388 



THE GEOLOGIST. 



north-east to south-south-west, these stony masses appear to the 

 artist hks insulated Cyclopean ruins jutting out upon a lofty moor- 

 land ridge, at heights varying from fifteen hundred to sixteen hundred 

 feet above the sea. On reaching the summit of this barren height, 

 the traveller sees below him, to the west, a rapid slope, and beyond it 

 a picturesque hilly tract, the strata of which are laden with Lower 

 Silurian fossils, and diversified by a variety of rocks of igneous origin. 

 In short he has then within his view the original type of formations 

 which, raised to greater altitudes, and effected by a slaty cleavage, 

 occupy large mountainous tracts in Wales." 



In the outstanding bosses of the siliceous ^^^^ ^^iii 

 sandstone of the Stiper-stones, fragments p 

 of Lingul89 have been met with, which, as ; } 



well as their relative position with respect to 

 the underlying and the superimposed beds, 

 identify these strata with the true Lingula- 

 flags of North Wales. 



In the Stiper-stone rocks Mr. Salter has 

 also found annelide-tubes, resembling, if not 

 indeed identical with, ScoUtJms linearis, 

 described by Prof. J. Hall, from the Potsdam 

 sandstone ; and with waving undulations and 

 ripple-marks in the flag-like beds ramose 

 and twisted forms are found, amongst which 

 casts of a so-called seaweed, the Cruziana or 

 Bilobites, are said to occur. The scolithi 

 are better known in the North American rocks 

 than in our own ; we have therefore chosen 

 our figure from a foreign specimen. 



The broken and contorted condition of the 

 Lingula met with in the Stiper-stone strata 

 renders it difficult to determine the species ; 

 but there appears reason to doubt its being Lign. 5.-Scolithus lineakis. 

 the Lingtda Davisii of the Welsh strata, with ^^^^^ ^P^^^-^-]- 

 which, however, it is well known some other forms, as yet un- 

 dcscribed, occur; and with some of these it may be hereafter 

 identified. 



