138 
ADAM SEDGWICK AND WILLIAM BUCKLAND. 
ham ; and in a paper published on this subject he refers them to an 
igneous origin, and points out that they are of all ages. In describing 
the columnar structure, it did not escape his notice that the prisms 
were arranged at right angles to the cooling surfaces. He also 
mentions that the common mode of weathering into great balls was 
by the exfoliation of successive layers from the faces of the joints. 
He fully recognised the value of palasontological evidence. As early 
as 1822 he 'vvi^ote to the Editor of the Annals of Philosophy," 
stating his view of the " importance of an intimate acquaintance 
with certain branches of natural history. Without such knowledge it 
must be impossible to ascertain the physical circumstances under 
which our newer strata had been deposited. To complete the zoo- 
logical history of any one of these forms many details are yet want- 
ing." He afterwards carefully collected fossils, and referred them to 
the best authorities he could find on each special group, but whilst 
he appealed to palaeontological evidence he fully recognised that the 
first thing was to get the rocks into the right order in the field. 
As a geological investigator and writer the chief object which he 
appears to have set before him was, as he himself used to say, " the 
unravelling of the story of the older Palaeozoic Rocks." The structure 
of the Cumbrian Mountains and their surrounding carboniferous 
margin formed the subject of more than one able paper. At this time 
he inclined to the opinion that Mountain Chains were the result of 
somewhat rapid upheaval, an opinion which in after years he con- 
siderably modified. From Cumberland he soon extended his exami- 
nations of the carboniferous rocks over a considerable area of the 
Yorkshire moorlands. He also investigated the Isle of Arran, and in 
conjunction with Sir R. Murchison published many sketches of 
the Geology of the Eastern Alps. It was about this time that he 
devoted considerable attention to the Magnesian Limestone of the 
north of England, and described the results of his investigations in 
the transactions of the Geological Society of London. He traced the 
character and extent of this formation, which had previously been 
indicated by Wm. Smith under the name of the Pontefract Rock, 
throughout the whole of Yorkshire and Durham. He was the first 
to notice the peculiar concretionary structure which characterises 
