ON THE FAUNA AND FLORA OF THE TRIAS OF THE BRITISH ISLES. 271 



shore. The beaded markings that are often seen in Gasteropod tracks 

 would hardly be visible on these small tracks, and would certainly not be 

 preserved in the sandstone cast.' Small cylindrical projections are often 

 found in the underside of the beds of sandstone, which may possibly be 

 casts of worm-burrows, but no connection has been found between them 

 and the tracks above described. 



In the underlying clay there are sometimes found horizontal lines of 

 small cylinders of sandstone about 3 mm. thick and of varying length, 

 mostly from 2 to 3 cm., and looking like strings of elongated beads. 

 These appear to be casts of horizontal burrows. As they are not 

 attached in any way to the overlying bed of sandstone they are usually 

 lost as the clay wears away. No connection has been seen between these 

 and the vertical projections mentioned above, nor with the horizontal 

 burrows sometimes seen in the overlying bed of sandstone. 



On the upper surface of the sandstone in two instances (one at 

 Storeton, another at Frodsham) are small horizontal tunnels, the roof 

 forming a ridge on the surface, but it is often broken in, leaving the 

 lower part of the tunnel as a groove. In accounting for some similar 

 markings in a bed of fine-grained sandstone in the Carboniferous Lime- 

 stone, Mr. Albany Hancock has described the superficial burrows of a 

 small amphipod,^ which was identified as Kroyera arenaria. Both the 

 fossil and the recent burrows bear a great resemblance to those in our 

 Keuper Sandstone. 



We occasionally find on the upper surface of the beds of sandstone 

 small heaps of rod-like bodies each about 5 ram. broad and from 

 2 to 10 cm. long, which look like worm castings ; they are, however, 

 nearly straight, and not bent and twisted like the castings of both land 

 and marine worms as usually seen ; but it should be noted that where 

 such castings are ejected under shallow water they are more or less 

 straight, and do not form the convolutions usually found in worm 

 castings. 



No connection has been clearly traced between the castings and any 

 burrows. 



We have no help from fossil remains in this investigation. The 

 remains of the worms themselves we could hardly expect to be pre- 

 served ; and, on the other hand, the absence of any remains of the hard 

 parts of amphipoda or any other crustaceans in the Keuper sandstones 

 is, we know, no proof of their non-existence. 



At present no opportunity of comparing the track of the only 

 invertebrate whose remains are present — Estheria — with the fossil 

 markings has presented itself. 



Tracks apparently formed by the appendages of some invertebrate 

 have been found on the upper surface of a bed of yellowish, soft, fine- 

 grained sandstone at Storeton. The track consists of two irregular but 

 approximately parallel rows, about 1 cm. apart, of small crescentic trans- 

 verse pits alternating with slight ridges apparently connected with the 

 convex margin of the pits, as if caused by the backward pressure of a 

 foot. The breadth across the crescents varies from 1 -5 to 2 mm. The 



' Nathorst, op. cit, plate vii. fig. I, ' Tracks of Montaouta biiientata.' For Fossil 

 Track see Trias Committee's Report, 1904, plate viii. 



" ' Remarks on Certain Vermiform Fossils found in the Mountain Limestone 

 Districts of the North of England,' by Albany Hancock. Ann. and Mag. Nat. Hist^ 

 vol. ii. 3rd Series, 1858, p. 443. 



