1854.] 



TRIMMER ON SAND-PIPES. 



237 



Fig. 5. A section of the Warp-drift and Boulder-clay near Hard- 

 ingham, Norfolk. Here the depth of the furrows and pipes filled 

 with Warp-drift varies from 3 to 6 feet ; one of the pipes, however, 

 extending to the depth of 9 feet. If all the projecting points of 

 Boulder-clay were removed to a level with the horizontal dotted line, 

 it would give to the soil a regular depth of 3 feet. 



Fig. 6. A section of the Warp-drift and Boulder-clay near Lang- 

 ham, Norfolk. In this case the greatest indentation is 3 feet deep, 

 the depth of the Warp-drift varying, in the space of a few yards, 

 from less than 6 inches to 3 feet. 



Fig. 6. — Section of Pipes in Boulder-clay, at Langham, Norfolk. 



a. Loamy warp-drift. 



b. Boulder-clay ; flints and rolled fragments of chalk, in a base of finely comminuted 



chalk and clay. 



In describing, in 1846, in the ' Journal of the Royal Agricultural 

 Society,' these furrows and pipes between the soil and subsoil, that is, 

 between the Warp-drift and whatever bed it rests upon, I pointed 

 out their very general occurrence, not only on calcareous, but on 

 non-calcareous strata ; showing that, while furrows are common to 

 both, cylindrical and conical cavities are more prevalent, and best 

 developed, in calcareous strata ; but that they are also occasionally 

 found in sand and gravel. 1 also adverted to the bearing of this 

 furrowed surface of the subsoil, not only as regards investigations in 



Fig. 7. — Section of Pipes in Boulder-clay, in a Sand-pit near 

 Raveningham Hall, South Norfolk. 



b. 5ft. 



a. Warp-drift; brown clayey loam ; 6 to 18 inches. 

 />. Boulder.clay, with fragments of Chalk, 

 c. Crag, with false uedding. 



