Part II. Review of Previous Investigations 



Ever since stylolites were first mentioned the question of 

 their nature and origin has been under controversy. Numer- 

 ous investigations of them have been made, and several the- 

 ories of their origin have been presented. The most ex- 

 haustive and conchisive studies have been made by German 

 scientists. PubHcations by American observers have been 

 few and are less satisfactory. The writer wishes to present 

 a complete summary of the investigations of both American 

 and foreign writers on the question of stylolitic phenomena. 



PHENOMENA SIMILAR OR ANALOGOUS TO 

 STYLOLITES 



A review of previous studies made of stylolites necessi- 

 tates a consideration of at least two phenomena whose nature, 

 origin, and relation to stylolites have been under discussion. 

 These are the phenomena of the so-called ''Drucksuturen" 

 (pressure-sutures) and ''Gerolleindriicke" (impressed, or 

 pitted, pebbles). Some observers have suggested that the 

 origin of the often-noticed ''cone-in-cone" structures may be 

 related to that of stylolites. 



1. "Drucksuturen" 



The term ''Drucksuturen" has been commonly used by 

 German scientists as applying to the irregular, finely ser- 

 rated, jagged lines, or sutures, common to many thick lime- 

 stones and dolomites of Germany, and which in America are 

 especially characteristic of the Tennessee marble. These 

 veins are brown, red, black, or gray in color, depending in 

 part upon the color of the rock containing them. Their 

 course is usually irregular; so that they often bear an espe- 

 cially close resemblance to the sutures of the human cranium 

 (see Fig. 16). The distinction between ''Drucksuturen" and 

 "Stylolithen" has been made by many German scientists, espe- 

 cially Rothpletz (1900, pp. 3-32), as follows: the individual, 

 interlocking serrations of ''Drucksuturen" are short in length, 

 usually not more than one-half to three-fourths of an inch, 

 giving a fine, narrow vein; the interlocked parts, instead of 



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