206 Br. Wheelton Hind— The Toredale Series. 



in the deposit, if such had been the case. Not only do the Yoredale 

 Rocks of the Wensleydale area contain no distinctive fossils peculiar 

 to themselves, but many species recur again and again in beds 

 separated from each other by many feet of different strata, in which 

 often plant beds occur and at times well-marked seams of coal, 

 proving that terrestrial conditions obtained between deposits con- 

 taining a similar fauna. There is no possibility, thanks to the 

 nature of the ground, that the series of limestones are only one bed, 

 repeated by a succession of folds ; and the only alternative is, that 

 owing to an unsuitable environment the fauna migrated and lived 

 on in an outside area, ready to return when suitable conditions 

 obtained. This was, of course, Barrande's theory for his "colonies," 

 for the truth of which it would appear that the Carboniferous rocks 

 afford abundant evidence, and the series of Carboniferous rocks in 

 Scotland give a good example. 



In Scotland, beneath the Coal-measures, there is a long series of 

 alternating beds of sandstones, shales, limestones, and coals as an 

 upper division, and the Calciferous Sandstone Series as a lower 

 division, consisting of shaly clays and argillaceous limestones, oil 

 shales and sandstones. The fossils characteristic of the Carboniferous 

 Limestone of England are found throughout the upper series in 

 those beds which are of marine origin, and occasionally in thin 

 bands in the Lower or Calciferous Sandstone Series. In the beds of 

 this series on the Fifeshire coast, Mr. J. W. Kirkby, of Leven, has 

 enumerated no less than eighteen such marine horizons distributed 

 chiefly in the upper and lower portions of 4000 feet of strata 

 ("On the Zones of Marine Fossils in the Calciferous Sandstone 

 Series of Fife": Quart. Journ. Geol. Soc. 1880, vol. xxxvi, p. 559). 

 One hundi-ed and fifty-two species are enumerated, of which only 

 seven appear to be new and thei-efore, as far as is known at present, 

 peculiar to the series ; but a few others belong to fresh- or brackish- 

 water beds. 



It is curious to note that between 500 and 2280 feet no marine 

 bands have as yet been discovered, and only four occur in the first 

 600 feet; the 1780 feet of intervening beds being composed of 

 repeated alternations of sandstones of various colours, shales, marls, 

 and ironstone bands, in several of which, but chiefly in the 

 argillaceous beds, plant-remains are fairly plentiful. 



It is evident, too, that the Carboniferous Limestone fauna did not 

 die out with the close of that period, even as expressed in the rocks 

 of the Derbyshire-Yorkshire area ; for, although absent from the 

 strata for intervals of time represented by many hundred feet of 

 deposit, there are occasional recurrences of certain typical fossils 

 of that fauna in certain widely separated localities at different 

 horizons. 



Mr. J. Ward has shown three bands with a marine fauna to exist 

 high up in the North Staffordshire Coalfield, two of which coutain 

 several well-known Carboniferous Limestone sjoecies, the third only 

 LinguJa squamiformis. I make no mention of the marine bands 

 containing Guniatites Listeri and Avlculoj^eden papyraceus, as these 



