1G6 



THE FARMER'S iMOIn'-THLY VISITOR. 



Frnm Dr. Jackson's Third Jtrpnrt on the 



Geology of Maine. 



As I have, formerly stated, it is evident from an 

 examination of the mineral ingredients of soils, 

 that they all originated from the dccumposition and 

 disintegration of rocks, which for ages huro I'ecn 

 acted upon liij air and water; ihose agents having, 

 by their nieelianical and chemical powers, shivered 

 and crumbled the solid ledges into those pulveru- 

 lent matters which form the basis of all soils — to 

 which, subsequently, small quantities of vegetable 

 Juimusare added by the decay of plants. 



A.\ciF..\T SOILS. There have been various epochs 

 in the earth's history, when the soils were thus 

 formed, and after hearing their luxuriant vegeta- 

 tion, were reconverted by aqueous and igneous 

 causes, into rocks, the structure, and fossil con- 

 tents of which, denote their origin to have been 

 from sedimentary matter, hardened bj' pressure and 

 heat. Thus, when we look back to the epoch of 

 the transition formations, we find the rocks com- 

 posing that series to be composed of agglomerated 

 sand and pebbles, cemented by clay, which presents 

 itself in an indurated form, the result of igneous 

 action. Marine shells, contained in the grauv.'acke 

 recks just described, evince that this deposit was 

 chiefly formed beneath the waters of the sea, v^fhile 

 some portions of it were deposited in fresh water, 

 as proved by the presence of certain plants, pecul- 

 iar to bogs and lakes. The slates of this formation 

 contain prints and casts of numerous plants — such 

 as ferns, equisetacece, Icpidodendrie and stigmarico), 

 while beds of anthracite coal, shewing by their 

 structure and composition their vegetable origin, 

 are also included between the strata. 



Nov/ it is evident, that the above mentioned 

 plants c.iuld not have grown without a soil, and the 

 rocks in which they are imbedded bear every proof 

 that they were once in that condition. 



Secondary soils. We come next to the secon- 

 dary epoch, and here again we .ire astonished to 

 find proofs of a numerous succession of alternating 

 beds of soil, each having, for long periods of time, 

 bore their perennial verdure of intertropical plants, 

 allied to those above noticed, but more complicated 

 and perfect in their structure. The sandstones and 

 shales of this formation are vast herbaricu of an- 

 cient vegetation, and their strata contain, well pre- 

 served between their sheets, perfect impressions of 

 numerous genera of plants, tlie species of which 

 are now e,\tinct. Large trunks of trees are also 

 exposed by opening coal mines and quarries of 

 sandstone, while the numerous and reiterated strata 

 of coal itself also bear ample proofs of their vege- 

 table origin. 



Here, then, wc have another epoch, at which 

 soils existed, produced their abundant vegetation, 

 stored the earth with fuel, and then were recon- 

 verted into solid rocks, to l>e again subjected to the 

 wear and tear of elemental strife. 



The TEKTi.iRV EPOCH was of a milder character, 

 and but little disturbance of the solid rocks appears 

 to have been effected during those submersions, 

 when the plastic clay, calcareous marls and strata 

 of perfectly preserved marine shells, were deposit- 

 ed. These scdemcntary matters appear to have re- 

 sulted from a slovf and gradual deposition of clay 

 and other fine sedementary ftatter, which beneatli 

 the sea, became soon inhabited by numerous shell 

 fish, and were imbedded in succession as we now 

 find them, since the elevation of the land, above 

 the encroachments of the sea. 



When we consider the several periods which 1 

 have briefly mentioned, it will at once reveal to a- 

 ny reflecting person, that the world has been, dur- 

 ing tlie lapse of ir.conceivable ages, subject to great 

 revolutions in its geological organization. At one 

 time, the rocks are worn down into soils, and bear 

 their vegetation — then continents were sunk in the 

 ocean's depths, and subsequently were raised a- 

 gain, the soils having in the mean time, been con- 

 verted, into rocks. By such considerations, we soon 

 learn to respect tlie antiquity of the world ; and 

 knowing that such records are legibly written xin 

 the tablets of stone, we feel a natural desire to read 

 and understand their meaning. 



Ancient allxjViai. soils, or riLtivicji. Subse- 

 quent to the epochs of which 1 have spoken, we 

 fiftd that another scene of violence disturbed the 

 tranquillity of the great deep, and the northern 

 ocean was liurled, with its seas of ice, over the 

 land, sweeping the loose materials from tlie very 

 mountain tops, and depositing them far south of 

 their former resting places — while the grooves, 

 scratches and water marks upon the surface of the 

 fixed ledges, shew the direction in which the cur- 

 rent passed. By ?uch a flood, (proofs'bf which are 

 nearly universal in Maine, as elsewhere,) the soils 

 were transported and commingled, so that we rare- 



ly find a soil similar to the rocks beneath it, but 

 identical with that derived from other rocks, which 

 occur to the north and northwest. Having already 

 cited so many localities in proof of this position, 1 

 shall not here recapitulate, and the intelligent ob 

 server will find so many iilustrations in Maine, to 

 satisfy his rational curi*.)sity on tlie subject, that he 

 need not long remain in duiibt as to the facts. 



