720 SHORT CONTRIBUTIONS TO VARIOUS WORKS, 



forms me that all the wood he found is coniferous." Gcol. 

 Trans., 2nd ser., vol. iv, p. 474 (1836). 



Mr. Charles Stokes in his " Notice respecting a piece of 

 Recent Wood partly petrified by Carbonate of Lime" 

 {Trans. Geol. Soc. of London, 2nd series, vol.v, p. 207, 1 840), 

 acknowledges assistance obtained from Mr. Brown, and in 

 a "Further Notice" appended to this paper (1. c, p. 213) 

 he says — 



" Since I communicated to the Geological Society the 

 preceding notice on the partly petrified wood from the 

 ancient Roman aqueduct of Eilsen, in the principality of 

 Lippe Buckeberg, Mr. Robert Brown has shown to me a 

 specimen from the same piece of wood, which was presented 

 to him at Tharand, in the month of October last, by M. 

 Cotta of that place, who discovered the wood in the aque- 

 duct, and remarked its peculiar condition. Mr. Brown 

 has pointed out to me, in the longitudinal section, that the 

 petrified portions, in his specimen, are about two inches in 

 length, and in the middle part, nearly a quarter of an inch 

 in diameter, and terminate in a point at each end. The 

 petrified portions are, in these instances, completely enclosed 

 within and surrounded by the unchanged wood. See pi. 

 xvi. fig. 3." 



"Mr. Brown has observed another remarkable circum- 

 stance in the condition of these petrified portions. The 

 change of the longitudinal fibres appears to be complete, 

 but the medullary rays, of which the ends are seen in this 

 section are still in their ligneous state, as shown in the mag- 

 nified engraving, pi. xvi, fig. 4." 



Dr. Fitton, in his paper " On the Strata below the 

 Chalk," says — 



" From the evidence afforded by thin transparent slices, 

 both of the transverse and longitudinal sections which have 

 been examined under the microscope by Mr. Brown, the 

 fossil trunks of Portland are found to possess the characters 

 uniformly belonging to coniferous wood ; but it must be 

 observed that these characters are not absolutely confined 



