Stockdale: Stylolites 



21 



In a paper read before the Geological Society of America, 

 J. M. Clarke (1915, p. 60) discussed the deformation of 

 pebbles of the Devonian conglomerate of the Scaumenac Bay 

 region, and suggested that the solution theory of Sorby is 

 inadequate and that the "effects described are in a large part 

 actually due to forcible contact resulting from internal fric- 

 tion". 



Conclusions. The controversy over the origin of im- 

 pressed pebbles may lie in the fact that the indentations dis- 

 cussed are of at least two kinds, each of which may have a 

 distinct origin. The fractured and distorted type of pebbles 

 shows evidence of having been subjected to the pressure and 

 squeeze of one another, and the origin of the impressions may 

 be, for the most part, a mechanical one. However, the sharp, 

 smooth impressions of the non-distorted, non-fractured type 

 of pebble are undoubtedly of chemical origin — a result of the 

 solution of one pebble at the point of contact of the other. 

 Sufficient evidence in support of this theory has been pro- 

 duced by Sorby, Daubree, Heim, Rothpletz, and Reade. The 

 theory is accepted by Fuchs, Reis, Wagner, Kayser, and 

 Geikie. 



THEORIES OF THE ORIGIN OF STYLOLITES 



1. Theories Regarded as Unestablished 



The earliest theories of the origin of stylolites were quite 

 hypothetical and had little evidence in their support. Most 

 of them are today entirely rejected; a few have a slight fol- 

 lowing. The following is a grouping of the theories, with 

 their principal advocates, which today are regarded as unes- 

 tablished : 



a. Organism Theory 



Eaton, 1824 

 Kloden, 1828 

 Leube, 1850 

 Quenstedt 



b. Crystallization Theory 



Bonnycastle, 1831 

 Vanuxem, 1838, 1842 

 Emmons, 1842 

 Hall, 1843 



Eossmassler and Cotta, 1846 

 Meyer, 1862 

 Hunt, 1863 