Modern ALLUVIAL soils. The present cau-es 

 which act upon the solid rocks, are both chemical 

 and mechanical. Oxygen, from the atmosphere and 

 from water, is constantly effecti.ig some portions 

 of the work, especially where the rocks con- 

 tain pyrites. Rivers, torrents, brooks, and even 

 rain, are gradually sweeping away the solid rocks, 

 by their continued action ; but mure pov.'erful than 

 all others, is tlie action of freezing water, which, 

 by an almost irresistibly expansive force, rends all 

 rocks, into which water can find a passage, and 

 crumbles down tliose which are poi'ous in their 

 structure. Upon the coast, tlie sea, ever beating 

 the solid rocks and hurling the loose fragments 

 with the force of battering ordnance against the 

 sliores, wears away the hn^ges, the detritus being 

 either spread out on the bottom, or sifted up at the 

 mouths of harbors and estuaries. 



Alluvial soils are produced by the transportation 

 of fine particles, by aqueous agency, from higher 

 sources, and are especially brought down and de- 

 posited during freshets, when a river bursts its con- 

 fines, and being diminished in its velocity, depos- 

 its its sedementary matter over the intervales. The 

 force of wind is also constantly removing fine par- 

 ticles of soil from one district to another, and the 

 dust of ages is of greater importance than is com- 

 monly behoved. Enough has been said on thissub- 

 ject to excite inquiry, and to stimulate others to 

 look over the pages of nature, for their own s.Ttis- 

 faction, and this is all that can be expected from 

 introductory remarks, such as I now ofi'er to the 

 reflecting observer. 



It must not be expected that any one locality is 

 to furnish all the data for theirelucidation of a gen- 

 eral theory ; but a discriminating eye will quickly 

 select such as may bear upon the sul ject in ques- 

 tion. Books, relatinjT the observations and experi- 

 ence of others, should also serve to guide those 

 who may engage in this study. 



In order to examine a soil, we must become fa- 

 miliar with the mineral ingredients which enter in- 

 to the composition of .ordinary rocks, and learn to 

 discriminate them, even when masked by a cover- 

 ing of stain from metallic oxides and vegetable hu- 

 mus. By practice, this is easily done, where the 

 particles arc distinctly visible to the eye, but when 

 they arc reduced to a fine powder, then recourse 

 must be had to the microscope, and to the separa- 

 tion by agitation with water. In the field, there is 

 but little difficulty in ascertaining the mineral in- 

 gredients of soils, for there we can alwaj's discov- 

 er some places, v.iiere they may be distinctly seen. 

 In case the particles are too small for ocular exam- 

 ination, then we must resort at once to chemical 

 tests. In all cases where the quantitative deter- 

 mination of the various ingredients of soil is un- 

 dertaken, the work is ex'remely difficult, and re- 

 quires a long course of experiments, which can on- 

 ly be made in a well furnished laboratory; but it 

 of\en happens that some more simple question is to 

 be settled, which is all that is required for direct- 

 ing the amendments or cultivation of the farm. 

 Such, for instance, as the presence and quantity of 

 vegetable matters, and of an)' salt or lime. These 

 substances, any in<>"enio;is farmer may learn to sep- 

 arate, or at least determine their presence or ab- 

 sence, which may be suiricient to direct his opera- 

 tions in the cultivation of his farm. A minute a- 

 nalysis, however, is too ditlicult and complicated a 

 task for any one who is not a professed chemist, 

 having at his disposal delicate balances, crucibles of 

 silver and platina, with all the other usual instru- 

 ments of analysis, and a complete set of all the vari- 

 ous reagents and tests, in a state of absolute purit}'. 

 To furnish such a laboratorj', the farmer would 

 have to expend tov much money. Considering how 

 seldom he would hove to make use of it, he will 

 find it vastly more economical to avail himself of 

 tl;e sliill and materials of those who are duly pre- 

 pared for such operations. 



While encraged in the geological survey of the 

 State, I have always considered it my duty to make 

 chemical analyses of such soils as were in any way 

 remarkable, and I shall herewith present some of 

 the results — such as will prove valuable to agricul- 

 tuiists. I shall also describe the method of making 

 a chemical examination of soils, for the purpose of 

 aiding those who may feel desirous of learning the 

 art. 



