THE 



GEOLOGICAL MAGAZINE 



NEW SERIES. DECADE III. VOL. VII. 



No. IX.— SEPTEMBER, 1890. 



OZR-IG-IZLsT^-Ij articles. 



I. — On some Fossil Estherije. 

 By Prof. T. Rupert Jones, F.R.S., F.G.S., etc. 



(PLATE XII.) 



A. Triassic Estherice. 



I. North-American Fossil Estheriae. 



1. Estheria Leivisii, sp. nov. 



2. Other North-American Estherice. 



II. E. minuta (Alberti) and laxitexta, Sandberger, from Bavaria. 



B. Purbeck Estherice. 



1. E. subquadrata (Sow.) 



2. E. sp. undescribed. 



A. Triassic Estherim. 



I. North- American Estherice. 



1. Estheria Lewisii, sp. nov. PI. XII. Figs. 3a, 3b. 



THIS species is represented by one cast and part of another, in 

 red sandstone from Bucks Co., Pennsylvania, given to rne not 

 long before his death by my lamented friend, Professor Henry 

 Carvill Lewis, F.G.S., etc., of Philadelphia. 



Length 5 mm. Height 3 mm. 



Valve narrow-subovate or oval-oblong; straight above (hinge-line 

 to length of valve nearly as 23 to 30), neatly curved below, though 

 the edge is not quite perfect; rounded at the extremities; umbo 

 strong, a sixth of the valve's length from the front end. The 

 concentric ridges of the surface, 19 or 20, strong and wide apart 

 in the early part of the valve, closer but very distinct afterwards. 

 The casts seem to show traces of interstitial markings in irregular 

 vertical lines (Fig. 3b) ; but unfortunately these are partly due to 

 the sand-grains of the matrix and the partial coating and staining 

 of iron -oxide. 



As this form differs from any other known, I propose to regard 

 it as a new species, Estheria Lewisii, dedicated to the memory of 

 one of the most promising and most regretted of geologists. His 

 short life and brilliant works are recorded in the Geol. Mag. for 

 September, 1888. 



A brief account of the geology of Bucks County, Penna, whence 

 Prof. H. C. Lewis received the specimens of Estheria Lewisii here 

 described, is given by Prof. J. P. Lesley in the " Geological Hand 

 Atlas of the Sixty-seven Counties of Pennsylvania," etc , in the 



DECADE III. — VOL. VII. NO. IX. 25 



