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Indiana University Studies 



Fuchs pointed out that the conditions of Giimbel's experi- 

 ment were by no means similar to those of nature ; that they 

 were merely mechanical conditions; and that the power of 

 the pressure was that of the experimentor, a thing external 

 from that occurring in nature, and the experiment was thus 

 not a result of a natural reaction. Fuchs raised the ques- 

 tions: *'By what in nature would the all-important, stiff, 

 metal plate be represented?" and ''By what in nature would 

 the necessary extra force of pressure be supplied?" He also 

 insisted that had Giimbel, after placing the metal plate be- 

 tween the two layers of plastic material, left the experiment 

 to itself, no columnar projections would have resulted, and 

 the experiment, thus, would have been a failure. 



Pressure Theory of Roth'pletz. The most plausible pres- 

 sure theory is the one offered by Rothpletz (1900, pp. 3-32), 

 who suggested that the necessary differential compression of 

 sediments to produce stylolites resulted from a differential 

 and irregular hardening of the plastic mass brought about by 

 the introduction of a cementing medium, at first unevenly 

 distributed. Rothpletz's principal points may be summarized 

 as follows : 



1. Stylolites give no indications pointing to any sort of 

 essential chemical activity. The fossils which often crown the 

 columns are constantly preserved whole, as are those found 

 in other portions of the limestone. There was no case ob- 

 served (by Rothpletz) where the larger fossils of the stylolite- 

 bands were considerably corroded. 



2. The lime must have been spongy and plastic, and the 

 lime grains must have been not entirely cemented. The 

 formation of stylolites in compact, completely hardened lime 

 is not possible. 



3. If the mass of plastic material were of uniform hard- 

 ness, and it were compressed together, the result of the com- 

 pression would not be differential. However, if a hardening 

 of portions of the lime ooze were brought about by the secre- 

 tion of a cementing medium, then compression of the over- 

 lying mass would little affect these hardened (cemented) 

 parts, and they would stand projected as columns, or pegs, 

 into the above, yet-soft mass. The overlying sediment would 

 sink down between the hardened portions, and the sides 

 would be fluted, or striated, by the grains (of the cemented 



