IIO MELLARD READE : THE NEW RED SANDSTONE. 



stones, none of which are to be met with in the great mass of the 

 l riassic Sandstones. On the other hand, river action, as suggested 

 by Prof. Bonney, presents difficulties, owing to the wide expansion 

 of the deposits and the absence of any indications in the rocks of 

 the former existence of definite river channels. When we consider 

 that the Bunter Sandstones at Bootle proved to be over 1,200 ft. 

 thick, and presented only the usual variations in the beds passed 

 through by the boring tool, it also becomes evident that the lower 

 beds, if fluviatile, could not have been laid down in water of that 

 depth. The difficulty might be met by assuming a synclinal sinking 

 to be proceeding pari passu with the accretion of the beds in the 

 river valley; but what evidence is there of such a movement having 

 taken place? Again, the shape and extension of the area of 

 deposit now existing, which is only a remnant of what has been, 

 does not lend itself to this explanation. The Triassic Sandstones 

 envelope, or rather surround, the Pennine chain, and are to be found 

 also in the Vale of Clwyd, flanked on either side by Silurian hills. 

 They exist even in Ireland, and doubtless are in considerable 

 development in the basin of the Irish Sea. If the deposit had taken 

 place in a large lake, we should surely find greater variations and 

 replacements of beds than what are met with in the rocks. The 

 shallow deposits might be sand ; the deeper, marl ; but this is not 

 the arrangement met with, the marls of the Trias occupying the 

 summit of the series, the sandstones the base. The subject is sur- 

 rounded with difficulties ; there are no fossils to tell us whether the 

 waters at first were fresh or saline, nor can we point with any certainty 

 to the locality from which the quartzite pebbles have been derived. 

 The uniformity of the deposits, their extent, and the prevalence of 

 current-bedding, incline me to think that the Bunter Sandstones 

 have been laid down in a tidal sea ; in which case it must have been 

 connected with the open ocean, otherwise a tidal wave of sufficient 

 magnitude to create such wide-spread current-bedding could not have 

 been originated. On the coming-in of the Keuper a different set of 

 conditions obtain ; we have the well-known reptilian foot-prints in 

 the Lower Keuper Sandstones at Storeton and Lymm, telling 

 eloquently, with ripple marks, of shelving shores ; and these are 

 succeeded by a vast thickness of marls, also full of ripple-marks, 

 pseudomorphs of chloride of sodium, and finally beds of salt, 

 together with gypseous deposits. Doubtless, all these latter were laid 

 down in a lake or lakes. The presence of ferric oxide as a coating 

 to the grains of the sandstones has been considered evidence of their 

 fresh-water origin ; but it would appear from microscopic examina- 

 tion that the infiltration of this mineral has been posterior to the 



Naturalist, 