Analysis of soils. We have first to inspect 

 the particles of the soil in question, in order to as- 



certain its principal mineral components, so as to 

 learn to what class it belongs. The method of do- 

 ing this has been described in my Second Annual 

 Report. The soil must then be dried, either by the 

 sun's rays, or by spreading it upon paper in a warm 

 and dry room. It is then ready for mechanical sep- 

 arations by seives. Having separated the pebbles, 

 sticks, and coarse particles, we take a portion of the 

 finest powder that passes the gauze seive, and agi- 

 tate it with water, pour off the suspended parti- 

 cles, and inspect the remainder, to discover the fine 

 mineral components, which may be done easily by 

 means of the microscope. The quantities of mat- 

 ter suspensilile and not suspensible in water, are as- 

 certained by drying and weighing the powders col- 

 lected, on a filter. 



The above operations belong to the mechanical 

 separation of the particles, and shed much light 

 upon the nature of the soils. 



Chemical analysis. After the above opera- 

 tions, wc have to make a chemical analysis ; and 

 for this purpose, one hundred grains of the fine 

 powder which passed the gauze seive, is to be 

 weighed out and plae.ed upon a piece of sheet pla- 

 tina, or even upon a quarter of a sheet of letter pa- 

 per, and is to be dried at a temperature of 300 deg- 

 grees F., or not above that point where white paper 

 begins to turn brown by heat. It is then freed from 

 water, and by weighing it a second time, the loss 

 in weight indicates its quantity, (a) 



The next operation is intended to determine the 

 quantity of vegetable matter in the soil ; and for 

 that purpose, the soil, freed from water, (a) is plac- 

 ed upon a slieet of platina, or in a platina capsule, 

 and introduced into a muffle, or small oven, which 

 is then heated red hot, until all the vegetable mat- 

 ter is burned out of the soil, (the odor while burn- 

 ing may be ascertained by smelting the gass given 

 out by means of a glass tube, placed over the burn- 

 ing soil,) and if animal matter be present, the odor 

 will be similar to that of burning feathers, while 

 the vegetable matter smells like that of burning peat. 

 After the vegetable and animal matters are burned 

 out, weigh the soil again, and the loss will indicate 

 the quantity of organic matter (b) 



The soil is now ready for the next step, which is 

 to ascertain the quantity of soluble matter it con- 

 tains. Place it in a thin glass flask, (a clean oil 

 flask will answer,) and pour upon it a sufficiency 

 of distilled water to cover it to the depth of half an 

 inch ; then pour in an ounce of pure muriatic acid, 

 and boil it for an hour. Then dilute with water, 

 and filter the solution through a folded double filter 

 of India paper, placed in a glass or wedgewood 

 ware funnel, collect the solution as it drops, in a 

 glas phial or decanting vessel — wash the soil, which 

 is all thrown on the filter, until the water passes 

 tasteless. Remove the filter — dry it, with its con- 

 tents — then separate the outside filter, and burn 

 the inside one, with the soil which it contains, in 

 the muflle,as before described. Burn also the out- 

 side filter, the ashes of which must be weighed and 

 deducted from the burnt soil and filter, (c) 



Weigh the insolulile soil, (c) and its loss indi- 

 cates tlie soluble matter taken up by the muriatic 

 acid. This serves as a check upon the next oper- 

 ations, and will shew if any matter has escaped de- 

 tection. The solution which had passed the filter, 

 is now to be returned to the clean flask, a small 

 quantity of nitric acid being added, to convert the 

 oxide of iron into the per-oxide. It is next to be 

 boiled for fifteen minutes, and then pure liquid am- 

 monia is to be added in excess, so as to precipitate 

 all the per-oxide of iron. The whole is now thrown 

 on a double filter, as before, and the per-oxide of 

 iron will remain upon it, while the solution passes 

 the filter, and must be collected, as before described 

 The per-oxide of iron, and the soluble alumina, are 

 now together upon the filter. Wash v/ith water, 

 until the solution passes tasteless ; then dry the fil- 

 ters, separate one from the other, and burn tliem 

 separately. Weigh one against the other, and tlie 

 per-oxide of iron and soluble alumina will be oli 

 tained. (d) From this, the alumina may be sepa- 

 rated by a new attack— or it might have been tak- 

 en from the iron, before weighing; the former op- 

 eration being preferable. Tiiis operation is done^ 

 by melting the alumina and per-oxide of iron in a 

 silver crucible, with thrice its weight of pure pot- 

 ash ; then dissolve in water and add more pure pot- 

 ash, until all the alumina is taken up, and the per- 

 oxide of iron, remains pure ; filter, wash dry, ig- 

 nite, and weigh — the loss is the alumina, (e) and 

 the remaining matter is per-oxide of iron, (f) 



Tbe filtered solution,, after the separation of the 

 oxide of iron an4 alumina, is now to be treated for 

 lime, by means of the oxalate of ammonia, and a 

 white preeipitato of oxalate of lime will form, if a- 

 ny is present, and may be s«'parated after it has 

 subsided, by filtr.ation. Wash, dry, ignite, to de^ 



