94 



FOSSIL PLANTS. 



in which they are now found, or intruding rootlets of Stipnaria, their structure is no 

 doubt the same, and therefore we cannot absolutely decide the question ; but still it 

 appears to me that it is under the circumstances more reasonable to believe that they are 

 vascular bundles belonging to the body in which they are now found than similar organs 

 belonging to another plant. 



Fig. 6 (magnified 10 diameters) represents the woody axis, exhibiting structure 

 throughout, except in the unshaded portion in the figure, which is composed of crystalline 

 carbonate of lime, and which appears as if the medulla and woody cylinder had been dis- 

 rupted prior to the mineralization of the specimen, and would no doubt have been taken 

 as such did it not occur immediately before the dichotomizing of the root, and had not 

 specimens Nos. 32 and 33, as well as others in our cabinet, been brought to our notice. 



§ 5. Specimen No. 38 {Halonia repdaris) . Plate XVIIL 



This is another specimen of Halonia regularis. It was found by Mr. Higson, one of 

 Her Majesty's Inspectors of Coal-mines, and presented by him to the Manchester Museum. 

 For permission to figure it I am indebted to the kindness of the Commissioners of that 

 Institution. It is from the sandstone quarry of Peel, near Bolton-le-Moors, a locality 

 noted for the beautiful specimens of Coal Plants which have been found there. The 

 specimen shows no traces of internal structure, being simply a cast in a very fine-grained 

 sandstone, with its thick epidermis converted into coal. The tubercles project from the 

 stem about a quarter of an inch, and show how the spaces intervening between them had 

 been once covered by a similar thick mass of coal. Where the outside matrix of the coal 

 has been removed, the tubercles are seen covered by the coaly envelope, and only exposing 

 a depressed areola, like that shown in specimen No. 36, and the areolse so generally 

 seen on the outside of Stigmaria. In fact, when seen with its epidermis preserved, 

 it is a Stigmaria in outside appearance ; but without that part of the plant it is a Halonia 

 regularis. The exterior of the root, when deprived of its coaly envelope, is seen to be 

 covered with numerous papillse as well as the tubercles previously described. The length 

 of the fossil is 9^ inches, and its diameter 2 inches, and its form is nearly as cylindrical 

 as it originally grew, apparently having been subjected to little or no pressure. 



In specimen No. 34 the structure of Halonia regularis is beautifully shown, but 

 nothing of its external character. In No. 35 the internal structure and the tubercles 

 are given. In specimen No. 36 are exhibited the internal structure and the areolae. 

 In specimen No. 37 we have evidence of the dichotomization of the plant, and 

 its internal structure. Lastly, in No. 38, although it affords no evidence of internal 

 structure, there is a most perfect representation of all the external characters of the plant, 

 without its being compressed, and before it was mineralized. The conditions in which 

 these fossils often occur clearly show that when deprived of its epidermis the plant has 



