30 The Ottawa Naturalist. [May 



burg, Bellefonte and elsewhere, has led to the belief that 

 a compilation and discussion of the evidence of the so-called 

 intraformational "conglomerates," breccias, or "corrugations," 

 is needed if we are to arrive at exact conclusions regarding cer- 

 tain common phenomena associated with the history of the 

 ancient seas. 



Grabau (2) states that intraformational brecciati on is "prob- 

 ably in all cases an extreme of subaquatic-gliding-deformation." 

 The write? does not feel that most of the phenomena observed 

 by him in the Appalachians will bear out this statement. The 

 principal example of folding and brecciation cited by Grabau as 

 due to this cause, is the one at Trenton Chasm, New York. 

 Hahn (3) described the folds as due to "subaqueous solifluction." 

 Grabau (sp. cit. p. 785) states that "Deformation through glid- 

 ing may result in complete brecciation of the deformed layers. 

 The fragments may lie in all positions, as in the ordinary intra- 

 formational conglomerates, or they may consist of thin cakes, 

 many of which in the gliding process have assumed a vertical 

 position in the mass. This forms the so-called 'edgewise con- 

 glomerate,' common in the Ordovician limestones of the Appal- 

 achian region. The characteristics of all these formations seem 

 to point to rather shallow water as the place of deposition of 

 these strata, and the possible periodic exposure and hardening 

 of the surface layers." The writer has been able to prove to 

 his own satisfaction that some of the edgewise conglomerates in 

 the Bellefonte section are certainly not due to subaquatic-gliding- 

 deformation, neither does he believe that any one hypothesis 

 is able to account for the formation of all intraformational con- 

 glomerates, whether the orientation of their fragments be "edge- 

 wise" or not. He feels convinced that the folds and edgewise 

 conglomerates exposed to view in the gorge at Trenton Falls 

 are, as previously supposed, truly of tectonic origin, and, there- 

 fore, not, in the sense of Walcott's definition, "intraformational 

 conglomerates" at all, since they were not "deposited in the 

 formation." A recent study of the Trenton Chasm, in com- 

 pany with Drs. Raymond and Shuler, produced evidence which 

 points conclusively to the tectonic origin of the folds and edge- 

 wise conglomerates, as is amply set forth in Miller's (4) recent 

 paper. 



It was only a few years ago that ripple-marks and mud- 

 cracks in limestone were conside "ed rare and unusual phenomena. 

 Indeed stratigraphers and paleontologists did not expect to 

 find and did not hunt for such structures in the Paleozoic lime- 

 stones. To-day the investigators of the Cambrian and the 

 Ordovician calcareous rocks are reporting such data from the 



