398 Linnarsson — On the Eophyton Sandstone. 



plants and animals which lived in, or were swept into, the water 

 where it was deposited, so that the most delicate parts can often be 

 distinguished with accuracy. The knowledge, however, to be gained 

 from the materials hitherto obtained is far from being satisfactory, 

 and the interpretations must often be uncertain. Still I have 

 thought it advisable not to delay publishing my observations, as 

 every contribution that may throw some light on so remote a period, 

 can hardly fail to be acceptable. 



Arenicolites spiralis, Torell. — The worm described under this name 

 by Professor Torell, at the last meeting of the Scandinavian 

 Naturalists in Christiana, is one of the commonest fossils, especially 

 in the shale. The spirally curled form, which has given rise to the 

 name, is easily recognized and is very constant. Its relations to the 

 numerous burrows which are found along with it are difficult to 

 decide. The thickness of the burrows — almost the only character to 

 be relied upon — is nearly the same as in the spiral form. 



Lingula (?) monilifera, n., Plate XL, Figs. 1 and 2. — Of this 

 species, with the exception of a nearly complete and very distinct 

 cast of the outside of the one valve, PL XL Figs. 1 and 2, I found 

 only a few fragments. The inner parts are not visible in any 

 specimen, and the generic determination therefore cannot be settled ; 

 but by the size and the general form, and, above all, by the sculpture 

 of the shell the species is easily distinguished from all the Brachio- 

 pods with which I am acquainted. In the cast the apex itself is not 

 visible, and one cannot therefore decide whether it is formed by the 

 dorsal or ventral valve. The shell would seem to have been oval 

 and very much depressed, except near the apex, where the sides are 

 more sloping. The length and breadth are about 22 millimetres. 

 The shell is ornamented with extremely close and fine longitudinal, 

 slightly diverging, raised and beaded liues, of which about five may 

 be counted within the breadth of a millimetre. The lines of growth 

 are apparent only near the front margin. Judging from the thick- 

 ness of the detached slabs in which this species was found, it would 

 seem to have made its appearance in the undermost layer of the 

 Eophyton sandstone, and may thus be considered the earliest Mol- 

 lusk hitherto known. 



In a slab of schistose sandstone I found a Brachiopod which, in 

 the sculj)ture of the shell, bears some resemblance to the preceding 

 species, but in other respects, as far as one can judge from the 

 indistinct fragments, is widely different. On the surface of the slab 

 lie two shells, of which the margins only are preserved, and even 

 these but incompletely, the middle part being totally effaced. The 

 contour seems to have been almost circular with a diameter of about 

 50 millimetres. The shell, like that of Lingula monilifera, bears 

 raised, beaded lines, but these lines here seem to be directed towards 

 the centre of the shell ; near the circumference their distance from 

 each other is somewhat less than a millimetre. From the general 

 form of the shell this species may most likely be supposed to be a 

 Discina or Trematis. 



