although water may remain running in their beds among the blufis during the whole year. A very large part of the surface of Fremont county is prairie, but yet it possesses quite enough woodland to furnish all necessary wood to the inhabitants for fuel and fencing. That peculiar lacustrine deposit described in another part of this report, under the name of Bluff Deposit, occupies almost the entire surface of Fremont county, except the bottoms of its valleys, constituting all its soil except that of its flood-plains, and even enters largely into the composition of the latter also, including that of the great flood-plain of the Missouri river. This remarkable deposit gives character to the entire surface of the county, which differs considerably, even in physical aspect, from any of those counties hitherto described. The bluffs which border the broad flood-plain of the Missouri river, form the most conspicuous feature of its surface, and they extend from its northern to its southern boundary. They reach a height \ GEOLOGY UF SOUTHWESTERN IOWA. 35D of from one hundred and fifty to nearly three hundred feet from the level of the flood-plain. Although they are in most places composed almost entirely of that fine homogeneous material, designated as Bluff Deposit, they are nearly as steep and abrupt as the rocky bluffs of the Mississippi valley. In many cases, these bluffs of the Missouri river valley are so steep that they appear almost perpendicular, but this is far from being. the case, appearances of this kind always being deceptive. The steepest fronts will average less than an angle of forty-five degrees with the horizon, and the boldest and most precipitous one observed, upon which the grass was growing, when tested by the clinometer, proved to have an angle of only fifty degrees. Some of the ravines which open into the flood-plain through these bluffs, are deep, wild gorges, such as one would hardly suspect the existence of, but they are usually short and end abruptly by slopes so steep that one can climb them only with difficulty. Proceeding inland from the border of the valley the surface quickly becomes much less broken, although the material that constitutes the ground for a great depth is the same, in the higher parts of the county near the great river reach- ing a depth of two hundred feet. The more level inland surfaces are prairie, which present much the same general appearance that. prairie surfaces elsewhere do, the peculiari- ties of the deposit being more especially shown where the surface is considerably broken. | Coming to the valleys of the East and West Nishnabota- ny’s, which have their confluence into a common stream near the center of the county, although they have eroded their valleys out of this deposit almost alone, we find none of those bold, precipitous bluffs, such as border the valley of the Missouri river. On the contrary, they are bordered by valley-sides of moderate height which gently slope from the high general su:face to the lowlands that more imme- diately border the streams. The lowlands of these two important tributaries of the Missouri river, although resulting as such from the same natural causes as the flood-plain of 356 COUNTY AND REGIONAL GEOLOGY. the great river, are nevertheless quite different from it in some respects. As one stands upon the uplands that border the valley, the lowlands at