208 



rock full of echiiioclerms is at the base of the clift', while actually 

 resting upon it are strata containing the bivalves which are 

 supposed to characterise the middle division ! Tlie fact is that 

 the section throughout contains practically the same fossils, and 

 the difference in the relative proportion of univalves, bivalves, 

 brachiopods, or echinoderms present may be due to such causes 

 as change in the sediments, and probably to certain portions of 

 the strata representing a deeper sea deposit than the rest. 



In general the polyzoal limestone is the chief repository of the 

 echinoids and palliobranchs ; the lamellibranchs are represented 

 by species of Ostrea, Pecten, and others whose test is calcitic, the 

 greater number of species of the class being known only as casts. 

 The clays are rich in gastropods, the lamellibranchs are fairly- 

 well represented, whilst palliobranchs are uncommon, and 

 echinoids rarely present. The high state of evolution of the 

 higher gastropods, e.g., Miirex, Fusits, T7'iton, Feristernia, 

 Voluta, Mitra, &,c., imparts to each chief locality a complexion of 

 its own, and increases the difficulty of correlating widely 

 separated fossiliferous clays; this phenomenon may be attributed 

 to a degree of isolation of the different areas greater than that 

 which obtains to-day in approximately the same areas, or it may 

 be due to climatic effects pertaining to different oceanic currents. 



The fossil-bearing cliffs "Commence about a mile from the mouth 

 of Spring Creek — at Bird Rock, a small outlier of the adjoining 

 cliff". This is a landmark well known to geologists, though quite 

 insignificant to the ordinary visitor. It is connected with the 

 mainland at low tide only, a circumstance which was forcibly 

 impressed upon us more than once, when we had to wait for 

 hours for the sea to subside between us and the fossil treasures 

 we expected to obtain on its sides. The difficulty of getting to 

 Bird Rock is not the only one which besets the geologist, who 

 does not carefully time his visits with the ebb of the tide. The 

 cliff' opposite, which protrudes as to a point, cannot be rounded 

 long after the turn of the tide, and there is no other passage to 

 the coast beyond. Even if this point is passed there is a second 

 formidable one a little farther on, and beyond that still another ; 

 while to be caught by the rising tide between any of these points 

 would be extremely dangerous, foi* the cliffs are too abrupt to be 

 scaled. Beyond the third point there is certainly a haven, which 

 we were always glad to reach, and where, though close prisoners 

 till the waters fell again, we spent many profitable hours. 



The lower part of the cliff opposite Bird Rock is hollowed out 

 into caves by the action of the waves, the strata being soft. 

 Both in the caves and on Bird Rock itself small shells can be 

 easily picked out with a penknife ; with patience, many varieties 

 of univalves may be collected, and generally in a good state of 

 preservation. 



