CANADIAN FOSSILS. 43 



Receptaculites. 



Decade I. Plate 10. 



Generic character. — Receptaculites, Defrance. Sub-kingdom Protozoa. 

 Order Foraminifera. Family Orbitolitidce. An infundibuli- 

 form disk, composed of vertical cells in a single series, having 

 rhomboidal thickened apices at each extremity : the casts of 

 these cells within are thick cylindrical columns (of sarcode) 

 connected by transverse stolons at their upper and lower ends ; 

 and by smaller ones in the middle of the columns. 



The clearing up of the affinities of a single doubtful fossil is never 

 barren of good results, since it may tend to throw light on other 

 forms as little understood, as well as upon the conditions under 

 which the organisms lived and were imbedded. And if, as in the 

 present instance, it should be rendered probable that an extinct 

 form was of much greater size and importance than its living conge- 

 ners, the excessive development in earlier times of a type now 

 existing, is a fact quite as significant in its bearing on the history of 

 organic life on the globe as the absolute replacement of one group by 

 another in geological time. 



The genus Receptaculites has long been known, having been 

 described and figured by Defrance so early as 1827, and quoted by 

 De Blainville from the Devonian rocks of Belgium. It is known in 

 the Silurian strata of Australia and in the northern parts of the 

 American continent, but has not yet been detected in strata of that 

 age in Britain. 



It has been referred to plants, and doubtfully to corals, but still 

 remains where it was first placed, among the group of " Incertae Sedis." 

 It does not seem to have occurred to naturalists* that a form fre- 

 quently five inches in diameter and not less than an inch in thickness 

 could be referable to the group of Foraminifera, and be allied not 

 very distantly to the genus Orbitolites. But the excellent figures and 

 elaborate descriptions by Dr. Carpenter of this group of the Forami- 

 nifera, and especially of some large species from Australia and the 



* Except my friend Mr. T. R. Jones, who, some years back, perceived the analogy 

 in form, but neither he nor myself at that time took any further notice of it. I had 

 forgotten his observation when Dr. Carpenter's memoir appeared. It is due to him to 

 recall it. 



