500 G. II. Morton — The Bunter and Keuper near Liverpool. 



grains and much resembles that of the Upper Soft Sandstone, though 

 usually much harder. There are, however, other beds, about the 

 middle of the Keuper Sandstone, remarkable for the large proportion 

 of kaolin they contain and the occurrence of crystallized grains. 



Although there is a difference between the quartz grains and the 

 relative proportion of kaolin associated with them in the sandstones 

 described, the chief distinction is in consequence of chemical changes 

 that have altered the sandstones since their deposition. 



The original felspar grains have been usually decomposed and the 

 silica so liberated deposited in optical and crystalline continuity on 

 the grains of quartz, while the percolation of water containing ferric- 

 oxide produced the various shades of red and yellow, and both the 

 silica and the iron form the cementing material with which the 

 grains are united. The great diversity in the colour and the varie- 

 gated appearance frequently seen, particularly about the base of 

 the Keuper, and the variation in the tenacity with which the grains 

 are held together in the Triassic Sandstones generally are interesting 

 subjects for investigation and often very difficult to explain. 1 



Pebbles in the Trias. 



The only pebbles that occur in the Bunter formation in the 

 country around Liverpool are found in the Lower Pebble-beds, and 

 considering the great thickness and the large area over which the 

 subdivision occurs, the variety is by no means remarkable and very 

 much alike in different localities. Most of the pebbles are less than 

 an inch across and very few reach the diameter of six inches. They 

 consist principally of white vein quartz, quartzite, and a few other 

 rocks and minerals. Nearly all are of a round or oval form, per- 

 fectly smooth and must have come from a great distance, and most 

 probably from the Cambrian and Silurian rocks of Central England 

 or Scotland. Next in frequency, though relatively few, are rough 

 pebbles and angular fragments of coarse felspathic grit, sandstone, 

 and chert, resembling beds in the Cefn-y-Fedw Sandstone, Millstone 

 Grit, and Coal-measures within twenty miles from Liverpool. They 

 could not have travelled far, and may have been derived from strata 

 at a less distance. Although it is assumed that the Coal-measures to 

 the east and north-east were covered by the Trias, it is certain that 

 they had been denuded about Parbold, Knowsley and much of Flint- 

 shire, before the latter formation was deposited on the Millstone Grit. 



At Middle Island and Hilbre Point, near Hoylake, there are beds 

 of breccia containing angular fragments of vein quartz, grit, and 

 sandstone, associated with strata containing scattered pebbles of the 

 quartzite characteristic of the Lower Pebble-beds. Similar brecciated 

 beds occur at Little Mollington, near Chester, but the fragments are 

 smaller than those at Hilbre. At Cuckoo Hill, near Hope in Flint- 

 shire, the sandstones and shales of the Millstone Grit are well 

 exposed with the Lower Soft Sandstone resting against them, and 

 the lowest beds of the latter form a breccia several feet thick of 

 angular fragments from the underlying strata. 



1 " Iron as a Colouring Matter of Rocks," by A. Norman Tate, F.C.S., Proc. 

 Liverpool Geol. Soc. vol. v. p. 284. 



