528 CJironicles of Science. [July 5 



and complete fish, including several species of Paheoniscus, also 

 Cycloptychius carbonarius, (Hux.), Caelacanthus, Diplodus, Megalich- 

 thys, and. Ctenoptychius. In the shale of the Bay coal, there are marine 

 fossils, which is remarkable, the seam being in the upper measures. 

 In the lower thick measures, we find that the Ash coal bass contains 

 several species of Pakeoniscus, one having characteristic granulated 

 scales ; also Ehizodus, Helodus, Clododus, and other fish. The 

 Burnwood ironstone has fine specimens of Anthracomya Adamsii. 

 The ten-foot coal measures have a " mussel bed " formed of the com- 

 pressed shells of Anthracosia and Anthracoptera. The 4th division, 

 or lowest measures, contain a valuable bed of earthy haematite. In 

 many of the shales of this division, there are multitudes of Aviculo- 

 pecten papyraceus, together with Posidonia, Goniatites, Lingula, and 

 Orthoceras. It appears that amongst the fish, the genera Megalichthys, 

 Palseoniscus, Coelacanthus, and Platysomus range throughout the 

 whole series forming the coal measures. The paper is followed by 

 detailed descriptions of the principal genera of fish found fossil in 

 the coal-field, and by a carefully drawn -up table of the organic 

 remains of the same series of rocks, both of plants and animals, the 

 species peculiar to each bed being indicated. Very great advantage 

 would result if each of our coal-fields were examined as closely and- 

 described as minutely as that of North Staffordshire is in this paper. 



The denudation of Bocks in Devonshire. — We have before us two 

 papers by Mr. W. Pengelly, F.R.S., reprinted from the ' Transactions 

 of the Devonshire Association for the Advancement of Science, Litera- 

 ture, and Art.' In the first the author brings under notice the prin- 

 cipal proofs of denudation evidenced by the present condition of the 

 rocks of Devonshire. Commencing with the axiom that " all strata 

 are immediately or mediately the offspring of unstratified rocks," he 

 proceeds to show that rocks of organic origin are equally derivative. 

 The limestones and chalk of Devon are due to animal agency; but 

 the carbonate of lime, of which they consist, was extracted from the 

 sea-water, which in turn derived it from the solution, through the 

 agency of thermal and acidulated waters, of rocks or rock detritus 

 which contained it ; in other words, by the destruction of earlier rocks. 

 The operation of building up the limestones by the growth of crinoids, 

 shells, and coral reefs, must have required an inconceivable space of 

 time, if the Devonian sea, like the present, contained no more than 

 3 parts in 100,000 of carbonate of lime. With regard to the original 

 source of lime, it is remarked that the granitic class of rocks is poor 

 in calcareous matter, but those of the augitic or hornblendic group, 

 including Basalt, Dolerite, and Diallage rock, often contain 10 per 

 cent, of lime ; it is not improbable, therefore, that there was an early 

 and large destruction of unstratified augitic rocks. The Bovey 

 Tracey lignite is of vegetable origin, but with it are interstratified 

 sands and clays derived from the Dartmoor granite. The whole 

 formation is at least 300 feet in thickness, of which the vegetable 

 matter barely constitutes 45 feet. The crystalline schists of the 

 Start and Bolt, at the southern angle of Devonshire, are meta- 

 morphic ; the change they have undergone implies the former exist- 



