On the Danger of Hasty Generalization in Geology. 431 



carboniferous fossils in the primitive limestone. Fortunately 

 for truth, a friend obtained many similar specimens in the 

 establishment of a marble-cutter in Leith Walk, where I 

 soon found the true explanation of the structure which had 

 led me to maintain its organic origin. 



It is usual for the marble-cutters at Carrara, before send- 

 ing out the blocks from the quarry, to reduce them into as 

 small dimensions as possible. This operation is performed by 

 what is called a matting-hammer, consisting of many separate 

 and blunt teeth placed alternate to each other, and is used by 

 bringing the hammer down, in a perpendicular direction, to 

 the flat face of the marble block. By this method a series of 

 quinquncial indentations are produced precisely similar to 

 those found in Stigmaria, and, to render the illusion more per- 

 fect, where the percussion of the teeth of the hammer is 

 greatest (which is at the point), the limestone at the bottom of 

 each depression is more crushed, and being deprived of its air 

 by the greater force, exhibits a different structure from the 

 surrounding walls, and thus presents the regularity, both in 

 shape and direction, of the protruding petioles of Stigmaria. 



Unfortunately, before this discovery was made, my dear 

 friend Professor Fleming died, and I have no doubt that this 

 specimen is now lying in his cabinet, labelled on my authority 

 as a Stigmaria. Another instance of the danger of hasty 

 generalization which occurred to myself — the supposed native 

 lead of Inch Mickery — was formerly brought before this So- 

 ciety, and is published in our Proceedings, vol. ii. p. 85. 



I have now to deal with another instance in which a hasty 

 generalization has met with more attention in the geological 

 world than any of those I have mentioned, but not less than 

 it deserved. Mr Geikie, in a paper published in the " Edin- 

 burgh Philosophical Journal," vol, xvi. p. 102, has stated his 

 belief that the ground on which Leith is situated has risen to 

 the extent of 25 feet since the Roman period. The section 

 from which he has come to this conclusion is in a sand-pit at the 

 Junction Road, Leith, and is represented in the diagram, which 

 is the same as Mr Geikie used to illustrate his paper. He thus 

 describes the succession of the strata as seen in the sand-pit 



" The lowest bed (1) visible is one of coarse gravel or 



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