224 



STKATIGKAPHICAL GEOLOGY 



three series, a Lower, Middle, and Upper, which may be homotaxial 

 with the Lower, Middle, and Upper Devonian, yet it is not certain 



Fig. 74. FOSSILS FROM THE OI,D UED SANDSTONE. 



. Estheria membranacea. c. Pterichthys Milleri. 



b. Coccosteus decipieiis. d. Pterygotus anglicus. 



e. Cephalaspis Lyelli. 



that all threei. divisions are found together in one area, and it is 

 certain that inonost parts of the country only two such series exist, 

 the Upper being unconfonnable to the Lower. 



