232 



A. S. PACKARD, Jr., ON THE GLACIAL PHENOMENA 



authors.) A fine series of specimens, recent and fossil, from Labrador, and fossil from Maine 

 and the river St. Lawrence, has convinced me that the numerous variations of form which 

 this species assumes, are of local origin arising from differences in habitat or age Among 

 a number of A. Laurentiana Lyell, received from Montreal through the kindness of Dr Daw- 

 son, are some thinner and more finely striated than usual, but I have recent specimens and 

 also fossils from Labrador agreeing with them. The species varies in the length of the 

 shell and the form of the posterior end, but the shape of the anterior end, the sulci and 

 the hinge characters, are in all the varieties very constant. 



Very elongated forms are like A. Warhami Hancock, which we would consider as a syn- 

 onym of this species. The varieties A. Richardsoni and A.fabula have occurred in the same 

 locality, at Dumplin Harbor at the mouth of Sandwich Bay, Labrador, where I have 

 dredged them alive. 



Astarte striata Gray. One specimen from Hopedale. It did not differ from drift shells 

 found at Brunswick, Maine. This shell, as it occurs fossil, is thicker, more ponderous 

 more equilaterally triangular; the beaks are directed more anteriorly, the teeth are 

 much larger, and the lunule broader and shorter, than in A. Banksii, 



Astarte compressa Linn. (.4. elliptica Brown.) Common in all the beds, but not so abun- 

 dant as A. Banksii. 



Cardita borealis Conr. Very abundant with the preceding. 

 Macoma sabnlosa Mbrch. ( Tellina proxima Brown.) Of frequent occurrence. 

 Cgrtodaria siliqua Daudin. Several valves at Caribou Island. 



Panopcea norvegica Sprengel. A perfect valve of this shell occurred at Caribou Island 

 Mya truncata Linn. Both the short and common elongated varieties of this species oc- 

 curred especially at Hopedale in great profusion. 



Saxicava arctica Desh. Large valves occurred in great profusion in all these beds 



Chiton marmoreus 0. Fabr. Several valves were found at Hopedale. 



Tectum testudinalis Gray. One specimen occurred, encrusted with Nullipora 



Lepeca cceca Mcill. (P. Candida Couth. ; P. cerea Moller, Reeve) ; frequent. 



Cemoria noachina Leach. (Diadora noachina Gray.) Frequent. 



Margarita cinerea Couth. One specimen. Hopedale. 



Margarita varicosa Mighl. et Adams. Frequent at Hopedale and Caribou Island 



Tm-ntella erosa Couth. As numerous in proportion to the succeeding species as at present 



Oil tllG CO clSt. 



Turritella reticulata Mighl. et Adams. (T. lactea Moll.) Profusely abundant in both places 

 umtella acicula Stimps. One specimen. Caribou Island. 



Aporrhais occidental Beck. Several. Caribou Island. 



Lunatia gronlandica Moll. Frequent. 



Natica clausa Sowb. Frequent. 



Admete viridula Stimps. At Caribou Island. 



Beta robusta n sp ; [Plate vii, fig. 12.] No specimens of this species occurred at Caribou 

 Island associated with the other species ; it seems quite rare, and has not occurred in a 

 living state. Though very distinct from any of the other species, it might be mistaken 

 for a very much shortened and thickened B. americana. It is much shorter and broader 

 than B. americana; the whorls are five in number, angulated, giving the shell a well-marked 

 turretted form ; the fourth whorl is one half to two thirds as long as the first, which is 

 unusually large m proportion to the rest of the shell. The aperture is broad, regularly 



