168 THE BEISLINGTON CUTTING. 



thicker mass of this calcareous sandstone from an upper and 

 thinner stratum of similar materials (see Figs. 1 and 2). The 

 u23per j)art of the section at the W. or Bristol end consists of 

 ordinary red Triassic marl. This is now a grass-grown slope. 

 The slope is carried along the whole length of the section (as 

 indicated in Fig. 1 by the line conformable to the surface). 

 This gives the appearance of the marl overlying the red 

 calcareous sandstone unconformably, an appearance which 

 deceived me at first. Subsequent examination, when the 

 sloping bank was being trimmed back, led me to see that the 

 slope to the Eastern end of the section is not in Trias marl, 

 but in decomjDosed calcareous sandstone, in which occasional 

 nodules which had escaped disintegration could be found. 



Fig, 2 was sketched while the walling up of parts of the 

 face of the cutting was in progress. At the surface is the 

 Triassic marl, now grass-grown. Below it is the band of red 

 calcareous sandstone, followed by a band of marl bricked in. 

 Between this and the Pennant at the base of the section are 

 the red calcareous basement beds. But the parts dotted and 

 partly bricked in, in the sketch, are composed of very soft 

 friable yellow and brown ferruginous sand. In it there are 

 nodules of calcareous sandstone of various sizes and shapes. 

 There were many such irregular patches of ferruginous sand, 

 so soft that it could be scraped away with the hand. These 

 are now bricked in. 



There can be little doubt that these were produced by the 

 solution of the cementing calcareous matter by water, con- 

 taining probably carbonic acid gas dissolved in it. The 

 contained nodules are masses of the original material which 

 have escaped disintegration in this way. 



