TRANSACTIONS OP THE SECTIONS. 77 



us how great are the resources and how infinite the wisdom of Him who has done all 

 things well. 



On the Corrugation of Strata in the Vicinity of Mountain Ranges. 

 By the Rev. J. Dingle. 



This paper was in continuation of an attempt to determine the mechanical causes 

 of the formation of the earth's crust, and to trace its progress. The author described 

 the varying forms of flexure, diminishing in intensity with their distance from the 

 igneous axis, which characterizes the strata in the neighbourhood of the mountain 

 chains; and showed how this form would arise from the action of the molten interior, 

 by referring to the result of experiments upon the action of fluids under like condi- 

 tions. He expressed his obligations to Professor Rogers for the valuable information 

 which he had derived from a paper of his in the Edinburgh Transactions, but de- 

 murred to some of his hypotheses. Flexures at definite points must be produced by 

 repeated or continued pressures, and not by paroxysmal action. The latter chiefly 

 spends itself in earthquakes and volcanoes, which, upon the whole, can produce no 

 continuous change of form. The two forces, however, seem to be intimately related 

 to each other; and if we suppose the one to be only the other in excess, we are 

 supplied with a simple explanation of the connexion between the corrugated moun- 

 tain chains and the lines of earthquakes and volcanoes. 



As a corollary from the above views, it might be observed that they destroyed the 

 idea of any distinct theory of volcanoes of elevation or eruption, as the quantities of 

 elevated or ejected matter in the case of a fissure or a ruptured corrugation might be 

 in any proportion whatever to each other. 



Remarks on the Ichthyolites of Farnell Road. 

 By Sir Philip de M. Grey Egerton, Bart., F.R.S. 



At the Meeting of the British Association last year at Aberdeen, I had an oppor- 

 tunity of examining several specimens of the small fishes found in the Old Red Sand- 

 stone deposits of Farnell, and in the discussion which ensued upon the reading of 

 Mr. Mitchell's paper, I took occasion to remark upon their several characters. I then 

 stated that all the specimens I had seen belonged to the family Acanthodei, and the 

 great majority of them to the genus Acanthodes, representing, however, a new species 

 of the genus. I proposed inconsiderately to name this species A. antiquus, a very 

 inappropriate title, inasmuch as two contemporaneous species were subsequently ex- 

 hibited by Mr. Peach. As, however, this name has not appeared in print, I propose 

 to cancel it, and substitute A. Mitchelli, as the original or type-specimen is in the 

 possession of the Rev. Hugh Mitchell, of Craig. The other specimens I described as 

 constituting a new genus corresponding in many characters with Diplacanthus, but 

 differing in the shortness and position of the spines of the fins. I proposed for this 

 genus the name Brachyacunthus. 



The specimens from the same locality recently received from Mr. Powrie are of the 

 same species as those examined at Aberdeen. I learn, however, in a letter received 

 from Mr. Powrie since I have examined his specimens, that he has in his possession 

 others comprising at least two very distinct species of Diplacanthus, one remarkable 

 for it3 very strong anterior dorsal spine, and fragments belonging probably to other 

 species. Mr. Mitchell also writes that another locality has been found rich in remains 

 of Acanthodian and other fishes. Under these circumstances it would be premature to 

 enter into any detailed account of these interesting ichthyolites. As the materials, how- 

 ever, are sufficiently complete, 1 append a short description of Acanthodes Mitchelli. 



The specimens I have examined vary in length from 2 to 2| inches. The one I 

 have selected for description attains nearly the latter dimensions. The greatest depth 

 of the trunk occurs in advance of the ventral fins, where it measures rather more than 

 half an inch. The head is small and elegantly sculptured. It measures about -1th of 

 the total length. The outline of the body is very graceful. It is fusiform anteriorly, 

 and tapers gradually posterior to the insertion of the highly heterocerque tail. The 

 orbit is placed very forward, and is embraced by the remarkable bony plates described 

 by Rbmer as characteristic of the genus. The peculiar structure of the gill-covers also 

 corresponds with that of other species of Acanthodes. The pectoral spines are long 

 and curved. The other fin-spines are slender and straight. The species differs from 

 all others of the same period in the ornament of the head-bones and the form of the 



