tiecent >Stnking of Ocean-level. 259 



Contemporaneity and Age of the Strands. 



A second test of the eustatic change is naturally to be found 

 in the expectation that the delevelling should be essentially 

 synchronous in all parts of the ocean. In fact, observers dwell on 

 the recency of the sea-level shifts registered in all of the illustrative 

 cases. Fossils in the St. Lawrence, Scottish, Irish, Cuban, 

 Patagonian, New Zealand, Australian, Funafuti, Murray Island, 

 New Jersey, Maryland, Georgia, and Florida beaches, reefs, or 

 coastal plains belong to species now living in the adjoining seas, 

 or, exceptionally, to species now living in slightly warmer water. 

 Great recency is also shown by the relatively small damage done by 

 erosion to the strand marks, except in the case of those exposed to 

 powerful surf. 



The beaches of the higher latitudes are clearly post-Glacial, 

 and also of date later than the post-Glacial uplifts following 

 deglaciation. Brogger puts the completion of the last 4 metre to 

 8 metre emergence of the Christiania region at about the year 500 B.C. 

 The development of the corresponding sea-cliffs, benches, and other 

 strand marks is referred by him to the late Tapes (Neolithic) period, 

 between 1400 B.C. and 2400 b.c. All Tapes time is taken to lie 

 between 1400 b.c. and 6700 b.c. During the late Tapes period 

 the Christiania climate was about 2° C. warmer than now.' Traces 

 of Neolithic man have been found in the 25 ft. beaches of the 

 British Isles. The emergence of this beach in North Ireland seems 

 to have been completed during Neolithic times." 



Perhaps fuller direct evidence for contemporaneity among the 

 lowest beaches may be discovered through the use of fossils. It is 

 significant that the fossils in the Patagonian beaches, like those of 

 Norway, betoken water warmer than the adjacent sea. 



Simultaneous emergence for the many separate regions is the 

 more credible because of the similarity in the histories of their 

 respective coasts before emergence. Repeatedly one encounters 

 the description of terrace, bench, or beach near the 20 ft. level 

 as the best developed, the most conspicuous, or the most persistent 

 in a region characterized by " raised " strand marks ; illustrations 

 are noted in the foregoing table. Thus, the different regions must 

 have had sea-level nearly constant for a considerable time, during 

 which the strand marks were well incised. This widespread 

 accordance itself must deepen suspicion that local diastrophism 

 has not been responsible for the recent emergence of so many 

 continental and island coasts. 



In conclusion, the facts in hand appear to permit belief in the 

 possible synchrony of the different strand markings and emergences 

 here considered, but this second test of the general hypothesis also 

 leads more surely to questions than to definite answers. 



1 W. C. Brogger, Norges geol. Undcrs., No." 31, 1901, p. 713, and No. 41, 

 1905. 

 ^ W. B. Wright, The Quaternary Ice Age, London, 1914, pp. 384-5. 



