090 MR. W. CARRUTHERS ON FOSSIL CYCADEAN STEMS 



This is a well-marked species. In the middle of the stem (fig. 8) there is the scar of a 

 j) dunel's which has been surrounded by a series of small scales, giving to the stem some- 

 what the appearance of the living West-Indian Microcycas calocoma, DC. The scar on 

 the opposite side (fig. 9) is evidently produced by the dichotomous division of the stem. 



Hugh Miller, in his 'Testimony of the Rocks ' (p. 476), has described several forms of 

 Cycadean foliage from the beds in which this species and Y. crassa were found; but 



there are no means of correlating any of them with these stems. 



III. Fittonia, gen. nov. 



I'nmk short obovate; woody axis slender, enlarging upwards; cortical layer large. Scales and bases of 

 thr petioles large, imbricated, at first reflexed, then ascending. 



The bases of the petioles are few in number in proportion to the scales, and occur 

 irregularly amongst lliem, though both organs are arranged in the same series. Neither 

 iVuit nor foliage has been found associated with this fossil; but from its striking aflinity 

 in those characters in which it can be compared with the South- African Encephalartos, 



V cannot hesitate in placing it with Yatesia, near that genus. 



I\ squamata, sp. nov. (Tab. LVI.) 



M ant ell 



Scales oblong, with an obtusely rounded apex; bases of the petioles contracted below the 



ane of articulation; cicatrix showing a continuous series of vascular bundles 

 parallel to the margin, except in the median line of the upper surface, where a large 

 loop penetrates into and beyond the centre of the petiole. The phyllotaxy is repre- 



ted by the fraction - 2 ^ 



Mantell, but believed bv Mr 



characte 



to be from the Wealden at Brook, Capt. Ibbetson. [Jermyn- Street Museum.] 



The only specimen hitherto found of this fossil is a singularly perfect cast of the stem. 

 The cavity originally occupied by it has been filled with the amorphous substance of the 

 r< k in which it was buried; and the cast thus made is so perfect that the external 

 markings of the scales and petioles and the impressions of the vascular bundles are exhi- 

 bited ; while each scale, though closely adpressed to its neighbours, is yet free from them 

 even at its base. The original organism must have been incrusted with a crystallized 

 mmeral like ealeite, which, after the decay of the vegetable tissues, received and moulded 

 the amorphous matter of the cast. This mineral has been redissolved and carried away, 



io that wh remains is a remarkable facsimile of the original, as far as the outer surface 

 w concern< 1. D * 



IV. Crossozamia, Pomel. 



' romozamia, Pomel, Amtlichor lfon^* \r 



ifLir ' *ao encht * XXV - ;ersara - d - Gesellsch. deutsch. Nat. und Aerzte in Aachen, 



1BV7, p. 342. 



Trunk oblong-el li psoid, coveted «•;+>, +1 t . . -, . , 



«i»y.J. ,. ' !" h " 1C short imbricated persistent bases of 



petiol 



Leavef 



oblong pinnae, contracted at the base. Fruits in a 



* 



