Chap. X.] PAL^ONTOLOGICAL COLLECTIONS. 63 



shallow and to embed and preserve the remains before 

 they had time to decay. On the other hand, as long as 

 the bed of the sea remains stationary, thick deposits 

 cannot have been accumulated in the shallow parts, 

 which are the most favourable to life. Still less can 

 this have happened during the alternate periods of 

 elevation ; or, to speak more accurately, the beds which 

 were then accumulated will generally have been 

 destroyed by being upraised and brought within the 

 limits of the coast-action. 



These remarks apply chiefly to littoral and sublittoral 

 deposits. In the case of an extensive and shallow sea, 

 such as that within a large part of the Malay Archi- 

 pelago, where the depth varies from 30 or 40 to 60 

 fathoms, a widely extended formation might be formed 

 during a period of elevation, and yet not suffer exces- 

 sively from denudation during its slow upheaval ; but 

 the thickness of the formation could not be great, for 

 owing to the elevatory movement it would be less than 

 the depth in which it was formed ; nor would the 

 deposit be much consolidated, nor be capped by over- 

 lying formations, so that it would run a good chance of 

 being worn away by atmospheric degradation and by 

 the action of the sea during subsequent oscillations 

 of level. It has, however, been suggested by Mr. 

 Hopkins, that if one part of the area, after rising and 

 before being denuded, subsided, the deposit formed 

 during the rising movement, though not thick, might 

 afterwards become protected by fresh accumulations, 

 and thus be preserved for a long period. 



Mr. Hopkins also expresses his belief that sedimentary 

 beds of considerable horizontal extent have rarely been 

 completely destroyed. But all geologists, excepting 



