BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 28, pp. 965-972 DECEMBER 19, 1917 



PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY 



GEOLOGIC SIGNIFICANCE OF FOSSIL EOCK-BORING 



ANIMALS^ 



BY 7ILBERT L. BAJIJIOWS 



{Presented before the Paleoniological Society December 21), 191G) 



CONTENTS 



Page 

 Sigiiificaiice of rock-borers distinguished from burrowers in mud and sand 965 



Roclv-boring sea-urcliins 966 



Rock-boring pelecypods 967 



Nestling pelecypods 967 



Characteristics of rock-borers 968« 



Characteristics of the borings 969 



Influence of environment 969 



Evidence furnished by rock-borers 970 



Evidence furnished by the pelecypods t)71 



Conclusions 971 



Significance of Kock-boukks distinguisiieu eijom Bukkovveks in 



Mud and Sand 



On seacoasts today, especially in tropic and temperate i-egions, aiiimals 

 are found boring into rocks which have been formed at various periods 

 from recent to those of early geologic date. Eelated forms are fre- 

 quently found as fossils in formations which are overlain by beds attrib- 

 uted to late Mesozoic or to Cenozoic times. The peculiar habitat of borers 

 suggests that acquaintance with the conditions under which the recent 

 forms live may offer distinct contributions to our knowledge of the depo- 

 sitional history of formations in which the fossilized forms are found. 

 It is, however, of primary importance to be able to distinguish with cer- 

 tainty the special characters of each of the large number of marine ani- 

 mals which seek refuge in natural crevices or in holes, in order to be able 

 to judge correctly the habits of fossils suspected of being rock-borers. 



Manuscript recpivod by the Secretary of the Geological Society April .30, 1917. 



(965) 



