near Coldstream, upon the Banks of the River Tweed. 21 



cayed portions of the plants. It is difficult also to ascertain 

 their height, as by the above description they must have been 

 liable to be fractured and broken. The highest stern I have 

 been able to obtain is not much more than four feet, and the 

 lower part of it is about six feet in circumference. No two 

 stems possess the woody appearances alike, some retaining it 

 in the centre of the stem, others having such appearances dis- 

 tributed in various parts of the stem. Owing to the immense 

 superincumbent mass, this part of the research is rendered both 

 tedious and expensive. 



By these examinations it is equally evident, that this un- 

 known extent of early vegetation seems to have been called 

 into existence during the formation of the carboniferous rocks, 

 or in the first period of Brongniart's division. Now, accord- 

 ing to that gentleman's opinion, out of six classes (with the ex- 

 ception of the marine and a few uncertain plants) only two 

 existed at that period ; namely, the vascular cryptogamic 

 plants, comprehending the Filices, Equisetacece, Lycopodice, 

 and the monocotyledons, containing a small number of plants 

 which appear to resemble the palms and arborescent Liiiaceae; 

 in fact, Mr. A. Brongniart states, that out of 260 species dis- 

 covered in this terrain, 220 belong to the vascular crypto- 

 gamic group. 



The existence, therefore, of so extensive a deposit of dico- 

 tyledonous plants at this early period of the earth's vegetation 

 appears to demand the attention of the naturalist ; and it does 

 indeed go far to prove the necessity of more minute examina- 

 tion amongst the dark and pathless repositories of an ante- 

 diluvian world. 



The following is the analysis of one of these plants : 



Twenty grains of Tweed fossil yields 



Carbonate of lime 16*65 



Carbon 3*30 



Iron (peroxide) 0'68 



Loss 0-37 



20*00 



The similarity of the above analysis to that of the fossil 

 stem found in Craigleith quarry, in the year 1826, is very re- 

 markable*. From recent minute examination and compari- 

 sons, there is reason to believe that plant to be a member of 

 the same class as the above-described ancient fossils. 



Edinburgh, May 10, 1830. 



* See Phil. Mag. and Annals, N.S. vol. vii. p. 29. — Edit. 



IV. On 



