IDENTITY OF LINEAMENTS WITH SEISMOTECTONIG LINES 



147 



the relief, they are 

 spoken of as mud vol- 

 canoes, and in some 

 cases these rise as 

 islands in the sea or 

 other bodies of water, 

 thus revealing facts of 

 •structure not other- 

 wise obtainable. An 

 island of this nature 

 formed near the head 

 of the Bay of Bengal, 

 in December, 1906.28 

 Under specially favor- 

 able circumstances the 

 repeating pattern of a 

 fracture system may 

 be brought out by the 

 arrangement of the 

 mud volcanoes. In the 

 southern half of the 

 Caspian Sea, islands 

 formed in this man- 

 ner and hills of like 

 formation upon the 

 shore reveal in great 

 perfection the outlines 

 of a structure pattern, 

 as was long ago shown 

 by Abich (see figure 

 23). 29 Here the north- 

 easterly series of linea- 

 ments is intersected 

 by a northwesterly 

 series, which not being 

 perpendicular to the 

 first produces a dia- 

 mond-shaped pattern. 

 There is, however, a 

 suggestion that a per- 



vinoi 



Qhlivnoi 



miiuznani 



(formed MajrlSGl) 



<!^Pogorel]aJa Plita 



Figure 23. — Fracture Pattern 



Revealed on the bottom and on the shore of the Caspian 

 Sea by the arrangement of mud cones and mud islands 

 (stippled) at the intersections of lineaments. (After 

 Abich.) 



28 E. J. Headlam : A new island in the Bay of Bengal. Geographical Journal, vol. 29, 

 1907. pp. 4.30-436, figs. 1-6. 



2» H. Abich : Fine im Caspischen Meere erschienene Insel nebst Beitragen zur Kenntniss 

 der Schlammvulkane der Caspischen Region. Mem. Acad. Imp. Sci. de St. Petprsburg, 

 1=0^. -ii. vol. 6, No. 5, 1S6.3, pp. 1-151, pis. 1-3. 



