32 



FOSSIL PLANTS. 



ele(jans. In tliis locality no seam of coal is found associated with the fossil plants ; and a 

 small bed, a few inches in thickness, occurs about fifty feet below them. ]\Iy observations 

 on this part of the subject have been made chiefly whilst searching for specimens affording 

 evidence of structure, and not over any great thickness of the strata, and therefore further 

 attention should be devoted to it in order to determine whether or no this condition 

 occurs throughout the Coal-measures where SicjiUaria and Calcmites zxq found associated. 

 Many years since, when examining the thick seams of coal which are found in the middle 

 division of the Lancashire Coal-field, I noticed the occurrence of large-ribbed and furrowed 

 Sicjillaria;, and I stated in a paper on the Origin of Coal, read before the British Associa- 

 tion in 1848, and printed in the Report of the Association's first Meeting at Manchester, 

 that where such large specimens occurred not only were the seams of coal thick, but they 

 were opc n-burning coals, leaving a white ash. Many years' observation on this subject 

 has confirmed my first impression. Of course it is not contended that ribbed and fur- 

 rowed SifjiUaricB are not to be met with from the lowest to the highest Carboniferous 

 strata and their roots {Stirjinaria) found in coal-floors throughout, but it is merely in- 

 tended to state that during the formation of the thick seams of the Middle Coal-measures 

 greater crops of these trees prevailed, and produced more mineral ingredients to form 

 the white ash, as well as the thicker seams of coal. 



Note. — The Author thinks it necessary to state that the Specimeus described in this Memoir were 

 discovered twelve years ago, and some of them immediately " mounted" and sent to Dr. Hooker, who had 

 consented to join in publishing a description of them. With the specimens was written, November 29th, 

 1854, "You will be delighted to find such beautiful sections of VolTcmannia in the large slide I now send. 

 "They are well worth the trouble and expense of the slide. These, doubtless, belong to Calamitesy 

 Soon afterwards the Author had the opportunity of pointing out under the microscope the spore-like bodies 

 in the sporangia to Dr. Hooker. 



At that time the whole of the structure of Calamodendron had been made out, with the exception of the 

 centre of the stem and the connection of Vollcmannia with it. The valuable paper of Dr. Ludwig on the 

 Calamite fruit, and Dr. Goeppert's on Aphjllostachjs, afforded the writer much information ; and he 

 obtained the evidence of Volkmannia being the fruit of Calamodendron from the similarity of the central 

 axes. About two years since he cleared up both the above points to his satisfaction, but Dr. Hooker had 

 returned the specimens, and was prevented by press of business from joining him in publishing. The author 

 then commenced the present IMemoir unaided, and the plates were put in the engraver's hand. Owing to 

 circumstances over which he had no control, the publication of the Memoir has been delayed longer than 

 he expected. 



In the mean time, in Memoirs referred to at page 10, Mr. Carruthers has described the Calamite and 

 its fruit mainly from some of the Author's specimens above mentioned, which Dr. Hooker had lent him with 

 others. The published observations are, of course, independent of each other ; and, whatever may be their 

 relative value, the Author wishes the dates and history of the specimens and investigations to be clearly 

 stated.— E. W. 13.— January 30th, 1SG8. 



