APPENDIX. 125 



sent to me by Mr. Wheatley (see above, p. 93), particularly in a hard red shale. It 

 appears, however, to be rare in some of these shales, for in a black shale, showing the 

 Cyprida in good preservation, there are but one or two of these associated with a multi- 

 tude of the pitted Candona (C. Emmonsii). Some of these Estherian and Cypridiferous 

 shales from Phoenixville, however, are largely made up of indistinguishable Cypridce, and 

 the smooth form may be abundant enough in several of the beds. 



Dr. E. Emmons, in his ' American Geology,' part VI, notices the abundant occur- 

 rence of these Cypridce " in the Chatham series of Deep and Dan Rivers ; l they are also 

 abundant in the black shales of Halifax County, Va., in the same geological position" 

 (p. 39). This author terms some of them ''Bairdiae:" 2 but they certainly do not belong 

 to that sub-genus of Cythere ; and the " lobulated" condition of the valves, as described 

 and figured by him (figs. 10 and 11, pp. 32, 40), is due merely to crush and frac- 

 ture ; others he seems to think may belong to Cypris 3 (pp. 39 and 54). He also observes 

 that these " minute Crustaceans frequently fill entire strata. The individuals are about 

 l-30th of an inch long. They have the form of a bean, and their carapaces are smooth. 

 They differ in size ; some are about half the length of the largest, and appear to be equally 

 numerous with the larger. They are numerous in all the upper part of the black shales. 4 

 About seventy feet above the coal-seam they become rare, and, indeed, I believe, are 

 not to be found below the level" (p. 39). "They do not exist at all in the immediate 

 vicinity of the coal-seams" (p. 40). They are abundant in some strata and absent in 

 others. 



In the "Upper Red Sandstone and Marls (Keuper), Chatham Co., North Carolina, 

 about seven miles south of Egypt [Deep River, North Carolina], there are Cyprides also, 

 which are quite numerous upon certain soft red layers" (p. 134). 



G. Candona (?) Emmonsii, sp. nov. Woodcut, fig. 12. 



Cypris ; granulated species (?), Rogers. Proceed. Boston Soc. Nat. Hist., vol. v, p. 15. 

 — „ Wheatley. Amer. Jour. Sci. and Arts, 2nd ser., 1861, 



vol. xxxii, p. 44. 



Length, J^ inch. Breadth, -fa inch. 



In one of the hard black shales sent from Phoenixville by Mr. Wheatley is a layer 

 of Cypridce, well preserved, their interior being filled with calcite, and their convex crusts 

 retaining perfect shape, and showing a neatly punctate surface, marked with minute sub- 



1 See above, p. 90. 



2 Because he regards the formation to be either marine or brackish, and because he supposes the 

 valves to have the hinge-joint of Bairdia. 



3 At p. 31 Dr. Emmons, it seems, refers all these Entomostracans to Cythere. 



4 See the section of the black shales at Egypt Pit, Deep River, p. 89. 



