INTRODUCTION 



BY 

 C. K. SWARTZ, CHARLES SCHUCHERT, AND CHAS. S. PROSSER 



GENEEAL RELATIONS OF THE DEVONIAN ' 



Murchison, eminent among the early students of the geology of Great 

 Britain, recognized a series of strata in western England rich in remains 

 of marine life, to which he applied the name Silurian System. These 

 beds are succeeded by others, red in color, continental in origin, and 

 characterized by a fauna comprising many species of fishes and eurypte- 

 rids, the latter being primitive Arthropoda (Merostomata) that at times 

 attained great size. The red beds were termed the Old Red Sandstone. 

 They are overlain in turn by the rocks of the Carboniferous System. 



Murchison and Sedgwick later visited Devonshire, England, where 

 they found a series of intricately folded and faulted rocks penetrated by 

 numerous igneous injections, and which hence differ greatly from the 

 less deformed strata of western England. To these rocks they gave the 

 name Devonian System from the locality in which they were found. The 

 strata contain a meager marine fauna which is poorly preserved owing to 

 the metamorphic character of the rocks. Lonsdale, who studied the corals, 

 came to the conclusion that the Devonian fauna is intermediate in age 

 between the Silurian and Carboniferous systems of western England, bas- 

 ing his deduction upon the fact that the fossils found in it possess a de- 

 velopment of life intermediate between that of the Silurian and Carbonif- 

 erous systems. The Devonian strata of southwestern England were thus 

 shown to be of the same general age as the Old Red Sandstone of the 



^ Contributed by C. K. Swartz. 



