172 



♦ KNOW^LKDGE ♦ 



[Apiul 1, 1886. 



The present agency of man is tending to diminish the 

 magnitude of these vegetable deposits— trees are cut down 

 for house-building, for" fuel, and for exportation During 

 only the present geological epoch, while these ijords and 

 their wooded slopes have existed as they now are, countless 

 millions of large trees must have thus been swept into the 

 deep water in latitudes of most unfiivourable climate for 

 luxuriant vegetable growth, where there are but three or 

 four months of growing summer time in the year. 



What has become of all these 'i Remembering that the 

 mountain slopes on which they grew continue downward at 

 about the same angle below water as above, and thus extend 

 to crj-eat depths, reaching in many cases to more than a thou- 

 sand feet, it is evident that the stony matter, the gravel, the 

 ground and splintered rock, will be deposited under water 

 at the foot of the slope, while the trees launched forward by 

 the impetus of their fall must tloat towards the middle of 

 the estuary, there loiter and linger, and drift afloat until they 

 become saturated with water, and then will sink to their 

 final resting-place at the bottom of the fjord, which they will 

 cover with some rude approach to uniformity, but thickening 

 towards the middle, if the bottom slope is considerable. 



The water of these fjords, and of such lakes as the 

 Achen See, is remarkably clear and free from sedimentary 

 matter, excepting at the mouths of the rivers that enter the 

 terminations of their minor branches. Thus the tree deposit 

 must consist of nearly pure vegetable matter, soddening, 

 softening, and settling down century after century, during 

 thousands and thou.sands of years, forming of necessity some 

 kind of coal. 



The difficulty that I have already pointed out as pre- 

 sented by the small quantity of mineral ash in coal does not 

 here present itself; no soil is demanded for the formation of 

 such a deposit as this. All the soluble mineral matter in 

 the original plant material, such as the potash salts, would be 

 washed out, and the only other material likely to take its 

 place would be the very small quantity of impalpable particles 

 that exist invisibly even in water that we call clear. Such 

 is the actual composition of the mineral ash of most of our 

 coal. Potash is nearly absent, and the material of the 

 impalpable powder remaining behind when the coal is 

 burnt ctjmpletely is of about the same composition as the 

 shaly strata above and below and beyond the coal seams. 



Our coal seams occur in the form of basins and oblong 

 troughs, i.e., the form of lake and fjord Ijottoms ; those who 

 have specially studied the matter agree in regarding the 

 material of coal as vegetable matter that has long been sub- 

 jected to the action of water. As an example of the shape 

 I quote the following description of our great northern 

 coal-field by Hull ("The Coal- Fields of Britain," page 253) : 

 " Recent observations have tended to confirm the opinion 

 that the structure of this coal-field is that of a trough, or 

 uregular basin, of which the longer axis lies in a north 

 and south direction, stretching from the apex near the 

 mouth of the Coquet, through North Seaton and Yarrow 

 collieries on the north of the Tyne, and through Monk- 

 wearmonth Colliery below the magnesian limestone to the 

 south of that river." I might quote a multitude of similar 

 descriptions of other coal-fields. On page 72 of the above- 

 quoted work, Hull says : — " There can be no doubt that the 

 laminated structure (of coal) is the result of accumulation 

 under water, and Bischof adopts this view upon other con- 

 siderations. He says: — 'The conversion of vegetable sub- 

 stances into coal has certainly been effected by the agency 

 of water.' The same great authoiity believes that coal has 

 been formed, not from the dwarfish mosses, sedges, and 

 other plants, which now contribute to the growth of our 

 peat-bogs, but from the stems and trunks of the forest trees 

 of the carlioniferous period." 



The fossils associated with coal are generally estuarine, 

 sometimes marine, and occasionally lacustrine. As I am 

 pleading for my own theory, I will quote again the same 

 writer (page GH), who wi'ites without any knowledge of my 

 observations. He says : — -" The coal seams are associated 

 with strata deposited under water, and all recent investi- 

 gation strengthens the probabdity that the water was 

 generallt/ estuarine, sometimes marine." He then specifies 

 and describes the particular fossils, such as Goniatites, 

 Aviculo-pecten, Ortlioceras, Spirifer, Prodiictiis, etc. He tells 

 us of Uiiios, i.e., fresh-water shells, found in the same 

 stratum with marine Modiola and Aviculo-pecten, and the 

 little coiled shell Microconchus carhonarius, which has puzzled 

 able palaeontologists, some having supposed it to be a coiled 

 Serpuld or Spirorbis. Also a minute crustacean abundant 

 in coal shales, and supposed to have belonged to the fresh- 

 genus Cypris, but is by some supposed to be a marine creature 

 of the genus L'ljthere. 



Here as in other descriptions I find a pala^ontological 

 paradox, a puzzling confusion of marine, lacustrine, and 

 estuarine creatures, that have .--orely exercised the ingenuity 

 of skilful pa!;eontologists. 



The great ijords of Norway, which for reasons I shall 

 further discus ^ presently, may be regarded as typical of the 

 configuration that prevailed during the carboniferous period, 

 ati'ord a key to this dilemma. The magnificent Hardanger- 

 fjord is still larger than the Sognetjord. There were no 

 steamers there at the date of my first visit, and consequently 

 I did much boating on it. One hot day, when on one of 

 its terminal branches, the Sorfjord, I was surprised to see 

 the boatman dip a tin can into what appeared sea- water, 

 and drink it freely. I did the same, and could distinguish 

 no salinity. Yet on the rocks close by there was bladder- 

 wrack (our familiar brown seaweed, that is buoyed by 

 little blister-like bladders) growing near the water's edge, 

 and many mussels. The mussels were all very small, 

 and the wrack of light colour. Here, then, were just 

 the anomalous conditions for sustaining such paradoxical 

 creatures as are found in the coal measures ; water certainly 

 fresh enough for many river animals to live in, and yet salt 

 enough to sustain marine aniuuils and plants. The place 

 where I drank the water was about ten miles from Odde, 

 where the fjord teimiuates, and nearly 100 miles from 

 the open sea. In one direction there is, of course, a 

 gradually increasing salinity : in the other, a gradual dimi- 

 nution, owing to the inflowing rivers. 



I should add that the upright trees found in the coal 

 measure strata, and occasionally with their roots actually in 

 the coal seams, which have mainly supported the theory 

 that the vegetation forming the coal seams actually grew on 

 the spot, are easily accounted for by my theory of coal 

 formation, seeing that some of the trees swept down carry 

 a certain quantity of soil or fragments of I'ock entangled in 

 their roots. These, of course, compel the tree to float ver- 

 tically in deep water, and if they are not washed away the 

 tree will sink in this position. This also accounts for the 

 anomalous fragments of shaly rock that every burner of 

 coal knows are sometimes imbedded in the best of samples. 

 Their frequent and yet anomalous occurrence in the midst 

 of a deposit where the general minei-al nratter is so very 

 finely divided, demands explanation, and no theory which 

 does not grasp them can be satisfactory. 



I may add that 1 have lately learned that vegetable 

 avalanches, similar to those above described, occur on a 

 very grand scale in the Straits of Magellan. They are 

 there associated with landslips, and their vestiges in the 

 form of smooth striated rock have, until lately, been attri- 

 buted to glaciation, but recent observers have corrected this 

 mistake. 



