348 E. M. KINDLE 



that such a movement of the water may be partly due to tidal currents, as 

 well as to the actual northward flow of the Gulf Stream which is here slow, even 

 at the surface.' 



Charles Darwin long ago discussed some of the striking examples 

 of inequalities in sedimentation which occur in the Red Sea and in 

 the West Indies. The extent to which the significance of his very 

 important observations appears to have been neglected by geolo- 

 gists may justify the following quotations from them. 



The area of deposition seems less intimately connected with the debouch- 

 ment of the great rivers than with the course of the sea-currents; as is evident 

 from the vast extension of the banks from the promontories of Yucutan and 

 Mosquito 



Besides the coast-banks there are many of various dimensions which 

 stand quite isolated; these closely resemble each other; they lie from 2 or 

 3 to 20 or 30 fathoms under water and are composed of sand, sometimes firmly 

 agglutinated with little or no coral; their surfaces are smooth and nearly 

 level, shelving only to the amount of a few fathoms very gradually all round 

 towards their edges, where they plunge abruptly into the unfathomable sea. 

 This steep inclination of their sides which is likewise characteristic of the coast 

 banks is very remarkable: I may give as an instance, the Misteriosa Bank 

 on the edges of which the soundings change in 250 fathoms horizontal distance 

 from II to 210 fathoms; ofT the northern point of the bank of Old Provi- 

 dence in 200 fathoms horizontal distance the change is from 10 to 152 

 fathoms; off the Great Bahama Bank in 160 fathoms horizontal distance the 

 inclination is in many places from 10 fathoms to no bottom with 190 fathoms. 

 On coasts in all parts of the world where sediment is accumulating something 

 of this kind may be observed ; the banks shelve very gently far out to sea and 



then terminate abruptly I may observe, although the remark is here 



irrelevant that geologists should be cautious in concluding that all the outliers 

 of any formation have once been connected together for we here see that 

 deposits, doubtless of exactly the same nature, may be deposited with large 

 valley-like spaces between them ^ 



I may instance the great banks of sediment within the West Indian Archi- 

 pelago, which terminate in submarine slopes, inclined at angles of between 



30 and 40 degrees, and sometimes even at more than 40 degrees 



That in some cases, the sea instead of spreading out sediment in a uniform 

 sheet, heaps it round submarine rocks and islands it is hardly possible to doubt, 

 after having examined the charts of the West Indies.^ 



' Verrill, "Marine Faunas off New England Coast," AJ.S., XXIV (1882), 449. 

 * Charles Darwin, Geological Observations (1851), Part I, pp. 196-97. 

 3 Ibid., Part II, pp. 133-37. 



