Correspondence— C. D. Sherborn—T. Sheppard. 575 



Series. Indeed, all but two plants have been recorded from the last 

 horizon. Thus the beds are the honiotaxial equivalents of the 

 jS'ewcastle, Etruria, and Black Band horizons of North Staffordshire, 

 the Hamstead Beds below 1,233 feet in South Staffordshire, the 

 Coed-yr-allt Beds and Ruabon Marls of Denbighshire, the Ardwick 

 Series and Beds above the Bradford Four Foot Coal in South 

 Lancashire, the Lower Pennant Grit of South Wales, and the New 

 Rock and Yobster Series of Somerset. The data with regard to 

 Dover are too scanty for certainty, but they seem to indicate 

 approximately the same horizon as the two other Kentish localities. 

 The majority of species are also common to the highest zone, or the 

 "Charbons Gras," in the Pas de Calais. The flora of these rocks, 

 and of those on the same tectonic line, belongs to the lower of the 

 two great Continental zones of the Fpper Carboniferous — the 

 Westphalian ; and the higher zone, the Stephanian, is unrepresented 

 in the Mendip-Artois series of basins. But, as this axis is followed 

 from east to west, it appears that continuously higher horizons are 

 met with. 



ooi^REs:F'OisriDE]isroE. 



HIPPONYX FEOM THE WHITE CHALK. 

 Sir, — It may be of interest to note that a third specimen of Hipponyx 

 Machmorei turned up almost immediately after the publication of my 

 note in the Geological Magazine for October. This was recoo'nised 

 by Dr. Rowe in the collection of Mr. J. R. Farmery, of Louth, who, 

 with other of our friends, has been patiently working out the Chalk, 

 fauna of Lincolnshire. The specimen came from the Rolaster planus- 

 zone of Boswell ; it is affixed to a specimen of Ilicraster prceciirsor, is 

 slightly better preserved than the type, and has an oval form, thus 

 showing a characteristic variation of growth. The age of this specimen 

 is of especial interest. Mr. Farmery has generously given this rare 

 fossil to the British Museum. 



C. Davies Sheeboeit. 



FOREIGN FLINTS IN THE EAST COAST DRIFTS. 

 Sir, — Referring to Mr. Bullerwell's note on the number of flints in 

 the old gravel-bed on the Northumberland coast, which appeared in 

 the Geological Magazine for November (p. 525), I can endorse what 

 he says as to the probable existence in the bed of the North Sea of 

 chalk deposits. In our Holderness drifts we find quite a large number 

 of masses of black flint and pink flint, both of which are different 

 from anything occurring in this county. Formerly their presence 

 was easily accounted for in the drift as being derived from Denmark, 

 A Danish geologist, however, informed us that there is no flint in 

 Denmark. In addition to the flint we obtain scores of chalk fossils, 

 from a different horizon, however, from anything that occurs in situ 

 in the county. These include, principally, the flint casts of a small 

 sea-urchin, resembling Anatichytes ovatus in general shape, and some 



