26 KANSAS CITY REVIEW OF SCIENCE. 



Second — Peat-bog theory : 



That originally coal was composed not only of land-plants, but that large 

 peat-bogs or marshes, slowly accumulating for centuries, were finally covered 

 over and filled up by changes in level of the earth caused by earthquakes, or 

 movements of elevation and depression ; that thus covered by the sea, a succes- 

 sion of rocky or sandy or muddy deposits covered these ancient marshes and 

 formed our coal basins; that several such alterations of level took place, each 

 accompanied by a new coal deposit, to be in its turn covered again by the grad- 

 ual erosion and dispersion of land formations caused by the action of the sea. 

 Admitting the possibility that the growth of vegetation took place, as claimed in 

 this theory, the alternate elevation and depression of the sea is too unnatural to 

 be received as a geological fact. 



Third — The Marine theory : 



Supposes that the vegetation of the primeval world grew either in the sea as 

 sea-weeds, or in shallow water ; that their roots grew in the fire clay of the coal 

 measures ; that the water abounded in carbonic acid, or, even hydro-carbon • that 

 a high temperature and greater internal heat was most favorable to plant-growth 

 and caused great uniformity of seasons, while the atmosphere, redolent with 

 smoke, steam and vapor, permitted but little effect from sun-heat; that, under 

 those conditions, vegetation grew rank, profuse and of wondrous rapidity. Thus 

 the presence of hydro-carbons, juices and sap was evoked to form coal 

 in which vegetable fiber has only a secondary part. Prof. Lesquereux has advo- 

 cated the theory that sea-weeds are the original source of the vast coal-oil depos- 

 its of Pennsylvania, and the United States, generally; that originally the vast 

 sea-weed forests of the ocean were covered by deposits ; that the effect of heat 

 and pressure has transformed the cellular matter into liquid hydro-carbon. 



Fourth — Petroleum theory : 



That when, as in the third theory, the beds of vegetable matter under 

 water were subjected to pressure, the hydro-carbon oils would be squeezed out of 

 them, then float on the surface among the growing plants, would aid to preserve 

 them; this, becoming heavier from dust, mud, evaporation and oxidation of veg- 

 etation, would continually add to the volume of the coal-bed below the level of 

 water. We think this theory is somewhat forced and of too refined a possibility. 



The fifth and sixth theories are linked together under the name of Mineral 

 and Volcanic theories : 



In the Mineral theory it is attempted to account for and prove the formation 

 of petroleum and its resultants coal and bitumen from chemical decomposition 

 of water caused by the heat of submarine volcanoes and currents of hot, molten 

 lava disengaging carbon, and that the petroleum or bitumen thus formed aided in 

 the production of coal, although the formation of these two hydro-carbons did 

 not require vegetable fibers for their formation. Messrs. Dadow and Bannan 

 maintain this opinion. 



The Volcanic theory, which is the last one, does not so much relate to the 



