438 Royal Society. 



But in palaeozoic strata the general assemblage of articulate, mol- 

 luscan and radiate forms is so dilFerent from any now existing with 

 which we can compare it, and so few species of generic types 

 still remaining are presented for our guidance, that in many in- 

 stances we can scarcely venture to infer with safety the original 

 bathymetrical zone of a deposit from its fossil contents. Con- 

 sequently any fact that will help us in elucidating this point be- 

 comes of considerable importance. 



Traces of colouring are rarely presented by palaeozoic fossils, and 

 the author knows of few examples in which they have been noticed. 

 Professor Phillips, in his ' Geology of Yorkshire,' represents the car- 

 boniferous species, Pleurotomaria flamniigera (i. e. carinata) and co- 

 nica, as marked with colour, and Sowerby has figured such mark- 

 ings in P. carinata and P. rotundata. In the excellent monograph 

 of the carboniferous fossils of Belgium, by Professor De Koninck of 

 Liege, indications of pattern-colouring are faintly shown in the 

 figures of Solarium pentangulatum, and distinctly in those of Pleu- 

 rotomaria carinata and Patella Solaris. 



In the cabinets of the Geological Survey of Great Britain are 

 some finely-preserved fossils from the carboniferous limestone of 

 Parkhill, near Longnor in Derbyshire. Among these are several 

 that present unmistakeable pattern- markings, evidently derived from 

 the original colouring. They are — 



Pleurotomaria carinata and conica, showing wavy blotches, resem- 

 bling the colouring of many recent Trochidee. 



An undescribed Trochus, showing a spiral band of colour. 



Metoptoma pileus, and 



Patella ? retrorsa, both with radiating stripes, such as are pre- 

 sented by numerous existing Patellida. 



Natica plicistria, with broad mottled bands. 



Aviculo-pecten, a large unnamed species, with spotty markings on 

 the ribs in the manner of many existing Pectines. 



Aviculo-pecten sublobatus, Ph. ? Beautifully marked with radiating, 

 well-defined stripes, varying in each individual, and resembling the 

 patterns presented by those recent Aviculce that inhabit shallows 

 and moderate depths. 



Aviculo-pecten intercostatus and elongatus also exhibit markings. 



Spiri/er decorus and Orthis resupinata, show fine radiating white 

 lines. 



Terebratula hastata, with radiating stripes. 



The analogy of any existing forms that can be compared with 

 those enumerated, would lead to the conclusion that the markings 

 in these instances are characteristic of mollusks living in a less 

 depth of water than 50 fathoms. In the case of the Terebratula, 

 which belongs to a genus the majority of whose living representa- 

 tives inhabit deep water, it may be noticed that all the living spe- 

 cies exhibiting striped shells are exceptions to the rule, and come 

 from shallow water. 



There are many circumstances which warrant us to suspect that 

 the carboniferous mountain limestone of most regions was a deposit 



