64 



parallel to the surface of the ground. This feature I have very 

 frequently observed in other places ; in one case, near Moresby, 

 on the Ullock and Parton Branch of the London and North 

 Western Railway, it was so notwithstanding that the longitudinal 

 section of the cutting resembled a steep-sided dome as shewn in 

 Fig. 2. 



Fig. 3 represents a section that was exposed near Walk Mill, in 

 the highway which was altered during the construction of the 

 Cleator and Workington Railway. There also the two Boulder 

 clays and the interbedded sands and gravels were to be seen. 



This tripartite form of the deposits is most frequently met with 

 in valley bottoms overlying the Coal Measures, or in similar situ- 

 ations over limestone or sandstone where they are adjacent to 

 rocks of an argillaceous character. At places, in any of these 

 positions, the deposits may be found with an aggregate thickness 

 of more than one hundred feet. At Salter Hall, on the Carbon- 

 iferous Limestone, but not far from the Skiddaw Slate on the rise, 

 they are, at one point, one hundred and thirty-two feet thick. On 

 the Coal Measures near Keekle, they are one hundred and eight 

 feet thick ; and on the same formation near Crossfield, they have 

 a thickness of one hundred and twenty-three feet. 



Frequently the triad form of the deposits is incomplete, and 

 only one or two of the members are represented. Sometimes only 

 the Lower Boulder Clay is found. In other sections this layer is 

 capped by the Middle Sands and Gravels, which in such cases are 

 often more fully developed than when they occur between the two 

 clays, as in Figs, i, 2, 3. 



Fig. 4 is a section of the Middle Sands and Gravels, as seen in 

 a tramway cutting near Crossfield. The upper clay is absent, but 

 the lower clay, though not shewn in the section, occurs just below 

 the formation line of the tramway. 



At Salter Hall there is a well marked instance of the thickening 

 of the Middle Sands and Gravels where the upper clay is absent 

 as just mentioned. Between the two clays the sands and gravels 

 seldom exceed four or five feet in thickness ; but in one or two 

 places where the upper clay is off, they are above twenty feet 

 thick. 



