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Indiana University Studies 



larity, are more or less irregular in shape and size, and present 

 an extremely jagged suture (see Figs. 3, 13, 14, and 15). The 

 parting is often just an undulating seam with only occasional 

 interpenetrating perfect columns. A few extensive partings, 

 with only a slight stylolitic structure, are to be found. The 

 length and shape of the penetrations are quite variable. Short 

 columns, between longer ones, are frequent. Some columns are 

 very broad, compared with their length, and have flat or un- 

 dulating ends. The ends of others show a subordinate inter- 

 penetration of minor columns (see Fig. 24). The sides of the 

 interpenetrating parts, instead of being parallel, frequently 

 converge towards the end, sometimes coming to a sharp point. 

 This is especially true of smaller penetrations. Along a frac- 

 tured surface of a block of stone, the jaggedness of the stylo- 

 lite-seams is often exaggerated because of the irregularity of 

 the fracture (see Fig. 12). The true seam is to be seen on the 

 face of a sawed block which has been cut parallel to the direc- 

 tion of the penetrating parts (see Fig. 15). Stjdolite-surfaces, 

 which have been exposed by the splitting of the strata along 

 the suture, present a dark, irregular, pinnacled appearance 

 (see Figs. 4, 5, and 6). The dark color is a result of the clay 

 deposit. 



In addition to the larger types of stylolite-partings, hun- 

 dreds of small, shaiply intertoothed sutures are found. Thej' 

 are sometimes so small as to present a barel}^ noticeable line 

 (see Fig. 16). These correspond to the so-called ''Druck- 

 suturen" of the German investigators. That no distinction 

 can be made between these and the larger stylolite-partings 

 is unquestionable, since the latter alwaj^s grade into this small 

 type of seam, and finally disappear as a barely noticeable 

 crevice. These small sutures have all of the fundamental 

 characteristics of the larger ones. The interpenetrating parts 

 are irregular and are usually more or less conically pointed. 

 In some, however, the penetrations are minutely columnar in 

 shape and occur with marked regularity. These are especially 

 noticeable in a fairly fine, even-grained limestone. Occasion- 

 ally are found two or three closely parallel small partings 

 which abruptly join and continue as one larger seam (see Figs. 

 16 and 35), the combined amount of penetration of the smaller 

 seams being equivalent to that of the larger one. 



Regardless of the size and the character of the stylolite- 

 seam, the striated sides of the penetrations and the clay part- 