its bottom, which average about a mile in width, appear to be quite as flat as flood-plains usually are, but upon going down upon them he finds in almost all cases that they slope very gently and uniformly from the valley-side to the stream, so that those portions only that are immediately adjacent to the stream are reached by the floods. This being the character of the lowlands of these valleys they are nearly all tillable without drainage. The undulatory slope of the valley-sides to the higher surface being so gentle, the valley is broad and shallow, averaging from three to four miles in width. Thus, although their scenery is lacking in boldness, that portion of the county traversed by these streams is one of delightful and quiet beauty. The usual narrow belt of woodland skirts the immediate banks of these streams as well as those of their larger branches. That part of the county lying east of the West Nishnabotany is with these exceptions, all prairie, including lowland, slope, and upland alike; but the part lying west of that river, and of the main stream below the confluence, is well supplied with timber for fuel, fencing, and common lumber. Besides the original forest trees that were of mature growth when the country was first occupied by white men, a dense growth of young trees of all the indigenous species have sprung up, covering large areas, and are rapidly encroaching upon the prairies wherever the fires have been incidentally or intentionally prevented from continuing their annual ravages. These trees are of the most vigorous and rapid growth, although the soil that supports them is entirely composed of that fine homogeneous material that everywhere forms the soil and subsoil, extending to a depth far beyond the possible reach of the rootlets of adult trees. This fact shows conclusively that the original absence of trees upon the prairies was not due to the fineness of prairie soil as some have supposed. oe eae GEOLOGY OF SOUTHWESTERN IOWA. 357 By referring to the descriptions of Ringgold, Union, Adair, and other counties to the eastward, it will be seen that the Drift Deposit there is stated to be very deep. Going westward from that region, we find the drift gradually diminishing in thickness until we reach the counties that border upon the Missouri river, where it is sometimes found not exceeding half a dozen feet in thickness between the stratified rocks beneath it, and the Bluff Deposit above it. The Bluff Deposit is so deep throughout Fremont county, and the drift so thin, it is only at a few points where the latter has been bared by the erosion of the valleys that it is seen at all. Thus, only the immediate beds of the larger streams contain any sand or gravel, while the banks of all of them, and the beds also of the smaller branches and creeks, are composed of the fine material of the Bluff Deposit, and are usually soft and muddy. Geology. The strata only of the Upper coal-measures have been found exposed in Fremont county, and in consequence of the great thickness of the Bluff Deposit, the exposures of these are very few. None have been found in the valleys of either the Nishnabotany’s, and, with the exception of a slight one in the valley of Walnut creek, the only exposures are to be found at distant intervals. along the base of the bluffs that border the Missouri river flood-plain. They usually extend only a few