Reviews — The Brachiopods of Scania. 35 



opposed to their "ageing" character of more intricate wrinkling, 

 assumed to he due to diminished gas-pressure. Psiloceras shows not 

 only complex suture-lines with dependent inner portions at first and 

 simpler ones with ascending auxiliaries at the end, hut also often 

 asymmetry of the suture-line, and approximation of the last few 

 septa, and these features will be considered in the following parts of 

 this paper. 



(To be continued.) 



BBVIEW8. 



I. — On the Bkachiopod Shales of Scania. 

 Om Skanks Brachiopodskijffer. By Gtjstav T. Troedsson. 

 Meddelande fran Lunds Geologiska Ealtklubb, ser. B, Nr. 10, 

 1918. 

 rpHE memoir by Dr. Troedsson on the BrachiopodskifFer of Scania 

 \_ is of importance to students of the Ordovician strata, and must 

 be consulted by anyone who proposes to work at the Ashgillian 

 faunas. These Scanian beds have long been recognized as the 

 general equivalents of theAshgill Shales of the North of England, 

 which they resemble in respect of lithological characters, fauna, 

 and stratigraphical position. 



The memoir is divided into two parts, the first stratigraphical, the 

 second palaeontological. In the first part the author gives a historical 

 sketch, which is followed by details of the succession in various 

 localities, and by a comparison of the beds with those of other areas. 

 The second part is concerned with a description of the species. 



The fauna consists largely of species which ascend from the 

 Staurocephalus beds, but is much poorer in species than are those 

 beds. The author, however, lias made a noteworthy addition to 

 the fauna; only five species were known before, whereas he gives 

 a list of forty-six forms. 



Although the beds as a whole are equivalent to the Ash gill Shales, 

 it is possible that they contain earlier strata than the lowest part of 

 those shales, for Dr. Troedsson divides them into two sub-zones, the 

 lower (that of Dalmanites eucentrus) being distinguished also by 

 the abundance of Ostracods. This is a characteristic feature of a 

 calcareous band with abundant D. eucentrus below the Ashgill Shales, 

 which has been bracketed with the underlying Staurocephalus beds, 

 and this calcareous band may represent the lowest BrachiopodskifFer, 

 though differing in lithological character. The summit of the 

 BrachiopodskifFer is probably older than the uppermost Ashgill 

 Shales, for the author separates from the former a zone of 

 Climacograptus scalaris, which, like the highest Ashgill Shales, is 

 succeeded by the beds of the zone of Diplograptus acuminatus. The 

 zone of C. scalaris is probably only of local value. C. normalis is 

 recorded in England in beds below the Ashgill Shales, and is 

 abundant in the succeeding Valentian rocks, and although it has not 

 yet been found in the shales themselves it must have lived at the 

 time of their formation. 



