Mr. Hawkshaw on certain Fossil Trees. 541 



His third brother, Captain Patrick Gerard, is remarkable as the 

 author of a Meteorological Journal, kept in 1819-20 at Kotgerh, 

 Subathu, and the intermediate places in the Himalaya mountains, 

 and recording hourly observations during nearly two years*. 



Feb. 26.- A paper was first read, entitled " Further observations 

 on the fossil trees found on the Manchester and Bolton railway ;" 

 by John Hawkshaw, Esq., F.G.S. 



Since Mr. Hawkshaw's former communication^ , another fossil 

 tree has been found on the opposite side of the railway. It is about 

 three feet in height, and three feet in circumference, and stands on 

 the same thin stratum of coal as those first discovered, and perpen- 

 dicularly to the surface of the bed. Mr. Hawkshaw is, therefore, 

 strengthened in his belief, that the trees grew in the position in 

 which they are found. 



After this notice of the recent discovery, he proceeds to describe 

 the effects produced in hot and moist climates on felled or pro- 

 strated solid dicotyledonous trees. The tropical forests with which 

 he is acquainted from personal examination, are situated in Vene- 

 zuela on the shore of the Carribean sea, and between the 8th and 

 10th degrees of north latitude, and the 65th and 70th of west longi- 

 tude. In these forests a few months are sufficient to destroy the 

 interior of the largest tree, little more being left than an outer shell, 

 consisting chiefly of the bark. Mr. Hawkshaw noticed this pecu- 

 liarity more frequently in dicotyledonous trees, having a proper bark, 

 than in monocotyledonous vegetation, excluding necessarily those 

 always hollow ; and he does not remember to have seen a single in- 

 stance of a palm similarly acted upon. Sometimes the portion of the 

 dicotyledonous tree remaining on the ground, presented very much 

 the appearance of the founder's mould, when the pattern has been 

 withdrawn from the sand, and before the metal has been run in ; 

 and by this kind of decay, a cavity is formed from which a fac simile 

 of the tree might be cast. In other cases, prostrated trunks having 

 the appearance of being solid, have yielded to the pressure of his 

 feet, and proved to be only hollow tubes. Dangerous accidents have 

 also occurred from temporary bridges constructed of dicotyledonous 

 trees having given way beneath the passenger, though there was 

 no outward indication of decay. The bark of these trees had 

 changed but little, though nothing of the interior remained but 

 dust, and a few remnants which crumbled beneath the slightest 

 touch. 



The low and flat tracts in which this destructive operation goes 

 on most rapidly, are those in which, from the deep rich soil and 

 excessive moisture, all below the tall forest trees and larger palms 

 is occupied by canes, bamboos, and minor palms. Such tracts would 

 be most easily submerged ; and in Mr. Hawkshaw's opinion they 



* See Journal of Asiatic Society of Bengal, vol. ii. p. 615. 

 t L. 8: E. Phil. Mag. vol. xv. p. 539. 



