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Dr. Macculloch describes and figures a congeries of 

 tubuli contained in an oriental agate : similar substances 

 are found in the pebbles on the Yorkshire coast ; and in 

 one which I possess, the tubules are disposed in a con- 

 fusedly radiated form, giving more of the idea of a zoophyte 

 than of a vegetable substance. 



A knowledge of the vegetable fossils peculiar to the 

 different strata will, in all probability, open to us con- 

 siderable stores of instruction. We may thereby learn, not 

 only the nature of the several vegetable beings of the 

 earlier ages of this planet, but may ascertain the order in 

 which the several tribes were created : and, reckoning upon 

 the considerable advance which has been made in our know- 

 ledge of the structure of the earth, and upon the eagerness 

 with which inquiries respecting the organic remains ot 

 former periods are pursued, the attainment of such know- 

 ledge, it may be presumed, is not far distant. 



At present we know of no vegetable remains of earlier 

 existence than those which belong to the coal formation ; 

 and these appear to be chiefly derived from various grasses 

 and reeds, and plants of the cryptogamous and succulent 

 tribes, many of which are not known to exist on the surface 

 of the earth at present. From the latter of these the coal 

 itself appears to have chiefly proceeded. In the mountain 

 limestone above the coal, and in the different members of 

 this formation existing between this and the blue lyas, 

 vegetable remains appear to be of but rare occurrence ; so 

 that particulars of such as have been discovered in these 

 situations may furnish much useful information ; and espe- 

 cially with respect to those fossils which have hitherto been 

 supposed to have derived their origin from wood. 



It has been assumed that wood, or parts of trees, have 

 been found in coal and in the accompanying coal-measures, 

 but some confirmation of these accounts seems to be re- 

 quired. The description of these fossils has seldom been 



