596 A. W. GRABAU LOWER ORDOVICIC FORMATIONS 



Columbia (base of Ordovicic) with Orthis mollinensis TValcott, a form 

 related to 0. salteri Hall of the Ceratopyge limestone of Scandinavia, and 

 by the fact that Megalaspis in America is practically confined to the early 

 Ordovicic (Beekmantown) of the Pacific region (inclusive of the Eoeky 

 Mountains) of Xorth and South America (two and four species respect- 

 ively), though one species also occurs in the "erratics" in the Levis for- 

 mation of Quebec and one is reported from the Eichmond of Iowa. 



Although Ceratopyge and Megalaspis are restricted to the Scandina- 

 vian-Eussian region, other trilobites associated with them in the Xor- 

 wegian region are widely distributed in the Atlantic province. These are 

 Euloma, ISTiobe, Angelina, Asaphellus, Cheirurus, Cyclognathus, Para- 

 bolinella, Shumardia, Symphysurus, etcetera. Several of these are al- 

 ready found associated with Dictyonema in the Lower Tremadoc, while 

 others characterize the Upper Tremadoc or the beds below the Phyllo- 

 graptus shales. This trilobite fauna, designated by Brogger the Euloma- 

 Xiobe fauna, is also known from the Christiania region, Bavaria, south- 

 ern France, Bohemia, Sardinia, and seems to be represented in eastern 

 Canada. The presence of some of these genera in the Ceratopyge lime- 

 stone of TYestergotland {Euloma ornatum A.. Xiobe insignis Lns., Sym- 

 physurus angustatus Boeck. etcetera) suggests that they, like the Cera- 

 topyge, are of I\~orth Pacific or Siberian origin. This may be true of 

 some of the other trilobites as well, their distribution westward being more 

 extensive than that of Ceratopyge. Some of them may have an Atlantic 

 origin, but our present knowledge of their distribution does not permit 

 us to form any more positive judgment in the matter. 



It should also be recalled that another fauna, the typical Beekmantown 

 fauna, existed at this time in the Champlain Valley. Newfoundland^ and 

 the north of Scotland, extending possibly to the Birikalk of Norway. 

 There can be little doubt that this fauna had a distinct origin, since it is 

 unknown from southern regions, or, for that matter, from any other 

 portion of the Old "World. 



The following diagram represents the interrelation of the three faunas 

 (figure -A). 



Turning now to Division B II. the "Glaukonitkalk*' of Fr. Schmidt 

 (exclusive of the Asaphus expansus beds), we find that Lamanskv has 

 been able to recognize three distinct divisions, which he has designated 

 from below upward B II a. B II /?. and B II y. 



The first of these, B II a. is quarried on the "Wolehow Eiver near Saint 

 Petersburg, under the name Dikari. The rock consists of limestone 

 layers 13 to 27 cm. thick. These have a bright red. yellow, violet, or gray 

 green color. The limestones have a thickness of 1.65 to 1.8 meters, but 