feet in height above the level of the plain, and are then lost from sight beneath the Bluff Deposit, or the slight intervening accumulation of drift, but in the northwestern part of the county a few exposures reach considerable height above the general level of the flood-plain. On land of Mr. John Wilson, section 23, township 70, range 43, there are some fine exposures of Upper coal-measure strata, which reach the greatest aggregate thickness of any yet known within the State; westward from Madison county. It is therefore a locality of great interest and importance in the study of that formation in southwestern Iowa. The strata observed there are represented by Fig. 35, and by the section following it. 308 COUNTY AND REGIONAL GEOLOGY. Fig. 35. iy (Le Z WZ) a“ I ex hen y Z : Sa Sr ———— ae > Se ~sh Se mo Ta ged fon? a Or = ie ——— te 2a ——————— pee), hy Ih Barn . 26. . 20. . 24, 20. 22. sete . 20, 19. ls) 2 NAG 06, Section at Wilson’s. Yellowish gray, impure limestone, in thin Jayers........ 2 teers Limestone in two layers, with a three inch marly parting 214 feet. Yellowish, shaly marl ...... big c hie bits. oo hehe tenets Rae eae 1 feet. Black, carbonaceous shale ys fe gt. ee eer A oe Ss 1% feet. Blush clayey Shale ci... ees eee cele aches) Seen 1 feet. Blackcarbenaceous Shaleyjs)4ea—. eee OE eae i foot Bluish, marly shale, with numerous fossils .........---- 116 feet. Timpurecoal 2.2.0. se elses ee ae eee ++ foot. Light-bluish, fossiliferous, shaly clay...........--.----- 2. feet. Compact, bluish limestone, with shaly partings........ 4 feet. Marly clay, with calcareous concretions...........----- 6 feet. Mieht, eray limestone ).\..o.eoca eee BA on Ee 4 feet. Unexposed ..:...4. ib.» sve e Sugita dhstiattet tee reteee de Reage mes Fetches eek 6 feet. Compact limestone....... uct uals bd ell acd Sa nee 11 feet. GEOLOGY OF SOUTHWESTERN IOWA. 359 Now tay Miohty cllawich indurated manly. 4.442% jn = 2+ tar 4 feet. No. 14. Yellowish, silicious limestone, with flinty concretions... 214 feet. No. 18. Yellowish, marly shale, with concretions of impure limc- SUOMICH cited aes aia, aic tia a aiejecer ss Dalal ta amen cate ene ache 3 feet. No. se; Compact, lmMestione. 62). 2 ee t= 2 oe Repas oie weiss wool ty ifoot. No. 11. Yellowish, marly stale ......1 oe ere Eee poe 2 feet. Nox 10:, «Gravebimestone, im thick ayers... 22 .\icce ne ole oes cae as 3 feet. NGe Orme Talis uC ANTO Ve SIMA Ghia": falare, sal s/t ai'e. (0 «nr jae! ar sa wie a's of ys’ 'e'« ay lf foot. No. 2S.) Yellowish silicious limestone 22.2... 150.22 secon cee 114 feet. No. %. Compact, gray limestone, with marly partings.......... 16 feet. Ge ence MENS in SlmeMlive IAN 15 5 whe), oio'cleie ci oles sired ewig tte qian saree eae es 116 feet. Nome Onlpachs lanier Of MMNCSEONE: yl. Ja 2.cjni dss eS 241 Coal-mining in Iowa, practical conclusions concerning.................e06- 258 CHOOSE? Tid GUNG URI me etch ad fy Ace cs ete 1 id Rae an gO ger ce 96 Cretaccomempeowles, LOSSils) Myc. clethete ore teMelote te Se cltia at eialeiehS cic cs aie ei eeiche'e es 290 PDD Ee i Ul tteg 2 C WEMG AENY ayo) chats crsteeabes Shey" aehatccy chs legetetane ase (shea. nilbva ie! d's de an'spayaliey ovonevollehe 318 De Wosutsy ame Te TM ATSI 5, &) ././ 6:04) oar 0: or rarerevelcbos relay savobale’ el/ersvesere TRebay tals aut edi htee Nations 1a Ne, 388 INDEX. PAGE Devomian System. os nck ees ek eae