IN THE STRATA OF THE CARBONIFEROUS SERIES. 27 



lary rays. In these two circumstances, the texture is alike in the fossil 

 plants here represented, and the recent plants ; but in the former, there is 

 no appearance of the concentric lines by which the woody layers of the lat- 

 ter are separated. 



The portions represented are chiefly calcareous ; but in some fragments 

 in which the cavities have been filled with siliceous matter, there is some 

 appearance of these concentric lines. Whether the want of them in the 

 calcareous portion be owing to a more advanced state of decomposition, 

 or to any other cause, must be merely conjectural ; and it is not my wish 

 to force the conclusion. In all, however, the resemblance to the Coniferae 

 is so striking, that unless the longitudinal sections present decided diffe- 

 rences, one could hardly hesitate to refer the fossil in question to the Gym- 

 nospermous Phanerogamic class. 



It is seldom that the central part of these stems is found entire ; but in 

 one specimen I have succeeded in detecting it of its natural form. It pre- 

 sents the appearance of a distinct medullary cylinder about two inches in 

 diameter. Externally of the pith is a broad zone of woody tissue, similar 

 to that of the Coniferae, but with the medullary rays more or less flexuous, 

 which, however, may be owing to distortion produced by various causes. 



No recent coniferous plant has a pith approaching in any degree to this 

 magnitude ; but whether this circumstance ought to induce us to eject the 

 Lennel Braes fossil from the class in question, seems a little doubtful. 



In this fine specimen, I cannot discover any decided traces of vessels, 

 although some of the apertures differ in form from the rest. 



The examination of the longitudinal sections may be deferred, owing 

 to the arrangement of the plates, until we have examined the structure of 

 some analogous species. 



FOSSIL TREES FOUND IN CRAIGLEITH QUARRY, NEAR EDINBURGH. 



In the year 1826, an enormous trunk was exposed in the lowest bed of 

 Craigleith Quarry, near Edinburgh, at a depth of upwards of 136 feet. The 



