1815.] On the OrthoCeraiitcs of Scotland. 205 



faction. The beleranite, we may add, is one of the rarest fossilsin 

 Scotland. Professor Jameson observed it in lime-stone connected 

 with snnd-stone and basalt in the Island of Mull ; and Mr. Neill 

 found it in slate-clay covered with columnar green-stone in the 

 Shiant Islands; but no other localities have hitherto been men- 

 tioned. 



It appears to be the opinion of Werner that different rock forma- 

 tions can be discriminated by the petrifactions which they contain. 

 How far this opinion may hold true with respect to the petrifactions 

 of Germany, we have not the means of ascertaining j but in this 

 country it cannot be considered as the expression of a general law 

 in the distribution of organic remains. In the Iransit'ion limestone 

 which occurs between the Crook and Noblehouse * there are a few 

 impressions of bivalve shells, so closely resembling in appearance 

 the shells found in the floetz lime-stones as to lead to the conclusion 

 that they belong to the same species. In the lime-stone connected 

 with the old red sand-stone in the Island of x\rran there is a parti- 

 cular species of the genus productus of Sowerl)y, which is one of 

 the most common petrifactions in the lime-stones of the Inde- 

 pendent Coal Formation of the Lothians and Fife. If we descend 

 from classes and formations to the individual members of ■& group, 

 it will be found that the remains of the same species of vegetable 

 are distributed through beds of clay-iron-stone, sand-stone, lime- 

 stone, slate-clay, and slate- coal, as I have frequently observed. 



The occurrence of the genus of shells which we have been con- 

 sidering in beds of lime-stone, is regarded by some as a proof of 

 such lime-stones belonging to the transition class of rocks. Thus 

 Von Buch, in his Travels through Norway, appears to have referred 

 the lime-stones of that country to the transition class, merely 

 from the circumstance of their containing the remains of orthoce- 

 ratites. In describing the mineralogical appearances which pre- 

 sented themselves in the neighbourhood of Christiana, where he 

 had discovered rocks of the transition class, he says, " How great 

 was my joy when, at the steep falls of Aggers Elv, above the lower 

 saw-mills, 1 discovered the orthoccratites, which so particularly 

 distinguish throughout all Europe this formation (transition lime- 

 stone), and this formation alone. They arc many feet in length, 

 divided into compartments, and for the most part at the edge and 

 the walls of the compartment changed into calcareous spar. They 

 are by no means unfrequent ; several of them generally lie in 

 various directions through one another. I'ectinitcs, and several 

 other not very distinguishable petrifactions, appear frequently 

 between them." English 'JVans. p. 'I/. — In the transition lime- 

 stones of this country no ortiioccratites have been found. They 

 occur in beds of slate-clay nnd lime-stone of a more recent period. 

 Thus it appears that the distingui:.liing character of a rock formation 



• See Professor Jamcson'it Miiu-ralu^y «f Uuinfricsshire, \t. 77. 



