Reviews — Skertchlt/'s Gun-Flints. 475 



amples. Furthermore, that the numerical abundance of a species, 

 on the same horizon, and with a limited area, has apparently no 

 influence upon, or connexion with, the origin of varieties. Some 

 appear simultaneously with the type, others during its existence, 

 while the mutatory forms do not come into being until after its 

 disappearance or extinction. The average vertical distribution is 

 extremely limited. These facts, M. Barrande concludes, are opposed 

 to the conception of the adaptability of the Brachiopods to the 

 environment, and afford no support to the theories of descent by 

 modification. At the same time, it is en evidence (Table, p. 162) 

 that generic forms enjoying the longest vertical range, such as 

 Atrypa, Biscina, Orthis, and RhyncJionella, are invariably represented 

 by the greatest number of species. 



These local studies in Brachiopoda may not perhaps be of such 

 general interest as the preceding volume on the Cephalopods, but 

 to the student and specialist they afford valuable and novel data 

 with reference to a group of organisms daily becoming more useful 

 as indices of palaeontological time. Nor can those who are not 

 prepared to accept M. Barrande's views with regard to the separate 

 origin of every individual species, or variety, fail to admire the 

 marvellous energy and vast labours of one of the most distinguished 

 and indefatigable of pioneers in paiaeontological science. A. C. 



IV. — On the Manufacture of Gun-flints, the Methods of Ex- 

 cavating for Flint, the Age of Paleolithic Man, and the 



CONNKXION BETWEEN NEOLITHIC Art AND THE GuN-FLINT TRADE. 



By Sydney B. J. Skertchly. [Memoirs of the Geological 

 Survey. 8vo. pp. 80. (London, 1879.) Price 17s. 6d.] 



THE title of this Geological Survey Memoir gives its contents at a 

 glance, and introduces to our notice subjects that possess a far 

 wider interest than do most of the Survey publications. The neigh- 

 bourhood of Brandon, so well known, through the labours of Messrs. 

 Prestwich, Evans, and Flower, for its palaeolithic and neolithic im- 

 plements, has recently been invested with much additional import- 

 ance from the researches made by Mr. Skertchly into the geological 

 position of the earlier works of art, and which he has determined 

 to belong to deposits of Interglacial age. 



In his present work, the author first places before his readers a 

 very careful and detailed account of the modern manufacture of 

 gun-flints, a trade now steadily dying out, though this decline is not 

 owing, as he tells us, to a falling off in the demand, but to a lack of 

 hands, the boys preferring agricultural and other labours to the con- 

 finement of a knapper's shop. 



Under such circumstances, the record of the trade, while illustrat- 

 ing the economic applications of geology, possesses an archaeological 

 value which time will no doubt enhance. 



The particular layers of flint with their local names are described 

 and illustrated in a section of the Chalk at Lingheath, where the 

 flint now manufactured at Brandon is obtained. Other localities, 



