DX tHE FAUNA AND FLORA OF THE TRIAS OF TflE BRITISH ISLE^. 273 



Storotou ; ^ it is accompauied on one side by two Clieirotheroid prints, 

 and numerous other prints are on the stone (the whole in relief). It is 

 about 90 cm. long by 4 to 5 cm. broad ; the ribs are close together, and 

 in the more perfect portion of the fossil are each covered by a row of 

 scutes or scales. The other end of the fossil seems rather narrower and 

 to have been crushed and the rods separated as in the Warwick fossil. 



It has been suggested that this represents the tail of some large 

 reptile ; the relative position of the footprints does not favour this, and 

 it would seem unwise to give any opinion here as to the nature of this 

 or the Warwick fossil. 



Markings of uncertain origin simidating Organic Forms, 



Plant Forms. — The commonest of these are in the form of branching 

 stems bordered by small leaflets and often marked with longitudinal 

 grooves and ridges. 



The whole of these features are seldom combined on one specimen, 

 but they are so associated that there is little doubt of their being all due 

 to one cause. 



A good example of a branching form fringed with leaflets is on .1 

 slab. No. 7, in the Bootle Museum (Plate VI., fig. 1). Another block of 

 stone in an old quarry at Runcorn has what resembles a root-stem, about 

 G inches broad and se\ eral feet in length, fringed along one border with 

 small rootlets at about right angles to its axis. 



- Both these are in relief, and a little examination shows the probability 

 of their being natural casts of stream courses of shallow water, such as 

 may be seen in formation wherever a broad shallow sheet of water is 

 passing over a very gently sloping surface of fine material. The forma- 

 tion of the grooves and ridges has also been noticed and of markings 

 similar to leaf scars ; in the latter case, however, the scars were of 

 organic origin, being due to some animal, probably a crustacean, taking 

 advantage of the rather deeper water to follow the retreating tide and 

 with its appendages making regular markings along the narrow channel. 

 In the natural cast formed on the under surface of a succeeding deposit 

 the stream course would be represented by a ridge with what might be 

 easily mistaken for scars or .scales upon it. 



The pseudo-leaflets ai-e the beginning of channels of small tributary 

 streamlets, and a combination of ridges and flutings on the main course 

 with the border of tributary streamlets has been observed on more than 

 one occasion. 



The instances given have been drawn from the seashore between 

 tide-marks of which we know nothing in the Trias, but exactly the 

 same action would take place where a .shallow current of fre.sh water 

 flowed over a similar surface ; in fact it has been seen to take place 

 under fresh-water conditions such as are perfectly compatible with what 

 we know of the Lower Keuper. 



Other branching forms are free from leaflets or ridges, but have a 

 roughened surface and the semblance of knots and stumps of broken off" 

 branches, simulating portions of our recent trees. A careful examination 

 shows that they are not really plant remains, although their origin is 

 very uncertain. 



' For figure of this, see Morton, Geology of Cmintry arovitd Liverpool, Appendix, 

 p. 300, Plate XXII. 



1908. T 



