ABSTRACTS OF PAPERS 25 



CANADIAN STUUIE8 IN SEDIMENTATION 

 BY E. M. KINDLE 



Presented without notes. 



At the conclusion of the reading of the foregoing reports the more 

 general jDrogram was taken up, beginning with the presentation of a 

 paper entitled 



ASSOCIATION OF GLAUCONITE WITH UNCONFORMITIES^ 

 BY MARCUS I. GOLDMAN 



(Abstract) 



The study of the so-called "Bend series" of Texas (Lower Pennsj'lvanian 

 and Mississippian), both in outcrops and in well drillings, brings out clearly 

 that the more pronounced changes in lithology are marked by a layer of au- 

 tochthonous glauconite at the base of the overlying lithologic unit. Autoch- 

 thonous glauconite is very little, or not at all, developed in other parts of this 

 section. The glauconite is often associated with phosphate granules or con- 

 cretions, generally with unusually abundant sulfide, with abundant shells or 

 coarse fragments of shells, and with coarse sand. The clearest instances of 

 this stratigraphic significance of glauconite are at the contact of the Missis- 

 sippian and the Ordovician (Ellenburger limestone). In the latter strati- 

 graphic position a coarse glauconite layer has been found at several points of 

 the outcrop — in a well 120 miles to the north of the outcrop and in two wells 

 in an intermediate position. The occurrence of phosphate at unconformities 

 has previously been noted by Cayeux, and its association with glauconite was 

 recognized. There is little doubt that glauconite, phosphate, and sulfide are 

 all related to the occurrence of organic matter. Cayeux has pointed out that 

 under present conditions phosphate associated with glauconite forms where 

 warm surface currents meet cold, causing a destruction especially of plank 

 tonic and nectonic animals ; but this condition is too local to account for such 

 widespread layers as are found. Cayeux has formulated the indicated condi- 

 tion in the more general term "rupture of (marine) equilibrium," producing 

 changes of current, of depth, etcetera. It should not be assumed that it is the 

 actual momentary change in the environmental conditions which causes most 

 of the destruction of life, but its more permanent effect in bringing into con- 

 tact mutually incompatible life environments. If the general fact of an un- 

 usual destruction of life at unconformities is accepted, it is significant for the 

 paleontologist as a possible factor in producing the differences between suc- 

 cessive paleontologic horizons. 



Presented in full Avithout notes. 



Eemarks on Doctor (^loldman's paper were made by Doctors I. C. White 

 and E. S. Moore. 



' Publishecl with tlie pt'rniission ot (lie Director of the TT. S. Geological Siu'vev. 



