18 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 2, 



rence of Stigmaria in a seam of coal, not compressed and bitnmen- 

 ized, but exhibiting its vascular system perfectly preserved in iron 

 pyrites, and that portion of the plant which was formerly filled mth 

 cellular tissue converted into clay ironstone fall of small spores, re- 

 sembling the spores of the Lepidodendron, as described by Dr. Joseph 

 Hooker in his valuable communication on Lepidodendron lately pub- 

 lished in vol. ii. of the ' Memoirs of the Geological Survey of Great 

 Britain.' 



The seam of coal known by the name of the King coal at Wigan is 

 a compound one, consisting of several distinct beds parted by depo- 

 sits of clay. It there lies immediately under the celebrated bed of 

 Cannel, so well known from its value in the manufacture of gas. Now, 

 although the Cannel is very free from pyrites, the King coal is not so, 

 but contains in the midst of it many large lumps, well known among 

 colliers by the name of "brasses." These have to be picked out 

 of the coal before it is sent to market. My observations on these 

 "brasses" have chiefly been made at the pits of the Ince Hall Coal 

 and Cannel Company near Wigan, in whose works great attention is 

 paid to picking them out of the King coal. Having heard that they 

 did not decompose so freely as those found in other mines, I was in- 

 duced to examine them closely, so as to ascertain the cause of this 

 diiference, and I then found that after breaking away the iron pyrites 

 with which they were surrounded, I nearly always came to a Stigmaria 

 very much compressed, composed of clay ironstone. 



In the course of my researches I met with two brasses containing 

 Stigmarise, round and apparently in the original form, without having 

 been subjected to much pressure. Observing a small axis of vascu- 

 lar tissue highly pyritized in one of them, I broke it in pieces and 

 took part of it home with me. On more careful examination of this 

 specimen (fig. 2) some time afterwards, I found the ironstone sur- 

 rounding the vascular tissue and occupying the space betwixt the 

 latter and the outside of the specimen, full of little bodies about the 

 size of a common pin's head. At first I did not know the nature 

 of these, except that they appeared to be like some kind of seeds ; 

 but on carefully comparing them with the spores of Lepidostrobi 

 figured in plates 5, 6, 8 and ] 0, in part 2, vol. ii. of the ' Memoirs 

 of the Geological Survey of Great Britain,' I became acquainted with 

 their true nature, and from their resemblance I am now led to believe 

 them to be the spores of Lej)idostrobus ornatus. 



Good round specimens of Stigmaria are seldom met with in coal- 

 measures in comparison to those found flattened. Wherever I have 

 met with the former in situ, I have found them considerably inclined 

 to the original planes of deposition of the strata, seldom less thau at 

 an angle of 15° to 20°; in fact, striking down into the soil in which 

 they formerly grew, and not running horizontally in it. This cir- 

 cumstance is easily explained when we consider how the interior sub- 

 stance of the root has been removed. In the first-named specimens 

 the interior would be decomposed and all removed \vith the excep- 

 tion of the vascular tissue, and in some cases that portion of the plant 

 as well, without much pressure being exerted against the bark com- 



