ESTHERIA OVATA. 87 



by Prof. E. Emmons in his ' Geol. Report of North Carolina/ 1856, pp. 337, 338, and in 

 his 'American Geology,' part VI, 1857, p. 134. They are from the upper part of the 

 Deep River series (referred by him to the Upper Trias), and occur abundantly six or seven 

 miles south of Mclnvess. 



E. multicostata 1 (here copied as fig. 6), §|ths inch in length, is described as being oval, 

 hinge-line nearly straight ; ribs fine, about twenty ; similar to an Edmondia in shape. 

 ('Geol. Report,' 185C, p. 337, fig. 10.) 



E. triangularis (no indication of size given) has the triangular form of Astarte (copied 

 here as 'fig. 7); shell thin; ribs strong and distant, with concave grooves between. 

 ('Geol. Report,' 1856, p. 338, fig. 5.) These occur in company " near the top of the 

 upper red sandstone and marls (Keuper), about seven miles south of Egypt. In these 

 upper beds there are Cyprides also, which are quite numerous upon certain soft red 

 layers." 



In his 'American Geology,' part VI, 1857, p. 40, Prof. E. Emmons, treating of the 

 animal remains from the shales of the Chatham Series (referred by him to the Lower 

 Permian formation), describes an Estheria under the name of Posidonia ovalis (previously 

 noticed by him in his 'Geological Report on North Carolina,' 1856 -), and illustrates it by a 

 woodcut (fig. 12, copied here as fig. 8). It is ^ths of an inch long, thin-shelled, ovate. 3 

 He says (p. 41) "It is very common. It extends through 

 the series of slates, but I have not observed it in the green Fig. 8. 



magnesian marls. It is also common in the shales of the 

 Richmond basin. Sir Charles Lyell has figured much 

 larger kinds than any which I have seen either in the Deep 

 or Dan River coal-fields." Two or three other little bivalve Estheria ovata (p. ovaiis, Emmons), f, 



rout 



., , , North Carolina, magnified, and of na- 



snells, possibly Estlterice, are also alluded to m the same twaisize. After Emmons. 

 page ; and one of them is figured (fig. 13). 



To illustrate the geological position of these North America Estheria, I subjoin an 

 account of the strata of some of the several basins of shale and sandstone, which belong 

 to the same geological horizon as the bituminous formation of Eastern Virginia. These 

 extend in three parallel, unequal, interrupted tracts or belts for nearly 700 miles ; from 

 Stony Point along the Hudson River to South Carolina, on the eastern border of the 

 Appalachian or Alleghany mountains.* 



1 Figured also in Emmons's ' Manual of Geology,' 2nd edition, 1860, p. 191, fig. 166, 4. 



2 It is again figured in Emmons's * Manual of Geology,' 2nd edit., 1860, p. 191, fig. 166, 3. 



3 It is figured also in this report (W. 1 and 2) ; and, referring it to the Mollusca, Prof. Emmons 

 here says (p. 323) that it is the only one of the class hitherto observed in the "Chatham formation." It 

 occurs in the "Black slates," and materially differs, according to Prof. Emmons, from that of the 

 Upper Red Sandstone. 



* A useful rhumS of the history of the researches into the geology of these tracts, and of the supposed 

 relationship of this strata, is given by Dr. I. Lea in the ' Journ. Acad. Nat. Sciences Philadelphia,' new 