euteces See ce me chee ee eee Seer cee ane 184 Dramage Systems of the Slate... cc se; a. eee eee eee ee ee eee 38 DUG ia eee colin eG euiere oie 6:0. le:piar eid uw SaeRe Ne ee ekea betel rotate Soon end ee ae 82 tei ie a rN SH) OAM Amer OMA A CEM 6 oe a he ya clies 101 OUlAETS OF. jo). oF. Swe oie oe eiatee ena eneune ee a ee ee Ree ee ee 85 OE AM a sears sid ia, Se POE Oe EL ak eros ts, Sean ce era ee 97 GOP PET VA in eso ad Shane Weidicince eho ee oleae ters meena ects eee ars te ee 96 distribution of....... aolails lara a fs altace waeeile cya tole melas le eke eee Sea pate aa 85 evidences-of glacial iongim ol ath csk coe Cer: eee ee eee 92 evidencesior Northern Origen Ot. 7-1. eee ee ek eee ee ee nero 90 TOSSES AM asd ie ete hee on b steels ieee ema lecen ice nase elt ee ete ene ce ae 98 OVA WIE Ease arch ls ks) crutciie ete ie See Welots otere eames eee te tate ee te a eee ae 97% STAVE] OT ir tai dial tele Fah BUR tet sistas uote ite oe ee ee ea 84 TEAC MOPE DMI Ail d ae Macht eos teverdarote ale ale Cees aera ae 96 moraimesi(?) OP. 5 +. ob Ok ee Renee uid Soin 4 cline he eRe eee 98 One Ol sees Wailidniie Gobtic gunaeie ees Aeeitts seu ete sick inie e SCE Aen eee 89 SATICAOE, Sata teh alates nie loin toe ee totate'ats alee lth ait te Seta Fone soe eee eae 84 thrckme ss Ol i6 eins AS tie tees ican ea re 88 WOOG EM soi ies + wiaistile ceeionle gem alee Sie «tee ee oe etn iepe Gee ie ae anna 9% Elevation of principal points in the State, table of ..................0000e 30 iMorest trees, oroywth of 1m jpraimie'soil..,. .....).1-c cere ces eee eee eee 129 Forest treesiof Towa 23s. «isis statues a.« s/o iereie ce eteenie nie See EEE ee eee eae 134 BTEMON (COWMEY |. ieicsc Cam sic de rsrete sete asl ote etd Peete le eareikeisio rceele nett eee d00 Galena limestone: occ 2c Ski eee ea oe ee eee err cee ere 176 Geological principles, popular explanationjot:... 4. eee - eee eee 12 Glacial currents, LLACES OL. « a.< aise dees hale e ae ai ehee cielo eee EE eee 92 Gilactal Scratches, .\. «00s ediats books Ge eam Sancta oie Whales 6 cee culede te yc tote’. re eeeeee eae 92 Glaciers, passing away Olt )cn - sas oa ace ec eeeeee eh eee eee seine eee 99 Hannilton limestone ‘and shales ’2 i. cc css sen oe ware eee eee ieee 184 Historical account of geological survey of LOwd...)..-..- cen. -- lyons r Hee ‘caveof Decorate... 3. iae 6 ose cwncoes acle sleds oo Sree ieee en 80 PM GLOGUCHUOM 5152 os, shece cal eie hare: ocel chal atorwis veoh laters faleNelehe/ozs tehchosfefaiicne foletatelels ete tele eielemen tenet 2 Imish,:©, W..; Ratlroad;ecleyvations, ..5. ceieuctees st ee oecee eter seater eer 31 Gok wk Mme StOne)’ joie. 6s sin cl iepopeie ee « om ee ie eis rsler cle taleteheme Rte tetera Gale eRe Meme Taleo 210 LOSSIIS! OF aes ste cooks Poe renee BAR er ee oes Se oe 9 oO Oe 213 Kanderbook beds: site cera sicicks schol tras o cies apstolevanalo oreo. =! ate ole ie oye ae ee REC Ieievs) odes 191 EXPOSUTeS OF, Meare OT ANNU fl. lerice wie elt eetteere ciel yele ett 197 in, Pocahontas county Seapets: 6s cack 199 thickness of, at surhine ton yc ce ee scree reper elie i ee 192 IA OS's inne bie deste tie) elie efetcios alesse aie Giete sole onetole ofits at Wet Cee eRCM tat alotel is mls eae eiee tems 70 / INDEX. 