226 /:'. M. Kindle — Criteria of Continental Deposits. 



short time ago, that the absence of fossils in a sandstone is due 

 to ' unfavorable conditions at the time of deposition,' or to sub- 

 sequent destruction of the fossils, in some mysterious way or 

 other. That fossils abound in marine sandstones of all kinds, and 

 even in conglomerates, is a well-known fact, and that the sands 

 along our modern sea-shores are rich in shells and other hard parts 

 of organisms, is equally a matter of common knowledge. The 

 argument that the absence of fossils in a rock which elsewhere 

 carries them, indicates some peculiarity of the sea-shore at that 

 point, capable of barring the life of the sea, is a laborious 

 explanation to fit a preconceived notion of the origin of the 

 formation in question."* 



Professor Grabauf has depended largely on the kind of 

 evidence outlined in the above paragraph in suggesting a con- 

 tinental origin for the Queenston shale, the Medina sandstone, 

 and the Esopus shale. Without raising the question of the 

 merits of any particular case to which this class of criteria has 

 been applied, the writer wishes to point out the fact that both 

 the features named, absence of fossils and cross-bedding, may 

 and do characterize both marine and non marine sediments. 

 Hence their presence in any particular formation can not be 

 regarded as evidence of continental origin. Not only is cross- 

 bedding a common characteristic of marine sediments, but it is 

 quite probable that itis often produced at considerable depths. 

 There is reliable evidence, according to A. R. Hunt, " that at 

 depths of about 40 fathoms in the English Channel and of 50 

 fathoms on the Banks of Newfoundland there is not only 

 motion at the bottom, but strong motion, far exceeding the 

 gentle oscillation of the water that is sufficient to ripple a 

 sandy sea bed.":]: We have the testimony of Rear Admiral Sir 

 W. J. L. Wharton§ that fine mud and sand may be moved to a 

 depth of 80 fathoms by wave action and that there is evidence 

 of the chafing of cables to a depth of 260 fathoms. It should 

 be recalled in this connection that many ocean currents have 

 in parts of their courses a velocity greater than most conti- 

 nental streams. 



The above citations sufficiently indicate that vigorous agita- 

 tion of the sea bottom occurs at considerable depths. For evi- 

 dence that this submarine disturbance often produces cross- 

 bedding we have only to go to the rocks themselves. Cross- 

 bedding instead of being a characteristic peculiar to nonmarine 

 or "continental deposits," is a common feature in almost if not 

 all classes of marine sediments which have accumulated in 



* Physical and Faunal Evolution of North America during Ordovicic, Siluric 

 and early Devonic time: Jour. Geology, vol. xvii, pp. 211-212, 1909. 

 t Idem. 



IProc. Roy. Soc. London, vol. xxxiv, p. 15, 1883. 

 § Foundations of Coral Atolls : Nature, vol. lv, 1897. 



