[MATTHEW] A REVIEW OF THE LITTLE RIVER GROUP 



111 



The following table gives the dimensions of several examples of 

 tliis mutation: — 



Horizon and 

 Locality 



FernLedges, Bed? 



N.H.S. 



Duck Cove, 



Dadoxylon Sand 



C. Cistii, mut 



" PI. III., fig, 2. 

 Coirn,as "C.transitionis"' 



fC. Cistii, mut, short \ 

 I nodes, PI. III., fig. L J 



I C. Cistii, mut, young ) 

 L shoot f 



Length 

 \ot stem 

 in mm. 



120 



130 

 90 

 70 



140 

 100 



Width 

 of stem 

 in mm. 



45 

 30 

 35 

 37 



65 

 11 



Length 

 of inter- 

 nodes 



85 

 70 



47 



37 



Number 

 of nodes 

 in 1 cm. 



10-11 

 12 

 10 

 9 



10 

 10 



For comparison with this ancient mutation of C. Cistii, one may; 

 present the characters of typical examples of this species from the 

 coal measures of Joggins, X.S., also having long internodes and narrow 

 ribs. They have the following characters : — The epidermis is thin and 

 in this flattened stem the ribs show quite distinctly, though less 

 markedly than in decorticated examples. The ribs are alternate, the 

 furrows shallow, and the leaf scars inconspicuous; these scars are 

 small, oval and placed on the sides of the ribs or between the ribs, 

 and thus are likely to be overlooked; thug a scar frequently comes 

 opposite the rib of the next node. A flattened stem 53 mm. wide 

 has the following proportions in its parts : — 



Length of internodes in mm. . 

 Number of ribs to 1 centimetre. 



70 

 9à 



The epidermis in this species is thin and is more obscurely and 

 more irregularly striate than in C. Suckovii, and its surface is less 

 brilliant; there are about twelve of these minute striae to a rib, and 

 where they approach the leaf-scars their course does not change much, 

 nor do they show the strong wrinkles, concentric to the leaf scar, seen 

 on the surface of the stems of C. Sucl-ovii. C. Cistii is striated on 

 the surface of the mould, but less distinctly than on the outer surface 

 of the bark. 



A flattened stem from the same bed of shale (over the Main seam 

 a I Joggins mine Coal jMoasures) has the following dimensions:" 



Length of internodes in mm... 

 Number of ribs to 1 centimetre. 



33 



10 



32 

 9 



30 

 8 



30 

 9 



30 