389 PAGE WEEE (0) GET CRAMER AMINE, Sila eatin ae idea of iaiay we a:cla'eoco code acdadnedaadsee os 1 TWEE Cee TOR ERE gto avclana fiom = cians oo mea caea ds oases adn ueaaudl ace 032 Maen ere eerie aie PINES ONE soo eosin a cnoe ca sc eins wesc pone vedo wadeeen sus 172 (ads Le aS Ae) a or sree 171 MER GIMEMOM MEME NS «Wise one tise = ese kh « «ss ones oR Sel os bade ede cede espe 305 fue Peswens for inine coal 18... 22 62) 2. us ts ee ee- .-- B14 Marcou, Prof. Jules, on Cretaceous rocks in western Iowa................--. 285 Maquoketa shales ......... PRA ad i ee ately talsihanredeara 2 weer an es-c 180 Melsaac, P. Cretaceous fessil found in the drift... 2... 02200050000 eee nee 98 Meek and Hayden on Cretaceous rocks of Upper Missouri...... ........... 288 Meck and Worthen on.Cincinnati -proup. ..... 2.0.0... ene ce wen ceca cccceee 181 MisgiMe COAL-MICASHEES © o..2 5 )5222'sscsscccesccacs «% LN ea” Pee 241, 265 BERCEID SOCIO - OF © ciel ene base a ais bees nts ooee as + 272 SCE ISMAN ct a eee oe wee nee ma tal ded a telah eek abl deca Bie eds ce 367 SenirceEl SANMoRe Pociten nt oe aoe Sots as ek ae ane da ak oa SUAS hs aaa ee Se okie se oe IDRC NONO ER re a ete 5S ye hao a wished gs 5 harem isla slag pl awe 298 suggestion for reclaiming overflowed land of ................. 303 depth of disturbed material in bed of.....................02: 300 eemeMEMER ENE WANEE@e, © 282625543 ssicsaccaeed 4 bb ey st oe one Sede x 56 we DT TEDL Rn Doe a ol ee eee 362 Pie Webern ROPLRe AGE a re tyres NP iw ars Selo Bo vib ated pbewost ohne dade ance 182 ulaRaDINGDE TENCE ees ies eae ahead aside a Sao ae Jen wd aon nee ouinds deeio A 72 Oiygete Phe Pee EDS erty Feistte, DIC HOSIE. OF POWAL carota ane ow ose OS ee ee 104 WileCtACCOMS FOCKS-GllGWal s26 2656602555 os Sue icnawess 5. 285 MLDS VEU eee a oi enn Se ee ee eee oe 348 Pan, Material at hed Oak, Mouteomery county ..:2.. 220 02.26...5-.4--.- 367 Panett tee bei eee) Ol MWe os So cua ces asthe deladede ieee eee 139 eG acd Sh uBEar ARIIEE COMES Ves ot 2 ols Sa els Riedie wth a eee, ces alee > ~ 339 SEPCREE Die MeCNERE Ro tent ts Dope e © Siac tweed oe a's tv's, 8 119 ME RLeTOR WER IO TNs sae ce ei einae oS oun soca dy mqaaes oxese see 120 Potsdam sandstone..,..... Pore tee ead $52 23s ae aed Seer a 171 Re ararC LLL be KBEAUe ANODE rr parton ees La ds oid id, 2S Sse vies Sees on os oe 376 ReetriGd: OF, Obie ceed, lanes ose sa eae Uee ts Ieisis Wale d cht oie ii 2 Tore siete 132 STOWLMOEARSER ON oe oni oe 2 ae Seldaae se dass « Mas Dia NES 131 Pratt, H. W., account of ancief peat near Davenport... ................... 119 DIG TEPID CRP UA ge ts ee a ee ee 328 LEUT ED. (ETT Soa pe a a 8 ee ee 53 a toe 8 oe a ene ene Reis yy Oe Gaal Sanu in we bile s «a hie 49 es. es es Vane See Rie Yi wcla gig eS own cone Ge 63 JALLEDIT LTE Se ee ee ee ee ee ee eee 4 390 , INDEX. PAGE PUINISE TOW Gis) o og shane raid ody Bisel s eats voece sae Ne eae eee d2 GAT oo aan oo 5 eres nte eves | peels a euere eae cae ear ane ene oe 144 TI WG ja ice sa)onokin syle uy (ete Vodwis & ober ere ese dere el ile te se ct te tel res ae 62 Little Sioux oc os e Y Ga elena ate ora ene ne 51 Maquoketa. )2.% 22s simian bin eiare'e alate leer een elena avaeae Seen rr 65 MBidGle 5... voc.ce ba ase te ce See ee eee ee 60 MISSISSIP Plein. « eyo 'strek a eereies enable miSete Merial eens Nero ee eee ee eee 67 MUESSOMEL A 125s 0.0 Ss be isin ie wines eles Wee EEA e ya ve eR Oe eee ae 55 Nishnabotany aig sno) ghinvgte, is Glee grates Rie ime Fe ce Ei ar i ane he ene 47 Nod aways 34 xchic: eR ARE siecto eee cieneneeie E shield Neva talbetwke eae Glam teiete os Eira Aq INCOR GI fick earn eseseieie wt PEA cle ok ee SE Ae: Ween hE eee aie Safe REE €0 One—Eundred-and=Two .2.