() TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



Nathorst* helped us to a proper understanding by simu- 

 lating the same appearances by experiments. Although 

 the passive effects in disintegration may be important in 

 some places, the conditions are of limited occurrence and 



the net results are not very great. 



The same may be said of passive effects in the 

 transport of material, but what is lacking in quantity is 

 made up in interest. 



Boulders of granite and other rocks are sometimes 

 found in chalk and similar rocks formed in the sea at 

 some distance from the land. It has been suggested that 

 they have been carried in the stomachs of reptiles, whose 

 bodies have floated out to sea and have been entombed in 

 the ooze on the ocean floor. These stones have been found 

 in association with reptilian remains, and in such a 

 position as makes it probable that the creature has first 

 swallowed the stones and then- carried them out in the 

 manner described. At the mouths of rivers, especial ly 

 after heavy floods, floating trees may often be noticed 

 carrying soil and stones gripped by the roots. 



Perhaps it is in the preservation of rocks and the 

 protection from disintegrating agents that plants and 

 animals are most effective in their passive capacity. 



The dense forests of Fueus. Laminaria and other sea 

 weeds, encrusting forms such as Barnacles. Nullipores, 

 &c., exert a great effect on the shores where they are 

 found. The force of the waves is broken before the rock 

 Is reached, and consequently little or no abrasion can take 

 place. The importance of this was pointed out by Prof. 

 Herdman many years ago.t 



^Nathorst, " Nouvelles obs< rvation sur des traces d'aniniaus el 

 autres phenomenes d'orrgine purement mecanique decrits comme 

 ■ alguesfossiles.'" Kongl. Svensk Vetenskaps— Akad. Hand. Vol. XXI. 

 N«>. 14, Stockholm, L88C. 



' Herdman, Proc. Liverpool Geol. Soc., 1884-5, p. 40. 



