300 



AUTOCLASTIC, INTRAFORMATIONAL. ENTEROLI TH IC, AND 

 DESICCATION BRECCIAS AND CONGLOMERATES, WITH 

 REFERENCES TO SOME SOUTH AUSTRALIAN OCCUR- 

 RENCES. 



By Professor Walter How chin, F.G.S. 

 [Read September 9, 1920.] 

 Plates XVI. to XXI. 



CONTENTS. 



Page. 

 I. Introduction 300 



II. LiTHOLOGICAL NOMENCLATUEE ... ... ... ... 301 



1. Autoclastic (dynamic breccias, pseudo-con- 



glomerates, friction-conglomerates, crush- 

 conglomerates). 



2. Intraformational Conglomerates. 



3. Intraformational Breccias. 



4. Enterolithic Structure. 



0. Desiccation Conglomerates, 



III. Classification 309 



IV. South Australian Examples 310 



1. Mount Remarkable. 



2. Upper Torrens-Limestone. 



3. Brighton Limestone Horizon (Lower Cambrian). 



(a J Brighton. 



(hj The Burra. 



(cj Pekina Creek. 



(d) Mount Remarkable. 



(ej Depot Creek. 



(fj General Remarks on Rock Structures. 



4. Beltana (Upper Cambrian). 



Introduction. 



Of late years miich attention has been directed by 

 geologists to certain phenomena in rock masses which indicate 

 the breaking up of rocks, in situ, by internal stresses. The 

 particular features shown by such processes vary considerably 

 in different cases, and are apt to be confounded with other 

 processes with which they have no direct relationship. They 

 have, at various times, in the past been erroneously described 

 as ''alluvium/' "boulder beds," ''ancient glacial deposits," 

 "basement beds," etc. That the several stratigraphical 

 features, whether clastic, dynamic, chemical, or otherwise, in 

 their origin should be clearly distinguished is often a matter 



