518 Geological Society. 



the facial pits in these two j^encra are liomok)gous structures, 

 despite their difference in position. The pit of Onohippidium 

 is larojer even than tliat of Hipparion and lies hig^her on the 

 face, in correlation Avith the extremely elevated f ronto-nasal 

 region of the skull. But in both the casts of the skull 

 of tlie former genus that I liave seen there may be noticed, 

 a little l)elo\v and in front of the orl)it, an additional, 

 quite shallow depression, forcibly recalling, both in position 

 and development, the preorbital muscular depression that 

 exists in some skulls of recent Equidae. 



This pit is well developed in the skull of the ([uagga in 

 the British ]\luseum, and is also shown, as Dr. Forsyth 

 IMajor has pointed out, in the drawing of a quagga's skull 

 published by de Hlaiuville. From these two data Mr. 

 Lydekker felt justified in concludiiig that it is a constant 

 characteristic of quaggas' skulls ; and, believing in its absence 

 from the skulls of BurchelFs Zebras, he went a step further 

 and used the character as a basis for separating specifically 

 the Quaggas from the Burchcll Zebras. This latter opinion 

 was easily refuted by the demonstration of the presence of 

 the pit in a skull of a specimen of (jrant's race of BurchelPs 

 Zebra : and I am now in a position to state that the con- 

 clusion as to the constancy of the occurrence of the pit in 

 quaggas^ skulls was also too hastily established ; for in the 

 Museum of the Royal College of Surgeons there are skulls 

 of two stallion quaggas, and in neither of them is a trace of 

 the depression perceptible *. 



PROCEEDINGS OF LEARNED SOCIETIES. 



GEOLOGICAL SOCIETY. 

 January 4th, 1905.— J. E. Marr, Sc.D., F.R.S., 



President, in the Chair. 



The following commumcation was read: — 



' The Marine Beds in the Coal-Measures of North Stafford- 

 shire.' By John T. Stobbs, Esq., F.G.S. With Notes on their 

 Palaeontology by Wheelton Hhid, M.D., B.S., FJI.C.S., F.G.S. 



Owing to the disposition of the rocks and other causes, the 

 stratigrapbieal position of the marine beds can be located with 

 exactness in situ, and a large quantity of material can be obtained 

 for examination. The horizons can be utilized for the identification 

 of coal-seams and for the subdivision of the Coal-Measures, as they 

 are remarkably persistent, and can be frequently traced not only 



* I am indebted to Mr. R. II. Burne for the oppdrtnnity of examinine^ 

 these two skulls and also casts of the skulls of Hippm\on and Ono- 

 hippidiion. 



