90 Hejjoris and Proceedings— 



The last two were considered representative by Sir E. Murchison, 

 and this view has never been disputed. 



It therefore appears tliat the Pennsylvanian Pteraspids from the 

 Bloomfield Sandstone are older than Scaphaspis ludensis of the 

 Lower Ludlow by the time required for the deposition of 200 feet 

 of strata. But 1000 feet below the horizon just named comminuted 

 fish-scales are found in beds containing Leperditia alta ; and again, 

 700 feet lower, in the iron sandstone near the middle of the Clinton 

 group, which corresponds to the English Upper Llandovery beds ; 

 and 200 feet below the Ore Sand-rock, broken plates, with the 

 superficial striation of Pcdaaspis and a few fine spines of Oiichns 

 (described as 0. Glintoni) are met with. The horizon is well defined, 

 for the Ore Sand-rock contains Beyrichia lata, Cahjmene Clint oni, 

 Ormoceras vertebratum, and other characteristic fossils. The iron 

 sandstone also contains white pellets, apparently of coprolitic origin, 

 and containing 32 per cent, of phosphate of lime. 



Previously reported discoveries of fish in American Silurian rocks 

 were discussed, and their supposed age shown to be erroneous. The 

 paper concluded with the description of two species of Palceaspis 

 (P. americnna and P. bitruncata). of Onclius Pennnylvanicus from the 

 Bloomfield Sandstone, Onondaga group, and of Onchus Glintoni from 

 the Iron Sandstone of the Clinton group. 



3. " On some West-Indian Phosphate Deposits," By George 

 Hughes. Esq., F.C.S. (communicated by W. T. Blanford, Esq., 

 LL.D., E.R.S., Sec. G.S.) 



Some West-Indian specimens of phosphates were exhibited, in 

 reference to which the author called attention to a description by 

 Dana of an instance in which the carbonate of lime in fragments 

 of coral was partially converted into phosphate, and also to the 

 apparent alteration of limestone rock into phosphate of lime in 

 Barbuda Island hy the action of water draining a guano-like deposit 

 of bats' dung in a cave. A specimen of the phosphate of lime thus 

 produced was exhibited. 



In Aruba Island the process of conversion of coral-rock into 

 phosphate of lime has been in operation on so extensive a scale that 

 the deposit is being largely worked for shipment. The alteration is 

 probably due to the action of water containing soluble })hosphates 

 derived from the excrements of sea-birds (guano). Of this guano 

 no trace remains ; but the fragments of coral in the underlying rock 

 have been altered into a substance containing 78 to 80 per cent, 

 of phosphate of lime ; and the deposit, as shipped, contains 35*7 per 

 cent, of phosphoric acid, equal to 77 9 per cent, of tribasic phosphate. 



Reference was also made to some other West-Indian phosphate- 

 deposits formed of bones, and to iron and alumina phosphates 

 found in Eedonda, Alta Vela, and Testigos Islands. 



4. " Notes on species of Fhyllopora and TJiamiiiscns from the 

 Lower Silurian Rocks, near Welshpool, Wales." By George Robert 

 Vine, Esq. (Communicated by Prof. P. Martin Duncan, F.R.S., 

 F.G.S.) 



In this paper a species of Phyllopora from the Caradoc beds of 



