Geological Society. 429 



Tartar side of tlie Himalaya Mountains. Cases of this kind teach 

 us to appreciate even still more highly than we have been wont to 

 do, the paramount value of Palaeontology in determining geological 

 equivalents. 



OUIGIN OF COAL. 



In the early part of last year some very interesting papers came 

 before us tending to throw light on the obscure and difficult ques- 

 tion of the formation of coal. 



Mr. J. Hawkshaw, having communicated to us in June 1839 a de- 

 scription of several large fossil trees found in a cut on the Bolton Kail- 

 way, near the Dixon-fold Station, five miles and a half N.W. of Man- 

 chester, standing immediately upon a thin bed of coal perpendicularly 

 to its surface, has added a statement of further facts, confirming his 

 opinion that these trees grew in the place and position where they are 

 now found. His reasons are grounded on observations he made near 

 the shores of the Caribbean sea, on the rapid decomposition of the 

 trunks of solid dicotyledonous trees in hot and moist climates. This 

 decomposition in a few months entirely destroys the timber, leaving 

 only the bark unbroken and hollow, like an empty mould in a foundry - 

 the form of this bark remains perfect after the interior is reduced 

 to dust. He infers from this example, that it does not follow that 

 fossil trees in the coal formation were originally hollow because we 

 find their interior entirely filled with indurated clay or sand, since 

 it appears from effects now proceeding in tropical climates, that the 

 entire bark may have retained its place and form and have been filled 

 with sand or silt after the interior of the trees had rapidly perished. 

 Similar observations as to the rapid decay of timber have been made 

 by Mr. Schomburgh. 



Mr. J. E. Bowman also has endeavoured to prove that coal has 

 been formed I'rom plants which grew on the present areas of the 

 coal seams, and that these beds of vegetable matter were at suc- 

 cessive intervals submerged, and covered by sediments, which ac- 

 cumulated until they formed a surface fit for the growth of an- 

 other series of land plants ; and that these processes M'ere repeated 

 in the production of each bed of coal. In this manner he would 

 explain the uniformity in thickness of individual coal beds over 

 very large areas. He furtlier admits, that other trees, branches, 

 and leaves, may have been drifted from the neighbouring lands, and 

 scattered through the beds of shale and sandstone, m hilst they were 

 in process of accumulation upon the subsiding or subsided beds of 

 coal. Mr. Bowman agrees with Mr. Hawkshaw in believing the 

 large trees upon the Bolton Railway, near Manchester, to be in their 

 native place and position, and to have been dicotyledonous. He 

 further mentions a similar case of at least forty trees, only three or 

 four feet apart, found in 1838, standing erect upon the upper surface 

 of a seam of coal fifteen inches thick in the railway tunnel at Clay 

 Cross, five miles south of Chesterfield ; these had no traces of large 

 roots, and tlieir exterior consisted of a thin film of coal, furrowed 

 and marked like a Sujilluriu reiiifortnis ?, the interior being occupied 

 by fine-grained sandstone. Mr. Bowman considers the trunks of 



