NOTES AND QUERIES. 



109 



exhausted ; for my good friend, Mr. Baugh, of Bewdley, who has 

 followed up myresearches in Worcestershire by constant and unwearied 

 attention, assures me that no other specimens can be got from the 

 stone brought up from the now filled-up quarry. Less is known about 

 the tuberculated Cephalaspides than of those whose head-shield is 

 ornamented by scale-like area, marked out by the out-cropping of minute 

 vascular canals, entering the disk from beneath, and exhausting them- 

 selves upon its surface. This true reading of the external appearance 

 of G. Injellii is contained in a paper by Prof. Huxley, in the Quart. 

 Joum. Greol. Soc, vol. xiv., p. 270. Equally careful and minute is 

 the description there given of the layers which unite to form the 

 cephalic shield of Pteraspis. Briefly their characters may be thus 

 given — the innermost layer is a thin delicate lamina of enamel, some- 

 what nacreous, and occasionally tinged with colour; the middle layer 

 is composed of vertical plates of like substance, so arranged as to 

 enclose polygonal cells, whose summits or external apertures are 

 closed by an excessively delicate filmy layer, minutely reticulated ; and 

 lastly the outer plate consists of a hard layer, strongly ridged, whose 

 summits are turned outwards. In one species I have observed the 

 external edges of these ridges to be minutely toothed. Most of the 

 characters of this triple armour are shown in the annexed sketch of 

 Pteraspis. 



Thus I have briefly called attention to the occurrence of these fishes 

 in several places, though their condition is usually fragmentary, in 

 the Old Red of England. 



And so, we bid our adieus to these shield-bearing ancients ; but 

 only that we may meet them elsewhere, and obtain from them in 

 the field their willing tribute to our scientific treasury. Much has 

 been written about them, but more remains to be said. And while 

 the story yet to be told is in the careful keeping of an accurate 

 naturalist, any collector who can find and contribute a readable frag- 

 ment may be proud of being associated, not only with a memoir of 

 the earliest known fish, but also with that which dignifies the study 

 of Cephalaspis and Pteraspis — the history of the first appearance of 

 vertebrated life. 



NOTES AND QUERIES. 



Tertiary Strata in Kent. — Dear Sir, — It has been aptly said by one of 

 your correspondents that deep railway-cuttings, though presenting difficulties 

 to the engineer, are great helps to the geologist ; and the sections exposed in 

 the new London, Chatham, and Dover Railway, are particularly interesting in 

 showing the geological features of East Kent. As one who has taken deep 

 interest in the geology of the county, and has studied these cuttings, particularly 

 that over the chalk near Canterbury, at Beakesbourn, perhaps I may be permitted 

 to give a short account of them, through the medium of your valuable journal. 