\,)..).ba ce. cre nee Dee eee ee eee 46 FRA CCOOM Seventies “ceva. caer, lala ieie cam leave fe estan Cer Ramee Nes sate ere ee 60 FROCK eee aa beak ele bo seks lbs eas, ete ciaete tet renee eee 53 TA oo ei wide ie ed ova yes tae e le beeper ele ciate ta ate ualane oes AOR eet or 61 Bolder. csi al eke cin Deke oie oo eee ie tnte meeieyencheie cunt ae a 50 Souths sus sch been en Rae eo Rees ches Se ne ei ane eee 60 PUP y vos ieee Sales. cate Ore scimieiak eo tele dedarn came IE Raine Oe ice Cee eee eee nee 65 Upper Lowe eo 2 eee be nlc eilates 2 oie ener ale demas wee eae mee Clea) ae ee tee 66 valleys, relative ages of.......... si gle) rc yl Td) Sheledepa. eet eb ole fel Skee team 69 Wiaip SUPUNI CON 2 cies eben guscleciee ia eee sie Weebly Nba e ene 64 Riversand their valleys crt. eects ha ways eo eto hie cel eresione ake eee ere een ee 38 of the eastern system of drainage of the State........ .........0s00. 57 of the western system of drainage of the State.............e+cee5 «« 44 table of slopes Of. cece silk gc eheeeicrels Saleen ievete Sees ee eae eee eee 40 Sinksholesas iit ac eee cee Oe ee ek FP Uc tetas eA Tae tamale Gel cue EAE tar A 78 STOU x" QuartZite ss eine ihe ieee ctel eRe ECR ated Ret teh totale En te eee eee 167 Slopes of eeneral Surtace of the State ta OletOles be nee eee eee 33 Wivers; ‘tables eee he a hele ne eine eee oe Clee Orta ct eee eee 40 Sinithia \Woodmani’ Geseriptioniol.....2 sce chee eee cee ee eee eee tee 188 Sol of Almy ial Deposits i. ire EN eG eee ete eae ence Atte 128 Blo Deposit: 22 CARs eee A GEG ee ak Caine ee lene te oecle ete heen 127 (DritE DepOsit cicisc Mester mete < eens cites mince Sais ere «© ol cement 123 DOS. ca olka ee oath a ce bee k ee tees bare uke ees Re en 6 nese Lee eee 122 Southwestern Towa; Geolovy of. oi. aio. ie eter ae eae ae ee ene 297 Spiel: AKO. OF a's Moelle ah ate atin Whe Ghee Oe ar cect es o-teceane ee ee 72 SSPTINGS so: 2.0 6 dre oe RR ee edits kw ere eo Nelahs ke Nee te eRe eee els ne Neca 78 Si ours dcimestomes cece. sees cella alebelaGinie Swale soe Be ac ote ce te de an meReReMene tate delete folie 215 Storm Tralee. sic cco ta yc eee eil te cree te ie lalle vere Se een a rc 73 St. Peter's isamdstome secs oo .a hola wiles eleree oie eke ee Coe ene fet ee nce 174 Sib-carboniterous OU ps 2 .0...ci. 656k we eae hp oe REO REE es cleats 189 general remarks Upolse eee ree ee ilaiela' Stabe ele eee 222 DSurlace Deposwsirs oc eteheie iio kw cs bade bel e Sea eee ene ERE So oe oe Roepe rep emer 82 Swallow, Prof. GC. on Blutt Deposit, .. 1 we ene eee team eye. eee nee 105 INDEX. . 391 PAGE Pity lor. © Oiygarmncett ey eraye act oie) sratera la! ata wie oe ania nena piwig & « oabsttia sreeie'e-s 344 Thielsen, H., quoted......... Be MPC 2s PUES. cd olan oes ee bach alas 331 Ropostapiageseweta Ol sue ShAteee a ale. ceialeas 25 s'e 2 a%s)s)cla aes a)e a «'s ta eadias 2 29 Ee mi hOniml une anon Cm tne vn mriet nel arelslaia (Tals ales he ssa « akelceis'eiw'a da emiela aie node suele a2 174 Wmcomtormapility of Coal-measure Strata... .......aces eu see eee eee ee Bhs st aD Sie Onis mo imMestome: Sitatan cue a J c3g8 ae. Oe a) ¥ 13 ee ae er 2 4 is, -— SMITHSONIAN INSTITUTION LIBRARIES a iin