466 REVIEWS — GEOLOGICAL SURVEY OF CANADA, 



Sir William Logan. The widely known Maclitrea Logani is one of 

 the most remarkable of these forms. It has been regarded popularly 

 as a left-handed or sinistral Euomphalus, but its affinities are quite 

 distinct from that type. Mr. Salter agrees with Woodward in re- 

 garding it as a Heteropod, or Nucleobranchiate Gasteropod, of the 

 family of the Atlantidse, and thus allied to Bellerophon and Cyrto- 

 lites; and also in looking upon the shell as dextral the flattened surface 

 with the whorl-markings being consequently the under part, in the 

 proper position of the shell, while the so-called umbilicus, on the other 

 hand constitutes a perforated spire. This apparently abnormal position 

 is sustained by an examination of the large and curious operculum, 

 the nucleus of which would otherwise be situated in the upper inner- 

 angle of the aperture, a position hitherto unrecognized in opercu- 

 lated shells. 



A good deal of confusion prevails in the writings of our New 

 World palaeontologists with regard to many of the turbinated and 

 discoidal types of the palaeozoic rocks. Mr. Salter has attempted to 

 clear this up with respect to some of the Lower Silurian forms. He 

 places, as sub-genera, under Conrad's genus Scalitea^ Hall's BapMs- 

 tojna, a new sub-genus of his own, called Helicotoma, and Vanuxem's 

 OpMleta ; making also a sub-genus of Scalites proper. All these he 

 regards, and truly, as belonging to the Family of Janthinidce ; whilst 

 MurcMsonia and Pleurotomaria, if not belonging to the same Family, 

 stand in the adjacent group of the Trochidis ; and Hall's Cyclonema 

 and Solopeay with his own Trochonema and JEunema fall into the 

 related group or Family of the LUorinidfs. It is, however, far from 

 improbable, that at some future time the limits of the JantMnidce 

 will be extended so as to include the whole of these types. 



Amongst the fossil forms of our older palaeozoic rocks, few have 

 occasioned more perplexity than the EeceptacuUtes of Defrance. 

 Although commonly placed amongst the corals, the true affinities of 

 this remarkable type have hitherto baffled observation. Mr. Salter, in 

 the work before us, enters into a somewhat extended discussion and 

 analysis of its structural peculiarities, and refers it to the Orlitolitidcs 

 Family of the Foeaminieeea.* If further investigations sustain this 

 view, we have in the BeceptacuUtes the earliest recognised foraminifera, 



* Mr. Salter states that this view had susgested itself, some years ago, to Mr. T. E. Jones 

 of the Geological Society of Londoiij but had never been followed up. 



