94 peesident's address. 



at greater or lesser distances from land as would constitute simi- 

 lar geological strata to those which, are presented to us in Con- 

 glomerates, coarser or finer grained Sandstones and Shales; 

 whilst the animals, which vary according to climate, the degree 

 of saltness of the water, and in a measure from the nature of the 

 comminuted material, present us with the facies of what will be 

 the Palseontological aspect of future Possiliferous Beds. It is 

 not until we are at a considerable distance from land — often 100 

 or 150 miles — that the effect upon the sea bottom of material 

 brought down by rivers and of tidal action upon the land ceases. 

 A. Agassiz, describing one of the most recent United States 

 Dredgings, writes: — "While dredging to the leeward of the 

 Carribbean Islands we could not fail to notice the large accu- 

 mulations of vegetable matter and of land debris brought up 

 from deep water, many miles from the shore. It was not an 

 uncommon thing to find, at a depth of over 1,000 fathoms, ten 

 or fifteen miles from land, masses of leaves, pieces of bamboo and 

 of sugar cane, dead land shells, and other land debris, which are 

 undoubtedly all blown out to sea by the prevailing easterly 

 trade winds. We frequently found floating on the surface 

 masses of vegetation more or less waterlogged, and ready to sink. 

 The contents of some of our trawls would certainly have puzzled 

 a Palaeontologist ; between the deep water forms of Crustacea, 

 Annelids, Mshes, Echinoderms, Sponges, etc., and the mango 

 and orange leaves mingled with branches of bamboo, nutmegs, 

 land shells, both animal and vegetable forms being in such pro- 

 fusion, he would have found it difficult to decide whether he had 

 to deal with a marine or a land fauna. Such a haul from some 

 fossil deposit would naturally be explained as representing a 

 shallow estuary surrounded by forests, and yet the depth might 

 have been 1,500 fathoms. This large amount of vegetable mat- 

 ter, thus carried out to sea, seems to have a material effect in 

 increasing, in certain localities, the number of marine forms."* 



Passing now over the littoral and estuarine deposits, which of 

 necessity take their character primarily from the nature of the 

 adjacent land, we come to 



* Bull. Museum, Oomp. Zool., Vol. V., p. 295. 



