138 Notices and Extracts from the Minutes of the Geological Society. 



Besides the narrow defile through which the Birmingham road passes, when 

 the rock dips to the south-west, I examined the rock at 5 or 6 other places, 

 and found it sometimes dipping at a high angle in an opposite direction, and 

 sometimes nearly horizontal. 



4. — Notice respecting the Pebbles in the Bed of Clay which covers the New 

 Red Sandstones in the S. W. of Lancashire. By Dr. Bostock. [Read 

 March 31st, and June 6th, 1823.] 



The extensive deposit of new red sandstone, which occupies nearly the whole 

 of the county of Chester and a part of that of Lancaster, at the S.W. angle 

 of the latter county is for the most part covered by a mass of sandy clay. The 

 colour of the clay is nearly that of the rock on which it rests ; its different 

 parts differ considerably in the proportion of its siliceous to its argillaceous 

 matter ; but although it is usually denominated a marl, and is employed in the 

 neighbourhood for the improvement of the soil, it contains but a very small 

 quantity of calcareous matter, and in many parts is entirely without it. It 

 abounds in rounded pebbles of all sizes, from the most minute to masses of 

 3 feet or more in diameter, which are deposited through every part of it. 

 The pebbles may be considered as about equally numerous in the upper and 

 lower portions of the clay, and deposited in it without any kind of arrange- 

 ment; but upon viewing an extensive section, certain parts are found to con- 

 tain a greater number than others ; in general the most argillaceous parts 

 contain the fewest pebbles. The thickness of the clay partly depends upon 

 the inclination of the upper surface of the rock on which it rests. On the 

 N.E. bank of the Mersey, about 3 miles above Liverpool the clay in some 

 parts presents a face of 30 or 40 feet in height, while those parts of the 

 red sandstone which are in any considerable degree elevated above the ordi- 

 nary level of the district, rise above the clay. Its upper surface is, how- 

 ever, far from being horizontal, although more nearly so than that of the 

 rock. In some parts, where fissures in the sandstone have produced narrow 

 valleys, or, as they are termed, dingles, the clay appears to be wanting ; while, 

 on the contrary, there are some knolls above the average level which are 

 covered by it. 



The upper portion of the bed of clay, for about 10 inches in depth, is 

 obviously of a somewhat different nature from the great mass of it, being more 

 sandy and of a lighter colour, and containing a great number of very small 

 pebbles, although seldom any of the large ones. This upper stratum differs 



