ETHERIDGE DEVO^'IAX EOCKS AND FOSSILS. 



615 



Table I. — SJioiving the present cemiis of species in the Palceozoic Bocks 

 of Great Britain. 



Classes. 



Plantffi 



Amorphozoa 



Eliizopoda 



Cceleiiteruta 



Echiiioderuuita 



Annelida 



Cx'ustiicea 



Iiisecta 



Polyzoa 



Bracbiopoda 



J in fMonomyaria 

 ame • | D^^^j^.^.i.^ _ ^ _ 



Grasteropoda 



Xucleobrancliiata 



Pteropoda 



Cephalopoda 



Pisces 



Reptilia 



10 

 19 



93 



S3 



37 



207 



79 



2U8 

 30 

 99 

 96 

 22 

 27 

 77 

 7 



1154 149 





1 



21 

 "l 



"i 



113 



O r- 



383 





56 



308 



119 

 129 



19 



59 

 3 



d5 

 157 

 140 

 194 

 174 



29 



1 



145 



202 



7 



1741 



20 

 5 

 

 5 

 2 



6 

 20 



6 

 20 



6 

 20 

 25 



1 



2 



21 



167 



The following complete Table (II.) lias been constructed to show the 

 whole of the fauna and flora of the Old Red Sandstone and Devonian 

 rocks in the British islands; and it shows in a marked and satisfac- 

 tory manner the palaeontological values of the two terms. It is con- 

 structed so as to show the natural-history grouping of the classes 

 and genera, with the number of species in each genus, and also 

 general or extended, j'et definite, geographical areas over which the 

 Devonian rocks are clearly distributed. Other Tables are constructed 

 out of this, and prepared for purposes of more detail. It is neces- 

 sary to establish one base for reference, either as a typical general 

 group, or a known and definite and received basis, by means of which 

 the species of one group of rocks may be collated or coordinated 

 with those of another, or for comparing the unknown with the 

 known. Stratigraphical sequence demands that we accept the Old 

 lied Sandstone here as our true base, as it is conformable to, and 

 immediately succeeds in time, the Upper Silurian; but on pala}onto- 

 logical grounds the Old Eed Sandstone stands alone, and can be 

 compared with no other hut itself. These conditioDs in Britain are 

 general ; everywhere is it, as Old Red Sandstone, in its three di- 

 visions, a barren series for comparison, — two groups onlj^, the class of 

 fishes among the Yertebrata, and the Merostomata (Poecilopoda) 

 among the Crustacea, being of any value. 



It will be found that there are only 149 known species in the Old 

 Red Sandstone proj^cr ; and these are distributed through only four 

 classes of the animal kingdom, but tliey include some plants. They 



