488 GOAL— FOSSIL FORESTS. [Cn. XXIV. 



the deciduous cypress {Taxodium distkhumf abounds in the marshes 

 of Louisiana even to the edge of the sea. 



When the carboniferous forests sank below high-water mark, a 

 species of Spirorbis or Serpula (fig. 545) attached itself to the outside 

 of the stumps and stems of the erect trees, adhering occasionally even 

 to the interior of the bark — another proof that the process of envelop- 

 ment was very gradual These hollow upright trees, covered with 

 innumerable marine annelids, reminded me of a "cane-brake," as it is 

 commonly called, consisting of tall reeds of Arundinaria macrosperma, 

 which I saw in 1846, at the Balize, or extremity of the delta of the 

 Mississippi. Although these reeds are freshwater plants, they were 

 covered with barnacles, having been killed by an incursion of salt 

 water over an extent of many acres, where the sea had for a season 

 usurped a space previously gained from it by the river. Yet the dead 

 reeds, in spite of this change, remained standing in the soft mud, show- 

 ing how easily the Sigillarice, hollow as they were but supported by 

 strong roots, may have resisted an incursion of the sea. 



The. high tides of the Bay of Fundy, rising more than 60 feet, are 

 so destructive as to undermine and sweep away continually the whole 

 face of the cliffs, and thus a new crop of erect fossil trees is brought 

 into view every, three or four years. They are known to extend over 

 a space between two or three miles from north to south, and more 

 than twice that distance from east to west, being seen in the banks of 

 streams intersecting the coal-field. 



In Cape Breton, Mr. Richard Brown has observed in the Sydney 

 coal-field a total thickness of coal-measures, without including the 

 underlying millstone-grit, of 1843 feet, dipping at an angle of 80°. 

 He has published minute details of the whole series, showing at how 

 many different levels erect trees occur, consisting of Sigillarice, Le- 

 pidodendron, Catamites, and other genera. In one place eight erect 

 trunks, with roots and rootlets attached to them, were seen at the 

 same level, within a horizontal space 80 feet in length. Beds of coal 

 of various thickness are interstratified. Taking into account forty- 

 one clays, filled with roots of Stigmaria in their natural position, 

 and eighteen layers of upright trees at other levels, there is, on the 

 whole, clear evidence of at least fifty-nine fossil forests, ranged one 

 above the other, in this coal-field, in the above-mentioned thickness of 

 strata.* 



The fossil shells of Cape Breton and those of the Nova Scotia sec- 

 tion, consist of species of Uniomdce, or an allied extinct family. None 

 of them agree with any shells known in the marine carboniferous lime- 

 stones. In some strata the shells of an annelid allied to the genus 

 Spirorbis (see fig. 545) seem to indicate brackish water; but we ought 

 never to be surprised if, in pursuing the same stratum, we should come 

 either to a freshwater or a purely marine deposit ; for this will depend 



* Geo!. Quart. Journ., vol. ii. p. 393 ; and vol. vi. p. 116. 



