44 KEPORT — 1870. 



viz. Milne-Edwards and Haime. Ttis great diversity of nomenclature we can 

 only attribute to the fact that non-essential and external characteristics 

 have been too implicitly trusted in drawing generic distinctions ; when we 

 examine their internal structures, genera named exhibit essential dif- 

 ferences of conformation. This genus is found all over Scotland, but is 

 restricted to the base of the Mountain Limestone. 



Plate VIII. figs. 4, 5, & 14 represent varieties of Cyclo])liylhim fungitus ; 

 fig. 13, G. BoiverhanUi. Pigs. 1, 2, 3, 6, 7, 8, 11, & 12 represent species 

 which have a distinctly marked difference from the two species named. Fig. 9 

 is Auloijhyllum Edwardsi (Duncan & Thomson). This is a section of the 

 typical specimen, the only one, so far as we are aware, that has been dis- 

 covered in British strata. These forms are aU restricted to the lower members 

 of the period ; they are found at Bathgate, Brockley, and Beith, Ayrshire. 



Plate IX, contains three varieties of the genus Lonsdalia, Fig. 4 repre- 

 sents L. foriformis. This species is restricted to the lower members of the 

 period, as found at Bathgate, Linlithgowshire. Figs. 1 & 2 are L. flori- 

 formis, var. major. This species is restricted to the position of the Main 

 Limestone, about 33 feet from the base of the Mountain-Limestone series, 

 and found at Bragliead, Lesmahagow, and Braidwood, Carluke, Lanarkshire. 

 Fig. 4 represents L. duplimia (Fleming). This is a section of the only speci- 

 men we have seen in Scotland. It is restricted to the lower member of the 

 period, and found at Glenmuirshaw, near Muirkirk, Ayrshire. 



Second Repoi-t of the Committee, consisting of C. W. MerrifielDj 

 F.R.S., G. P. Bidder, C.E., F.R.G.S., Capt. Douglas Galton, 

 F.R.S., F. Galton, F.R.S., Prof. Rankine, F.R.S., and W. Froude, 

 appointed to report on the state of existing knoivledge on the Sta- 

 bility, Propulsion, and Sea-going Qualities of Ships, and as to the 

 application which it may be desirable to make to Her Majesty's 

 Govei'nment on these subjects. Prepared for the Committee by 

 C. W. Merrifield, F.R.S. 



We have to report that we have availed ourselves of your permission to 

 apply to the Admiralty to carry out the experiments recommended in our 

 first Eeport, presented to the British Association at Exeter last year, and 

 that the Admiralty have declined to carry out these experiments, but they 

 have sanctioned certain experiments upon models to be conducted by Mr. 

 Froude, one of our number. 



The following is a copy of the correspondence on the subject. 



Institution of Naval Arcbit^cts, 

 9 Adelphi Terrace, London, W.C. 

 28th September, 1869. 



To the Secretary of the Admiralty. 



Sir, — At a Meeting of the British Association for the Advancement of 

 Science, held at Norwich in 1868, the attention of the Association was 

 drawn to the deficiency of existing knowledge on the stability, propulsion, 



