1846.] BINNEY ON THE DUKINFIELD SIGILLARIA. S91 



in all probability, discoloured the deposit with the carbon liberated 

 by their decomposition. 



The fossil, as it now lies in the museum of the Manchester Geo- 

 logical Society, consists of a detached stem and three main roots. 

 The stem is unquestionably that of a Sigillaria, exhibiting all the 

 ribs, furrows and scars of that genus. It is about fifteen inches 

 high, four feet ten inches in circumference at its base, and four feet 

 one inch at the top. The diameter at the top measures one foot 

 five inches by one foot three inches. Down the side is a longitu- 

 dinal depression, like those so generally found on the stems of Si- 

 gillaria. The inside presents no trace of structure, being filled with 

 dark fire-clay. On the outside is a coating of bright coal one-third 

 of an inch in thickness, very much resembling that found on the *S'. 

 pachyderma. Prominent ribs project, and rather irregular furrows 

 of about an inch in breadth intervene. On removing the coal, the 

 decorticated part of the stem presents the usual fine longitudinal 

 striae, together with ribs of about an inch in breadth, parted by fur- 

 rows. On the surface of the inner ribs are markings, some of which 

 resembled the double impressions characteristic of Sigillaria reni- 

 formis*y and others a single impression resembling that of S. orga- 

 num. Some of the upper portions of the stem, which exhibited these 

 characters in a more marked degree than appear in the drawing, 

 were destroyed in removing the specimen. Owing to the circum- 

 stance of the fire-clay filling up and adhering to the furrows upon 

 the outside of the fossil, it is difficult to detach the former and exa- 

 mine the external markings without removing the whole of the coaly 

 envelope. In every respect this stem resembles the two St. Helens* 

 trees before alluded to, and also bears great resemblance to the 

 Dixon Fold treesf described by the late Mr. Bowman J. 



Although the stem is now separated from the roots, there is no 

 question but that it was connected with them. Independently of the 

 evidence of Mr. Dunn and the men who removed the fossil, it bears 

 sufficient proofs of its having been attached. 



In the present paper it is only intended to describe one main 

 root, namely that marked A in the drawing. At its commencement 

 it is covered with a smoothish coating of thin coal, which on being 

 removed shows a wrinkled surface (covered with iron pyrites), like 

 that seen upon the roots of recent aged trees. The breadth across this 

 main root, as it now lies on the floor, is three feet one inch. After 

 running nearly level for sixteen inches, it divides into two secondary 



* A specimen of Sigillaria in the Manchester Museum exhibits all the different 

 characters of S. catenulata, S. reniformis, S. organum and S.alteniaiis, on one stem. 

 Many of the present specific characters are probably to be attributed to the various 

 stages of the growth of the plant and the circumstances under which it has been 

 preserved. 



t The author of this paper accompanied Mr. Bowman, and showed that gentle- 

 man the Dixon Fold trees. As only parts of the main roots of these fossils were 

 exposed, there was no chance of seeing whether or not they possessed Stigmaria 

 roots. 



J ride Transactions of the Manchester Geological Society, vol. i. p. 112. . 



