FOSSIL REEFS: TERTIARY 443 



ranges of hills known as "Mjodoboren" in Galicia (Austria), and as 

 "Toltry" in Podolia across the border in Russia, and which extend 

 northward into Volhynia and southward into Bessarabia, have com- 

 monly been explained as representing Bryozoa reefs (Hieber-48; 

 Teisseyre-83) of Upper Miocenic (Sarmatian) age. In reality they 

 represent reefs of earlier Miocenic age (Mediterranstufe) covered 

 by bryozoan layers of Sarmatian age (Michalski). The Toltry 

 reefs consist chiefly of corals and Vermetus masses, and form a 

 structureless limestone, which eastward and westward passes into 

 stratified clastic limestones and nullipore beds. These are on the 

 whole horizontal, but in the neighborhood of the reefs have an ir- 

 regular and often inclined position, similar to the overlap and inter- 

 lap structure on the borders of modern reefs. The reef limestone, 

 called Vermetus limestone, rises above the level of the enclosing 

 bedded limestones and constituted a barrier reef parallel to the 

 Miocenic shore which existed several kilometers to the east. Upon 

 these mid-Miocenic reefs settled in later Miocenic (Sarmatian) time 

 the Bryozoa LcpraiUa tcrchrata Sinz, and the worm tubes Serpula 

 grcgalis Eichw., which formed structureless limestone masses cover- 

 ing the older reefs. Over the clastic limestones enclosing the older 

 reefs and in the depressions in the Vermetus limestones were 

 formed oolitic and conglomeratic limestones containing Ervilia 

 podolica, Cardium obsoletum, Trochus, etc. 



Pliocenic Bryozoa Reefs of Kertch. The peninsula of 

 Kertch, which partly separates the Black Sea and the Sea of Azov, 

 has been famous for more than a century for its remarkable reef 

 limestones, first described as composed of Bryozoa by Pallas in 1803. 

 They form picturesque hillocks and stacks along both the Azov and 

 Black Sea coasts, many of them dissociated by erosion from the 

 mainland and rising as partly submerged towers and stacks from 

 the shallow waters. They are developed in a less degree on the 

 opposite peninsula of Taman, where the same formations are repre- 

 sented by more clastic and argillaceous deposits. These reefs have 

 been described and illustrated in great detail in a monograph de- 

 voted to them by Andrussow (11). They form knolls or tower-like 

 masses of unstratified limestone, consisting almost wholly of the 

 Bryozoan Membranipora (Pleiiropora) lapidosa (Pallas), and are 

 embedded in stratified clastic limestones and argillaceous beds be- 

 longing to the Maotic stage of the Pliocenic. Many of these beds 

 are largely composed of molluscan shells, chiefly Modiola volhynica 

 Eichw. var. minor Andrussow, while others are fragmental layers 

 in which the material is largely broken shells, mingled with Bryo- 

 zoa and Serpula fragments. Where these layers meet the reef 



