694 REPORT— 1895. 



value, botli for imperial and local purposes. The averag-e for tlie whole countrj' of 

 the rates raised by local taxation alone was, for 1891, 3s. 8d. in the £, to which 

 mnst be added imperial taxes and the tithe. It may be stated roughly, that for 

 every 100/. of yearly ' unearned increment ' the State is benefited in one way or 

 another by 25;., or one-fourth of the amount. The discovery of a new coal-field 

 would cause increased prosperity in the district in which it occurred, and from this 

 the State, through taxation, would derive great though indirect advantage. 



The growing difficulty of finding employment for the ever-increasing popula- 

 tion of these islands is a strong reason why this Survey' should be undertaken. 



Part of the cost might be borne by the landowners under whose property any 

 minerals were discovered. Certain districts should be selected with the consent of 

 the Local Authorities, and Parliamentary power taken to charge a royalty on any 

 minerals obtained below a certain depth. Landowners would probably welcome 

 proposals to make borings on their estates on such conditions. In the first instance, 

 however, the Survey should map out accurately the subterranean limits of existing 

 coal-fields, or mineral-bearing rocks, but trial borings sliould be put down in dif- 

 ferent localities, and each new boring would help to show more plainly the direc- 

 tion in which farther investigations should be made. Much light would be thrown 

 by such a Survey on the circulation of underground waters, a matter of great 

 practical importance. 



The expense of boring would be much reduced if undertaken on a large scale, 

 as machinery and apparatus would be available again and again. The Survey 

 would employ its own workmen, who would become increasingly efficient and 

 economical. 



4. The Cladoclonts of the Uj^per Devonian of Ohio. 

 By Professor E. W. Claypole, D.Sc. (Lond.) 



Numerous specimens of the Cladodonts of the Cleveland Shale in Ohio have 

 been found by Dr. William Clark. They for the first time reveal to us the general 

 form of the fishes to which belonged the teeth that have alone so long represented 

 the genus Cladodus. The fossils are in very fair preservation, but their state of 

 pyritisation has obscured many of the details of their structure. So far as regards 

 their form, however, we now know that they were long, slender fishes, resembling 

 in their character the sharks of the present day ; that they possessed well-deve- 

 loped and powerful pectoral and caudal, with weak ventral, fins, the dorsals being 

 tmknown ; that they were for the most part, or altogether, spiueless ; that at least 

 one species possessed cladadont teeth of more than one pattern ; and that they had 

 near the hind end of the body a peculiar fiat expansion or membrane of rudely 

 semicircular form, which gave to the caudal extremity when seen from above the 

 outline of a sharp-pointed shovel. 



The largest whole specimen yet found shows a fish of about G feet in length, 

 but detached teeth and other fragments indicate others of double this size, and 

 supply abundant proof that in late Devonian times, and in the North American 

 area, the elasmobranch fishes had attained very great proportions and a high 

 stage of development. 



Hitherto the Cladodonts have been regarded as, in the main, characterising the 

 Lower Carboniferous rocks, but we now find them abounding in the earlier Devonian 

 strata, and, as shown by the contents of their stomachs, preying — in some cases at 

 least — on the smaller placoderms of the same area. 



From the evidence of the new specimens it appears most likely that the 

 species already defined from single and isolated teeth can no longer be main- 

 tained. 



For details see the author's papers in the 'American Geologist' for 1893-4-5. 



